[PATCH 6/6] revision: add parents after child for ^!

["René Scharfe" <l.s.r@web.de>]

gitrevisions(7) says: "A suffix '^' followed by an exclamation mark is
the same as giving commit '<rev>' and then all its parents prefixed with
'^' to exclude them (and their ancestors)."

handle_revision_arg_1() however adds the negated parents first.  This
leads to unexpected results with git diff and merge commits, as that
command expects the documented order.

Split up the handling of ^! by moving the actual addition of the parents
after the addition of the child.

Reported-by: Tim Jaacks <tim.jaacks@garz-fricke.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
---
 revision.c               | 13 ++++++-------
 t/t4038-diff-combined.sh | 10 ++++++++++
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/revision.c b/revision.c
index 5e756b76aa..8385127f1a 100644
--- a/revision.c
+++ b/revision.c
@@ -2107,6 +2107,7 @@ static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int fl
 	const char *arg = arg_;
 	int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
 	unsigned get_sha1_flags = GET_OID_RECORD_PATH;
+	struct commit *caret_bang_commit = NULL;

 	flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;

@@ -2135,14 +2136,9 @@ static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int fl
 	}
 	mark = strstr(arg, "^!");
 	if (mark && !mark[2]) {
-		struct commit *commit;
-
 		*mark = 0;
-		commit = get_commit(revs, arg);
-		if (commit)
-			add_parents(revs, commit->parents, arg,
-				    flags ^ (UNINTERESTING | BOTTOM));
-		else
+		caret_bang_commit = get_commit(revs, arg);
+		if (!caret_bang_commit)
 			*mark = '^';
 	}
 	mark = strstr(arg, "^-");
@@ -2179,6 +2175,9 @@ static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int fl
 	add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
 	add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
 	free(oc.path);
+	if (caret_bang_commit)
+		add_parents(revs, caret_bang_commit->parents, arg,
+			    flags ^ (UNINTERESTING | BOTTOM));
 	return 0;
 }

diff --git a/t/t4038-diff-combined.sh b/t/t4038-diff-combined.sh
index 9a292bac70..2ce26e585c 100755
--- a/t/t4038-diff-combined.sh
+++ b/t/t4038-diff-combined.sh
@@ -80,11 +80,21 @@ test_expect_success 'check combined output (1)' '
 	verify_helper sidewithone
 '

+test_expect_success 'check combined output (1) with git diff <rev>^!' '
+	git diff sidewithone^! -- >sidewithone &&
+	verify_helper sidewithone
+'
+
 test_expect_success 'check combined output (2)' '
 	git show sidesansone -- >sidesansone &&
 	verify_helper sidesansone
 '

+test_expect_success 'check combined output (2) with git diff <rev>^!' '
+	git diff sidesansone^! -- >sidesansone &&
+	verify_helper sidesansone
+'
+
 test_expect_success 'diagnose truncated file' '
 	>file &&
 	git add file &&
--
2.37.3