cache-tree: simplify locking logic

After we have taken the lock using `LOCK_DIE_ON_ERROR`, we know that
`newfd` is non-negative. So when we check for exactly that property
before calling `write_locked_index()`, the outcome is guaranteed.

If we write and commit successfully, we set `newfd = -1`, so that we can
later avoid calling `rollback_lock_file` on an already-committed lock.
But we might just as well unconditionally call `rollback_lock_file()` --
it will be a no-op if we have already committed.

All in all, we use `newfd` as a bool and the only benefit we get from it
is that we can avoid calling a no-op. Remove `newfd` so that we have one
variable less to reason about.

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

diff --git a/cache-tree.c b/cache-tree.c
index 71d092ed514549f03407aef4fd17ab1467191c68..f646f567317a3eefcfcd60484d15f319e22549a4 100644 (file)
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -602,11 +602,11 @@ static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *pat
 
 int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 {
-       int entries, was_valid, newfd;
+       int entries, was_valid;
        struct lock_file lock_file = LOCK_INIT;
        int ret = 0;
 
-       newfd = hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
+       hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 
        entries = read_index_from(index_state, index_path);
        if (entries < 0) {
@@ -625,10 +625,7 @@ int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, co
                        ret = WRITE_TREE_UNMERGED_INDEX;
                        goto out;
                }
-               if (0 <= newfd) {
-                       if (!write_locked_index(index_state, &lock_file, COMMIT_LOCK))
-                               newfd = -1;
-               }
+               write_locked_index(index_state, &lock_file, COMMIT_LOCK);
                /* Not being able to write is fine -- we are only interested
                 * in updating the cache-tree part, and if the next caller
                 * ends up using the old index with unupdated cache-tree part
@@ -650,8 +647,7 @@ int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, co
                hashcpy(sha1, index_state->cache_tree->oid.hash);
 
 out:
-       if (0 <= newfd)
-               rollback_lock_file(&lock_file);
+       rollback_lock_file(&lock_file);
        return ret;
 }