-#!/bin/bash
+#!/usr/bin/perl
+
+# git-branchmove -- move branches to or from a remote
+
+# Copyright (C) 2019 Sean Whitton
+#
+# This program 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.
+#
+# This program 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.
#
-# Moves a branch to or from the current git tree to or from
-# another git tree
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This script is based on Ian Jackson's git-branchmove script, in the
+# chiark-utils Debian source package. Ian's script assumes throughout
+# that it is possible to have unrestricted shell access to the remote,
+# however, while this script avoids that global assumption.
#
-# usage: git-branchmove get|put REMOTE PATTERN
-
-set -e
-set -o posix
-
-fail () { echo >&2 "git-branchmove: $*"; exit 16; }
-badusage () { fail "bad usage: $*"; }
-
-if [ $# -lt 3 ]; then badusage "too few arguments"; fi
-
-op="$1"; shift
-case "$op" in get|put) ;; *) badusage "unknown operation \`$op'"; esac
-
-remote="$1"; shift
-
-# Plan of attack:
-# determine execute-sh runes for src and dst trees
-# list affected branches on source
-# check that source branches are not checked out
-# list affected branches on destination and moan if any nonequal overlap
-# transfer src->dst refs/heads/BRANCH:refs/heads/BRANCH
-# transfer and merge reflog(s) xxx todo
-# delete src refs
-
-case "$remote" in
-*:*) remoteurl="$remote" ;;
-[/.]*) remoteurl="$remote" ;;
-*) remoteurl="$(
- git config remote."$remote".pushurl ||
- git config remote."$remote".url ||
- fail "no pushurl or url defined for remote $remote"
- )"
- remotename="$remote"
-esac
-
-remote_spec="$(perl -e '
- $_ = $ARGV[0];
- if (m#^ssh://([^:/]+)(?:\:(\w+))?#) {
- print "$'\''|ssh ";
- print " -p $3" if $2;
- print "$1\n";
- } elsif (m#^([-+_.0-9a-zA-Z\@]+):(?!//|:)#) {
- print "$'\''|ssh $1\n";
- } elsif (m#^[/.]#) {
- print "$_|sh -c $1\n";
+# As much as possible we treat the remote argument as opaque, i.e., we
+# don't distinguish between git URIs and named remotes. That means
+# that git will expand insteadOf and pushInsteadOf user config for us.
+
+=head1 NAME
+
+git-branchmove - move branches to or from a remote
+
+=head1 SYNOPSIS
+
+B<git-branchmove> [B<--detach>|B<-d>] B<get>|B<put> I<remote> I<pattern>...
+
+=head1 DESCRIPTION
+
+Move branches matching I<pattern> to or from git remote I<remote>.
+
+=head1 OPTIONS
+
+=over 4
+
+=item B<--detach>|B<-d>
+
+If the move would delete the currently checked out branch in the
+source repository, attempt to detach HEAD first.
+
+Note that in the case of the B<get> operation, the attempt to detach
+HEAD is somewhat fragile. You will need unrestricted SSH access to
+the remote, and pushInsteadOf git configuration keys will not always
+be expanded, due to limitations in git.
+
+=back
+
+=head1 AUTHOR
+
+This Perl version of B<git-branchmove> was written by Sean Whitton
+<spwhitton@spwhitton.name>, based on an earlier shell script by Ian
+Jackson. That script made some assumptions that we try to avoid, for
+compatibility with more git remotes and local git configurations.
+
+=cut
+
+use strict;
+use warnings;
+
+use Git::Wrapper;
+use Try::Tiny;
+
+# git wrapper setup
+my $git = Git::Wrapper->new(".");
+try {
+ $git->rev_parse({ git_dir => 1 });
+} catch {
+ die "git-branchmove: pwd doesn't look like a git repository ..\n";
+};
+
+# process arguments
+die "git-branchmove: not enough arguments\n" if @ARGV < 3;
+my $attempt_detach = 0;
+if ($ARGV[0] eq '-d' or $ARGV[0] eq '--detach') {
+ $attempt_detach = 1;
+ shift @ARGV;
+}
+my ($op, $remote, @patterns) = @ARGV;
+die "git-branchmove: unknown operation\n"
+ unless $op eq 'get' or $op eq 'put';
+
+# is this a named remote or a git URL? See "GIT URLS" in git-fetch(1)
+my $named_remote = not($remote =~ m|:| or $remote =~ m|^[/.]|);
+
+# Attempt to determine how we might be able to run commands in the
+# remote repo. This will only be used if we need to try to detach the
+# remote HEAD. These regexps are lifted from Ian's version of
+# git-branchmove
+my ($rurl, $rrune, $rdir);
+if ($named_remote) {
+ # this will expand insteadOf and pushInsteadOf
+ ($rurl) = $git->remote("get-url", "--push", $remote);
+} else {
+ # this will expand insteadOf but not pushInsteadOf, which is the
+ # best we can do; see <https://stackoverflow.com/a/32991784>
+ ($rurl) = $git->ls_remote("--get-url", $remote);
+}
+if ($rurl =~ m#^ssh://([^:/]+)(?:\:(\w+))?#) {
+ $rdir = $';
+ $rrune = "ssh ";
+ $rrune .= "-p $2 " if $2;
+ $rrune .= $1;
+} elsif ($rurl =~ m#^([-+_.0-9a-zA-Z\@]+):(?!//|:)#) {
+ $rdir = $';
+ $rrune = "ssh $1";
+} elsif ($rurl =~ m#^[/.]#) {
+ $rdir = $rurl;
+}
+
+# If we don't prefix the patterns, we might match branches the user
+# doesn't intend. E.g. 'foo' would match 'wip/foo'
+my @branch_pats = map { s|^|[r]efs/heads/|r } @patterns;
+
+# get lists of branches, prefixed with 'refs/heads/' in each case
+my (@source_branches, @dest_branches);
+my @local_branches = map {
+ my ($hash, undef, $ref) = split ' ';
+ { hash => $hash, ref => $ref }
+} $git->for_each_ref(@branch_pats);
+my @remote_branches = map {
+ my ($hash, $ref) = split ' ';
+ { hash => $hash, ref => $ref }
+} $git->ls_remote($remote, @branch_pats);
+if ($op eq 'put') {
+ @source_branches = @local_branches;
+ @dest_branches = @remote_branches;
+} elsif ($op eq 'get') {
+ @source_branches = @remote_branches;
+ @dest_branches = @local_branches;
+}
+
+# do we have anything to move?
+die "git-branchmove: nothing to do\n" unless @source_branches;
+
+# check for deleting the current branch on the source
+my $source_head;
+if ($op eq "put") {
+ my @lines = try { $git->symbolic_ref('-q', 'HEAD') };
+ $source_head = $lines[0] if @lines; # the HEAD is not detached
+} elsif ($op eq "get") {
+ my @lines = try { $git->ls_remote('--symref', $remote, 'HEAD') };
+ if (@lines and $lines[0] =~ m|^ref: refs/heads/|) {
+ # the HEAD is not detached
+ (undef, $source_head) = split ' ', $lines[0];
+ }
+}
+if (defined $source_head and grep /^\Q$source_head\E$/,
+ map { $_->{ref} } @source_branches) {
+ if ($attempt_detach) {
+ if ($op eq 'put') {
+ $git->checkout('--detach');
+ } elsif ($op eq 'get') {
+ if (defined $rrune and defined $rdir) {
+ system "$rrune \"set -e; cd $rdir; git checkout --detach\"";
+ die "failed to detach remote HEAD" unless $? eq 0;
+ } elsif (!defined $rrune and defined $rdir) {
+ my $dest_git = Git::Wrapper->new($rdir);
+ $dest_git->checkout('--detach');
+ } else {
+ die "git-branchmove: don't know how to detach remote HEAD";
+ }
+ }
} else {
- die "git-branchmove: unsupported remote url \`$_'\''\n";
+ die "git-branchmove: would delete checked-out branch $source_head\n";
+ }
+}
+
+# check whether we would overwrite anything
+foreach my $source_branch (@source_branches) {
+ foreach my $dest_branch (@dest_branches) {
+ die "git-branchmove: would overwrite $source_branch->{ref}"
+ if ( $source_branch->{ref} eq $dest_branch->{ref}
+ and $source_branch->{hash} ne $dest_branch->{hash});
+ }
+}
+
+# time to actually move the branches
+my @refspecs = map { "$_->{ref}:$_->{ref}" } @source_branches;
+my @nuke_refspecs = map { ":$_->{ref}" } @source_branches;
+if ($op eq 'put') {
+ $git->push('--no-follow-tags', $remote, @refspecs);
+ $git->update_ref('-m', "git-branchmove: moved to $remote ($rurl)",
+ '-d', $_->{ref}, $_->{hash})
+ for @source_branches;
+} elsif ($op eq 'get') {
+ $git->fetch('--no-tags', $remote, @refspecs);
+ $git->push('--no-follow-tags', $remote, @nuke_refspecs);
+}
+
+# if the remote is a named remote, rather than just a URI, update
+# remote-tracking branches
+if ($named_remote) {
+ foreach my $source_branch (@source_branches) {
+ my $branch = $source_branch->{ref} =~ s|^refs/heads/||r;
+ my $tracking_ref = "refs/remotes/$remote/$branch";
+ if ($op eq 'put') {
+ $git->update_ref($tracking_ref, $source_branch->{hash});
+ } elsif ($op eq 'get') {
+ $git->update_ref('-d', $tracking_ref);
+ }
}
-' "$remoteurl")"
-
-remote_path="${remote_spec%%|*}"
-remote_rune="${remote_spec#*|}"
-
-case $op in
-get)
- src_rune="$remote_rune"
- src_path="$remote_path"
- dst_rune="sh -c"
- dst_path=.
- updatemsg="git-branchmove: moved to $remote ($remoteurl)"
- push_fetch=fetch
- ;;
-put)
- dst_rune="$remote_rune"
- dst_path="$remote_path"
- src_rune="sh -c"
- src_path=.
- updatemsg="git-branchmove; moved to `hostname -f` by `whoami`"
- push_fetch=push
- ;;
-esac
-
-on_src () { $src_rune "set -e; cd $src_path; $*"; }
-on_dst () { $dst_rune "set -e; cd $dst_path; $*"; }
-
-
-#----- fetch the current refs from both sides -----
-
-branch_pats=''
-for branch_pat in "$@"; do
- branch_pats+=" '[r]efs/heads/$branch_pat'"
-done
-
-get_branches_rune='
- git for-each-ref --format="%(refname)=%(objectname)" '"$branch_pats"'
-'
-
-src_branches=( $(
- on_src '
- printf H
- git symbolic-ref -q HEAD || test $? = 1
- echo " "
- '"$get_branches_rune"'
- '
-))
-
-src_head="${src_branches[0]}"
-unset src_branches[0]
-: "${src_branches[@]}"
-
-case "$src_head" in
-H) ;; # already detached
-*)
- src_head="${src_head#H}"
- for check in "${src_branches[@]}"; do
- case "$check" in
- "$src_head"=*)
- fail "would delete checked-out branch $src_head"
- ;;
- esac
- done
- ;;
-esac
-
-
-if [ "${#src_branches[@]}" = 0 ]; then
- echo >&2 "git-branchmove: nothing to do"
- exit 1
-fi
-
-dst_branches=( $(on_dst "$get_branches_rune") )
-: "${dst_branches[@]}"
-
-
-#----- check for nonequal overlaps -----
-
-ok=true
-for dst_check in "${dst_branches[@]}"; do
- dst_ref="${dst_check%=*}"
- for src_check in "${src_branches[@]}"; do
- case "$src_check" in
- "$dst_check") ;;
- "$dst_ref"=*)
- ok=false
- echo >&2 "src: $src_check dst: $dst_check"
- ;;
- esac
- done
-done
-
-$ok || fail "would overwrite some destination branch(es)"
-
-
-#----- do the transfer -----
-
-refspecs=()
-for src_xfer in "${src_branches[@]}"; do
- src_ref="${src_xfer%=*}"
- refspecs+=("$src_ref:$src_ref")
-done
-
-case "$op" in
-put) git push --no-follow-tags "$remote" "${refspecs[@]}" ;;
-get) git fetch --no-tags "$remote" "${refspecs[@]}" ;;
-*) fail "unknown $op ???" ;;
-esac
-
-
-#----- delete the refs on the source -----
-
-(
- printf "%s\n" "$updatemsg"
- for src_rm in "${src_branches[@]}"; do printf "%s\n" "$src_rm"; done
-) | on_src '
- read updatemsg
- while read src_rm; do
- src_ref="${src_rm%=*}"
- src_obj="${src_rm##*=}"
- git update-ref -m "$updatemsg" -d "$src_ref" "$src_obj"
- echo "moved: $src_ref"
- done
-'
-
-#----- update the remote tracking branches -----
-
-if [ "x$remotename" != x ]; then
- for src_rm in "${src_branches[@]}"; do
- src_ref="${src_rm%=*}"
- src_obj="${src_rm##*=}"
-
- case "$src_ref" in
- refs/heads/*) ;;
- *) continue ;;
- esac
-
- branch="${src_ref#refs/heads/}"
- track_ref="refs/remotes/$remotename/$branch"
- case $op in
- get) git update-ref -d "$track_ref" ;;
- put) git update-ref "$track_ref" "$src_obj" ;;
- *) fail "unknown $op ???"
- esac
- done
-fi
-
-echo "git-repomove: moved ${#src_branches[@]} branches."
+}
~ian / chiark-utils.git / commitdiff