Merge branch 'pw/diff-color-moved-ws-fix'
authorJunio C Hamano <gitster@pobox.com>
Tue, 29 Jan 2019 20:47:53 +0000 (12:47 -0800)
committerJunio C Hamano <gitster@pobox.com>
Tue, 29 Jan 2019 20:47:53 +0000 (12:47 -0800)
"git diff --color-moved-ws" updates.

* pw/diff-color-moved-ws-fix:
diff --color-moved-ws: handle blank lines
diff --color-moved-ws: modify allow-indentation-change
diff --color-moved-ws: optimize allow-indentation-change
diff --color-moved=zebra: be stricter with color alternation
diff --color-moved-ws: fix false positives
diff --color-moved-ws: demonstrate false positives
diff: allow --no-color-moved-ws
Use "whitespace" consistently
diff: document --no-color-moved

Documentation/diff-options.txt
Documentation/git-cat-file.txt
diff.c
t/t4015-diff-whitespace.sh
index b94d332f71b0ff58fb12527f8ba13788b8aa6eeb..554a34080d7081da917cd54cd34eceb7bf4cd95c 100644 (file)
@@ -293,8 +293,12 @@ dimmed-zebra::
        `dimmed_zebra` is a deprecated synonym.
 --
 
+--no-color-moved::
+       Turn off move detection. This can be used to override configuration
+       settings. It is the same as `--color-moved=no`.
+
 --color-moved-ws=<modes>::
-       This configures how white spaces are ignored when performing the
+       This configures how whitespace is ignored when performing the
        move detection for `--color-moved`.
 ifdef::git-diff[]
        It can be set by the `diff.colorMovedWS` configuration setting.
@@ -302,6 +306,8 @@ endif::git-diff[]
        These modes can be given as a comma separated list:
 +
 --
+no::
+       Do not ignore whitespace when performing move detection.
 ignore-space-at-eol::
        Ignore changes in whitespace at EOL.
 ignore-space-change::
@@ -312,12 +318,17 @@ ignore-all-space::
        Ignore whitespace when comparing lines. This ignores differences
        even if one line has whitespace where the other line has none.
 allow-indentation-change::
-       Initially ignore any white spaces in the move detection, then
+       Initially ignore any whitespace in the move detection, then
        group the moved code blocks only into a block if the change in
        whitespace is the same per line. This is incompatible with the
        other modes.
 --
 
+--no-color-moved-ws::
+       Do not ignore whitespace when performing move detection. This can be
+       used to override configuration settings. It is the same as
+       `--color-moved-ws=no`.
+
 --word-diff[=<mode>]::
        Show a word diff, using the <mode> to delimit changed words.
        By default, words are delimited by whitespace; see
index 74013335a1ccd18228a53acbd8dd7f5fe1ab40ca..9a2e9cdafba59cf731f8e7c2bc564d7942977996 100644 (file)
@@ -23,8 +23,8 @@ In the second form, a list of objects (separated by linefeeds) is provided on
 stdin, and the SHA-1, type, and size of each object is printed on stdout. The
 output format can be overridden using the optional `<format>` argument. If
 either `--textconv` or `--filters` was specified, the input is expected to
-list the object names followed by the path name, separated by a single white
-space, so that the appropriate drivers can be determined.
+list the object names followed by the path name, separated by a single
+whitespace, so that the appropriate drivers can be determined.
 
 OPTIONS
 -------
@@ -79,7 +79,7 @@ OPTIONS
        Print object information and contents for each object provided
        on stdin.  May not be combined with any other options or arguments
        except `--textconv` or `--filters`, in which case the input lines
-       also need to specify the path, separated by white space.  See the
+       also need to specify the path, separated by whitespace.  See the
        section `BATCH OUTPUT` below for details.
 
 --batch-check::
@@ -87,7 +87,7 @@ OPTIONS
        Print object information for each object provided on stdin.  May
        not be combined with any other options or arguments except
        `--textconv` or `--filters`, in which case the input lines also
-       need to specify the path, separated by white space.  See the
+       need to specify the path, separated by whitespace.  See the
        section `BATCH OUTPUT` below for details.
 
 --batch-all-objects::
diff --git a/diff.c b/diff.c
index b96b7a4fc61fcdd63dee0a890eb3b40be5d0414b..084bf542931e09c03a7627740f9177e5c9fac5d9 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -304,7 +304,9 @@ 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;
@@ -322,7 +324,7 @@ 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;
        }
 
@@ -754,6 +756,8 @@ 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}
@@ -784,44 +788,85 @@ 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 (strncmp(longer->line + d, shorter->line, shorter->len))
+       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 (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;
 }
@@ -833,51 +878,53 @@ 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,
@@ -943,6 +990,9 @@ 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;
@@ -1021,8 +1071,7 @@ 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++;
                }
@@ -1042,14 +1091,17 @@ 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++) {
@@ -1057,11 +1109,12 @@ 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 */
@@ -1071,7 +1124,7 @@ 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++) {
@@ -1079,6 +1132,7 @@ 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:
@@ -1094,7 +1148,7 @@ static void mark_color_as_moved(struct diff_options *o,
                        free(key);
                        break;
                default:
-                       flipped_block = 1;
+                       flipped_block = 0;
                }
 
                if (!match) {
@@ -1105,13 +1159,16 @@ 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)
@@ -1134,21 +1191,27 @@ 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);
 
@@ -1492,7 +1555,7 @@ 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);
@@ -5042,6 +5105,8 @@ int diff_opt_parse(struct diff_options *options,
                if (cm < 0)
                        return error("bad --color-moved argument: %s", arg);
                options->color_moved = cm;
+       } else if (!strcmp(arg, "--no-color-moved-ws")) {
+               options->color_moved_ws_handling = 0;
        } else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
                unsigned cm = parse_color_moved_ws(arg);
                if (cm & COLOR_MOVED_WS_ERROR)
index 9a3e4fdfecef4fa00d12b6ff32fc5b0beaff089e..ab4670d23653eca46292b13ef1559584aae5c3a6 100755 (executable)
@@ -1802,8 +1802,8 @@ test_expect_success 'only move detection ignores white spaces' '
        <BOLD;MAGENTA>-a long line to exceed per-line minimum<RESET>
        <BOLD;MAGENTA>-another long line to exceed per-line minimum<RESET>
        <RED>-original file<RESET>
-       <BOLD;YELLOW>+<RESET>Q<BOLD;YELLOW>a long line to exceed per-line minimum<RESET>
-       <BOLD;YELLOW>+<RESET>Q<BOLD;YELLOW>another long line to exceed per-line minimum<RESET>
+       <BOLD;CYAN>+<RESET>Q<BOLD;CYAN>a long line to exceed per-line minimum<RESET>
+       <BOLD;CYAN>+<RESET>Q<BOLD;CYAN>another long line to exceed per-line minimum<RESET>
        <GREEN>+<RESET><GREEN>new file<RESET>
        EOF
        test_cmp expected actual
@@ -1827,6 +1827,7 @@ test_expect_success 'compare whitespace delta across moved blocks' '
        QQQthat has similar lines
        QQQto previous blocks, but with different indent
        QQQYetQAnotherQoutlierQ
+       QLine with internal w h i t e s p a c e change
        EOF
 
        git add text.txt &&
@@ -1847,6 +1848,7 @@ test_expect_success 'compare whitespace delta across moved blocks' '
        QQthat has similar lines
        QQto previous blocks, but with different indent
        QQYetQAnotherQoutlier
+       QLine with internal whitespace change
        EOF
 
        git diff --color --color-moved --color-moved-ws=allow-indentation-change >actual.raw &&
@@ -1856,7 +1858,7 @@ test_expect_success 'compare whitespace delta across moved blocks' '
                <BOLD>diff --git a/text.txt b/text.txt<RESET>
                <BOLD>--- a/text.txt<RESET>
                <BOLD>+++ b/text.txt<RESET>
-               <CYAN>@@ -1,14 +1,14 @@<RESET>
+               <CYAN>@@ -1,15 +1,15 @@<RESET>
                <BOLD;MAGENTA>-QIndented<RESET>
                <BOLD;MAGENTA>-QText across<RESET>
                <BOLD;MAGENTA>-Qsome lines<RESET>
@@ -1871,6 +1873,7 @@ test_expect_success 'compare whitespace delta across moved blocks' '
                <BOLD;MAGENTA>-QQQthat has similar lines<RESET>
                <BOLD;MAGENTA>-QQQto previous blocks, but with different indent<RESET>
                <RED>-QQQYetQAnotherQoutlierQ<RESET>
+               <RED>-QLine with internal w h i t e s p a c e change<RESET>
                <BOLD;CYAN>+<RESET>QQ<BOLD;CYAN>Indented<RESET>
                <BOLD;CYAN>+<RESET>QQ<BOLD;CYAN>Text across<RESET>
                <BOLD;CYAN>+<RESET>QQ<BOLD;CYAN>some lines<RESET>
@@ -1885,6 +1888,7 @@ test_expect_success 'compare whitespace delta across moved blocks' '
                <BOLD;CYAN>+<RESET>QQ<BOLD;CYAN>that has similar lines<RESET>
                <BOLD;CYAN>+<RESET>QQ<BOLD;CYAN>to previous blocks, but with different indent<RESET>
                <GREEN>+<RESET>QQ<GREEN>YetQAnotherQoutlier<RESET>
+               <GREEN>+<RESET>Q<GREEN>Line with internal whitespace change<RESET>
        EOF
 
        test_cmp expected actual
@@ -1915,4 +1919,93 @@ test_expect_success 'compare whitespace delta incompatible with other space opti
        test_i18ngrep allow-indentation-change err
 '
 
+EMPTY=''
+test_expect_success 'compare mixed whitespace delta across moved blocks' '
+
+       git reset --hard &&
+       tr Q_ "\t " <<-EOF >text.txt &&
+       ${EMPTY}
+       ____too short without
+       ${EMPTY}
+       ___being grouped across blank line
+       ${EMPTY}
+       context
+       lines
+       to
+       anchor
+       ____Indented text to
+       _Q____be further indented by four spaces across
+       ____Qseveral lines
+       QQ____These two lines have had their
+       ____indentation reduced by four spaces
+       Qdifferent indentation change
+       ____too short
+       EOF
+
+       git add text.txt &&
+       git commit -m "add text.txt" &&
+
+       tr Q_ "\t " <<-EOF >text.txt &&
+       context
+       lines
+       to
+       anchor
+       QIndented text to
+       QQbe further indented by four spaces across
+       Q____several lines
+       ${EMPTY}
+       QQtoo short without
+       ${EMPTY}
+       Q_______being grouped across blank line
+       ${EMPTY}
+       Q_QThese two lines have had their
+       indentation reduced by four spaces
+       QQdifferent indentation change
+       __Qtoo short
+       EOF
+
+       git -c color.diff.whitespace="normal red" \
+               -c core.whitespace=space-before-tab \
+               diff --color --color-moved --ws-error-highlight=all \
+               --color-moved-ws=allow-indentation-change >actual.raw &&
+       grep -v "index" actual.raw | test_decode_color >actual &&
+
+       cat <<-\EOF >expected &&
+       <BOLD>diff --git a/text.txt b/text.txt<RESET>
+       <BOLD>--- a/text.txt<RESET>
+       <BOLD>+++ b/text.txt<RESET>
+       <CYAN>@@ -1,16 +1,16 @@<RESET>
+       <BOLD;MAGENTA>-<RESET>
+       <BOLD;MAGENTA>-<RESET><BOLD;MAGENTA>    too short without<RESET>
+       <BOLD;MAGENTA>-<RESET>
+       <BOLD;MAGENTA>-<RESET><BOLD;MAGENTA>   being grouped across blank line<RESET>
+       <BOLD;MAGENTA>-<RESET>
+        <RESET>context<RESET>
+        <RESET>lines<RESET>
+        <RESET>to<RESET>
+        <RESET>anchor<RESET>
+       <BOLD;MAGENTA>-<RESET><BOLD;MAGENTA>    Indented text to<RESET>
+       <BOLD;MAGENTA>-<RESET><BRED> <RESET>    <BOLD;MAGENTA>    be further indented by four spaces across<RESET>
+       <BOLD;MAGENTA>-<RESET><BRED>    <RESET> <BOLD;MAGENTA>several lines<RESET>
+       <BOLD;BLUE>-<RESET>             <BOLD;BLUE>    These two lines have had their<RESET>
+       <BOLD;BLUE>-<RESET><BOLD;BLUE>    indentation reduced by four spaces<RESET>
+       <BOLD;MAGENTA>-<RESET>  <BOLD;MAGENTA>different indentation change<RESET>
+       <RED>-<RESET><RED>    too short<RESET>
+       <BOLD;CYAN>+<RESET>     <BOLD;CYAN>Indented text to<RESET>
+       <BOLD;CYAN>+<RESET>             <BOLD;CYAN>be further indented by four spaces across<RESET>
+       <BOLD;CYAN>+<RESET>     <BOLD;CYAN>    several lines<RESET>
+       <BOLD;YELLOW>+<RESET>
+       <BOLD;YELLOW>+<RESET>           <BOLD;YELLOW>too short without<RESET>
+       <BOLD;YELLOW>+<RESET>
+       <BOLD;YELLOW>+<RESET>   <BOLD;YELLOW>       being grouped across blank line<RESET>
+       <BOLD;YELLOW>+<RESET>
+       <BOLD;CYAN>+<RESET>     <BRED> <RESET>  <BOLD;CYAN>These two lines have had their<RESET>
+       <BOLD;CYAN>+<RESET><BOLD;CYAN>indentation reduced by four spaces<RESET>
+       <BOLD;YELLOW>+<RESET>           <BOLD;YELLOW>different indentation change<RESET>
+       <GREEN>+<RESET><BRED>  <RESET>  <GREEN>too short<RESET>
+       EOF
+
+       test_cmp expected actual
+'
+
 test_done