HEAD and MERGE_HEAD (among other branch tips) should never hold a
tag. That can only be caused by broken tools and is cumbersome to fix
by an end user with:
$ git update-ref HEAD $(git rev-parse HEAD^{commit})
which may look like a magic to a new person.
Be easy, warn users (so broken tools can be fixed) and move on.
Be robust, if the given SHA-1 cannot be resolved to a commit object,
die (therefore return value is always valid).
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
builtin/commit.c | 25 ++++++++++++-------------
builtin/fmt-merge-msg.c | 2 +-
builtin/merge.c | 19 +++++++++++--------
commit.c | 12 ++++++++++++
commit.h | 1 +
http-push.c | 8 ++++----
revision.c | 6 ++++--
7 files changed, 45 insertions(+), 28 deletions(-)
diff --git a/builtin/commit.c b/builtin/commit.c
index cb73857..f78b449 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -63,6 +63,7 @@ N_("The previous cherry-pick is now empty, possibly due to conflict resolution.\
"Otherwise, please use 'git reset'\n");
static unsigned char head_sha1[20];
+static struct commit *head_commit;
static const char *use_message_buffer;
static const char commit_editmsg[] = "COMMIT_EDITMSG";
@@ -518,11 +519,8 @@ static int run_status(FILE *fp, const char *index_file, const char *prefix, int
return s->commitable;
}
-static int is_a_merge(const unsigned char *sha1)
+static int is_a_merge(struct commit *commit)
{
- struct commit *commit = lookup_commit(sha1);
- if (!commit || parse_commit(commit))
- die(_("could not parse HEAD commit"));
return !!(commit->parents && commit->parents->next);
}
@@ -848,7 +846,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
* empty due to conflict resolution, which the user should okay.
*/
if (!commitable && whence != FROM_MERGE && !allow_empty &&
- !(amend && is_a_merge(head_sha1))) {
+ !(amend && is_a_merge(head_commit))) {
run_status(stdout, index_file, prefix, 0, s);
if (amend)
fputs(_(empty_amend_advice), stderr);
@@ -1028,6 +1026,9 @@ static int parse_and_validate_options(int argc, const char *argv[],
if (get_sha1("HEAD", head_sha1))
initial_commit = 1;
+ else
+ head_commit = lookup_expect_commit(head_sha1, "HEAD");
+
/* Sanity check options */
if (amend && initial_commit)
@@ -1421,23 +1422,20 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
reflog_msg = "commit (initial)";
} else if (amend) {
struct commit_list *c;
- struct commit *commit;
if (!reflog_msg)
reflog_msg = "commit (amend)";
- commit = lookup_commit(head_sha1);
- if (!commit || parse_commit(commit))
- die(_("could not parse HEAD commit"));
- for (c = commit->parents; c; c = c->next)
+ for (c = head_commit->parents; c; c = c->next)
pptr = &commit_list_insert(c->item, pptr)->next;
} else if (whence == FROM_MERGE) {
struct strbuf m = STRBUF_INIT;
+ struct commit *commit;
FILE *fp;
if (!reflog_msg)
reflog_msg = "commit (merge)";
- pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
+ pptr = &commit_list_insert(head_commit, pptr)->next;
fp = fopen(git_path("MERGE_HEAD"), "r");
if (fp == NULL)
die_errno(_("could not open '%s' for reading"),
@@ -1446,7 +1444,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
unsigned char sha1[20];
if (get_sha1_hex(m.buf, sha1) < 0)
die(_("Corrupt MERGE_HEAD file (%s)"), m.buf);
- pptr = &commit_list_insert(lookup_commit(sha1), pptr)->next;
+ commit = lookup_expect_commit(sha1, "MERGE_HEAD");
+ pptr = &commit_list_insert(commit, pptr)->next;
}
fclose(fp);
strbuf_release(&m);
@@ -1463,7 +1462,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
reflog_msg = (whence == FROM_CHERRY_PICK)
? "commit (cherry-pick)"
: "commit";
- pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
+ pptr = &commit_list_insert(head_commit, pptr)->next;
}
/* Finally, get the commit message */
diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 7581632..1a31b64 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -293,7 +293,7 @@ static int do_fmt_merge_msg(int merge_title, struct strbuf *in,
struct commit *head;
struct rev_info rev;
- head = lookup_commit(head_sha1);
+ head = lookup_expect_commit(head_sha1, "HEAD");
init_revisions(&rev, NULL);
rev.commit_format = CMIT_FMT_ONELINE;
rev.ignore_merges = 1;
diff --git a/builtin/merge.c b/builtin/merge.c
index 325891e..22e98e8 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -51,6 +51,7 @@ static int allow_trivial = 1, have_message;
static struct strbuf merge_msg;
static struct commit_list *remoteheads;
static unsigned char head[20], stash[20];
+static struct commit* head_commit;
static struct strategy **use_strategies;
static size_t use_strategies_nr, use_strategies_alloc;
static const char **xopts;
@@ -326,7 +327,7 @@ static void squash_message(void)
rev.ignore_merges = 1;
rev.commit_format = CMIT_FMT_MEDIUM;
- commit = lookup_commit(head);
+ commit = head_commit;
commit->object.flags |= UNINTERESTING;
add_pending_object(&rev, &commit->object, NULL);
@@ -709,7 +710,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
commit_list_insert(j->item, &reversed);
index_fd = hold_locked_index(lock, 1);
- clean = merge_recursive(&o, lookup_commit(head),
+ clean = merge_recursive(&o, head_commit,
remoteheads->item, reversed, &result);
if (active_cache_changed &&
(write_cache(index_fd, active_cache, active_nr) ||
@@ -867,7 +868,7 @@ static int merge_trivial(void)
write_tree_trivial(result_tree);
printf(_("Wonderful.\n"));
- parent->item = lookup_commit(head);
+ parent->item = head_commit;
parent->next = xmalloc(sizeof(*parent->next));
parent->next->item = remoteheads->item;
parent->next->next = NULL;
@@ -889,12 +890,12 @@ static int finish_automerge(struct commit_list *common,
free_commit_list(common);
if (allow_fast_forward) {
parents = remoteheads;
- commit_list_insert(lookup_commit(head), &parents);
+ commit_list_insert(head_commit, &parents);
parents = reduce_heads(parents);
} else {
struct commit_list **pptr = &parents;
- pptr = &commit_list_insert(lookup_commit(head),
+ pptr = &commit_list_insert(head_commit,
pptr)->next;
for (j = remoteheads; j; j = j->next)
pptr = &commit_list_insert(j->item, pptr)->next;
@@ -1030,6 +1031,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
branch += 11;
if (is_null_sha1(head))
head_invalid = 1;
+ else
+ head_commit = lookup_expect_commit(head, "HEAD");
git_config(git_merge_config, NULL);
@@ -1203,11 +1206,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
}
if (!remoteheads->next)
- common = get_merge_bases(lookup_commit(head),
+ common = get_merge_bases(head_commit,
remoteheads->item, 1);
else {
struct commit_list *list = remoteheads;
- commit_list_insert(lookup_commit(head), &list);
+ commit_list_insert(head_commit, &list);
common = get_octopus_merge_bases(list);
free(list);
}
@@ -1292,7 +1295,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
* merge_bases again, otherwise "git merge HEAD^
* HEAD^^" would be missed.
*/
- common_one = get_merge_bases(lookup_commit(head),
+ common_one = get_merge_bases(head_commit,
j->item, 1);
if (hashcmp(common_one->item->object.sha1,
j->item->object.sha1)) {
diff --git a/commit.c b/commit.c
index ac337c7..dc22695 100644
--- a/commit.c
+++ b/commit.c
@@ -39,6 +39,18 @@ struct commit *lookup_commit_reference(const unsigned char *sha1)
return lookup_commit_reference_gently(sha1, 0);
}
+struct commit *lookup_expect_commit(const unsigned char *sha1,
+ const char *ref_name)
+{
+ struct commit *c = lookup_commit_reference(sha1);
+ if (!c)
+ die(_("could not parse %s"), ref_name);
+ if (hashcmp(sha1, c->object.sha1))
+ warning(_("%s %s is not a commit!"),
+ ref_name, sha1_to_hex(sha1));
+ return c;
+}
+
struct commit *lookup_commit(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
diff --git a/commit.h b/commit.h
index a2d571b..f36c913 100644
--- a/commit.h
+++ b/commit.h
@@ -37,6 +37,7 @@ struct commit *lookup_commit_reference(const unsigned char *sha1);
struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
int quiet);
struct commit *lookup_commit_reference_by_name(const char *name);
+struct commit *lookup_expect_commit(const unsigned char *sha1, const char *ref_name);
int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size);
int parse_commit(struct commit *item);
diff --git a/http-push.c b/http-push.c
index 6e8f6d0..31297af 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1606,10 +1606,10 @@ static void fetch_symref(const char *path, char **symref, unsigned char *sha1)
strbuf_release(&buffer);
}
-static int verify_merge_base(unsigned char *head_sha1, unsigned char *branch_sha1)
+static int verify_merge_base(unsigned char *head_sha1, struct ref *remote)
{
- struct commit *head = lookup_commit(head_sha1);
- struct commit *branch = lookup_commit(branch_sha1);
+ struct commit *head = lookup_expect_commit(head_sha1, "HEAD");
+ struct commit *branch = lookup_expect_commit(remote->old_sha1, remote->name);
struct commit_list *merge_bases = get_merge_bases(head, branch, 1);
return (merge_bases && !merge_bases->next && merge_bases->item == branch);
@@ -1680,7 +1680,7 @@ static int delete_remote_branch(const char *pattern, int force)
return error("Remote branch %s resolves to object %s\nwhich does not exist locally, perhaps you need to fetch?", remote_ref->name, sha1_to_hex(remote_ref->old_sha1));
/* Remote branch must be an ancestor of remote HEAD */
- if (!verify_merge_base(head_sha1, remote_ref->old_sha1)) {
+ if (!verify_merge_base(head_sha1, remote_ref)) {
return error("The branch '%s' is not an ancestor "
"of your current HEAD.\n"
"If you are sure you want to delete it,"
diff --git a/revision.c b/revision.c
index c46cfaa..f926412 100644
--- a/revision.c
+++ b/revision.c
@@ -986,10 +986,12 @@ static void prepare_show_merge(struct rev_info *revs)
const char **prune = NULL;
int i, prune_num = 1; /* counting terminating NULL */
- if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
+ if (get_sha1("HEAD", sha1))
die("--merge without HEAD?");
- if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
+ head = lookup_expect_commit(sha1, "HEAD");
+ if (get_sha1("MERGE_HEAD", sha1))
die("--merge without MERGE_HEAD?");
+ other = lookup_expect_commit(sha1, "MERGE_HEAD");
add_pending_object(revs, &head->object, "HEAD");
add_pending_object(revs, &other->object, "MERGE_HEAD");
bases = get_merge_bases(head, other, 1);
--
1.7.4.74.g639db
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