[PATCH v5 2/3] range-diff/format-patch: handle commit ranges other than A..B

From: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date: Feb 4, 2021, 23:29 UTC
Message-ID: <04b5d75adbc3d80e9f9cf9cd380294949e7c68e8.1612481392.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.841.v5.git.1612481392.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

In the `SPECIFYING RANGES` section of gitrevisions[7], two ways are described to specify commit ranges that `range-diff` does not yet accept: "<commit>^!" and "<commit>^-<n>".

Let's accept them, by parsing them via the revision machinery and looking for at least one interesting and one uninteresting revision in the resulting `pending` array.

This also finally lets us reject arguments that _do_ contain `..` but are not actually ranges, e.g. `HEAD^{/do.. match this}`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 range-diff.c          | 24 +++++++++++++++++++++++-
 range-diff.h          |  4 +---
 t/t3206-range-diff.sh | 13 +++++++++++++
 3 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/range-diff.c b/range-diff.c
index 9b93e08e8407..c307bca9de23 100644
--- a/range-diff.c
+++ b/range-diff.c
@@ -11,6 +11,7 @@
 #include "pretty.h"
 #include "userdiff.h"
 #include "apply.h"
+#include "revision.h"
 
 struct patch_util {
 	/* For the search for an exact match */
@@ -567,5 +568,26 @@ int show_range_diff(const char *range1, const char *range2,
 
 int is_range_diff_range(const char *arg)
 {
-	return !!strstr(arg, "..");
+	char *copy = xstrdup(arg); /* setup_revisions() modifies it */
+	const char *argv[] = { "", copy, "--", NULL };
+	int i, positive = 0, negative = 0;
+	struct rev_info revs;
+
+	init_revisions(&revs, NULL);
+	if (setup_revisions(3, argv, &revs, 0) == 1)
+		for (i = 0; i < revs.pending.nr; i++) {
+			struct object *obj = revs.pending.objects[i].item;
+
+			if (obj->flags & UNINTERESTING)
+				negative++;
+			else
+				positive++;
+			if (obj->type == OBJ_COMMIT)
+				clear_commit_marks((struct commit *)obj,
+						   ALL_REV_FLAGS);
+		}
+
+	free(copy);
+	object_array_clear(&revs.pending);
+	return negative > 0 && positive > 0;
 }
diff --git a/range-diff.h b/range-diff.h
index c17dbc2e75a8..4abd70c40fed 100644
--- a/range-diff.h
+++ b/range-diff.h
@@ -18,9 +18,7 @@ int show_range_diff(const char *range1, const char *range2,
 
 /*
  * 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.
+ * range-diff`, e.g. A..B.
  */
 int is_range_diff_range(const char *arg);
 
diff --git a/t/t3206-range-diff.sh b/t/t3206-range-diff.sh
index 6eb344be0312..45f21ee215d7 100755
--- a/t/t3206-range-diff.sh
+++ b/t/t3206-range-diff.sh
@@ -150,6 +150,19 @@ test_expect_success 'simple A B C (unmodified)' '
 	test_cmp expect actual
 '
 
+test_expect_success 'A^! and A^-<n> (unmodified)' '
+	git range-diff --no-color topic^! unmodified^-1 >actual &&
+	cat >expect <<-EOF &&
+	1:  $(test_oid t4) = 1:  $(test_oid u4) s/12/B/
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'A^{/..} is not mistaken for a range' '
+	test_must_fail git range-diff topic^.. topic^{/..} 2>error &&
+	test_i18ngrep "not a commit rang" error
+'
+
 test_expect_success 'trivial reordering' '
 	git range-diff --no-color master topic reordered >actual &&
 	cat >expect <<-EOF &&

-- 
gitgitgadget