From 3ab65121d229e64915c7b4c89fe53f80cb34ebff Mon Sep 17 00:00:00 2001 From: Sean Whitton Date: Fri, 18 Oct 2024 17:19:45 +0800 Subject: [PATCH v2] Support modifying VC change comments for Git * lisp/vc/vc-git.el (vc-git-allow-rewriting-history): New option. (vc-git--assert-allowed-rewrite, vc-git-modify-change-comment): New functions (bug#64055). (vc-git--current-branch): Factor out of vc-git-dir--branch-headers. (vc-git--log-edit-extract-headers): Factor out of vc-git-checkin. * etc/NEWS: Announce the new support and option. --- etc/NEWS | 15 +++++ lisp/vc/vc-git.el | 167 ++++++++++++++++++++++++++++++++++++++-------- 2 files changed, 154 insertions(+), 28 deletions(-) diff --git a/etc/NEWS b/etc/NEWS index 10d86173235..d2e72bc537a 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -568,6 +568,21 @@ a desktop notification when the song changes, using customized using the new user options 'mpc-notifications-title' and 'mpc-notifications-body'. +** VC + +--- +*** Using 'e' from Log View mode to modify change comments now works for Git. + +--- +*** New user option 'vc-git-allow-rewriting-history'. +Many Git commands can change your copy of published change history +without warning. If VC commands detect that this could happen, they +will stop. You can customize this variable to permit rewriting history +even though Emacs thinks it is dangerous. + +So far, this applies only to the 'log-view-modify-change-comment' +command. + * New Modes and Packages in Emacs 31.1 diff --git a/lisp/vc/vc-git.el b/lisp/vc/vc-git.el index f77bf0cc5ff..59d5386bc72 100644 --- a/lisp/vc/vc-git.el +++ b/lisp/vc/vc-git.el @@ -252,6 +252,27 @@ vc-git-revision-complete-only-branches :type 'boolean :version "28.1") +;; The default is nil because only a VC user who also possesses a lot of +;; Git-specific knowledge can know when it is okay to rewrite history, +;; and we can't convey to a relatively Git-naïve user the potential +;; risks in only the space of a minibuffer y/n prompt. +(defcustom vc-git-allow-rewriting-history nil + "When non-nil, permit Git operations that may rewrite published history. + +Many Git commands can change your copy of published change history +without warning. If this occurs, you won't be able to pull and push in +the ordinary way until you take special action. See \"Recovering from +Upstream Rebase\" in the Man page git-rebase(1). + +Normally, Emacs refuses to run Git commands that it thinks will rewrite +published history. If you customize this variable to a non-nil value, +Emacs will instead prompt you to confirm that you really want to perform +the rewrite. A value of `no-ask' means to proceed with no prompting." + :type '(choice (const :tag "Don't allow" nil) + (const :tag "Prompt to allow" t) + (const :tag "Allow without prompting" no-ask)) + :version "31.1") + ;; History of Git commands. (defvar vc-git-history nil) @@ -728,11 +749,13 @@ vc-git-dir-status-files :files files :update-function update-function))) +(defun vc-git--current-branch () + (vc-git--out-match '("symbolic-ref" "HEAD") + "^\\(refs/heads/\\)?\\(.+\\)$" 2)) + (defun vc-git-dir--branch-headers () "Return headers for branch-related information." - (let ((branch (vc-git--out-match - '("symbolic-ref" "HEAD") - "^\\(refs/heads/\\)?\\(.+\\)$" 2)) + (let ((branch (vc-git--current-branch)) tracking remote-url) (if branch (when-let ((branch-merge @@ -1082,6 +1105,17 @@ vc-git-checkin-patch (autoload 'vc-switches "vc") +(defun vc-git--log-edit-extract-headers (comment) + (cl-flet ((boolean-arg-fn (argument) + (lambda (v) (and (equal v "yes") (list argument))))) + (log-edit-extract-headers + `(("Author" . "--author") + ("Date" . "--date") + ("Amend" . ,(boolean-arg-fn "--amend")) + ("No-Verify" . ,(boolean-arg-fn "--no-verify")) + ("Sign-Off" . ,(boolean-arg-fn "--signoff"))) + comment))) + (defun vc-git-checkin (files comment &optional _rev) (let* ((file1 (or (car files) default-directory)) (root (vc-git-root file1)) @@ -1180,31 +1214,23 @@ vc-git-checkin (vc-git-command nil 0 patch-file "apply" "--cached") (delete-file patch-file)))) (when to-stash (vc-git--stash-staged-changes files))) - (cl-flet ((boolean-arg-fn - (argument) - (lambda (value) (when (equal value "yes") (list argument))))) - ;; When operating on the whole tree, better pass "-a" than ".", since "." - ;; fails when we're committing a merge. - (apply #'vc-git-command nil 0 (if (and only (not vc-git-patch-string)) files) - (nconc (if msg-file (list "commit" "-F" - (file-local-name msg-file)) - (list "commit" "-m")) - (let ((args - (log-edit-extract-headers - `(("Author" . "--author") - ("Date" . "--date") - ("Amend" . ,(boolean-arg-fn "--amend")) - ("No-Verify" . ,(boolean-arg-fn "--no-verify")) - ("Sign-Off" . ,(boolean-arg-fn "--signoff"))) - comment))) - (when msg-file - (let ((coding-system-for-write - (or pcsw vc-git-commits-coding-system))) - (write-region (car args) nil msg-file)) - (setq args (cdr args))) - args) - (unless vc-git-patch-string - (if only (list "--only" "--") '("-a")))))) + ;; When operating on the whole tree, better pass "-a" than ".", + ;; since "." fails when we're committing a merge. + (apply #'vc-git-command nil 0 + (if (and only (not vc-git-patch-string)) files) + (nconc (if msg-file (list "commit" "-F" + (file-local-name msg-file)) + (list "commit" "-m")) + (let ((args + (vc-git--log-edit-extract-headers comment))) + (when msg-file + (let ((coding-system-for-write + (or pcsw vc-git-commits-coding-system))) + (write-region (car args) nil msg-file)) + (setq args (cdr args))) + args) + (unless vc-git-patch-string + (if only (list "--only" "--") '("-a"))))) (if (and msg-file (file-exists-p msg-file)) (delete-file msg-file)) (when to-stash (let ((cached (make-nearby-temp-file "git-cached"))) @@ -1960,6 +1986,91 @@ vc-git-get-change-comment (vc-git-command standard-output 1 nil "log" "--max-count=1" "--pretty=format:%B" rev))) +(defun vc-git--assert-allowed-rewrite (rev) + (when (and (not (eq vc-git-allow-rewriting-history 'no-ask)) + ;; Check there is an upstream. + (with-temp-buffer + (vc-git--out-ok "config" "--get" + (format "branch.%s.merge" + (vc-git--current-branch))))) + (let ((outgoing (split-string + (with-output-to-string + (vc-git-command standard-output 0 nil "log" + "--pretty=format:%H" + "@{upstream}..HEAD"))))) + (unless (or (cl-member rev outgoing :test #'string-prefix-p) + (and vc-git-allow-rewriting-history + (yes-or-no-p + (format +"Commit %s looks to be published; are you sure you want to rewrite history?" + rev)))) + (user-error "Will not rewrite likely-public Git history"))))) + +(defun vc-git-modify-change-comment (files rev comment) + (vc-git--assert-allowed-rewrite rev) + (let* ((args (delete "--amend" + (vc-git--log-edit-extract-headers comment))) + (message (format "amend! %s\n\n%s" rev (pop args))) + (msg-file + ;; On MS-Windows, pass the message through a file, to work + ;; around how command line arguments must be in the system + ;; codepage, and therefore might not support non-ASCII. + ;; + ;; As our other arguments are static, we need not be concerned + ;; about the encoding of command line arguments in general. + ;; See `vc-git-checkin' for the more complex case. + (and (eq system-type 'windows-nt) + (let ((default-directory + (or (file-name-directory (or (car files) + default-directory)) + default-directory))) + (make-nearby-temp-file "git-msg")))) + (nothing-staged + (zerop + (vc-git-command nil t nil "diff" "--cached" "--quiet")))) + ;; We want to do just + ;; + ;; % git commit --only --allow-empty -m... + ;; % git rebase --autostash --autosquash -i REV~1 + ;; + ;; because the first command is guaranteed to create an empty commit + ;; regardless of the state of the index and working tree. However, + ;; that requires git.git commit 319d835, released in Git 2.11.1. + ;; In order to support older Git we do this longer, slower sequence: + ;; + ;; % git stash push + ;; % git commit --allow-empty -m... + ;; % git rebase --autosquash -i REV~1 + ;; % git stash pop + (unless nothing-staged + (vc-git-command nil 0 nil "stash" "push")) + (unwind-protect + (progn + (when (cl-intersection '("--author" "--date") args + :test #'string=) + ;; 'git rebase --autosquash' cannot alter authorship. + ;; See the description of --fixup in git-commit(1). + (error +"Author: and Date: not supported when modifying existing commits")) + (when msg-file + (let ((coding-system-for-write + (or coding-system-for-write + vc-git-commits-coding-system))) + (write-region message nil msg-file))) + (apply #'vc-git-command nil 0 nil + "commit" "--allow-empty" + (nconc (if msg-file + (list "-F" (file-local-name msg-file)) + (list "-m" message)) + args))) + (when (and msg-file (file-exists-p msg-file)) + (delete-file msg-file))) + (with-environment-variables (("GIT_SEQUENCE_EDITOR" "true")) + (vc-git-command nil 0 nil "rebase" "--autosquash" "-i" + (format "%s~1" rev))) + (unless nothing-staged + (vc-git-command nil 0 nil "stash" "pop" "--index")))) + (defvar vc-git-extra-menu-map (let ((map (make-sparse-keymap))) (define-key map [git-grep] -- 2.45.2