A new option drives underlying in_merge_bases() function to
determine if a commit is reachable from any of the other commits
supplied on the command line.
Signed-off-by: Junio C Hamano <junkio@xxxxxxx>
---
Documentation/git-merge-base.txt | 13 +++++++++++-
merge-base.c | 39 ++++++++++++++++++++++++++++++++++++-
2 files changed, 49 insertions(+), 3 deletions(-)
diff --git a/Documentation/git-merge-base.txt b/Documentation/git-merge-base.txt
index 6099be2..7d4d027 100644
--- a/Documentation/git-merge-base.txt
+++ b/Documentation/git-merge-base.txt
@@ -8,7 +8,9 @@ git-merge-base - Finds as good a common ancestor as possible for a merge
SYNOPSIS
--------
+[verse]
'git-merge-base' [--all] <commit> <commit>
+'git-merge-base' --check-ancestry <commit> <commit>...
DESCRIPTION
-----------
@@ -21,7 +23,10 @@ the parent relationship.
Given a selection of equally good common ancestors it should not be
relied on to decide in any particular way.
-The "git-merge-base" algorithm is still in flux - use the source...
+With `--check-ancestry` option, the command can be used to check
+if the first commit is an ancestor of any of the remaining
+commits.
+
OPTIONS
-------
@@ -29,6 +34,12 @@ OPTIONS
Output all common ancestors for the two commits instead of
just one.
+--check-ancestry::
+
+ Check if the first commit is an ancestor of any of the
+ remaining commits. If so, exit with status 0, otherwise
+ non-zero.
+
Author
------
Written by Linus Torvalds <torvalds@xxxxxxxx>
diff --git a/merge-base.c b/merge-base.c
index 385f4ba..bc478eb 100644
--- a/merge-base.c
+++ b/merge-base.c
@@ -2,6 +2,8 @@
#include "commit.h"
static int show_all;
+static const char merge_base_usage[] =
+"git-merge-base [--all] <commit> <commit> | --check-ancestry <commit> <commit>...";
static int merge_base(struct commit *rev1, struct commit *rev2)
{
@@ -20,13 +22,37 @@ static int merge_base(struct commit *rev1, struct commit *rev2)
return 0;
}
-static const char merge_base_usage[] =
-"git-merge-base [--all] <commit-id> <commit-id>";
+static int check_ancestry(int argc, char **argv)
+{
+ struct commit *one, *two, **reference;
+ unsigned char sha1[20];
+ int i;
+
+ if (argc < 2)
+ usage(merge_base_usage);
+ if (get_sha1(argv[0], sha1))
+ die("Not a valid object name %s", argv[0]);
+ one = lookup_commit_reference(sha1);
+ if (!one)
+ return 1;
+
+ reference = xcalloc(argc - 1, sizeof(struct commit *));
+ for (i = 1; i < argc; i++) {
+ if (get_sha1(argv[i], sha1))
+ die("Not a valid object name %s", argv[i]);
+ two = lookup_commit_reference(sha1);
+ if (!two)
+ return 1;
+ reference[i - 1] = two;
+ }
+ return !!in_merge_bases(one, reference, argc - 1);
+}
int main(int argc, char **argv)
{
struct commit *rev1, *rev2;
unsigned char rev1key[20], rev2key[20];
+ int check = 0;
setup_git_directory();
git_config(git_default_config);
@@ -35,10 +61,19 @@ int main(int argc, char **argv)
char *arg = argv[1];
if (!strcmp(arg, "-a") || !strcmp(arg, "--all"))
show_all = 1;
+ else if (!strcmp(arg, "-c") || !strcmp(arg, "--check-ancestry"))
+ check = 1;
else
usage(merge_base_usage);
argc--; argv++;
}
+
+ if (check) {
+ if (show_all)
+ die("--all and --check-ancestry are mutually incompatible");
+ return check_ancestry(argc - 1, argv + 1);
+ }
+
if (argc != 3)
usage(merge_base_usage);
if (get_sha1(argv[1], rev1key))
--
1.4.4.4.g564d
-
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