[nongnu] elpa/git-commit 557ab2c062 4/4: magit-diff-wash-diff: Fix headers for "git log -L --no-prefix"

[ELPA Syncer]

branch: elpa/git-commit
commit 557ab2c0620930afc0b1da3453c42fa2b5d86145
Author: Jonas Bernoulli <jonas@bernoul.li>
Commit: Jonas Bernoulli <jonas@bernoul.li>

    magit-diff-wash-diff: Fix headers for "git log -L --no-prefix"
    
    It was already possible to apply commits shown by "git log -L
    --no-prefix", but to allow applying files and hunks, we also
    have to fix the file headers.
---
 lisp/magit-diff.el | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/lisp/magit-diff.el b/lisp/magit-diff.el
index 3ba2eed4bf..d169a015e4 100644
--- a/lisp/magit-diff.el
+++ b/lisp/magit-diff.el
@@ -2312,14 +2312,23 @@ section or a child thereof."
       (when orig
         (setq orig (magit-decode-git-path orig)))
       (setq file (magit-decode-git-path file))
-      (setq header (mapconcat #'identity (nreverse header) ""))
+      (setq header (nreverse header))
       ;; KLUDGE `git-log' ignores `--no-prefix' when `-L' is used.
       (when (and (derived-mode-p 'magit-log-mode)
                  (seq-some (lambda (arg) (string-prefix-p "-L" arg))
                            magit-buffer-log-args))
         (when orig
           (setq orig (substring orig 2)))
-        (setq file (substring file 2)))
+        (setq file (substring file 2))
+        (setq header (list (save-excursion
+                             (string-match "diff [^ ]+" (car header))
+                             (format "%s %s %s\n"
+                                     (match-string 0 (car header))
+                                     (or orig file)
+                                     (or file orig)))
+                           (format "--- %s\n" (or orig "/dev/null"))
+                           (format "+++ %s\n" (or file "/dev/null")))))
+      (setq header (mapconcat #'identity header ""))
       (magit-diff-insert-file-section
        file orig status modes rename header binary nil)))))