reduce_heads: fix memory leaks

We currently have seven callers of `reduce_heads(foo)`. Six of them do
not use the original list `foo` again, and actually, all six of those
end up leaking it.

Introduce and use `reduce_heads_replace(&foo)` as a leak-free version of
`foo = reduce_heads(foo)` to fix several of these. Fix the remaining
leaks using `free_commit_list()`.

While we're here, document `reduce_heads()` and mark it as `extern`.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/builtin/merge-base.c b/builtin/merge-base.c
index e17835fabb..24f6c71935 100644
--- a/builtin/merge-base.c
+++ b/builtin/merge-base.c
@@ -57,7 +57,7 @@ static int handle_independent(int count, const char **args)
 	for (i = count - 1; i >= 0; i--)
 		commit_list_insert(get_commit_reference(args[i]), &revs);
 
-	revs = reduce_heads(revs);
+	reduce_heads_replace(&revs);
 
 	if (!revs)
 		return 1;
@@ -78,7 +78,9 @@ static int handle_octopus(int count, const char **args, int show_all)
 	for (i = count - 1; i >= 0; i--)
 		commit_list_insert(get_commit_reference(args[i]), &revs);
 
-	result = reduce_heads(get_octopus_merge_bases(revs));
+	result = get_octopus_merge_bases(revs);
+	free_commit_list(revs);
+	reduce_heads_replace(&result);
 
 	if (!result)
 		return 1;