[PATCH 2/3] worktree: add utility to find worktree by pathname

[Eric Sunshine <sunshine@xxxxxxxxxxxxx>]

find_worktree() employs heuristics to match user provided input -- which
may be a pathname or some sort of shorthand -- with an actual worktree.
Although this convenience allows a user to identify a worktree with
minimal typing, the black-box nature of these heuristics makes it
potentially difficult for callers which already know the exact path of a
worktree to be confident that the correct worktree will be returned for
any specific pathname (particularly a relative one), especially as the
heuristics are enhanced and updated.

Therefore, add a companion function, find_worktree_by_path(), which
deterministically identifies a worktree strictly by pathname with no
interpretation and no magic matching.

Signed-off-by: Eric Sunshine <sunshine@xxxxxxxxxxxxxx>
---
 worktree.c | 16 ++++++++++------
 worktree.h |  6 ++++++
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/worktree.c b/worktree.c
index 5b4793caa3..43c6685d4e 100644
--- a/worktree.c
+++ b/worktree.c
@@ -215,7 +215,6 @@ struct worktree *find_worktree(struct worktree **list,
 			       const char *arg)
 {
 	struct worktree *wt;
-	char *path;
 	char *to_free = NULL;
 
 	if ((wt = find_worktree_by_suffix(list, arg)))
@@ -223,11 +222,17 @@ struct worktree *find_worktree(struct worktree **list,
 
 	if (prefix)
 		arg = to_free = prefix_filename(prefix, arg);
-	path = real_pathdup(arg, 0);
-	if (!path) {
-		free(to_free);
+	wt = find_worktree_by_path(list, arg);
+	free(to_free);
+	return wt;
+}
+
+struct worktree *find_worktree_by_path(struct worktree **list, const char *p)
+{
+	char *path = real_pathdup(p, 0);
+
+	if (!path)
 		return NULL;
-	}
 	for (; *list; list++) {
 		const char *wt_path = real_path_if_valid((*list)->path);
 
@@ -235,7 +240,6 @@ struct worktree *find_worktree(struct worktree **list,
 			break;
 	}
 	free(path);
-	free(to_free);
 	return *list;
 }
 
diff --git a/worktree.h b/worktree.h
index b8a851b92b..d242a6e71c 100644
--- a/worktree.h
+++ b/worktree.h
@@ -61,6 +61,12 @@ struct worktree *find_worktree(struct worktree **list,
 			       const char *prefix,
 			       const char *arg);
 
+/*
+ * Return the worktree corresponding to `path`, or NULL if no such worktree
+ * exists.
+ */
+struct worktree *find_worktree_by_path(struct worktree **, const char *path);
+
 /*
  * Return true if the given worktree is the main one.
  */
-- 
2.25.1.526.gf05a752211