[PATCH v3 0/3] Range diff with ranges lacking dotdot

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

In
https://lore.kernel.org/git/20200306091933.mx2jmurmdnsjua4b@pengutronix.de/,
it was reported that git range-diff does not handle commit ranges like
rev^!. This patch series fixes that.

Changes since v2:

 * Move the helper function from revision.c to range-diff.c and rename it.
 * Use a regex to make it easier to understand what we're trying to match.
 * Fix the documentation that claimed that we used git merge-base internally
   when git range-diff parses ...-style arguments, which is not the case.

Changes since v1:

 * In addition to git range-diff, git format-patch --range-diff gets the
   same improvement.
 * The comment talking about ^@ was removed.
 * The parsing was made a bit safer (e.g. catching ! by its own as an
   invalid range).

Johannes Schindelin (3):
  range-diff/format-patch: refactor check for commit range
  range-diff/format-patch: handle commit ranges other than A..B
  range-diff(docs): explain how to specify commit ranges

 Documentation/git-range-diff.txt | 12 ++++++++++++
 builtin/log.c                    |  2 +-
 builtin/range-diff.c             |  9 +++++----
 range-diff.c                     | 17 +++++++++++++++++
 range-diff.h                     |  8 ++++++++
 t/t3206-range-diff.sh            |  8 ++++++++
 6 files changed, 51 insertions(+), 5 deletions(-)


base-commit: 71ca53e8125e36efbda17293c50027d31681a41f
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-841%2Fdscho%2Frange-diff-with-ranges-lacking-dotdot-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-841/dscho/range-diff-with-ranges-lacking-dotdot-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/841

Range-diff vs v2:

 1:  3f21e10f919 ! 1:  b98fa94b870 range-diff/format-patch: refactor check for commit range
     @@ builtin/log.c: static void infer_range_diff_ranges(struct strbuf *r1,
       {
       	const char *head_oid = oid_to_hex(&head->object.oid);
      -	int prev_is_range = !!strstr(prev, "..");
     -+	int prev_is_range = specifies_commit_range(prev);
     ++	int prev_is_range = is_range_diff_range(prev);
       
       	if (prev_is_range)
       		strbuf_addstr(r1, prev);
     @@ builtin/range-diff.c: int cmd_range_diff(int argc, const char **argv, const char
       	if (argc == 2) {
      -		if (!strstr(argv[0], ".."))
      -			die(_("no .. in range: '%s'"), argv[0]);
     -+		if (!specifies_commit_range(argv[0]))
     ++		if (!is_range_diff_range(argv[0]))
      +			die(_("not a commit range: '%s'"), argv[0]);
       		strbuf_addstr(&range1, argv[0]);
       
      -		if (!strstr(argv[1], ".."))
      -			die(_("no .. in range: '%s'"), argv[1]);
     -+		if (!specifies_commit_range(argv[1]))
     ++		if (!is_range_diff_range(argv[1]))
      +			die(_("not a commit range: '%s'"), argv[1]);
       		strbuf_addstr(&range2, argv[1]);
       	} else if (argc == 3) {
       		strbuf_addf(&range1, "%s..%s", argv[0], argv[1]);
      
     - ## revision.c ##
     -@@ revision.c: void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
     - 	fputs(mark, stdout);
     - 	putchar(' ');
     + ## range-diff.c ##
     +@@ range-diff.c: int show_range_diff(const char *range1, const char *range2,
     + 
     + 	return res;
       }
      +
     -+int specifies_commit_range(const char *range)
     ++int is_range_diff_range(const char *arg)
      +{
     -+	return !!strstr(range, "..");
     ++	return !!strstr(arg, "..");
      +}
      
     - ## revision.h ##
     -@@ revision.h: int rewrite_parents(struct rev_info *revs,
     -  */
     - struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit);
     + ## range-diff.h ##
     +@@ range-diff.h: int show_range_diff(const char *range1, const char *range2,
     + 		    const struct diff_options *diffopt,
     + 		    const struct strvec *other_arg);
       
      +/*
     -+ * Determine whether the given argument defines a commit range, e.g. A..B.
     -+ * Note that this only validates the format but does _not_ parse it, i.e.
     -+ * it does _not_ look up the specified commits in the local repository.
     ++ * Determine whether the given argument is usable as a range argument of `git
     ++ * range-diff`, e.g. A..B. Note that this only validates the format but does
     ++ * _not_ parse it, i.e. it does _not_ look up the specified commits in the
     ++ * local repository.
      + */
     -+int specifies_commit_range(const char *range);
     ++int is_range_diff_range(const char *arg);
      +
       #endif
 2:  2c2744333ec ! 2:  0880ca587e6 range-diff/format-patch: handle commit ranges other than A..B
     @@ Commit message
      
          Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
      
     - ## revision.c ##
     -@@ revision.c: void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
     + ## range-diff.c ##
     +@@ range-diff.c: int show_range_diff(const char *range1, const char *range2,
       
     - int specifies_commit_range(const char *range)
     + int is_range_diff_range(const char *arg)
       {
     --	return !!strstr(range, "..");
     -+	size_t i;
     -+	char c;
     +-	return !!strstr(arg, "..");
     ++	static regex_t *regex;
      +
     -+	if (strstr(range, ".."))
     ++	if (strstr(arg, ".."))
      +		return 1;
      +
     -+	i = strlen(range);
     -+	c = i > 2 ? range[--i] : 0;
     -+	if (c == '!')
     -+		i--; /* might be ...^! */
     -+	else if (isdigit(c)) {
     -+		/* handle ...^-<n> */
     -+		while (i > 2 && isdigit(range[--i]))
     -+			; /* keep trimming trailing digits */
     -+		if (i < 2 || range[i--] != '-')
     -+			return 0;
     -+	} else
     -+		return 0;
     ++	/* match `<rev>^!` and `<rev>^-<n>` */
     ++	if (!regex) {
     ++		regex = xmalloc(sizeof(*regex));
     ++		if (regcomp(regex, "\\^(!|-[0-9]*)$", REG_EXTENDED) < 0)
     ++			BUG("could not compile range-diff regex");
     ++	}
      +
     -+	/* Before the `!` or the `-<n>`, we expect `<rev>^` */
     -+	return i > 0 && range[i] == '^';
     ++	return !regexec(regex, arg, 0, NULL, 0);
       }
      
       ## t/t3206-range-diff.sh ##
 3:  4f5e5acd954 ! 3:  5ab9321a34c range-diff(docs): explain how to specify commit ranges
     @@ Documentation/git-range-diff.txt: Finally, the list of matching commits is shown
      +
      +- `<rev1>...<rev2>`. This resembles the symmetric ranges mentioned in
      +  the `SPECIFYING RANGES` section of linkgit:gitrevisions[7], and is
     -+  equivalent to `<base>..<rev1> <base>..<rev2>` where `<base>` is the
     -+  merge base as obtained via `git merge-base <rev1> <rev2>`.
     ++  equivalent to `<rev2>..<rev1> <rev1>..<rev2>`.
      +
      +- `<base> <rev1> <rev2>`: This is equivalent to `<base>..<rev1>
      +  <base>..<rev2>`.

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