admin/bzrmerge.el

   1 ;;; bzrmerge.el --- help merge one Emacs bzr branch to another
   2
   3 ;; Copyright (C) 2010-2018 Free Software Foundation, Inc.
   4
   5 ;; Author: Stefan Monnier <monnier@iro.umontreal.ca>
   6 ;; Keywords: maint
   7
   8 ;; GNU Emacs is free software: you can redistribute it and/or modify
   9 ;; it under the terms of the GNU General Public License as published by
  10 ;; the Free Software Foundation, either version 3 of the License, or
  11 ;; (at your option) any later version.
  12
  13 ;; GNU Emacs is distributed in the hope that it will be useful,
  14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;; GNU General Public License for more details.
  17
  18 ;; You should have received a copy of the GNU General Public License
  19 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  20
  21 ;;; Commentary:
  22
  23 ;; Some usage notes are in admin/notes/bzr.
  24
  25 ;;; Code:
  26
  27 (eval-when-compile (require 'cl-lib))
  28
  29 (defvar bzrmerge-skip-regexp
  30   "back[- ]?port\\|merge\\|sync\\|re-?generate\\|bump version\\|from trunk\\|\
  31 Auto-commit"
  32   "Regexp matching logs of revisions that might be skipped.
  33 `bzrmerge-missing' will ask you if it should skip any matches.")
  34
  35 (defconst bzrmerge-buffer "*bzrmerge*"
  36   "Working buffer for bzrmerge.")
  37
  38 (defconst bzrmerge-warning-buffer "*bzrmerge warnings*"
  39   "Buffer where bzrmerge will display any warnings.")
  40
  41 (defun bzrmerge-merges ()
  42   "Return the list of already merged (not yet committed) revisions.
  43 The list returned is sorted by oldest-first."
  44   (with-current-buffer (get-buffer-create bzrmerge-buffer)
  45     (erase-buffer)
  46     ;; We generally want to make sure we start with a clean tree, but we also
  47     ;; want to allow restarts (i.e. with some part of FROM already merged but
  48     ;; not yet committed).  Unversioned (unknown) files in the tree
  49     ;; are also ok.
  50     (call-process "bzr" nil t nil "status" "-v")
  51     (goto-char (point-min))
  52     (when (re-search-forward "^conflicts:\n" nil t)
  53       (user-error "You still have unresolved conflicts"))
  54     (let ((merges ())
  55           found)
  56       (if (not (re-search-forward "^pending merges:\n" nil t))
  57           (when (save-excursion
  58                   (goto-char (point-min))
  59                   (while (and
  60                           (re-search-forward "^\\([a-z ]*\\):\n" nil t)
  61                           (not
  62                            (setq found
  63                                  (not (equal "unknown" (match-string 1)))))))
  64                   found)
  65             (user-error "You still have uncommitted changes"))
  66         ;; This is really stupid, but it seems there's no easy way to figure
  67         ;; out which revisions have been merged already.  The only info I can
  68         ;; find is the "pending merges" from "bzr status -v", which is not
  69         ;; very machine-friendly.
  70         (while (not (eobp))
  71           (skip-chars-forward " ")
  72           (push (buffer-substring (point) (line-end-position)) merges)
  73           (forward-line 1)))
  74       merges)))
  75
  76 (defun bzrmerge-check-match (merge)
  77   ;; Make sure the MERGES match the revisions on the FROM branch.
  78   ;; Stupidly the best form of MERGES I can find is the one from
  79   ;; "bzr status -v" which is very machine non-friendly, so I have
  80   ;; to do some fuzzy matching.
  81   (let ((author
  82          (or
  83           (save-excursion
  84             (if (re-search-forward "^author: *\\([^<]*[^ ]\\) +<.*"
  85                                    nil t)
  86                 (match-string 1)))
  87           (save-excursion
  88             (if (re-search-forward
  89                  "^committer: *\\([^<]*[^< ]\\) +<" nil t)
  90                 (match-string 1)))))
  91         (timestamp
  92          (save-excursion
  93            (if (re-search-forward
  94                 "^timestamp:[^0-9]*\\([-0-9]+\\)" nil t)
  95                (match-string 1))))
  96         (line1
  97          (save-excursion
  98            (if (re-search-forward "^message:[ \n]*" nil t)
  99                (buffer-substring (point) (line-end-position))))))
 100     ;; The `merge' may have a truncated line1 with "...", so get
 101     ;; rid of any "..." and then look for a prefix match.
 102     (when (string-match "\\.+\\'" merge)
 103       (setq merge (substring merge 0 (match-beginning 0))))
 104     (or (string-prefix-p
 105          merge (concat author " " timestamp " " line1))
 106         (string-prefix-p
 107          merge (concat author " " timestamp " [merge] " line1)))))
 108
 109 (defun bzrmerge-missing (from merges)
 110   "Return the list of revisions that need to be merged.
 111 MERGES is the revisions already merged but not yet committed.
 112 Asks about skipping revisions with logs matching `bzrmerge-skip-regexp'.
 113 The result is of the form (TOMERGE . TOSKIP) where TOMERGE and TOSKIP
 114 are both lists of revnos, in oldest-first order."
 115   (with-current-buffer (get-buffer-create bzrmerge-buffer)
 116     (erase-buffer)
 117     (call-process "bzr" nil t nil "missing" "--theirs-only"
 118                   (expand-file-name from))
 119     (let ((revnos ()) (skipped ()))
 120       (pop-to-buffer (current-buffer))
 121       (goto-char (point-max))
 122       (while (re-search-backward "^------------------------------------------------------------\nrevno: \\([0-9.]+\\).*" nil t)
 123         (save-excursion
 124           (if merges
 125               (while (not (bzrmerge-check-match (pop merges)))
 126                 (unless merges
 127                   (error "Unmatched tip of merged revisions")))
 128             (let ((case-fold-search t)
 129                   (revno (match-string 1))
 130                   (skip nil))
 131               (if (string-match "\\." revno)
 132                   (error "Unexpected dotted revno!")
 133                 (setq revno (string-to-number revno)))
 134               (re-search-forward "^message:\n")
 135               (while (and (not skip)
 136                           (re-search-forward bzrmerge-skip-regexp nil t))
 137                 (let ((str (buffer-substring (line-beginning-position)
 138                                              (line-end-position))))
 139                   (when (string-match "\\` *" str)
 140                     (setq str (substring str (match-end 0))))
 141                   (when (string-match "[.!;, ]+\\'" str)
 142                     (setq str (substring str 0 (match-beginning 0))))
 143                   (let ((help-form (substitute-command-keys "\
 144 Type `y' to skip this revision,
 145 `N' to include it and go on to the next revision,
 146 `n' to not skip, but continue to search this log entry for skip regexps,
 147 `q' to quit merging.")))
 148                     (pcase (save-excursion
 149                             (read-char-choice
 150                              (format "%s: Skip (y/n/N/q/%s)? " str
 151                                      (key-description (vector help-char)))
 152                              '(?y ?n ?N ?q)))
 153                       (`?y (setq skip t))
 154                       (`?q (keyboard-quit))
 155                       ;; A single log entry can match skip-regexp multiple
 156                       ;; times.  If you are sure you don't want to skip it,
 157                       ;; you don't want to be asked multiple times.
 158                       (`?N (setq skip 'no))))))
 159               (if (eq skip t)
 160                   (push revno skipped)
 161                 (push revno revnos)))))
 162         (delete-region (point) (point-max)))
 163       (and (or revnos skipped)
 164            (cons (nreverse revnos) (nreverse skipped))))))
 165
 166 (defun bzrmerge-resolve (file)
 167   (unless (file-exists-p file) (error "Bzrmerge-resolve: Can't find %s" file))
 168   (with-demoted-errors
 169     (let ((exists (find-buffer-visiting file)))
 170       (with-current-buffer (let ((enable-local-variables :safe)
 171                                  (enable-local-eval nil))
 172                              (find-file-noselect file))
 173         (if (buffer-modified-p)
 174             (user-error "Unsaved changes in %s" (current-buffer)))
 175         (save-excursion
 176           (cond
 177            ((derived-mode-p 'change-log-mode)
 178             ;; Fix up dates before resolving the conflicts.
 179             (goto-char (point-min))
 180             (let ((diff-auto-refine-mode nil))
 181               (while (re-search-forward smerge-begin-re nil t)
 182                 (smerge-match-conflict)
 183                 (smerge-ensure-match 3)
 184                 (let ((start1 (match-beginning 1))
 185                       (end1 (match-end 1))
 186                       (start3 (match-beginning 3))
 187                       (end3 (copy-marker (match-end 3) t)))
 188                   (goto-char start3)
 189                   (while (re-search-forward change-log-start-entry-re end3 t)
 190                     (let* ((str (match-string 0))
 191                            (newstr (save-match-data
 192                                      (concat (add-log-iso8601-time-string)
 193                                              (when (string-match " *\\'" str)
 194                                                (match-string 0 str))))))
 195                       (replace-match newstr t t)))
 196                   ;; change-log-resolve-conflict prefers to put match-1's
 197                   ;; elements first (for equal dates), whereas we want to put
 198                   ;; match-3's first.
 199                   (let ((match3 (buffer-substring start3 end3))
 200                         (match1 (buffer-substring start1 end1)))
 201                     (delete-region start3 end3)
 202                     (goto-char start3)
 203                     (insert match1)
 204                     (delete-region start1 end1)
 205                     (goto-char start1)
 206                     (insert match3)))))
 207             ;; (pop-to-buffer (current-buffer)) (debug 'before-resolve)
 208             ))
 209           ;; Try to resolve the conflicts.
 210           (cond
 211            ((member file '("configure" "lisp/ldefs-boot.el"
 212                            "lisp/emacs-lisp/cl-loaddefs.el"))
 213             ;; We are in the file's buffer, so names are relative.
 214             (call-process "bzr" nil t nil "revert"
 215                           (file-name-nondirectory file))
 216             (revert-buffer nil 'noconfirm))
 217            (t
 218             (goto-char (point-max))
 219             (while (re-search-backward smerge-begin-re nil t)
 220               (save-excursion
 221                 (ignore-errors
 222                   (smerge-match-conflict)
 223                   (smerge-resolve))))
 224             ;; (when (derived-mode-p 'change-log-mode)
 225             ;;   (pop-to-buffer (current-buffer)) (debug 'after-resolve))
 226             (save-buffer)))
 227           (goto-char (point-min))
 228           (prog1 (re-search-forward smerge-begin-re nil t)
 229             (unless exists (kill-buffer))))))))
 230
 231 (defun bzrmerge-add-metadata (from endrevno)
 232   "Add the metadata for a merge of FROM upto ENDREVNO.
 233 Does not make other difference."
 234   (if (with-temp-buffer
 235         (call-process "bzr" nil t nil "status")
 236         (goto-char (point-min))
 237         (re-search-forward "^conflicts:\n" nil t))
 238       (error "Don't know how to add metadata in the presence of conflicts")
 239     (call-process "bzr" nil t nil "shelve" "--all"
 240                   "-m" "Bzrmerge shelved merge during skipping")
 241     (call-process "bzr" nil t nil "revert")
 242     (call-process "bzr" nil t nil
 243                   "merge" "-r" (format "%s" endrevno) from)
 244     (call-process "bzr" nil t nil "revert" ".")
 245     (call-process "bzr" nil t nil "unshelve")))
 246
 247 (defvar bzrmerge-already-done nil)
 248
 249 (defun bzrmerge-apply (missing from)
 250   (setq from (expand-file-name from))
 251   (with-current-buffer (get-buffer-create bzrmerge-buffer)
 252     (erase-buffer)
 253     (when (equal (cdr bzrmerge-already-done) (list from missing))
 254       (setq missing (car bzrmerge-already-done)))
 255     (setq bzrmerge-already-done nil)
 256     (let ((merge (car missing))
 257           (skip (cdr missing))
 258           (unsafe nil)
 259           beg end)
 260       (when (or merge skip)
 261         (cond
 262          ((and skip (or (null merge) (< (car skip) (car merge))))
 263           ;; Do a "skip" (i.e. merge the meta-data only).
 264           (setq beg (1- (car skip)))
 265           (while (and skip (or (null merge) (< (car skip) (car merge))))
 266             (cl-assert (> (car skip) (or end beg)))
 267             (setq end (pop skip)))
 268           (message "Skipping %s..%s" beg end)
 269           (bzrmerge-add-metadata from end))
 270
 271          (t
 272           ;; Do a "normal" merge.
 273           (cl-assert (or (null skip) (< (car merge) (car skip))))
 274           (setq beg (1- (car merge)))
 275           (while (and merge (or (null skip) (< (car merge) (car skip))))
 276             (cl-assert (> (car merge) (or end beg)))
 277             (setq end (pop merge)))
 278           (message "Merging %s..%s" beg end)
 279           (if (with-temp-buffer
 280                 (call-process "bzr" nil t nil "status")
 281                 (zerop (buffer-size)))
 282               (call-process "bzr" nil t nil
 283                             "merge" "-r" (format "%s" end) from)
 284             ;; Stupidly, "bzr merge --force -r A..B" dos not maintain the
 285             ;; metadata properly except when the checkout is clean.
 286             (call-process "bzr" nil t nil "merge"
 287                           "--force" "-r" (format "%s..%s" beg end) from)
 288             ;; The merge did not update the metadata, so force the next time
 289             ;; around to update it (as a "skip").
 290             (setq unsafe t)
 291             (push end skip))
 292           (pop-to-buffer (current-buffer))
 293           (sit-for 1)
 294           ;; (debug 'after-merge)
 295           ;; Check the conflicts.
 296           ;; FIXME if using the helpful bzr changelog_merge plugin,
 297           ;; there are normally no conflicts in ChangeLogs.
 298           ;; But we still want the dates fixing, like bzrmerge-resolve does.
 299           (let ((conflicted nil)
 300                 (files ()))
 301             (goto-char (point-min))
 302             (when (re-search-forward "bzr: ERROR:" nil t)
 303               (error "Internal Bazaar error!!"))
 304             (while (re-search-forward "^Text conflict in " nil t)
 305               (push (buffer-substring (point) (line-end-position)) files))
 306             (if (re-search-forward "^\\([0-9]+\\) conflicts encountered" nil t)
 307                 (if (/= (length files) (string-to-number (match-string 1)))
 308                     (setq conflicted t))
 309               (if files (setq conflicted t)))
 310             (dolist (file files)
 311               (if (bzrmerge-resolve file)
 312                   (setq conflicted t)))
 313             (when conflicted
 314               (setq bzrmerge-already-done
 315                     (list (cons merge skip) from missing))
 316               (if unsafe
 317                   ;; FIXME: Obviously, we'd rather make it right rather
 318                   ;; than output such a warning.  But I don't know how to add
 319                   ;; the metadata to bzr's since the technique used in
 320                   ;; bzrmerge-add-metadata does not work when there
 321                   ;; are conflicts.
 322                   (display-warning 'bzrmerge "Resolve conflicts manually.
 323 BEWARE!  Important metadata is kept in this Emacs session!
 324 Do not commit without re-running `M-x bzrmerge' first!"
 325                                    :warning bzrmerge-warning-buffer))
 326               (user-error "Resolve conflicts manually")))))
 327         (cons merge skip)))))
 328
 329 (defun bzrmerge (from)
 330   "Merge from branch FROM into `default-directory'."
 331   (interactive
 332    (list
 333     (let ((def
 334            (with-temp-buffer
 335              (call-process "bzr" nil t nil "info")
 336              (goto-char (point-min))
 337              (when (re-search-forward "submit branch: *" nil t)
 338                (buffer-substring (point) (line-end-position))))))
 339       (read-file-name "From branch: " nil nil nil def))))
 340   ;; Eg we ran bzrmerge once, it stopped with conflicts, we fixed them
 341   ;; and are running it again.
 342   (if (get-buffer bzrmerge-warning-buffer)
 343       (kill-buffer bzrmerge-warning-buffer))
 344   (message "Merging from %s..." from)
 345   (require 'vc-bzr)
 346   (let ((default-directory (or (vc-bzr-root default-directory)
 347                                (error "Not in a Bzr tree"))))
 348     ;; First, check the status.
 349     (let* ((merges (bzrmerge-merges))
 350            ;; OK, we have the status, now check the missing data.
 351            (missing (bzrmerge-missing from merges)))
 352       (if (not missing)
 353           (message "Merging from %s...nothing to merge" from)
 354         (while missing
 355           (setq missing (bzrmerge-apply missing from)))
 356         (message "Merging from %s...done" from)))))
 357
 358 (provide 'bzrmerge)
 359 ;;; bzrmerge.el ends here