Re: [PATCH v2 2/6] worktree: teach worktree to lazy-load "prunable" reason

Eric Sunshine writes:

On Sun, Jan 17, 2021 at 6:43 PM Rafael Silva
[off-list ref] wrote:

quoted

Add worktree_prune_reason() to allow a caller to discover whether a
worktree is prunable and the reason that it is, much like
worktree_lock_reason() indicates whether a worktree is locked and the
reason for the lock. As with worktree_lock_reason(), retrieve the
prunable reason lazily and cache it in the `worktree` structure.

Signed-off-by: Rafael Silva <redacted>
---

diff --git a/worktree.c b/worktree.c

@@ -245,6 +246,25 @@ const char *worktree_lock_reason(struct worktree *wt)
+const char *worktree_prune_reason(struct worktree *wt, timestamp_t expire)
+{
+       struct strbuf reason = STRBUF_INIT;
+       char *path;

The `path` variable is uninitialized...

quoted

+       if (should_prune_worktree(wt->id, &reason, &path, expire))
+               wt->prune_reason = strbuf_detach(&reason, NULL);

...but the very first thing should_prune_worktree() does is
unconditionally set it to NULL, so it's either NULL or an allocated
string regardless of the value returned by should_prune_worktree()...

quoted

+       strbuf_release(&reason);
+       free(path);

...which makes the behavior of `free(path)` deterministic. Good.

I'm on the fence about whether or not we should initialize `path` to NULL:

    char *path = NULL;

just to make it easier for the next person to reason about it without
having to dig into the implementation of should_prune_worktree(). This
is a really minor point, though, not worth a re-roll.

This is a good point and totally agreed. I'm going to include this
change in the next revision.

-- 
Thanks
Rafael