[PATCH v2 2/3] merge-recursive: provide pair of `unpack_trees_{start,finish}()`

[Martin Ågren]

From: Elijah Newren <new...@gmail.com>

Rename `git_merge_trees()` to `unpack_trees_start()` and extract the
call to `discard_index()` into a new function `unpack_trees_finish()`.
As a result, these are called early resp. late in `merge_trees()`,
making the resource handling clearer. The next commit will expand on
that, teaching `..._finish()` to free more memory. (So rather than
moving the FIXME-comment, just drop it, since it will be addressed soon
enough.)

Also call `..._finish()` when `merge_trees()` returns early.

Signed-off-by: Elijah Newren <new...@gmail.com>
Signed-off-by: Martin Ågren <martin.ag...@gmail.com>
---
 merge-recursive.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 680e01226b..ddb0fa7369 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -337,10 +337,10 @@ static void init_tree_desc_from_tree(struct tree_desc 
*desc, struct tree *tree)
        init_tree_desc(desc, tree->buffer, tree->size);
 }
 
-static int git_merge_trees(struct merge_options *o,
-                          struct tree *common,
-                          struct tree *head,
-                          struct tree *merge)
+static int unpack_trees_start(struct merge_options *o,
+                             struct tree *common,
+                             struct tree *head,
+                             struct tree *merge)
 {
        int rc;
        struct tree_desc t[3];
@@ -379,6 +379,11 @@ static int git_merge_trees(struct merge_options *o,
        return rc;
 }
 
+static void unpack_trees_finish(struct merge_options *o)
+{
+       discard_index(&o->orig_index);
+}
+
 struct tree *write_tree_from_memory(struct merge_options *o)
 {
        struct tree *result = NULL;
@@ -3088,13 +3093,14 @@ int merge_trees(struct merge_options *o,
                return 1;
        }
 
-       code = git_merge_trees(o, common, head, merge);
+       code = unpack_trees_start(o, common, head, merge);
 
        if (code != 0) {
                if (show(o, 4) || o->call_depth)
                        err(o, _("merging of trees %s and %s failed"),
                            oid_to_hex(&head->object.oid),
                            oid_to_hex(&merge->object.oid));
+               unpack_trees_finish(o);
                return -1;
        }
 
@@ -3147,20 +3153,15 @@ int merge_trees(struct merge_options *o,
 
                hashmap_free(&o->current_file_dir_set, 1);
 
-               if (clean < 0)
+               if (clean < 0) {
+                       unpack_trees_finish(o);
                        return clean;
+               }
        }
        else
                clean = 1;
 
-       /* Free the extra index left from git_merge_trees() */
-       /*
-        * FIXME: Need to also free data allocated by
-        * setup_unpack_trees_porcelain() tucked away in o->unpack_opts.msgs,
-        * but the problem is that only half of it refers to dynamically
-        * allocated data, while the other half points at static strings.
-        */
-       discard_index(&o->orig_index);
+       unpack_trees_finish(o);
 
        if (o->call_depth && !(*result = write_tree_from_memory(o)))
                return -1;
-- 
2.17.0.583.g9a75a153ac