The usage string for this option is:
git replace [-f] --graft <commit> [<parent>...]
First we create a new commit that is the same as <commit>
except that its parents are [<parents>...]
Then we create a replace ref that replace <commit> with
the commit we just created.
With this new option, it should be straightforward to
convert grafts to replace refs, with something like:
cat .git/info/grafts | while read line
do git replace --graft $line; done
Signed-off-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
---
builtin/replace.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 78 insertions(+), 1 deletion(-)
diff --git a/builtin/replace.c b/builtin/replace.c
index 1bb491d..4b3705d 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -17,6 +17,7 @@
static const char * const git_replace_usage[] = {
N_("git replace [-f] <object> <replacement>"),
N_("git replace [-f] --edit <object>"),
+ N_("git replace [-f] --graft <commit> [<parent>...]"),
N_("git replace -d <object>..."),
N_("git replace [--format=<format>] [-l [<pattern>]]"),
NULL
@@ -294,6 +295,71 @@ static int edit_and_replace(const char *object_ref, int force)
return replace_object_sha1(object_ref, old, "replacement", new, force);
}
+static int read_sha1_commit(const unsigned char *sha1, struct strbuf *dst)
+{
+ void *buf;
+ enum object_type type;
+ unsigned long size;
+
+ buf = read_sha1_file(sha1, &type, &size);
+ if (!buf)
+ return error(_("cannot read object %s"), sha1_to_hex(sha1));
+ if (type != OBJ_COMMIT) {
+ free(buf);
+ return error(_("object %s is not a commit"), sha1_to_hex(sha1));
+ }
+ strbuf_attach(dst, buf, size, size + 1);
+ return 0;
+}
+
+static int create_graft(int argc, const char **argv, int force)
+{
+ unsigned char old[20], new[20];
+ const char *old_ref = argv[0];
+ struct strbuf buf = STRBUF_INIT;
+ struct strbuf new_parents = STRBUF_INIT;
+ const char *parent_start, *parent_end;
+ int i;
+
+ if (get_sha1(old_ref, old) < 0)
+ die(_("Not a valid object name: '%s'"), old_ref);
+ lookup_commit_or_die(old, old_ref);
+ if (read_sha1_commit(old, &buf))
+ die(_("Invalid commit: '%s'"), old_ref);
+
+ /* find existing parents */
+ parent_start = buf.buf;
+ parent_start += 46; /* "tree " + "hex sha1" + "\n" */
+ parent_end = parent_start;
+
+ while (starts_with(parent_end, "parent "))
+ parent_end += 48; /* "parent " + "hex sha1" + "\n" */
+
+ /* prepare new parents */
+ for (i = 1; i < argc; i++) {
+ unsigned char sha1[20];
+ if (get_sha1(argv[i], sha1) < 0)
+ die(_("Not a valid object name: '%s'"), argv[i]);
+ lookup_commit_or_die(sha1, argv[i]);
+ strbuf_addf(&new_parents, "parent %s\n", sha1_to_hex(sha1));
+ }
+
+ /* replace existing parents with new ones */
+ strbuf_splice(&buf, parent_start - buf.buf, parent_end - parent_start,
+ new_parents.buf, new_parents.len);
+
+ if (write_sha1_file(buf.buf, buf.len, commit_type, new))
+ die(_("could not write replacement commit for: '%s'"), old_ref);
+
+ strbuf_release(&new_parents);
+ strbuf_release(&buf);
+
+ if (!hashcmp(old, new))
+ return error("new commit is the same as the old one: '%s'", sha1_to_hex(old));
+
+ return replace_object_sha1(old_ref, old, "replacement", new, force);
+}
+
int cmd_replace(int argc, const char **argv, const char *prefix)
{
int force = 0;
@@ -303,12 +369,14 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
MODE_LIST,
MODE_DELETE,
MODE_EDIT,
+ MODE_GRAFT,
MODE_REPLACE
} cmdmode = MODE_UNSPECIFIED;
struct option options[] = {
OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
+ OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
OPT_BOOL('f', "force", &force, N_("replace the ref if it exists")),
OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
OPT_END()
@@ -325,7 +393,10 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
usage_msg_opt("--format cannot be used when not listing",
git_replace_usage, options);
- if (force && cmdmode != MODE_REPLACE && cmdmode != MODE_EDIT)
+ if (force &&
+ cmdmode != MODE_REPLACE &&
+ cmdmode != MODE_EDIT &&
+ cmdmode != MODE_GRAFT)
usage_msg_opt("-f only makes sense when writing a replacement",
git_replace_usage, options);
@@ -348,6 +419,12 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
git_replace_usage, options);
return edit_and_replace(argv[0], force);
+ case MODE_GRAFT:
+ if (argc < 1)
+ usage_msg_opt("-g needs at least one argument",
+ git_replace_usage, options);
+ return create_graft(argc, argv, force);
+
case MODE_LIST:
if (argc > 1)
usage_msg_opt("only one pattern can be given with -l",
--
1.9.rc0.17.g651113e
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