;;; magit-bisect.el --- Bisect support for Magit -*- lexical-binding:t -*-
;; Copyright (C) 2008-2023 The Magit Project Contributors
;; Author: Jonas Bernoulli <jonas@bernoul.li>
;; Maintainer: Jonas Bernoulli <jonas@bernoul.li>
;; SPDX-License-Identifier: GPL-3.0-or-later
;; Magit is free software: you can redistribute it and/or modify it
;; under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; Magit is distributed in the hope that it will be useful, but WITHOUT
;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
;; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
;; License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with Magit. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Use a binary search to find the commit that introduced a bug.
;;; Code:
(require 'magit)
;;; Options
(defcustom magit-bisect-show-graph t
"Whether to use `--graph' in the log showing commits yet to be bisected."
:package-version '(magit . "2.8.0")
:group 'magit-status
:type 'boolean)
(defface magit-bisect-good
'((t :foreground "DarkOliveGreen"))
"Face for good bisect revisions."
:group 'magit-faces)
(defface magit-bisect-skip
'((t :foreground "DarkGoldenrod"))
"Face for skipped bisect revisions."
:group 'magit-faces)
(defface magit-bisect-bad
'((t :foreground "IndianRed4"))
"Face for bad bisect revisions."
:group 'magit-faces)
;;; Commands
;;;###autoload (autoload 'magit-bisect "magit-bisect" nil t)
(transient-define-prefix magit-bisect ()
"Narrow in on the commit that introduced a bug."
:man-page "git-bisect"
[:class transient-subgroups
:if-not magit-bisect-in-progress-p
["Arguments"
("-n" "Don't checkout commits" "--no-checkout")
("-p" "Follow only first parent of a merge" "--first-parent"
:if (lambda () (magit-git-version>= "2.29")))
(6 magit-bisect:--term-old
:if (lambda () (magit-git-version>= "2.7")))
(6 magit-bisect:--term-new
:if (lambda () (magit-git-version>= "2.7")))]
["Actions"
("B" "Start" magit-bisect-start)
("s" "Start script" magit-bisect-run)]]
["Actions"
:if magit-bisect-in-progress-p
("B" "Bad" magit-bisect-bad)
("g" "Good" magit-bisect-good)
(6 "m" "Mark" magit-bisect-mark
:if (lambda () (magit-git-version>= "2.7")))
("k" "Skip" magit-bisect-skip)
("r" "Reset" magit-bisect-reset)
("s" "Run script" magit-bisect-run)])
(transient-define-argument magit-bisect:--term-old ()
:description "Old/good term"
:class 'transient-option
:key "=o"
:argument "--term-old=")
(transient-define-argument magit-bisect:--term-new ()
:description "New/bad term"
:class 'transient-option
:key "=n"
:argument "--term-new=")
;;;###autoload
(defun magit-bisect-start (bad good args)
"Start a bisect session.
Bisecting a bug means to find the commit that introduced it.
This command starts such a bisect session by asking for a known
good and a known bad commit. To move the session forward use the
other actions from the bisect transient command (\
\\<magit-status-mode-map>\\[magit-bisect])."
(interactive (if (magit-bisect-in-progress-p)
(user-error "Already bisecting")
(magit-bisect-start-read-args)))
(unless (magit-rev-ancestor-p good bad)
(user-error
"The %s revision (%s) has to be an ancestor of the %s one (%s)"
(or (transient-arg-value "--term-old=" args) "good")
good
(or (transient-arg-value "--term-new=" args) "bad")
bad))
(when (magit-anything-modified-p)
(user-error "Cannot bisect with uncommitted changes"))
(magit-git-bisect "start" (list args bad good) t))
(defun magit-bisect-start-read-args ()
(let* ((args (transient-args 'magit-bisect))
(bad (magit-read-branch-or-commit
(format "Start bisect with %s revision"
(or (transient-arg-value "--term-new=" args)
"bad")))))
(list bad
(magit-read-other-branch-or-commit
(format "%s revision" (or (transient-arg-value "--term-old=" args)
"Good"))
bad)
args)))
;;;###autoload
(defun magit-bisect-reset ()
"After bisecting, cleanup bisection state and return to original `HEAD'."
(interactive)
(magit-confirm 'reset-bisect)
(magit-run-git "bisect" "reset")
(ignore-errors (delete-file (magit-git-dir "BISECT_CMD_OUTPUT"))))
;;;###autoload
(defun magit-bisect-good ()
"While bisecting, mark the current commit as good.
Use this after you have asserted that the commit does not contain
the bug in question."
(interactive)
(magit-git-bisect (or (cadr (magit-bisect-terms))
(user-error "Not bisecting"))))
;;;###autoload
(defun magit-bisect-bad ()
"While bisecting, mark the current commit as bad.
Use this after you have asserted that the commit does contain the
bug in question."
(interactive)
(magit-git-bisect (or (car (magit-bisect-terms))
(user-error "Not bisecting"))))
;;;###autoload
(defun magit-bisect-mark ()
"While bisecting, mark the current commit with a bisect term.
During a bisect using alternate terms, commits can still be
marked with `magit-bisect-good' and `magit-bisect-bad', as those
commands map to the correct term (\"good\" to --term-old's value
and \"bad\" to --term-new's). However, in some cases, it can be
difficult to keep that mapping straight in your head; this
command provides an interface that exposes the underlying terms."
(interactive)
(magit-git-bisect
(pcase-let ((`(,term-new ,term-old) (or (magit-bisect-terms)
(user-error "Not bisecting"))))
(pcase (read-char-choice
(format "Mark HEAD as %s ([n]ew) or %s ([o]ld)"
term-new term-old)
(list ?n ?o))
(?n term-new)
(?o term-old)))))
;;;###autoload
(defun magit-bisect-skip ()
"While bisecting, skip the current commit.
Use this if for some reason the current commit is not a good one
to test. This command lets Git choose a different one."
(interactive)
(magit-git-bisect "skip"))
;;;###autoload
(defun magit-bisect-run (cmdline &optional bad good args)
"Bisect automatically by running commands after each step.
Unlike `git bisect run' this can be used before bisecting has
begun. In that case it behaves like `git bisect start; git
bisect run'."
(interactive (let ((args (and (not (magit-bisect-in-progress-p))
(magit-bisect-start-read-args))))
(cons (read-shell-command "Bisect shell command: ") args)))
(when (and bad good)
;; Avoid `magit-git-bisect' because it's asynchronous, but the
;; next `git bisect run' call requires the bisect to be started.
(magit-with-toplevel
(magit-process-git
(list :file (magit-git-dir "BISECT_CMD_OUTPUT"))
(magit-process-git-arguments
(list "bisect" "start" bad good args)))
(magit-refresh)))
(magit--with-connection-local-variables
(magit-git-bisect "run" (list shell-file-name
shell-command-switch cmdline))))
(defun magit-git-bisect (subcommand &optional args no-assert)
(unless (or no-assert (magit-bisect-in-progress-p))
(user-error "Not bisecting"))
(message "Bisecting...")
(magit-with-toplevel
(magit-run-git-async "bisect" subcommand args))
(set-process-sentinel
magit-this-process
(lambda (process event)
(when (memq (process-status process) '(exit signal))
(if (> (process-exit-status process) 0)
(magit-process-sentinel process event)
(process-put process 'inhibit-refresh t)
(magit-process-sentinel process event)
(when (buffer-live-p (process-buffer process))
(with-current-buffer (process-buffer process)
(when-let* ((section (magit-section-at))
(output (buffer-substring-no-properties
(oref section content)
(oref section end))))
(with-temp-file (magit-git-dir "BISECT_CMD_OUTPUT")
(insert output)))))
(magit-refresh))
(message "Bisecting...done")))))
;;; Sections
(defun magit-bisect-in-progress-p ()
(file-exists-p (magit-git-dir "BISECT_LOG")))
(defun magit-bisect-terms ()
(magit-file-lines (magit-git-dir "BISECT_TERMS")))
(defun magit-insert-bisect-output ()
"While bisecting, insert section with output from `git bisect'."
(when (magit-bisect-in-progress-p)
(let* ((lines
(or (magit-file-lines (magit-git-dir "BISECT_CMD_OUTPUT"))
(list "Bisecting: (no saved bisect output)"
"It appears you have invoked `git bisect' from a shell."
"There is nothing wrong with that, we just cannot display"
"anything useful here. Consult the shell output instead.")))
(done-re "^\\([a-z0-9]\\{40,\\}\\) is the first bad commit$")
(bad-line (or (and (string-match done-re (car lines))
(pop lines))
(--first (string-match done-re it) lines))))
(magit-insert-section ((eval (if bad-line 'commit 'bisect-output))
(and bad-line (match-string 1 bad-line)))
(magit-insert-heading
(propertize (or bad-line (pop lines))
'font-lock-face 'magit-section-heading))
(dolist (line lines)
(insert line "\n"))))
(insert "\n")))
(defun magit-insert-bisect-rest ()
"While bisecting, insert section visualizing the bisect state."
(when (magit-bisect-in-progress-p)
(magit-insert-section (bisect-view)
(magit-insert-heading "Bisect Rest:")
(magit-git-wash (apply-partially #'magit-log-wash-log 'bisect-vis)
"bisect" "visualize" "git" "log"
"--format=%h%x00%D%x00%s" "--decorate=full"
(and magit-bisect-show-graph "--graph")))))
(defun magit-insert-bisect-log ()
"While bisecting, insert section logging bisect progress."
(when (magit-bisect-in-progress-p)
(magit-insert-section (bisect-log)
(magit-insert-heading "Bisect Log:")
(magit-git-wash #'magit-wash-bisect-log "bisect" "log")
(insert ?\n))))
(defun magit-wash-bisect-log (_args)
(let (beg)
(while (progn (setq beg (point-marker))
(re-search-forward "^\\(git bisect [^\n]+\n\\)" nil t))
(magit-bind-match-strings (heading) nil
(magit-delete-match)
(save-restriction
(narrow-to-region beg (point))
(goto-char (point-min))
(magit-insert-section (bisect-item heading t)
(insert (propertize heading 'font-lock-face
'magit-section-secondary-heading))
(magit-insert-heading)
(magit-wash-sequence
(apply-partially #'magit-log-wash-rev 'bisect-log
(magit-abbrev-length)))
(insert ?\n)))))
(when (re-search-forward
"# first bad commit: \\[\\([a-z0-9]\\{40,\\}\\)\\] [^\n]+\n" nil t)
(magit-bind-match-strings (hash) nil
(magit-delete-match)
(magit-insert-section (bisect-item)
(insert hash " is the first bad commit\n"))))))
;;; _
(provide 'magit-bisect)
;;; magit-bisect.el ends here