fix: Address edge case in file rename tracking in vc-dir buffersexternals/vc-jj

Also add a new test case for it.

2 files changed, 39 insertions, 12 deletions

diff --git a/vc-jj-tests.el b/vc-jj-tests.el
index 1155ecf..389635b 100644
--- a/vc-jj-tests.el
+++ b/vc-jj-tests.el
@@ -291,7 +291,7 @@ When a file is renamed, its old file path should have a VC state of
 
 When a directory is renamed, the files contained within it are reported
 along the same lines."
-  ;; Rename file
+  ;; Rename root-level file
   (vc-jj-test--with-repo repo
     ;; 2026-04-26: It seems like Jujutsu's rename detection requires
     ;; file content to identify a single-file rename: without content,
@@ -311,7 +311,26 @@ along the same lines."
                ("after rename.txt" added ( :rename-state added
                                            :rename-other-filename "before rename.txt"))))))
 
-  ;; Rename subdirectory
+  ;; Rename file in subdirectory
+  (vc-jj-test--with-repo repo
+    (make-directory "subdir")
+    (write-region "foo bar" nil "subdir/before rename.txt")
+    (shell-command "jj new")
+    (shell-command "mv 'subdir/before rename.txt' 'subdir/after rename.txt'")
+    
+    (should (eq (vc-jj-state "subdir/before rename.txt") 'removed))
+    (should (eq (vc-jj-state "subdir/after rename.txt") 'added))
+    (should (seq-set-equal-p
+             (vc-jj-dir-status-files repo nil
+                                     #'vc-jj-test--dir-status-files-update-function)
+             '(("subdir/before rename.txt" removed
+                ( :rename-state removed
+                  :rename-other-filename "subdir/after rename.txt"))
+               ("subdir/after rename.txt" added
+                ( :rename-state added
+                  :rename-other-filename "subdir/before rename.txt"))))))
+
+  ;; Rename entire subdirectory
   (vc-jj-test--with-repo repo
     (make-directory "dir before rename/subdir" t)
     ;; 2026-04-26: It seems that, unlike single-file renames,
diff --git a/vc-jj.el b/vc-jj.el
index 65f5397..71a0e80 100644
--- a/vc-jj.el
+++ b/vc-jj.el
@@ -465,19 +465,27 @@ path prepended with a two-character type string indicating the before
 and after types of the file."
   (let ((table (make-hash-table :test #'equal)))
     (mapc (lambda (line)
-            (if (string-match (rx "{" (group (1+ anychar)) " => " (group (1+ anychar)) "}"
-                                  (opt "/" (group (1+ anychar))))
+            (if (string-match (rx (group-n 1 (* anychar))
+                                  "{"
+                                  (group-n 2 (1+ (not (any "}"))))
+                                  " => "
+                                  (group-n 3 (1+ (not (any "}"))))
+                                  "}"
+                                  (group-n 4 (* anychar)))
                               line)
                 ;; For renamed files, create separate entries for the
-                ;; before-rename and after-rename files
-                (let ((before (match-string 1 line))
-                      (after (match-string 2 line))
-                      (subdir-file (match-string 3 line)))
-                  (when subdir-file     ; When a directory was renamed
-                    (setq before (file-name-concat before subdir-file)
-                          after (file-name-concat after subdir-file)))
+                ;; before-rename and after-rename files.  The rename
+                ;; block {before => after} may appear mid-path, so we
+                ;; reconstruct full paths using the surrounding
+                ;; context.
+                (let* ((prefix (substring (match-string 1 line) 3))
+                       (before-part (match-string 2 line))
+                       (after-part (match-string 3 line))
+                       (suffix (match-string 4 line))
+                       (before (concat prefix before-part suffix))
+                       (after (concat prefix after-part suffix)))
                   (puthash before "F-" table) ; Removed state
-                  (puthash after "-F" table) ; Added state
+                  (puthash after "-F" table)  ; Added state
                   (when extra-table
                     ;; Populate EXTRA-TABLE with rename information
                     (puthash before (list :rename-state 'removed :rename-other-filename after)