master 208f0578d1: Add a script to ease bisecting.

[Gregory Heytings]

branch: master
commit 208f0578d1e523762c356895c21cde47f909fd7c
Author: Gregory Heytings <gregory@heytings.org>
Commit: Gregory Heytings <gregory@heytings.org>

    Add a script to ease bisecting.
    
    * admin/git-bisect-start: New script.
    
    * admin/notes/repo (Bisecting): Mention the script.
    
    * admin/emake: Add a Copyright blurb.
---
 admin/emake            | 17 +++++++++++++++++
 admin/git-bisect-start | 27 +++++++++++++++++++++++++++
 admin/notes/repo       |  7 +++----
 3 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/admin/emake b/admin/emake
index e2f38501e9..09f7410779 100755
--- a/admin/emake
+++ b/admin/emake
@@ -1,5 +1,22 @@
 #!/bin/bash
 
+# Copyright (C) 2022 Free Software Foundation, Inc.
+
+# This file is part of GNU Emacs.
+
+# GNU Emacs 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.
+
+# GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
 # This script is meant to be used as ./admin/emake, and will compile
 # the Emacs tree with virtually all of the informational messages
 # removed, and with errors/warnings highlighted in red.  It'll give a
diff --git a/admin/git-bisect-start b/admin/git-bisect-start
new file mode 100755
index 0000000000..889c959875
--- /dev/null
+++ b/admin/git-bisect-start
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+# Start a git bisection, and prune the branches that are the result of
+# merging external trees into the Emacs repository.
+
+# Copyright (C) 2022 Free Software Foundation, Inc.
+
+# This file is part of GNU Emacs.
+
+# GNU Emacs 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.
+
+# GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+git bisect start
+
+# Prune commits 1e5b753bf4..806734c1b1 introduced by 0186faf2a1 (Eglot
+# merge on Oct 20 2022)
+git bisect good 806734c1b1
diff --git a/admin/notes/repo b/admin/notes/repo
index afba3dca8f..97f02ab605 100644
--- a/admin/notes/repo
+++ b/admin/notes/repo
@@ -128,10 +128,9 @@ again.
 This is a semi-automated way to find the revision that introduced a bug.
 Browse 'git help bisect' for technical instructions.
 
-Depending on what you want to do, it can be helpful to start bisecing
-with the option '--first-parent', like `git bisect start
---first-parent', which makes bisect ignore commits coming into a
-branch from merges.
+It is recommended to start a bisection with the admin/git-bisect-start
+script.  This script prunes the branches that are the result of
+merging external trees into the Emacs repository.
 
 * Maintaining ChangeLog history