Merge branch 'kg/external-diff-save-env'

The code to drive GIT_EXTERNAL_DIFF command relied on the string
returned from getenv() to be non-volatile, which is not true, that
has been corrected.

* kg/external-diff-save-env:
diff: ensure correct lifetime of external_diff_cmd

diff --combined diff.c
index 1b5f27636061feb0ecf273f257c5e080c5ff7481,5634992bbc374442d68ee8b9fb3f881bd417b2b1..b96b7a4fc61fcdd63dee0a890eb3b40be5d0414b
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -291,7 -291,7 +291,7 @@@ static int parse_color_moved(const cha
                return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
  }
  
 -static int parse_color_moved_ws(const char *arg)
 +static unsigned parse_color_moved_ws(const char *arg)
  {
        int ret = 0;
        struct string_list l = STRING_LIST_INIT_DUP;
@@@ -312,19 -312,15 +312,19 @@@
                        ret |= XDF_IGNORE_WHITESPACE;
                else if (!strcmp(sb.buf, "allow-indentation-change"))
                        ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
 -              else
 -                      error(_("ignoring unknown color-moved-ws mode '%s'"), sb.buf);
 +              else {
 +                      ret |= COLOR_MOVED_WS_ERROR;
 +                      error(_("unknown color-moved-ws mode '%s', possible values are 'ignore-space-change', 'ignore-space-at-eol', 'ignore-all-space', 'allow-indentation-change'"), sb.buf);
 +              }
  
                strbuf_release(&sb);
        }
  
        if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
 -          (ret & XDF_WHITESPACE_FLAGS))
 -              die(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
 +          (ret & XDF_WHITESPACE_FLAGS)) {
 +              error(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
 +              ret |= COLOR_MOVED_WS_ERROR;
 +      }
  
        string_list_clear(&l, 0);
  
@@@ -345,8 -341,8 +345,8 @@@ int git_diff_ui_config(const char *var
                return 0;
        }
        if (!strcmp(var, "diff.colormovedws")) {
 -              int cm = parse_color_moved_ws(value);
 -              if (cm < 0)
 +              unsigned cm = parse_color_moved_ws(value);
 +              if (cm & COLOR_MOVED_WS_ERROR)
                        return -1;
                diff_color_moved_ws_default = cm;
                return 0;
@@@ -493,7 -489,7 +493,7 @@@ 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;
@@@ -1641,8 -1637,7 +1641,8 @@@ static void emit_hunk_header(struct emi
        strbuf_release(&msgbuf);
  }
  
 -static struct diff_tempfile *claim_diff_tempfile(void) {
 +static struct diff_tempfile *claim_diff_tempfile(void)
 +{
        int i;
        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
                if (!diff_temp[i].name)
@@@ -3318,14 -3313,14 +3318,14 @@@ void diff_set_mnemonic_prefix(struct di
                options->b_prefix = b;
  }
  
 -struct userdiff_driver *get_textconv(struct index_state *istate,
 +struct userdiff_driver *get_textconv(struct repository *r,
                                     struct diff_filespec *one)
  {
        if (!DIFF_FILE_VALID(one))
                return NULL;
  
 -      diff_filespec_load_driver(one, istate);
 -      return userdiff_get_textconv(one->driver);
 +      diff_filespec_load_driver(one, r->index);
 +      return userdiff_get_textconv(r, one->driver);
  }
  
  static void builtin_diff(const char *name_a,
@@@ -3374,8 -3369,8 +3374,8 @@@
        }
  
        if (o->flags.allow_textconv) {
 -              textconv_one = get_textconv(o->repo->index, one);
 -              textconv_two = get_textconv(o->repo->index, two);
 +              textconv_one = get_textconv(o->repo, one);
 +              textconv_two = get_textconv(o->repo, two);
        }
  
        /* Never use a non-valid filename anywhere if at all possible */
@@@ -4824,8 -4819,7 +4824,8 @@@ static int parse_diff_filter_opt(const 
        return 0;
  }
  
 -static void enable_patch_output(int *fmt) {
 +static void enable_patch_output(int *fmt)
 +{
        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
        *fmt |= DIFF_FORMAT_PATCH;
  }
@@@ -5040,13 -5034,10 +5040,13 @@@ int diff_opt_parse(struct diff_options 
        else if (skip_prefix(arg, "--color-moved=", &arg)) {
                int cm = parse_color_moved(arg);
                if (cm < 0)
 -                      die("bad --color-moved argument: %s", arg);
 +                      return error("bad --color-moved argument: %s", arg);
                options->color_moved = cm;
        } else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
 -              options->color_moved_ws_handling = parse_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;
@@@ -6443,7 -6434,7 +6443,7 @@@ int textconv_object(struct repository *
  
        df = alloc_filespec(path);
        fill_filespec(df, oid, oid_valid, mode);
 -      textconv = get_textconv(r->index, df);
 +      textconv = get_textconv(r, df);
        if (!textconv) {
                free_filespec(df);
                return 0;