Re: [PATCH 03/15] do not create "struct commit" with xcalloc
From: Junio C Hamano <hidden>
Date: 2016-06-15 23:01:34
Jeff King [off-list ref] writes:
In both blame and merge-recursive, we sometimes create a "fake" commit struct for convenience (e.g., to represent the HEAD state as if we would commit it). By allocating ourselves rather than using alloc_commit_node, we do not properly set the "index" field of the commit. This can produce subtle bugs if we then use commit-slab on the resulting commit, as we will share the "0" index with another commit.
The change I see here is all good, but I wonder if it is too late to
start the real index from 1 and catch anything that has 0 index with
a BUG("do not hand-allocate a commit").
quoted hunk
We can fix this by using alloc_commit_node() to allocate. Note that we cannot free the result, as it is part of our commit allocator. However, both cases were already leaking the allocated commit anyway, so there's nothing to fix up. Signed-off-by: Jeff King <redacted> --- builtin/blame.c | 2 +- merge-recursive.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)diff --git a/builtin/blame.c b/builtin/blame.c index a52a279..d6056a5 100644 --- a/builtin/blame.c +++ b/builtin/blame.c@@ -2286,7 +2286,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt, struct strbuf msg = STRBUF_INIT; time(&now); - commit = xcalloc(1, sizeof(*commit)); + commit = alloc_commit_node(); commit->object.parsed = 1; commit->date = now; commit->object.type = OBJ_COMMIT;diff --git a/merge-recursive.c b/merge-recursive.c index cab16fa..2b37d42 100644 --- a/merge-recursive.c +++ b/merge-recursive.c@@ -40,7 +40,7 @@ static struct tree *shift_tree_object(struct tree *one, struct tree *two, static struct commit *make_virtual_commit(struct tree *tree, const char *comment) { - struct commit *commit = xcalloc(1, sizeof(struct commit)); + struct commit *commit = alloc_commit_node(); struct merge_remote_desc *desc = xmalloc(sizeof(*desc)); desc->name = comment;