From 5ba3fc32c00cbce8ebb2dd6b3e34fe91a9a02216 Mon Sep 17 00:00:00 2001
From: Kyle Meyer <kyle@kyleam.com>
Date: Tue, 1 Sep 2020 22:15:45 -0400
Subject: magit: Add two custom patch commands

---
 init.el          |  9 ++++++-
 lisp/km-magit.el | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 1 deletion(-)

diff --git a/init.el b/init.el
index 530efd3..3001f8f 100644
--- a/init.el
+++ b/init.el
@@ -1190,7 +1190,14 @@
     '("V" "Back up current branch, v" km/magit-branch-version))
 
   (transient-append-suffix 'magit-branch "c"
-    '("m" "Checkout master" km/magit-checkout-master)))
+    '("m" "Checkout master" km/magit-checkout-master))
+
+  (after 'magit-patch
+    (transient-append-suffix 'magit-patch-create "c"
+      '("u" "@{upstream}.." km/magit-patch-create-from-upstream))
+
+    (transient-append-suffix 'magit-patch-create "u"
+      '("s" "series" km/magit-patch-create-series))))
 
 (use-package magit-annex
   :load-path "~/src/emacs/magit-annex/"
diff --git a/lisp/km-magit.el b/lisp/km-magit.el
index f0819de..8f2179a 100644
--- a/lisp/km-magit.el
+++ b/lisp/km-magit.el
@@ -26,6 +26,7 @@
 (require 'km-util)
 (require 'magit)
 (require 'projectile)
+(require 'seq)
 
 ;;;###autoload
 (defun km/magit-status (&optional default-display)
@@ -832,6 +833,83 @@ category."
     (magit-run-git-async "for-each-ref" (format "--contains=%s" rev)
                          "--sort=v:refname" "refs/tags")))
 
+(defun km/magit-patch-create-from-upstream (&optional args)
+  (interactive (list (transient-args 'magit-patch-create)))
+  (if-let ((upstream (magit-get-upstream-branch)))
+      (apply #'magit-run-git "format-patch" upstream args)
+    (user-error "No upstream branch")))
+
+(defun km/magit-tweak-patch-series-summary ()
+  "Restyle \"My Name (N):\" heading.
+Drop author for single author series by `user-full-name',
+appending [M/N] to each entry."
+  (interactive)
+  (save-excursion
+    (goto-char (point-min))
+    (search-forward "*** BLURB HERE ***")
+    (let ((author-regexp (rx line-start word (zero-or-more not-newline)
+                             "(" (one-or-more digit) "):" line-end)))
+      ;; Don't proceed if there looks to be more than one author.
+      (unless (and (re-search-forward author-regexp nil t)
+                   (re-search-forward author-regexp nil t))
+        (let ((buffer-read-only nil))
+          (save-excursion
+            (goto-char (point-min))
+            (when-let ((total (and (re-search-forward
+                                    (rx line-start (eval user-full-name) " ("
+                                        (group (one-or-more digit))
+                                        "):" line-end)
+                                    nil t)
+                                   (match-string 1)))
+                       (prefix (format "[%%%dd/%s] " (length total) total))
+                       (idx 1))
+              (delete-region (line-beginning-position) (1+ (line-end-position)))
+              (while (and (not (eobp))
+                          (not (looking-at-p "^$")))
+                (goto-char (line-beginning-position))
+                (skip-chars-forward " ")
+                (insert (format prefix idx))
+                (cl-incf idx)
+                (forward-line)))))))))
+
+(defun km/magit-patch-create-series (&optional args)
+  (interactive (list (transient-args 'magit-patch-create)))
+  (when (magit-anything-modified-p t)
+    (user-error "There are uncommitted changes"))
+  (setq args (seq-remove
+              (lambda (a) (string-match-p "\\`--base=" a))
+              args))
+  (if-let ((current (magit-get-current-branch))
+           (upstream (magit-get-upstream-branch current)))
+      (let ((patch-branch (concat "patches/" current)))
+        (if (not (magit-local-branch-p patch-branch))
+            (magit-branch-and-checkout patch-branch current)
+          (magit-update-ref (concat "refs/heads/" patch-branch)
+                            (concat "reset: moving back to " current)
+                            current)
+          (magit-branch-checkout patch-branch))
+        (apply #'magit-run-git "format-patch"
+               upstream (concat "--base=" upstream) args)
+        (let* ((patches (or (seq-filter
+                             (lambda (f) (string-match-p "\\.patch\\'" f))
+                             (magit-untracked-files))
+                            (error "There should be patches")))
+               (cover (seq-find (lambda (f) (string-match-p "\\`0+-" f))
+                                patches)))
+          (magit-call-git "add" patches)
+          (magit-run-git "commit" "-mpatches")
+          (when cover
+            (with-temp-buffer
+              (insert-file-contents cover)
+              (km/magit-tweak-patch-series-summary)
+              (write-region nil nil cover))
+            (magit-call-git "commit" "-mtweak cover" "--" cover))
+          (when cover
+            (find-file-other-window cover)
+            (re-search-forward (rx "Subject: [PATCH" (zero-or-more not-newline) "] "))
+            (setq buffer-read-only nil))))
+    (user-error "No upstream branch")))
+
 
 ;;; Copy functions
 
-- 
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