mingw: get pw_name in UTF-8 format
[gitweb.git] / diff.c
diff --git a/diff.c b/diff.c
index 0abab4a0b1d51acdc85ab5d0a30f87bb004c2027..1ee04e321b1b5cc4e3f6bde37f49b7d3c0694aa6 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -25,6 +25,7 @@
 #include "packfile.h"
 #include "parse-options.h"
 #include "help.h"
+#include "fetch-object.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -104,11 +105,6 @@ static const char *color_diff_slots[] = {
        [DIFF_FILE_NEW_BOLD]          = "newBold",
 };
 
-static NORETURN void die_want_option(const char *option_name)
-{
-       die(_("option '%s' requires a value"), option_name);
-}
-
 define_list_config_array_extra(color_diff_slots, {"plain"});
 
 static int parse_diff_color_slot(const char *var)
@@ -179,6 +175,10 @@ static int parse_submodule_params(struct diff_options *options, const char *valu
                options->submodule_format = DIFF_SUBMODULE_SHORT;
        else if (!strcmp(value, "diff"))
                options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
+       /*
+        * Please update $__git_diff_submodule_formats in
+        * git-completion.bash when you add new formats.
+        */
        else
                return -1;
        return 0;
@@ -205,6 +205,10 @@ long parse_algorithm_value(const char *value)
                return XDF_PATIENCE_DIFF;
        else if (!strcasecmp(value, "histogram"))
                return XDF_HISTOGRAM_DIFF;
+       /*
+        * Please update $__git_diff_algorithms in git-completion.bash
+        * when you add new algorithms.
+        */
        return -1;
 }
 
@@ -305,7 +309,9 @@ static unsigned parse_color_moved_ws(const char *arg)
                strbuf_addstr(&sb, i->string);
                strbuf_trim(&sb);
 
-               if (!strcmp(sb.buf, "ignore-space-change"))
+               if (!strcmp(sb.buf, "no"))
+                       ret = 0;
+               else if (!strcmp(sb.buf, "ignore-space-change"))
                        ret |= XDF_IGNORE_WHITESPACE_CHANGE;
                else if (!strcmp(sb.buf, "ignore-space-at-eol"))
                        ret |= XDF_IGNORE_WHITESPACE_AT_EOL;
@@ -323,7 +329,7 @@ static unsigned parse_color_moved_ws(const char *arg)
 
        if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
            (ret & XDF_WHITESPACE_FLAGS)) {
-               error(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
+               error(_("color-moved-ws: allow-indentation-change cannot be combined with other whitespace modes"));
                ret |= COLOR_MOVED_WS_ERROR;
        }
 
@@ -494,7 +500,7 @@ static const char *external_diff(void)
 
        if (done_preparing)
                return external_diff_cmd;
-       external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
+       external_diff_cmd = xstrdup_or_null(getenv("GIT_EXTERNAL_DIFF"));
        if (!external_diff_cmd)
                external_diff_cmd = external_diff_cmd_cfg;
        done_preparing = 1;
@@ -755,6 +761,8 @@ struct emitted_diff_symbol {
        const char *line;
        int len;
        int flags;
+       int indent_off;   /* Offset to first non-whitespace character */
+       int indent_width; /* The visual width of the indentation */
        enum diff_symbol s;
 };
 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
@@ -785,44 +793,85 @@ struct moved_entry {
        struct moved_entry *next_line;
 };
 
-/**
- * The struct ws_delta holds white space differences between moved lines, i.e.
- * between '+' and '-' lines that have been detected to be a move.
- * The string contains the difference in leading white spaces, before the
- * rest of the line is compared using the white space config for move
- * coloring. The current_longer indicates if the first string in the
- * comparision is longer than the second.
- */
-struct ws_delta {
-       char *string;
-       unsigned int current_longer : 1;
-};
-#define WS_DELTA_INIT { NULL, 0 }
-
 struct moved_block {
        struct moved_entry *match;
-       struct ws_delta wsd;
+       int wsd; /* The whitespace delta of this block */
 };
 
 static void moved_block_clear(struct moved_block *b)
 {
-       FREE_AND_NULL(b->wsd.string);
-       b->match = NULL;
+       memset(b, 0, sizeof(*b));
 }
 
-static int compute_ws_delta(const struct emitted_diff_symbol *a,
-                            const struct emitted_diff_symbol *b,
-                            struct ws_delta *out)
+#define INDENT_BLANKLINE INT_MIN
+
+static void fill_es_indent_data(struct emitted_diff_symbol *es)
 {
-       const struct emitted_diff_symbol *longer =  a->len > b->len ? a : b;
-       const struct emitted_diff_symbol *shorter = a->len > b->len ? b : a;
-       int d = longer->len - shorter->len;
+       unsigned int off = 0, i;
+       int width = 0, tab_width = es->flags & WS_TAB_WIDTH_MASK;
+       const char *s = es->line;
+       const int len = es->len;
+
+       /* skip any \v \f \r at start of indentation */
+       while (s[off] == '\f' || s[off] == '\v' ||
+              (s[off] == '\r' && off < len - 1))
+               off++;
+
+       /* calculate the visual width of indentation */
+       while(1) {
+               if (s[off] == ' ') {
+                       width++;
+                       off++;
+               } else if (s[off] == '\t') {
+                       width += tab_width - (width % tab_width);
+                       while (s[++off] == '\t')
+                               width += tab_width;
+               } else {
+                       break;
+               }
+       }
+
+       /* check if this line is blank */
+       for (i = off; i < len; i++)
+               if (!isspace(s[i]))
+                   break;
+
+       if (i == len) {
+               es->indent_width = INDENT_BLANKLINE;
+               es->indent_off = len;
+       } else {
+               es->indent_off = off;
+               es->indent_width = width;
+       }
+}
+
+static int compute_ws_delta(const struct emitted_diff_symbol *a,
+                           const struct emitted_diff_symbol *b,
+                           int *out)
+{
+       int a_len = a->len,
+           b_len = b->len,
+           a_off = a->indent_off,
+           a_width = a->indent_width,
+           b_off = b->indent_off,
+           b_width = b->indent_width;
+       int delta;
+
+       if (a_width == INDENT_BLANKLINE && b_width == INDENT_BLANKLINE) {
+               *out = INDENT_BLANKLINE;
+               return 1;
+       }
+
+       if (a->s == DIFF_SYMBOL_PLUS)
+               delta = a_width - b_width;
+       else
+               delta = b_width - a_width;
 
-       if (strncmp(longer->line + d, shorter->line, shorter->len))
+       if (a_len - a_off != b_len - b_off ||
+           memcmp(a->line + a_off, b->line + b_off, a_len - a_off))
                return 0;
 
-       out->string = xmemdupz(longer->line, d);
-       out->current_longer = (a == longer);
+       *out = delta;
 
        return 1;
 }
@@ -834,51 +883,53 @@ static int cmp_in_block_with_wsd(const struct diff_options *o,
                                 int n)
 {
        struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
-       int al = cur->es->len, cl = l->len;
+       int al = cur->es->len, bl = match->es->len, cl = l->len;
        const char *a = cur->es->line,
                   *b = match->es->line,
                   *c = l->line;
-
-       int wslen;
+       int a_off = cur->es->indent_off,
+           a_width = cur->es->indent_width,
+           c_off = l->indent_off,
+           c_width = l->indent_width;
+       int delta;
 
        /*
-        * We need to check if 'cur' is equal to 'match'.
-        * As those are from the same (+/-) side, we do not need to adjust for
-        * indent changes. However these were found using fuzzy matching
-        * so we do have to check if they are equal.
+        * We need to check if 'cur' is equal to 'match'.  As those
+        * are from the same (+/-) side, we do not need to adjust for
+        * indent changes. However these were found using fuzzy
+        * matching so we do have to check if they are equal. Here we
+        * just check the lengths. We delay calling memcmp() to check
+        * the contents until later as if the length comparison for a
+        * and c fails we can avoid the call all together.
         */
-       if (strcmp(a, b))
+       if (al != bl)
                return 1;
 
-       if (!pmb->wsd.string)
-               /*
-                * The white space delta is not active? This can happen
-                * when we exit early in this function.
-                */
-               return 1;
+       /* If 'l' and 'cur' are both blank then they match. */
+       if (a_width == INDENT_BLANKLINE && c_width == INDENT_BLANKLINE)
+               return 0;
 
        /*
-        * The indent changes of the block are known and stored in
-        * pmb->wsd; however we need to check if the indent changes of the
-        * current line are still the same as before.
-        *
-        * To do so we need to compare 'l' to 'cur', adjusting the
-        * one of them for the white spaces, depending which was longer.
+        * The indent changes of the block are known and stored in pmb->wsd;
+        * however we need to check if the indent changes of the current line
+        * match those of the current block and that the text of 'l' and 'cur'
+        * after the indentation match.
         */
+       if (cur->es->s == DIFF_SYMBOL_PLUS)
+               delta = a_width - c_width;
+       else
+               delta = c_width - a_width;
 
-       wslen = strlen(pmb->wsd.string);
-       if (pmb->wsd.current_longer) {
-               c += wslen;
-               cl -= wslen;
-       } else {
-               a += wslen;
-               al -= wslen;
-       }
-
-       if (al != cl || memcmp(a, c, al))
-               return 1;
+       /*
+        * If the previous lines of this block were all blank then set its
+        * whitespace delta.
+        */
+       if (pmb->wsd == INDENT_BLANKLINE)
+               pmb->wsd = delta;
 
-       return 0;
+       return !(delta == pmb->wsd && al - a_off == cl - c_off &&
+                !memcmp(a, b, al) && !
+                memcmp(a + a_off, c + c_off, al - a_off));
 }
 
 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
@@ -944,6 +995,9 @@ static void add_lines_to_move_detection(struct diff_options *o,
                        continue;
                }
 
+               if (o->color_moved_ws_handling &
+                   COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
+                       fill_es_indent_data(&o->emitted_symbols->buf[n]);
                key = prepare_entry(o, n);
                if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
                        prev_line->next_line = key;
@@ -1022,8 +1076,7 @@ static int shrink_potential_moved_blocks(struct moved_block *pmb,
 
                if (lp < pmb_nr && rp > -1 && lp < rp) {
                        pmb[lp] = pmb[rp];
-                       pmb[rp].match = NULL;
-                       pmb[rp].wsd.string = NULL;
+                       memset(&pmb[rp], 0, sizeof(pmb[rp]));
                        rp--;
                        lp++;
                }
@@ -1043,14 +1096,17 @@ static int shrink_potential_moved_blocks(struct moved_block *pmb,
  * The last block consists of the (n - block_length)'th line up to but not
  * including the nth line.
  *
+ * Returns 0 if the last block is empty or is unset by this function, non zero
+ * otherwise.
+ *
  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
  * Think of a way to unify them.
  */
-static void adjust_last_block(struct diff_options *o, int n, int block_length)
+static int adjust_last_block(struct diff_options *o, int n, int block_length)
 {
        int i, alnum_count = 0;
        if (o->color_moved == COLOR_MOVED_PLAIN)
-               return;
+               return block_length;
        for (i = 1; i < block_length + 1; i++) {
                const char *c = o->emitted_symbols->buf[n - i].line;
                for (; *c; c++) {
@@ -1058,11 +1114,12 @@ static void adjust_last_block(struct diff_options *o, int n, int block_length)
                                continue;
                        alnum_count++;
                        if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
-                               return;
+                               return 1;
                }
        }
        for (i = 1; i < block_length + 1; i++)
                o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
+       return 0;
 }
 
 /* Find blocks of moved code, delegate actual coloring decision to helper */
@@ -1072,7 +1129,7 @@ static void mark_color_as_moved(struct diff_options *o,
 {
        struct moved_block *pmb = NULL; /* potentially moved blocks */
        int pmb_nr = 0, pmb_alloc = 0;
-       int n, flipped_block = 1, block_length = 0;
+       int n, flipped_block = 0, block_length = 0;
 
 
        for (n = 0; n < o->emitted_symbols->nr; n++) {
@@ -1080,6 +1137,7 @@ static void mark_color_as_moved(struct diff_options *o,
                struct moved_entry *key;
                struct moved_entry *match = NULL;
                struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
+               enum diff_symbol last_symbol = 0;
 
                switch (l->s) {
                case DIFF_SYMBOL_PLUS:
@@ -1095,7 +1153,7 @@ static void mark_color_as_moved(struct diff_options *o,
                        free(key);
                        break;
                default:
-                       flipped_block = 1;
+                       flipped_block = 0;
                }
 
                if (!match) {
@@ -1106,13 +1164,16 @@ static void mark_color_as_moved(struct diff_options *o,
                                moved_block_clear(&pmb[i]);
                        pmb_nr = 0;
                        block_length = 0;
+                       flipped_block = 0;
+                       last_symbol = l->s;
                        continue;
                }
 
-               l->flags |= DIFF_SYMBOL_MOVED_LINE;
-
-               if (o->color_moved == COLOR_MOVED_PLAIN)
+               if (o->color_moved == COLOR_MOVED_PLAIN) {
+                       last_symbol = l->s;
+                       l->flags |= DIFF_SYMBOL_MOVED_LINE;
                        continue;
+               }
 
                if (o->color_moved_ws_handling &
                    COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
@@ -1135,21 +1196,27 @@ static void mark_color_as_moved(struct diff_options *o,
                                                             &pmb[pmb_nr].wsd))
                                                pmb[pmb_nr++].match = match;
                                } else {
-                                       pmb[pmb_nr].wsd.string = NULL;
+                                       pmb[pmb_nr].wsd = 0;
                                        pmb[pmb_nr++].match = match;
                                }
                        }
 
-                       flipped_block = (flipped_block + 1) % 2;
+                       if (adjust_last_block(o, n, block_length) &&
+                           pmb_nr && last_symbol != l->s)
+                               flipped_block = (flipped_block + 1) % 2;
+                       else
+                               flipped_block = 0;
 
-                       adjust_last_block(o, n, block_length);
                        block_length = 0;
                }
 
-               block_length++;
-
-               if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
-                       l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
+               if (pmb_nr) {
+                       block_length++;
+                       l->flags |= DIFF_SYMBOL_MOVED_LINE;
+                       if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
+                               l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
+               }
+               last_symbol = l->s;
        }
        adjust_last_block(o, n, block_length);
 
@@ -1493,7 +1560,7 @@ static void emit_diff_symbol_from_struct(struct diff_options *o,
 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
                             const char *line, int len, unsigned flags)
 {
-       struct emitted_diff_symbol e = {line, len, flags, s};
+       struct emitted_diff_symbol e = {line, len, flags, 0, 0, s};
 
        if (o->emitted_symbols)
                append_emitted_diff_symbol(o, &e);
@@ -1551,8 +1618,7 @@ static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line
        return ws_blank_line(line, len, ecbdata->ws_rule);
 }
 
-static void emit_add_line(const char *reset,
-                         struct emit_callback *ecbdata,
+static void emit_add_line(struct emit_callback *ecbdata,
                          const char *line, int len)
 {
        unsigned flags = WSEH_NEW | ecbdata->ws_rule;
@@ -1562,16 +1628,14 @@ static void emit_add_line(const char *reset,
        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
 }
 
-static void emit_del_line(const char *reset,
-                         struct emit_callback *ecbdata,
+static void emit_del_line(struct emit_callback *ecbdata,
                          const char *line, int len)
 {
        unsigned flags = WSEH_OLD | ecbdata->ws_rule;
        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
 }
 
-static void emit_context_line(const char *reset,
-                             struct emit_callback *ecbdata,
+static void emit_context_line(struct emit_callback *ecbdata,
                              const char *line, int len)
 {
        unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
@@ -1680,7 +1744,6 @@ static void emit_rewrite_lines(struct emit_callback *ecb,
                               int prefix, const char *data, int size)
 {
        const char *endp = NULL;
-       const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 
        while (0 < size) {
                int len;
@@ -1689,10 +1752,10 @@ static void emit_rewrite_lines(struct emit_callback *ecb,
                len = endp ? (endp - data + 1) : size;
                if (prefix != '+') {
                        ecb->lno_in_preimage++;
-                       emit_del_line(reset, ecb, data, len);
+                       emit_del_line(ecb, data, len);
                } else {
                        ecb->lno_in_postimage++;
-                       emit_add_line(reset, ecb, data, len);
+                       emit_add_line(ecb, data, len);
                }
                size -= len;
                data += len;
@@ -2229,7 +2292,7 @@ const char *diff_line_prefix(struct diff_options *opt)
        return msgbuf->buf;
 }
 
-static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
+static unsigned long sane_truncate_line(char *line, unsigned long len)
 {
        const char *cp;
        unsigned long allot;
@@ -2263,7 +2326,6 @@ static void find_lno(const char *line, struct emit_callback *ecbdata)
 static void fn_out_consume(void *priv, char *line, unsigned long len)
 {
        struct emit_callback *ecbdata = priv;
-       const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
        struct diff_options *o = ecbdata->opt;
 
        o->found_changes = 1;
@@ -2294,7 +2356,7 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
        if (line[0] == '@') {
                if (ecbdata->diff_words)
                        diff_words_flush(ecbdata);
-               len = sane_truncate_line(ecbdata, line, len);
+               len = sane_truncate_line(line, len);
                find_lno(line, ecbdata);
                emit_hunk_header(ecbdata, line, len);
                return;
@@ -2330,16 +2392,16 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
        switch (line[0]) {
        case '+':
                ecbdata->lno_in_postimage++;
-               emit_add_line(reset, ecbdata, line + 1, len - 1);
+               emit_add_line(ecbdata, line + 1, len - 1);
                break;
        case '-':
                ecbdata->lno_in_preimage++;
-               emit_del_line(reset, ecbdata, line + 1, len - 1);
+               emit_del_line(ecbdata, line + 1, len - 1);
                break;
        case ' ':
                ecbdata->lno_in_postimage++;
                ecbdata->lno_in_preimage++;
-               emit_context_line(reset, ecbdata, line + 1, len - 1);
+               emit_context_line(ecbdata, line + 1, len - 1);
                break;
        default:
                /* incomplete line at the end */
@@ -3482,7 +3544,7 @@ static void builtin_diff(const char *name_a,
                o->found_changes = 1;
        } else {
                /* Crazy xdl interfaces.. */
-               const char *diffopts = getenv("GIT_DIFF_OPTS");
+               const char *diffopts;
                const char *v;
                xpparam_t xpp;
                xdemitconf_t xecfg;
@@ -3525,12 +3587,15 @@ static void builtin_diff(const char *name_a,
                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
                if (pe)
                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
+
+               diffopts = getenv("GIT_DIFF_OPTS");
                if (!diffopts)
                        ;
                else if (skip_prefix(diffopts, "--unified=", &v))
                        xecfg.ctxlen = strtoul(v, NULL, 10);
                else if (skip_prefix(diffopts, "-u", &v))
                        xecfg.ctxlen = strtoul(v, NULL, 10);
+
                if (o->word_diff)
                        init_diff_words_data(&ecbdata, o, one, two);
                if (xdi_diff_outf(&mf1, &mf2, NULL, fn_out_consume,
@@ -4118,7 +4183,6 @@ static void run_external_diff(const char *pgm,
                              struct diff_filespec *one,
                              struct diff_filespec *two,
                              const char *xfrm_msg,
-                             int complete_rewrite,
                              struct diff_options *o)
 {
        struct argv_array argv = ARGV_ARRAY_INIT;
@@ -4276,8 +4340,7 @@ static void run_diff_cmd(const char *pgm,
        }
 
        if (pgm) {
-               run_external_diff(pgm, name, other, one, two, xfrm_msg,
-                                 complete_rewrite, o);
+               run_external_diff(pgm, name, other, one, two, xfrm_msg, o);
                return;
        }
        if (one && two)
@@ -4578,68 +4641,6 @@ void diff_setup_done(struct diff_options *options)
        FREE_AND_NULL(options->parseopts);
 }
 
-static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
-{
-       char c, *eq;
-       int len;
-
-       if (*arg != '-')
-               return 0;
-       c = *++arg;
-       if (!c)
-               return 0;
-       if (c == arg_short) {
-               c = *++arg;
-               if (!c)
-                       return 1;
-               if (val && isdigit(c)) {
-                       char *end;
-                       int n = strtoul(arg, &end, 10);
-                       if (*end)
-                               return 0;
-                       *val = n;
-                       return 1;
-               }
-               return 0;
-       }
-       if (c != '-')
-               return 0;
-       arg++;
-       eq = strchrnul(arg, '=');
-       len = eq - arg;
-       if (!len || strncmp(arg, arg_long, len))
-               return 0;
-       if (*eq) {
-               int n;
-               char *end;
-               if (!isdigit(*++eq))
-                       return 0;
-               n = strtoul(eq, &end, 10);
-               if (*end)
-                       return 0;
-               *val = n;
-       }
-       return 1;
-}
-
-static int diff_scoreopt_parse(const char *opt);
-
-static inline int short_opt(char opt, const char **argv,
-                           const char **optarg)
-{
-       const char *arg = argv[0];
-       if (arg[0] != '-' || arg[1] != opt)
-               return 0;
-       if (arg[2] != '\0') {
-               *optarg = arg + 2;
-               return 1;
-       }
-       if (!argv[1])
-               die("Option '%c' requires a value", opt);
-       *optarg = argv[1];
-       return 2;
-}
-
 int parse_long_opt(const char *opt, const char **argv,
                   const char **optarg)
 {
@@ -4661,77 +4662,56 @@ int parse_long_opt(const char *opt, const char **argv,
        return 2;
 }
 
-static int stat_opt(struct diff_options *options, const char **av)
+static int diff_opt_stat(const struct option *opt, const char *value, int unset)
 {
-       const char *arg = av[0];
-       char *end;
+       struct diff_options *options = opt->value;
        int width = options->stat_width;
        int name_width = options->stat_name_width;
        int graph_width = options->stat_graph_width;
        int count = options->stat_count;
-       int argcount = 1;
+       char *end;
 
-       if (!skip_prefix(arg, "--stat", &arg))
-               BUG("stat option does not begin with --stat: %s", arg);
-       end = (char *)arg;
+       BUG_ON_OPT_NEG(unset);
 
-       switch (*arg) {
-       case '-':
-               if (skip_prefix(arg, "-width", &arg)) {
-                       if (*arg == '=')
-                               width = strtoul(arg + 1, &end, 10);
-                       else if (!*arg && !av[1])
-                               die_want_option("--stat-width");
-                       else if (!*arg) {
-                               width = strtoul(av[1], &end, 10);
-                               argcount = 2;
-                       }
-               } else if (skip_prefix(arg, "-name-width", &arg)) {
-                       if (*arg == '=')
-                               name_width = strtoul(arg + 1, &end, 10);
-                       else if (!*arg && !av[1])
-                               die_want_option("--stat-name-width");
-                       else if (!*arg) {
-                               name_width = strtoul(av[1], &end, 10);
-                               argcount = 2;
-                       }
-               } else if (skip_prefix(arg, "-graph-width", &arg)) {
-                       if (*arg == '=')
-                               graph_width = strtoul(arg + 1, &end, 10);
-                       else if (!*arg && !av[1])
-                               die_want_option("--stat-graph-width");
-                       else if (!*arg) {
-                               graph_width = strtoul(av[1], &end, 10);
-                               argcount = 2;
-                       }
-               } else if (skip_prefix(arg, "-count", &arg)) {
-                       if (*arg == '=')
-                               count = strtoul(arg + 1, &end, 10);
-                       else if (!*arg && !av[1])
-                               die_want_option("--stat-count");
-                       else if (!*arg) {
-                               count = strtoul(av[1], &end, 10);
-                               argcount = 2;
-                       }
+       if (!strcmp(opt->long_name, "stat")) {
+               if (value) {
+                       width = strtoul(value, &end, 10);
+                       if (*end == ',')
+                               name_width = strtoul(end+1, &end, 10);
+                       if (*end == ',')
+                               count = strtoul(end+1, &end, 10);
+                       if (*end)
+                               return error(_("invalid --stat value: %s"), value);
                }
-               break;
-       case '=':
-               width = strtoul(arg+1, &end, 10);
-               if (*end == ',')
-                       name_width = strtoul(end+1, &end, 10);
-               if (*end == ',')
-                       count = strtoul(end+1, &end, 10);
-       }
+       } else if (!strcmp(opt->long_name, "stat-width")) {
+               width = strtoul(value, &end, 10);
+               if (*end)
+                       return error(_("%s expects a numerical value"),
+                                    opt->long_name);
+       } else if (!strcmp(opt->long_name, "stat-name-width")) {
+               name_width = strtoul(value, &end, 10);
+               if (*end)
+                       return error(_("%s expects a numerical value"),
+                                    opt->long_name);
+       } else if (!strcmp(opt->long_name, "stat-graph-width")) {
+               graph_width = strtoul(value, &end, 10);
+               if (*end)
+                       return error(_("%s expects a numerical value"),
+                                    opt->long_name);
+       } else if (!strcmp(opt->long_name, "stat-count")) {
+               count = strtoul(value, &end, 10);
+               if (*end)
+                       return error(_("%s expects a numerical value"),
+                                    opt->long_name);
+       } else
+               BUG("%s should not get here", opt->long_name);
 
-       /* Important! This checks all the error cases! */
-       if (*end)
-               return 0;
        options->output_format |= DIFF_FORMAT_DIFFSTAT;
        options->stat_name_width = name_width;
        options->stat_graph_width = graph_width;
        options->stat_width = width;
        options->stat_count = count;
-       return argcount;
+       return 0;
 }
 
 static int parse_dirstat_opt(struct diff_options *options, const char *params)
@@ -4749,14 +4729,6 @@ static int parse_dirstat_opt(struct diff_options *options, const char *params)
        return 1;
 }
 
-static int parse_submodule_opt(struct diff_options *options, const char *value)
-{
-       if (parse_submodule_params(options, value))
-               die(_("Failed to parse --submodule option parameter: '%s'"),
-                       value);
-       return 1;
-}
-
 static const char diff_status_letters[] = {
        DIFF_STATUS_ADDED,
        DIFF_STATUS_COPIED,
@@ -4788,10 +4760,19 @@ static unsigned filter_bit_tst(char status, const struct diff_options *opt)
        return opt->filter & filter_bit[(int) status];
 }
 
-static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
+unsigned diff_filter_bit(char status)
 {
+       prepare_filter_bits();
+       return filter_bit[(int) status];
+}
+
+static int diff_opt_diff_filter(const struct option *option,
+                               const char *optarg, int unset)
+{
+       struct diff_options *opt = option->value;
        int i, optch;
 
+       BUG_ON_OPT_NEG(unset);
        prepare_filter_bits();
 
        /*
@@ -4822,7 +4803,8 @@ static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
 
                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
                if (!bit)
-                       return optarg[i];
+                       return error(_("unknown change class '%c' in --diff-filter=%s"),
+                                    optarg[i], optarg);
                if (negate)
                        opt->filter &= ~bit;
                else
@@ -4837,25 +4819,29 @@ static void enable_patch_output(int *fmt)
        *fmt |= DIFF_FORMAT_PATCH;
 }
 
-static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
+static int diff_opt_ws_error_highlight(const struct option *option,
+                                      const char *arg, int unset)
 {
+       struct diff_options *opt = option->value;
        int val = parse_ws_error_highlight(arg);
 
-       if (val < 0) {
-               error("unknown value after ws-error-highlight=%.*s",
-                     -1 - val, arg);
-               return 0;
-       }
+       BUG_ON_OPT_NEG(unset);
+       if (val < 0)
+               return error(_("unknown value after ws-error-highlight=%.*s"),
+                            -1 - val, arg);
        opt->ws_error_highlight = val;
-       return 1;
+       return 0;
 }
 
-static int parse_objfind_opt(struct diff_options *opt, const char *arg)
+static int diff_opt_find_object(const struct option *option,
+                               const char *arg, int unset)
 {
+       struct diff_options *opt = option->value;
        struct object_id oid;
 
+       BUG_ON_OPT_NEG(unset);
        if (get_oid(arg, &oid))
-               return error("unable to resolve '%s'", arg);
+               return error(_("unable to resolve '%s'"), arg);
 
        if (!opt->objfind)
                opt->objfind = xcalloc(1, sizeof(*opt->objfind));
@@ -4864,7 +4850,357 @@ static int parse_objfind_opt(struct diff_options *opt, const char *arg)
        opt->flags.recursive = 1;
        opt->flags.tree_in_recursive = 1;
        oidset_insert(opt->objfind, &oid);
-       return 1;
+       return 0;
+}
+
+static int diff_opt_anchored(const struct option *opt,
+                            const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
+       ALLOC_GROW(options->anchors, options->anchors_nr + 1,
+                  options->anchors_alloc);
+       options->anchors[options->anchors_nr++] = xstrdup(arg);
+       return 0;
+}
+
+static int diff_opt_binary(const struct option *opt,
+                          const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       BUG_ON_OPT_ARG(arg);
+       enable_patch_output(&options->output_format);
+       options->flags.binary = 1;
+       return 0;
+}
+
+static int diff_opt_break_rewrites(const struct option *opt,
+                                  const char *arg, int unset)
+{
+       int *break_opt = opt->value;
+       int opt1, opt2;
+
+       BUG_ON_OPT_NEG(unset);
+       if (!arg)
+               arg = "";
+       opt1 = parse_rename_score(&arg);
+       if (*arg == 0)
+               opt2 = 0;
+       else if (*arg != '/')
+               return error(_("%s expects <n>/<m> form"), opt->long_name);
+       else {
+               arg++;
+               opt2 = parse_rename_score(&arg);
+       }
+       if (*arg != 0)
+               return error(_("%s expects <n>/<m> form"), opt->long_name);
+       *break_opt = opt1 | (opt2 << 16);
+       return 0;
+}
+
+static int diff_opt_char(const struct option *opt,
+                        const char *arg, int unset)
+{
+       char *value = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (arg[1])
+               return error(_("%s expects a character, got '%s'"),
+                            opt->long_name, arg);
+       *value = arg[0];
+       return 0;
+}
+
+static int diff_opt_color_moved(const struct option *opt,
+                               const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       if (unset) {
+               options->color_moved = COLOR_MOVED_NO;
+       } else if (!arg) {
+               if (diff_color_moved_default)
+                       options->color_moved = diff_color_moved_default;
+               if (options->color_moved == COLOR_MOVED_NO)
+                       options->color_moved = COLOR_MOVED_DEFAULT;
+       } else {
+               int cm = parse_color_moved(arg);
+               if (cm < 0)
+                       return error(_("bad --color-moved argument: %s"), arg);
+               options->color_moved = cm;
+       }
+       return 0;
+}
+
+static int diff_opt_color_moved_ws(const struct option *opt,
+                                  const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+       unsigned cm;
+
+       if (unset) {
+               options->color_moved_ws_handling = 0;
+               return 0;
+       }
+
+       cm = parse_color_moved_ws(arg);
+       if (cm & COLOR_MOVED_WS_ERROR)
+               return error(_("invalid mode '%s' in --color-moved-ws"), arg);
+       options->color_moved_ws_handling = cm;
+       return 0;
+}
+
+static int diff_opt_color_words(const struct option *opt,
+                               const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       options->use_color = 1;
+       options->word_diff = DIFF_WORDS_COLOR;
+       options->word_regex = arg;
+       return 0;
+}
+
+static int diff_opt_compact_summary(const struct option *opt,
+                                   const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_ARG(arg);
+       if (unset) {
+               options->flags.stat_with_summary = 0;
+       } else {
+               options->flags.stat_with_summary = 1;
+               options->output_format |= DIFF_FORMAT_DIFFSTAT;
+       }
+       return 0;
+}
+
+static int diff_opt_diff_algorithm(const struct option *opt,
+                                  const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+       long value = parse_algorithm_value(arg);
+
+       BUG_ON_OPT_NEG(unset);
+       if (value < 0)
+               return error(_("option diff-algorithm accepts \"myers\", "
+                              "\"minimal\", \"patience\" and \"histogram\""));
+
+       /* clear out previous settings */
+       DIFF_XDL_CLR(options, NEED_MINIMAL);
+       options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
+       options->xdl_opts |= value;
+       return 0;
+}
+
+static int diff_opt_dirstat(const struct option *opt,
+                           const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (!strcmp(opt->long_name, "cumulative")) {
+               if (arg)
+                       BUG("how come --cumulative take a value?");
+               arg = "cumulative";
+       } else if (!strcmp(opt->long_name, "dirstat-by-file"))
+               parse_dirstat_opt(options, "files");
+       parse_dirstat_opt(options, arg ? arg : "");
+       return 0;
+}
+
+static int diff_opt_find_copies(const struct option *opt,
+                               const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (!arg)
+               arg = "";
+       options->rename_score = parse_rename_score(&arg);
+       if (*arg != 0)
+               return error(_("invalid argument to %s"), opt->long_name);
+
+       if (options->detect_rename == DIFF_DETECT_COPY)
+               options->flags.find_copies_harder = 1;
+       else
+               options->detect_rename = DIFF_DETECT_COPY;
+
+       return 0;
+}
+
+static int diff_opt_find_renames(const struct option *opt,
+                                const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (!arg)
+               arg = "";
+       options->rename_score = parse_rename_score(&arg);
+       if (*arg != 0)
+               return error(_("invalid argument to %s"), opt->long_name);
+
+       options->detect_rename = DIFF_DETECT_RENAME;
+       return 0;
+}
+
+static int diff_opt_follow(const struct option *opt,
+                          const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_ARG(arg);
+       if (unset) {
+               options->flags.follow_renames = 0;
+               options->flags.default_follow_renames = 0;
+       } else {
+               options->flags.follow_renames = 1;
+       }
+       return 0;
+}
+
+static int diff_opt_ignore_submodules(const struct option *opt,
+                                     const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (!arg)
+               arg = "all";
+       options->flags.override_submodule_config = 1;
+       handle_ignore_submodules_arg(options, arg);
+       return 0;
+}
+
+static int diff_opt_line_prefix(const struct option *opt,
+                               const char *optarg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       options->line_prefix = optarg;
+       options->line_prefix_length = strlen(options->line_prefix);
+       graph_setup_line_prefix(options);
+       return 0;
+}
+
+static int diff_opt_no_prefix(const struct option *opt,
+                             const char *optarg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       BUG_ON_OPT_ARG(optarg);
+       options->a_prefix = "";
+       options->b_prefix = "";
+       return 0;
+}
+
+static enum parse_opt_result diff_opt_output(struct parse_opt_ctx_t *ctx,
+                                            const struct option *opt,
+                                            const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+       char *path;
+
+       BUG_ON_OPT_NEG(unset);
+       path = prefix_filename(ctx->prefix, arg);
+       options->file = xfopen(path, "w");
+       options->close_file = 1;
+       if (options->use_color != GIT_COLOR_ALWAYS)
+               options->use_color = GIT_COLOR_NEVER;
+       free(path);
+       return 0;
+}
+
+static int diff_opt_patience(const struct option *opt,
+                            const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+       int i;
+
+       BUG_ON_OPT_NEG(unset);
+       BUG_ON_OPT_ARG(arg);
+       options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
+       /*
+        * Both --patience and --anchored use PATIENCE_DIFF
+        * internally, so remove any anchors previously
+        * specified.
+        */
+       for (i = 0; i < options->anchors_nr; i++)
+               free(options->anchors[i]);
+       options->anchors_nr = 0;
+       return 0;
+}
+
+static int diff_opt_pickaxe_regex(const struct option *opt,
+                                 const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       options->pickaxe = arg;
+       options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
+       return 0;
+}
+
+static int diff_opt_pickaxe_string(const struct option *opt,
+                                  const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       options->pickaxe = arg;
+       options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
+       return 0;
+}
+
+static int diff_opt_relative(const struct option *opt,
+                            const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       options->flags.relative_name = 1;
+       if (arg)
+               options->prefix = arg;
+       return 0;
+}
+
+static int diff_opt_submodule(const struct option *opt,
+                             const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (!arg)
+               arg = "log";
+       if (parse_submodule_params(options, arg))
+               return error(_("failed to parse --submodule option parameter: '%s'"),
+                            arg);
+       return 0;
+}
+
+static int diff_opt_textconv(const struct option *opt,
+                            const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_ARG(arg);
+       if (unset) {
+               options->flags.allow_textconv = 0;
+       } else {
+               options->flags.allow_textconv = 1;
+               options->flags.textconv_set_via_cmdline = 1;
+       }
+       return 0;
 }
 
 static int diff_opt_unified(const struct option *opt,
@@ -4885,6 +5221,44 @@ static int diff_opt_unified(const struct option *opt,
        return 0;
 }
 
+static int diff_opt_word_diff(const struct option *opt,
+                             const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (arg) {
+               if (!strcmp(arg, "plain"))
+                       options->word_diff = DIFF_WORDS_PLAIN;
+               else if (!strcmp(arg, "color")) {
+                       options->use_color = 1;
+                       options->word_diff = DIFF_WORDS_COLOR;
+               }
+               else if (!strcmp(arg, "porcelain"))
+                       options->word_diff = DIFF_WORDS_PORCELAIN;
+               else if (!strcmp(arg, "none"))
+                       options->word_diff = DIFF_WORDS_NONE;
+               else
+                       return error(_("bad --word-diff argument: %s"), arg);
+       } else {
+               if (options->word_diff == DIFF_WORDS_NONE)
+                       options->word_diff = DIFF_WORDS_PLAIN;
+       }
+       return 0;
+}
+
+static int diff_opt_word_diff_regex(const struct option *opt,
+                                   const char *arg, int unset)
+{
+       struct diff_options *options = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+       if (options->word_diff == DIFF_WORDS_NONE)
+               options->word_diff = DIFF_WORDS_PLAIN;
+       options->word_regex = arg;
+       return 0;
+}
+
 static void prep_parse_options(struct diff_options *options)
 {
        struct option parseopts[] = {
@@ -4892,6 +5266,9 @@ static void prep_parse_options(struct diff_options *options)
                OPT_BITOP('p', "patch", &options->output_format,
                          N_("generate patch"),
                          DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
+               OPT_BIT_F('s', "no-patch", &options->output_format,
+                         N_("suppress diff output"),
+                         DIFF_FORMAT_NO_OUTPUT, PARSE_OPT_NONEG),
                OPT_BITOP('u', NULL, &options->output_format,
                          N_("generate patch"),
                          DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
@@ -4903,6 +5280,243 @@ static void prep_parse_options(struct diff_options *options)
                OPT_BIT_F(0, "raw", &options->output_format,
                          N_("generate the diff in raw format"),
                          DIFF_FORMAT_RAW, PARSE_OPT_NONEG),
+               OPT_BITOP(0, "patch-with-raw", &options->output_format,
+                         N_("synonym for '-p --raw'"),
+                         DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW,
+                         DIFF_FORMAT_NO_OUTPUT),
+               OPT_BITOP(0, "patch-with-stat", &options->output_format,
+                         N_("synonym for '-p --stat'"),
+                         DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT,
+                         DIFF_FORMAT_NO_OUTPUT),
+               OPT_BIT_F(0, "numstat", &options->output_format,
+                         N_("machine friendly --stat"),
+                         DIFF_FORMAT_NUMSTAT, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "shortstat", &options->output_format,
+                         N_("output only the last line of --stat"),
+                         DIFF_FORMAT_SHORTSTAT, PARSE_OPT_NONEG),
+               OPT_CALLBACK_F('X', "dirstat", options, N_("<param1,param2>..."),
+                              N_("output the distribution of relative amount of changes for each sub-directory"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_dirstat),
+               OPT_CALLBACK_F(0, "cumulative", options, NULL,
+                              N_("synonym for --dirstat=cumulative"),
+                              PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+                              diff_opt_dirstat),
+               OPT_CALLBACK_F(0, "dirstat-by-file", options, N_("<param1,param2>..."),
+                              N_("synonym for --dirstat=files,param1,param2..."),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_dirstat),
+               OPT_BIT_F(0, "check", &options->output_format,
+                         N_("warn if changes introduce conflict markers or whitespace errors"),
+                         DIFF_FORMAT_CHECKDIFF, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "summary", &options->output_format,
+                         N_("condensed summary such as creations, renames and mode changes"),
+                         DIFF_FORMAT_SUMMARY, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "name-only", &options->output_format,
+                         N_("show only names of changed files"),
+                         DIFF_FORMAT_NAME, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "name-status", &options->output_format,
+                         N_("show only names and status of changed files"),
+                         DIFF_FORMAT_NAME_STATUS, PARSE_OPT_NONEG),
+               OPT_CALLBACK_F(0, "stat", options, N_("<width>[,<name-width>[,<count>]]"),
+                              N_("generate diffstat"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_stat),
+               OPT_CALLBACK_F(0, "stat-width", options, N_("<width>"),
+                              N_("generate diffstat with a given width"),
+                              PARSE_OPT_NONEG, diff_opt_stat),
+               OPT_CALLBACK_F(0, "stat-name-width", options, N_("<width>"),
+                              N_("generate diffstat with a given name width"),
+                              PARSE_OPT_NONEG, diff_opt_stat),
+               OPT_CALLBACK_F(0, "stat-graph-width", options, N_("<width>"),
+                              N_("generate diffstat with a given graph width"),
+                              PARSE_OPT_NONEG, diff_opt_stat),
+               OPT_CALLBACK_F(0, "stat-count", options, N_("<count>"),
+                              N_("generate diffstat with limited lines"),
+                              PARSE_OPT_NONEG, diff_opt_stat),
+               OPT_CALLBACK_F(0, "compact-summary", options, NULL,
+                              N_("generate compact summary in diffstat"),
+                              PARSE_OPT_NOARG, diff_opt_compact_summary),
+               OPT_CALLBACK_F(0, "binary", options, NULL,
+                              N_("output a binary diff that can be applied"),
+                              PARSE_OPT_NONEG | PARSE_OPT_NOARG, diff_opt_binary),
+               OPT_BOOL(0, "full-index", &options->flags.full_index,
+                        N_("show full pre- and post-image object names on the \"index\" lines")),
+               OPT_COLOR_FLAG(0, "color", &options->use_color,
+                              N_("show colored diff")),
+               OPT_CALLBACK_F(0, "ws-error-highlight", options, N_("<kind>"),
+                              N_("highlight whitespace errors in the 'context', 'old' or 'new' lines in the diff"),
+                              PARSE_OPT_NONEG, diff_opt_ws_error_highlight),
+               OPT_SET_INT('z', NULL, &options->line_termination,
+                           N_("do not munge pathnames and use NULs as output field terminators in --raw or --numstat"),
+                           0),
+               OPT__ABBREV(&options->abbrev),
+               OPT_STRING_F(0, "src-prefix", &options->a_prefix, N_("<prefix>"),
+                            N_("show the given source prefix instead of \"a/\""),
+                            PARSE_OPT_NONEG),
+               OPT_STRING_F(0, "dst-prefix", &options->b_prefix, N_("<prefix>"),
+                            N_("show the given destination prefix instead of \"b/\""),
+                            PARSE_OPT_NONEG),
+               OPT_CALLBACK_F(0, "line-prefix", options, N_("<prefix>"),
+                              N_("prepend an additional prefix to every line of output"),
+                              PARSE_OPT_NONEG, diff_opt_line_prefix),
+               OPT_CALLBACK_F(0, "no-prefix", options, NULL,
+                              N_("do not show any source or destination prefix"),
+                              PARSE_OPT_NONEG | PARSE_OPT_NOARG, diff_opt_no_prefix),
+               OPT_INTEGER_F(0, "inter-hunk-context", &options->interhunkcontext,
+                             N_("show context between diff hunks up to the specified number of lines"),
+                             PARSE_OPT_NONEG),
+               OPT_CALLBACK_F(0, "output-indicator-new",
+                              &options->output_indicators[OUTPUT_INDICATOR_NEW],
+                              N_("<char>"),
+                              N_("specify the character to indicate a new line instead of '+'"),
+                              PARSE_OPT_NONEG, diff_opt_char),
+               OPT_CALLBACK_F(0, "output-indicator-old",
+                              &options->output_indicators[OUTPUT_INDICATOR_OLD],
+                              N_("<char>"),
+                              N_("specify the character to indicate an old line instead of '-'"),
+                              PARSE_OPT_NONEG, diff_opt_char),
+               OPT_CALLBACK_F(0, "output-indicator-context",
+                              &options->output_indicators[OUTPUT_INDICATOR_CONTEXT],
+                              N_("<char>"),
+                              N_("specify the character to indicate a context instead of ' '"),
+                              PARSE_OPT_NONEG, diff_opt_char),
+
+               OPT_GROUP(N_("Diff rename options")),
+               OPT_CALLBACK_F('B', "break-rewrites", &options->break_opt, N_("<n>[/<m>]"),
+                              N_("break complete rewrite changes into pairs of delete and create"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_break_rewrites),
+               OPT_CALLBACK_F('M', "find-renames", options, N_("<n>"),
+                              N_("detect renames"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_find_renames),
+               OPT_SET_INT_F('D', "irreversible-delete", &options->irreversible_delete,
+                             N_("omit the preimage for deletes"),
+                             1, PARSE_OPT_NONEG),
+               OPT_CALLBACK_F('C', "find-copies", options, N_("<n>"),
+                              N_("detect copies"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_find_copies),
+               OPT_BOOL(0, "find-copies-harder", &options->flags.find_copies_harder,
+                        N_("use unmodified files as source to find copies")),
+               OPT_SET_INT_F(0, "no-renames", &options->detect_rename,
+                             N_("disable rename detection"),
+                             0, PARSE_OPT_NONEG),
+               OPT_BOOL(0, "rename-empty", &options->flags.rename_empty,
+                        N_("use empty blobs as rename source")),
+               OPT_CALLBACK_F(0, "follow", options, NULL,
+                              N_("continue listing the history of a file beyond renames"),
+                              PARSE_OPT_NOARG, diff_opt_follow),
+               OPT_INTEGER('l', NULL, &options->rename_limit,
+                           N_("prevent rename/copy detection if the number of rename/copy targets exceeds given limit")),
+
+               OPT_GROUP(N_("Diff algorithm options")),
+               OPT_BIT(0, "minimal", &options->xdl_opts,
+                       N_("produce the smallest possible diff"),
+                       XDF_NEED_MINIMAL),
+               OPT_BIT_F('w', "ignore-all-space", &options->xdl_opts,
+                         N_("ignore whitespace when comparing lines"),
+                         XDF_IGNORE_WHITESPACE, PARSE_OPT_NONEG),
+               OPT_BIT_F('b', "ignore-space-change", &options->xdl_opts,
+                         N_("ignore changes in amount of whitespace"),
+                         XDF_IGNORE_WHITESPACE_CHANGE, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "ignore-space-at-eol", &options->xdl_opts,
+                         N_("ignore changes in whitespace at EOL"),
+                         XDF_IGNORE_WHITESPACE_AT_EOL, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "ignore-cr-at-eol", &options->xdl_opts,
+                         N_("ignore carrier-return at the end of line"),
+                         XDF_IGNORE_CR_AT_EOL, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "ignore-blank-lines", &options->xdl_opts,
+                         N_("ignore changes whose lines are all blank"),
+                         XDF_IGNORE_BLANK_LINES, PARSE_OPT_NONEG),
+               OPT_BIT(0, "indent-heuristic", &options->xdl_opts,
+                       N_("heuristic to shift diff hunk boundaries for easy reading"),
+                       XDF_INDENT_HEURISTIC),
+               OPT_CALLBACK_F(0, "patience", options, NULL,
+                              N_("generate diff using the \"patience diff\" algorithm"),
+                              PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+                              diff_opt_patience),
+               OPT_BITOP(0, "histogram", &options->xdl_opts,
+                         N_("generate diff using the \"histogram diff\" algorithm"),
+                         XDF_HISTOGRAM_DIFF, XDF_DIFF_ALGORITHM_MASK),
+               OPT_CALLBACK_F(0, "diff-algorithm", options, N_("<algorithm>"),
+                              N_("choose a diff algorithm"),
+                              PARSE_OPT_NONEG, diff_opt_diff_algorithm),
+               OPT_CALLBACK_F(0, "anchored", options, N_("<text>"),
+                              N_("generate diff using the \"anchored diff\" algorithm"),
+                              PARSE_OPT_NONEG, diff_opt_anchored),
+               OPT_CALLBACK_F(0, "word-diff", options, N_("<mode>"),
+                              N_("show word diff, using <mode> to delimit changed words"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_word_diff),
+               OPT_CALLBACK_F(0, "word-diff-regex", options, N_("<regex>"),
+                              N_("use <regex> to decide what a word is"),
+                              PARSE_OPT_NONEG, diff_opt_word_diff_regex),
+               OPT_CALLBACK_F(0, "color-words", options, N_("<regex>"),
+                              N_("equivalent to --word-diff=color --word-diff-regex=<regex>"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_color_words),
+               OPT_CALLBACK_F(0, "color-moved", options, N_("<mode>"),
+                              N_("moved lines of code are colored differently"),
+                              PARSE_OPT_OPTARG, diff_opt_color_moved),
+               OPT_CALLBACK_F(0, "color-moved-ws", options, N_("<mode>"),
+                              N_("how white spaces are ignored in --color-moved"),
+                              0, diff_opt_color_moved_ws),
+
+               OPT_GROUP(N_("Other diff options")),
+               OPT_CALLBACK_F(0, "relative", options, N_("<prefix>"),
+                              N_("when run from subdir, exclude changes outside and show relative paths"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_relative),
+               OPT_BOOL('a', "text", &options->flags.text,
+                        N_("treat all files as text")),
+               OPT_BOOL('R', NULL, &options->flags.reverse_diff,
+                        N_("swap two inputs, reverse the diff")),
+               OPT_BOOL(0, "exit-code", &options->flags.exit_with_status,
+                        N_("exit with 1 if there were differences, 0 otherwise")),
+               OPT_BOOL(0, "quiet", &options->flags.quick,
+                        N_("disable all output of the program")),
+               OPT_BOOL(0, "ext-diff", &options->flags.allow_external,
+                        N_("allow an external diff helper to be executed")),
+               OPT_CALLBACK_F(0, "textconv", options, NULL,
+                              N_("run external text conversion filters when comparing binary files"),
+                              PARSE_OPT_NOARG, diff_opt_textconv),
+               OPT_CALLBACK_F(0, "ignore-submodules", options, N_("<when>"),
+                              N_("ignore changes to submodules in the diff generation"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_ignore_submodules),
+               OPT_CALLBACK_F(0, "submodule", options, N_("<format>"),
+                              N_("specify how differences in submodules are shown"),
+                              PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+                              diff_opt_submodule),
+               OPT_SET_INT_F(0, "ita-invisible-in-index", &options->ita_invisible_in_index,
+                             N_("hide 'git add -N' entries from the index"),
+                             1, PARSE_OPT_NONEG),
+               OPT_SET_INT_F(0, "ita-visible-in-index", &options->ita_invisible_in_index,
+                             N_("treat 'git add -N' entries as real in the index"),
+                             0, PARSE_OPT_NONEG),
+               OPT_CALLBACK_F('S', NULL, options, N_("<string>"),
+                              N_("look for differences that change the number of occurrences of the specified string"),
+                              0, diff_opt_pickaxe_string),
+               OPT_CALLBACK_F('G', NULL, options, N_("<regex>"),
+                              N_("look for differences that change the number of occurrences of the specified regex"),
+                              0, diff_opt_pickaxe_regex),
+               OPT_BIT_F(0, "pickaxe-all", &options->pickaxe_opts,
+                         N_("show all changes in the changeset with -S or -G"),
+                         DIFF_PICKAXE_ALL, PARSE_OPT_NONEG),
+               OPT_BIT_F(0, "pickaxe-regex", &options->pickaxe_opts,
+                         N_("treat <string> in -S as extended POSIX regular expression"),
+                         DIFF_PICKAXE_REGEX, PARSE_OPT_NONEG),
+               OPT_FILENAME('O', NULL, &options->orderfile,
+                            N_("control the order in which files appear in the output")),
+               OPT_CALLBACK_F(0, "find-object", options, N_("<object-id>"),
+                              N_("look for differences that change the number of occurrences of the specified object"),
+                              PARSE_OPT_NONEG, diff_opt_find_object),
+               OPT_CALLBACK_F(0, "diff-filter", options, N_("[(A|C|D|M|R|T|U|X|B)...[*]]"),
+                              N_("select files by diff type"),
+                              PARSE_OPT_NONEG, diff_opt_diff_filter),
+               { OPTION_CALLBACK, 0, "output", options, N_("<file>"),
+                 N_("Output to a specific file"),
+                 PARSE_OPT_NONEG, NULL, 0, diff_opt_output },
+
                OPT_END()
        };
 
@@ -4913,10 +5527,6 @@ static void prep_parse_options(struct diff_options *options)
 int diff_opt_parse(struct diff_options *options,
                   const char **av, int ac, const char *prefix)
 {
-       const char *arg = av[0];
-       const char *optarg;
-       int argcount;
-
        if (!prefix)
                prefix = "";
 
@@ -4927,307 +5537,7 @@ int diff_opt_parse(struct diff_options *options,
                           PARSE_OPT_ONE_SHOT |
                           PARSE_OPT_STOP_AT_NON_OPTION);
 
-       if (ac)
-               return ac;
-
-       /* Output format options */
-       if (!strcmp(arg, "--patch-with-raw")) {
-               enable_patch_output(&options->output_format);
-               options->output_format |= DIFF_FORMAT_RAW;
-       } else if (!strcmp(arg, "--numstat"))
-               options->output_format |= DIFF_FORMAT_NUMSTAT;
-       else if (!strcmp(arg, "--shortstat"))
-               options->output_format |= DIFF_FORMAT_SHORTSTAT;
-       else if (skip_prefix(arg, "-X", &arg) ||
-                skip_to_optional_arg(arg, "--dirstat", &arg))
-               return parse_dirstat_opt(options, arg);
-       else if (!strcmp(arg, "--cumulative"))
-               return parse_dirstat_opt(options, "cumulative");
-       else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
-               parse_dirstat_opt(options, "files");
-               return parse_dirstat_opt(options, arg);
-       }
-       else if (!strcmp(arg, "--check"))
-               options->output_format |= DIFF_FORMAT_CHECKDIFF;
-       else if (!strcmp(arg, "--summary"))
-               options->output_format |= DIFF_FORMAT_SUMMARY;
-       else if (!strcmp(arg, "--patch-with-stat")) {
-               enable_patch_output(&options->output_format);
-               options->output_format |= DIFF_FORMAT_DIFFSTAT;
-       } else if (!strcmp(arg, "--name-only"))
-               options->output_format |= DIFF_FORMAT_NAME;
-       else if (!strcmp(arg, "--name-status"))
-               options->output_format |= DIFF_FORMAT_NAME_STATUS;
-       else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
-               options->output_format |= DIFF_FORMAT_NO_OUTPUT;
-       else if (starts_with(arg, "--stat"))
-               /* --stat, --stat-width, --stat-name-width, or --stat-count */
-               return stat_opt(options, av);
-       else if (!strcmp(arg, "--compact-summary")) {
-                options->flags.stat_with_summary = 1;
-                options->output_format |= DIFF_FORMAT_DIFFSTAT;
-       } else if (!strcmp(arg, "--no-compact-summary"))
-                options->flags.stat_with_summary = 0;
-       else if (skip_prefix(arg, "--output-indicator-new=", &arg))
-               options->output_indicators[OUTPUT_INDICATOR_NEW] = arg[0];
-       else if (skip_prefix(arg, "--output-indicator-old=", &arg))
-               options->output_indicators[OUTPUT_INDICATOR_OLD] = arg[0];
-       else if (skip_prefix(arg, "--output-indicator-context=", &arg))
-               options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = arg[0];
-
-       /* renames options */
-       else if (starts_with(arg, "-B") ||
-                skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
-               if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
-                       return error("invalid argument to -B: %s", arg+2);
-       }
-       else if (starts_with(arg, "-M") ||
-                skip_to_optional_arg(arg, "--find-renames", NULL)) {
-               if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
-                       return error("invalid argument to -M: %s", arg+2);
-               options->detect_rename = DIFF_DETECT_RENAME;
-       }
-       else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
-               options->irreversible_delete = 1;
-       }
-       else if (starts_with(arg, "-C") ||
-                skip_to_optional_arg(arg, "--find-copies", NULL)) {
-               if (options->detect_rename == DIFF_DETECT_COPY)
-                       options->flags.find_copies_harder = 1;
-               if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
-                       return error("invalid argument to -C: %s", arg+2);
-               options->detect_rename = DIFF_DETECT_COPY;
-       }
-       else if (!strcmp(arg, "--no-renames"))
-               options->detect_rename = 0;
-       else if (!strcmp(arg, "--rename-empty"))
-               options->flags.rename_empty = 1;
-       else if (!strcmp(arg, "--no-rename-empty"))
-               options->flags.rename_empty = 0;
-       else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
-               options->flags.relative_name = 1;
-               if (arg)
-                       options->prefix = arg;
-       }
-
-       /* xdiff options */
-       else if (!strcmp(arg, "--minimal"))
-               DIFF_XDL_SET(options, NEED_MINIMAL);
-       else if (!strcmp(arg, "--no-minimal"))
-               DIFF_XDL_CLR(options, NEED_MINIMAL);
-       else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
-               DIFF_XDL_SET(options, IGNORE_WHITESPACE);
-       else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
-               DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
-       else if (!strcmp(arg, "--ignore-space-at-eol"))
-               DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
-       else if (!strcmp(arg, "--ignore-cr-at-eol"))
-               DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
-       else if (!strcmp(arg, "--ignore-blank-lines"))
-               DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
-       else if (!strcmp(arg, "--indent-heuristic"))
-               DIFF_XDL_SET(options, INDENT_HEURISTIC);
-       else if (!strcmp(arg, "--no-indent-heuristic"))
-               DIFF_XDL_CLR(options, INDENT_HEURISTIC);
-       else if (!strcmp(arg, "--patience")) {
-               int i;
-               options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
-               /*
-                * Both --patience and --anchored use PATIENCE_DIFF
-                * internally, so remove any anchors previously
-                * specified.
-                */
-               for (i = 0; i < options->anchors_nr; i++)
-                       free(options->anchors[i]);
-               options->anchors_nr = 0;
-       } else if (!strcmp(arg, "--histogram"))
-               options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
-       else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
-               long value = parse_algorithm_value(optarg);
-               if (value < 0)
-                       return error("option diff-algorithm accepts \"myers\", "
-                                    "\"minimal\", \"patience\" and \"histogram\"");
-               /* clear out previous settings */
-               DIFF_XDL_CLR(options, NEED_MINIMAL);
-               options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
-               options->xdl_opts |= value;
-               return argcount;
-       } else if (skip_prefix(arg, "--anchored=", &arg)) {
-               options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
-               ALLOC_GROW(options->anchors, options->anchors_nr + 1,
-                          options->anchors_alloc);
-               options->anchors[options->anchors_nr++] = xstrdup(arg);
-       }
-
-       /* flags options */
-       else if (!strcmp(arg, "--binary")) {
-               enable_patch_output(&options->output_format);
-               options->flags.binary = 1;
-       }
-       else if (!strcmp(arg, "--full-index"))
-               options->flags.full_index = 1;
-       else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
-               options->flags.text = 1;
-       else if (!strcmp(arg, "-R"))
-               options->flags.reverse_diff = 1;
-       else if (!strcmp(arg, "--find-copies-harder"))
-               options->flags.find_copies_harder = 1;
-       else if (!strcmp(arg, "--follow"))
-               options->flags.follow_renames = 1;
-       else if (!strcmp(arg, "--no-follow")) {
-               options->flags.follow_renames = 0;
-               options->flags.default_follow_renames = 0;
-       } else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
-               int value = git_config_colorbool(NULL, arg);
-               if (value < 0)
-                       return error("option `color' expects \"always\", \"auto\", or \"never\"");
-               options->use_color = value;
-       }
-       else if (!strcmp(arg, "--no-color"))
-               options->use_color = 0;
-       else if (!strcmp(arg, "--color-moved")) {
-               if (diff_color_moved_default)
-                       options->color_moved = diff_color_moved_default;
-               if (options->color_moved == COLOR_MOVED_NO)
-                       options->color_moved = COLOR_MOVED_DEFAULT;
-       } else if (!strcmp(arg, "--no-color-moved"))
-               options->color_moved = COLOR_MOVED_NO;
-       else if (skip_prefix(arg, "--color-moved=", &arg)) {
-               int cm = parse_color_moved(arg);
-               if (cm < 0)
-                       return error("bad --color-moved argument: %s", arg);
-               options->color_moved = cm;
-       } else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
-               unsigned cm = parse_color_moved_ws(arg);
-               if (cm & COLOR_MOVED_WS_ERROR)
-                       return -1;
-               options->color_moved_ws_handling = cm;
-       } else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
-               options->use_color = 1;
-               options->word_diff = DIFF_WORDS_COLOR;
-       }
-       else if (!strcmp(arg, "--word-diff")) {
-               if (options->word_diff == DIFF_WORDS_NONE)
-                       options->word_diff = DIFF_WORDS_PLAIN;
-       }
-       else if (skip_prefix(arg, "--word-diff=", &arg)) {
-               if (!strcmp(arg, "plain"))
-                       options->word_diff = DIFF_WORDS_PLAIN;
-               else if (!strcmp(arg, "color")) {
-                       options->use_color = 1;
-                       options->word_diff = DIFF_WORDS_COLOR;
-               }
-               else if (!strcmp(arg, "porcelain"))
-                       options->word_diff = DIFF_WORDS_PORCELAIN;
-               else if (!strcmp(arg, "none"))
-                       options->word_diff = DIFF_WORDS_NONE;
-               else
-                       die("bad --word-diff argument: %s", arg);
-       }
-       else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
-               if (options->word_diff == DIFF_WORDS_NONE)
-                       options->word_diff = DIFF_WORDS_PLAIN;
-               options->word_regex = optarg;
-               return argcount;
-       }
-       else if (!strcmp(arg, "--exit-code"))
-               options->flags.exit_with_status = 1;
-       else if (!strcmp(arg, "--quiet"))
-               options->flags.quick = 1;
-       else if (!strcmp(arg, "--ext-diff"))
-               options->flags.allow_external = 1;
-       else if (!strcmp(arg, "--no-ext-diff"))
-               options->flags.allow_external = 0;
-       else if (!strcmp(arg, "--textconv")) {
-               options->flags.allow_textconv = 1;
-               options->flags.textconv_set_via_cmdline = 1;
-       } else if (!strcmp(arg, "--no-textconv"))
-               options->flags.allow_textconv = 0;
-       else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
-               options->flags.override_submodule_config = 1;
-               handle_ignore_submodules_arg(options, arg);
-       } else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
-               return parse_submodule_opt(options, arg);
-       else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
-               return parse_ws_error_highlight_opt(options, arg);
-       else if (!strcmp(arg, "--ita-invisible-in-index"))
-               options->ita_invisible_in_index = 1;
-       else if (!strcmp(arg, "--ita-visible-in-index"))
-               options->ita_invisible_in_index = 0;
-
-       /* misc options */
-       else if (!strcmp(arg, "-z"))
-               options->line_termination = 0;
-       else if ((argcount = short_opt('l', av, &optarg))) {
-               options->rename_limit = strtoul(optarg, NULL, 10);
-               return argcount;
-       }
-       else if ((argcount = short_opt('S', av, &optarg))) {
-               options->pickaxe = optarg;
-               options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
-               return argcount;
-       } else if ((argcount = short_opt('G', av, &optarg))) {
-               options->pickaxe = optarg;
-               options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
-               return argcount;
-       }
-       else if (!strcmp(arg, "--pickaxe-all"))
-               options->pickaxe_opts |= DIFF_PICKAXE_ALL;
-       else if (!strcmp(arg, "--pickaxe-regex"))
-               options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
-       else if ((argcount = short_opt('O', av, &optarg))) {
-               options->orderfile = prefix_filename(prefix, optarg);
-               return argcount;
-       } else if (skip_prefix(arg, "--find-object=", &arg))
-               return parse_objfind_opt(options, arg);
-       else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
-               int offending = parse_diff_filter_opt(optarg, options);
-               if (offending)
-                       die("unknown change class '%c' in --diff-filter=%s",
-                           offending, optarg);
-               return argcount;
-       }
-       else if (!strcmp(arg, "--no-abbrev"))
-               options->abbrev = 0;
-       else if (!strcmp(arg, "--abbrev"))
-               options->abbrev = DEFAULT_ABBREV;
-       else if (skip_prefix(arg, "--abbrev=", &arg)) {
-               options->abbrev = strtoul(arg, NULL, 10);
-               if (options->abbrev < MINIMUM_ABBREV)
-                       options->abbrev = MINIMUM_ABBREV;
-               else if (the_hash_algo->hexsz < options->abbrev)
-                       options->abbrev = the_hash_algo->hexsz;
-       }
-       else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
-               options->a_prefix = optarg;
-               return argcount;
-       }
-       else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
-               options->line_prefix = optarg;
-               options->line_prefix_length = strlen(options->line_prefix);
-               graph_setup_line_prefix(options);
-               return argcount;
-       }
-       else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
-               options->b_prefix = optarg;
-               return argcount;
-       }
-       else if (!strcmp(arg, "--no-prefix"))
-               options->a_prefix = options->b_prefix = "";
-       else if (opt_arg(arg, '\0', "inter-hunk-context",
-                        &options->interhunkcontext))
-               ;
-       else if ((argcount = parse_long_opt("output", av, &optarg))) {
-               char *path = prefix_filename(prefix, optarg);
-               options->file = xfopen(path, "w");
-               options->close_file = 1;
-               if (options->use_color != GIT_COLOR_ALWAYS)
-                       options->use_color = GIT_COLOR_NEVER;
-               free(path);
-               return argcount;
-       } else
-               return 0;
-       return 1;
+       return ac;
 }
 
 int parse_rename_score(const char **cp_p)
@@ -5266,47 +5576,6 @@ int parse_rename_score(const char **cp_p)
        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
 }
 
-static int diff_scoreopt_parse(const char *opt)
-{
-       int opt1, opt2, cmd;
-
-       if (*opt++ != '-')
-               return -1;
-       cmd = *opt++;
-       if (cmd == '-') {
-               /* convert the long-form arguments into short-form versions */
-               if (skip_prefix(opt, "break-rewrites", &opt)) {
-                       if (*opt == 0 || *opt++ == '=')
-                               cmd = 'B';
-               } else if (skip_prefix(opt, "find-copies", &opt)) {
-                       if (*opt == 0 || *opt++ == '=')
-                               cmd = 'C';
-               } else if (skip_prefix(opt, "find-renames", &opt)) {
-                       if (*opt == 0 || *opt++ == '=')
-                               cmd = 'M';
-               }
-       }
-       if (cmd != 'M' && cmd != 'C' && cmd != 'B')
-               return -1; /* that is not a -M, -C, or -B option */
-
-       opt1 = parse_rename_score(&opt);
-       if (cmd != 'B')
-               opt2 = 0;
-       else {
-               if (*opt == 0)
-                       opt2 = 0;
-               else if (*opt != '/')
-                       return -1; /* we expect -B80/99 or -B80 */
-               else {
-                       opt++;
-                       opt2 = parse_rename_score(&opt);
-               }
-       }
-       if (*opt != 0)
-               return -1;
-       return opt1 | (opt2 << 16);
-}
-
 struct diff_queue_struct diff_queued_diff;
 
 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
@@ -5721,6 +5990,22 @@ static int remove_space(char *line, int len)
        return dst - line;
 }
 
+void flush_one_hunk(struct object_id *result, git_SHA_CTX *ctx)
+{
+       unsigned char hash[GIT_MAX_RAWSZ];
+       unsigned short carry = 0;
+       int i;
+
+       git_SHA1_Final(hash, ctx);
+       git_SHA1_Init(ctx);
+       /* 20-byte sum, with carry */
+       for (i = 0; i < GIT_SHA1_RAWSZ; ++i) {
+               carry += result->hash[i] + hash[i];
+               result->hash[i] = carry;
+               carry >>= 8;
+       }
+}
+
 static void patch_id_consume(void *priv, char *line, unsigned long len)
 {
        struct patch_id_t *data = priv;
@@ -5745,8 +6030,8 @@ static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
        git_SHA1_Update(ctx, buf, len);
 }
 
-/* returns 0 upon success, and writes result into sha1 */
-static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
+/* returns 0 upon success, and writes result into oid */
+static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only, int stable)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
        int i;
@@ -5756,6 +6041,7 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
        git_SHA1_Init(&ctx);
        memset(&data, 0, sizeof(struct patch_id_t));
        data.ctx = &ctx;
+       oidclr(oid);
 
        for (i = 0; i < q->nr; i++) {
                xpparam_t xpp;
@@ -5831,17 +6117,22 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
                                  patch_id_consume, &data, &xpp, &xecfg))
                        return error("unable to generate patch-id diff for %s",
                                     p->one->path);
+
+               if (stable)
+                       flush_one_hunk(oid, &ctx);
        }
 
-       git_SHA1_Final(oid->hash, &ctx);
+       if (!stable)
+               git_SHA1_Final(oid->hash, &ctx);
+
        return 0;
 }
 
-int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
+int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only, int stable)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
        int i;
-       int result = diff_get_patch_id(options, oid, diff_header_only);
+       int result = diff_get_patch_id(options, oid, diff_header_only, stable);
 
        for (i = 0; i < q->nr; i++)
                diff_free_filepair(q->queue[i]);
@@ -5943,8 +6234,10 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o)
 
                for (i = 0; i < esm.nr; i++)
                        free((void *)esm.buf[i].line);
+               esm.nr = 0;
+
+               o->emitted_symbols = NULL;
        }
-       esm.nr = 0;
 }
 
 void diff_flush(struct diff_options *options)
@@ -6203,14 +6496,47 @@ static int diffnamecmp(const void *a_, const void *b_)
        return strcmp(name_a, name_b);
 }
 
-void diffcore_fix_diff_index(struct diff_options *options)
+void diffcore_fix_diff_index(void)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
        QSORT(q->queue, q->nr, diffnamecmp);
 }
 
+static void add_if_missing(struct repository *r,
+                          struct oid_array *to_fetch,
+                          const struct diff_filespec *filespec)
+{
+       if (filespec && filespec->oid_valid &&
+           oid_object_info_extended(r, &filespec->oid, NULL,
+                                    OBJECT_INFO_FOR_PREFETCH))
+               oid_array_append(to_fetch, &filespec->oid);
+}
+
 void diffcore_std(struct diff_options *options)
 {
+       if (options->repo == the_repository &&
+           repository_format_partial_clone) {
+               /*
+                * Prefetch the diff pairs that are about to be flushed.
+                */
+               int i;
+               struct diff_queue_struct *q = &diff_queued_diff;
+               struct oid_array to_fetch = OID_ARRAY_INIT;
+
+               for (i = 0; i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+                       add_if_missing(options->repo, &to_fetch, p->one);
+                       add_if_missing(options->repo, &to_fetch, p->two);
+               }
+               if (to_fetch.nr)
+                       /*
+                        * NEEDSWORK: Consider deduplicating the OIDs sent.
+                        */
+                       fetch_objects(repository_format_partial_clone,
+                                     to_fetch.oid, to_fetch.nr);
+               oid_array_clear(&to_fetch);
+       }
+
        /* NOTE please keep the following in sync with diff_tree_combined() */
        if (options->skip_stat_unmatch)
                diffcore_skip_stat_unmatch(options);