Before this patch "git merge-base" accepted only 2 arguments, so
only merge bases between 2 references could be computed.
The purpose of this patch is to make "git merge-base" accept more
than 2 arguments, so that the merge bases between the first given
reference and all the other references can be computed.
This is easily implemented because the "get_merge_bases_many"
function in "commit.c" already implements the needed computation.
Signed-off-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
---
Documentation/git-merge-base.txt | 27 +++++++++++++++-------
builtin-merge-base.c | 45 ++++++++++++++++++++++++++-----------
commit.h | 2 +
3 files changed, 51 insertions(+), 23 deletions(-)
Hi,
No tests yet, but the following changes since the first version:
- added documentation
- don't use static variables anymore
Thanks for your comments,
Christian.
diff --git a/Documentation/git-merge-base.txt b/Documentation/git-merge-base.txt
index 1a7ecbf..463c230 100644
--- a/Documentation/git-merge-base.txt
+++ b/Documentation/git-merge-base.txt
@@ -8,26 +8,35 @@ git-merge-base - Find as good common ancestors as possible for a merge
SYNOPSIS
--------
-'git merge-base' [--all] <commit> <commit>
+'git merge-base' [--all] <commit> <commit>...
DESCRIPTION
-----------
-'git-merge-base' finds as good a common ancestor as possible between
-the two commits. That is, given two commits A and B, `git merge-base A
-B` will output a commit which is reachable from both A and B through
-the parent relationship.
+'git-merge-base' finds as good common ancestors as possible between
+the first commit and the other commits. The default behavior is to
+output only one as good as possible common ancestor, called a merge
+base.
+
+For example, given two commits A and B, `git merge-base A B` will
+output a commit which is reachable from both A and B through the
+parent relationship.
+
+Given three commits A, B and C, `git merge-base A B C` will output a
+commit which is reachable through the parent relationship from both A
+and B, or from both A and C.
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...
-
OPTIONS
-------
--all::
- Output all common ancestors for the two commits instead of
- just one.
+ Output all merge bases for the commits instead of just one. No
+ merge bases in the output should be an ancestor of another
+ merge base in the output. Each common ancestor of the first
+ commit and any of the other commits passed as arguments,
+ should be an ancestor of one of the merge bases in the output.
Author
------
diff --git a/builtin-merge-base.c b/builtin-merge-base.c
index 1cb2925..f2c9756 100644
--- a/builtin-merge-base.c
+++ b/builtin-merge-base.c
@@ -2,9 +2,11 @@
#include "cache.h"
#include "commit.h"
-static int show_merge_base(struct commit *rev1, struct commit *rev2, int show_all)
+static int show_merge_base(struct commit *rev1, int prev2_nr,
+ struct commit **prev2, int show_all)
{
- struct commit_list *result = get_merge_bases(rev1, rev2, 0);
+ struct commit_list *result = get_merge_bases_many(rev1, prev2_nr,
+ prev2, 0);
if (!result)
return 1;
@@ -20,12 +22,20 @@ static int show_merge_base(struct commit *rev1, struct commit *rev2, int show_al
}
static const char merge_base_usage[] =
-"git merge-base [--all] <commit-id> <commit-id>";
+"git merge-base [--all] <commit-id> <commit-id>...";
+
+static struct commit *get_commit_reference(const char *arg)
+{
+ unsigned char revkey[20];
+ if (get_sha1(arg, revkey))
+ die("Not a valid object name %s", arg);
+ return lookup_commit_reference(revkey);
+}
int cmd_merge_base(int argc, const char **argv, const char *prefix)
{
- struct commit *rev1, *rev2;
- unsigned char rev1key[20], rev2key[20];
+ struct commit *rev1, **prev2 = NULL;
+ size_t prev2_nr = 0, prev2_alloc = 0;
int show_all = 0;
git_config(git_default_config, NULL);
@@ -38,15 +48,22 @@ int cmd_merge_base(int argc, const char **argv, const char *prefix)
usage(merge_base_usage);
argc--; argv++;
}
- if (argc != 3)
+ if (argc < 3)
usage(merge_base_usage);
- if (get_sha1(argv[1], rev1key))
- die("Not a valid object name %s", argv[1]);
- if (get_sha1(argv[2], rev2key))
- die("Not a valid object name %s", argv[2]);
- rev1 = lookup_commit_reference(rev1key);
- rev2 = lookup_commit_reference(rev2key);
- if (!rev1 || !rev2)
+
+ rev1 = get_commit_reference(argv[1]);
+ if (!rev1)
return 1;
- return show_merge_base(rev1, rev2, show_all);
+ argc--; argv++;
+
+ do {
+ struct commit *rev2 = get_commit_reference(argv[1]);
+ if (!rev2)
+ return 1;
+ ALLOC_GROW(prev2, prev2_nr + 1, prev2_alloc);
+ prev2[prev2_nr++] = rev2;
+ argc--; argv++;
+ } while (argc > 1);
+
+ return show_merge_base(rev1, prev2_nr, prev2, show_all);
}
diff --git a/commit.h b/commit.h
index 77de962..4829a5c 100644
--- a/commit.h
+++ b/commit.h
@@ -121,6 +121,8 @@ int read_graft_file(const char *graft_file);
struct commit_graft *lookup_commit_graft(const unsigned char *sha1);
extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
+extern struct commit_list *get_merge_bases_many(struct commit *one,
+ int n, struct commit **twos, int cleanup);
extern struct commit_list *get_octopus_merge_bases(struct commit_list *in);
extern int register_shallow(const unsigned char *sha1);
--
1.6.0.rc0.43.g00eb.dirty
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
