#!/usr/bin/perl -w
+# usage:
+# .../badcommit-fixup --test
+# .../badcommit-fixup --real
+
use strict;
-set -e
-set -o pipefail
-
-tmp=.git/dgit-badcommit-fixup-tmp
-rm -rf $tmp
-mkdir $tmp
-
-LC_MESSAGES=C git fsck --no-dangling >$tmp/gfo 2>&1 || test $? = 1
-
-perl -ne '
- print $1, "\n" or die $! if
- m/^error in commit (\w+):.*invalid format - expected '\''committer/;
-' <$tmp/gfo >$tmp/bad
-
-case `wc -l <$tmp/bad` in
- 0)
- echo >&2 'nothing bad found - is git-fsck doing as we expect?' ;
- exit 8 ;;
- 1)
- read <$tmp/bad bads
- nots="^$bads^0 ^$bads^1"
- ;;
- *)
- bads="cat $tmp/bad"
- ;;
-esac
-
-args="$nots"
-
-refs=`git-for-each-ref --format='%(refname)'`
-
-if git-symbolic-ref HEAD >/dev/null 2>&1; then
- refs+=' HEAD'
-fi
-
-for head in $refs; do
- exec <$tmp/bad
- needed=false
- for bad in $bads; do
- if git merge-base --is-ancestor $bad $head; then
- needed=true
- break
- fi
- done
- if ! $needed; then continue; fi
- args+=" $head"
-done
-
-git filter-branch --original dgit-badcommit --commit-filter '
-echo >&2 "FOO $*"
-cat >&2
-echo >&2 ====
-false
- sed -e '\''1,/^$/ s/^commiter /committer /'\''
-' $args
+use POSIX;
+use IPC::Open2;
+use Data::Dumper;
+
+die unless "@ARGV" eq "--test" or "@ARGV" eq "--real";
+
+my ($modeopt) = @ARGV;
+my $real = ($modeopt eq '--real');
+
+my $gcfpid = open2 \*GCFO, \*GCFI, 'git cat-file --batch' or die $!;
+
+our %count;
+
+no warnings qw(recursion);
+
+sub getobj ($$) {
+ my ($obj, $type) = @_;
+ print GCFI $obj, "\n" or die $!;
+ my $x = <GCFO>;
+ my ($gtype, $gsize) = $x =~ m/^\w+ (\w+) (\d+)\n/ or die "$obj ?";
+ $gtype eq $type or die "$obj $gtype != $type ?";
+ my $gdata;
+ (read GCFO, $gdata, $gsize) == $gsize or die "$obj $!";
+#print STDERR ">$obj|$x|$gdata|$gsize<\n";
+ $x = <GCFO>;
+ $x eq "\n" or die "$obj ($_) $!";
+ $count{inspected}++;
+ return $gdata;
+}
+
+sub hashobj ($$) {
+ my ($data,$type) = @_;
+ my $gwopid = open2 \*GWO, \*GWI,
+ "git hash-object -w -t $type --stdin"
+ or die $!;
+ print GWI $data or die $!;
+ close GWI or die $!;
+ $_ = <GWO>;
+ close GWO or die $!;
+ waitpid $gwopid,0 == $gwopid or die $!;
+ die $? if $?;
+ m/^(\w+)\n/ or die "$_ ?";
+ $count{"rewritten $type"}++;
+ return $1;
+}
+
+our %memo;
+
+sub rewrite_commit ($);
+sub rewrite_commit ($) {
+ my ($obj) = @_;
+ my $m = \ $memo{$obj};
+ return $$m if defined $$m;
+ my $olddata = getobj $obj, 'commit';
+ $olddata =~ m/(?<=\n)(?=\n)/ or die "$obj ?";
+ my $msg = $';
+ $_ = $`;
+ s{^(parent )(\w+)$}{ $1 . rewrite_commit($2) }gme;
+ $count{'fix overwrite'} += s{^commiter }{committer }gm;
+ if (!m{^author }m && !m{^committer }m) {
+ m{^parent (\w+)}m or die "$obj ?";
+ my $parent = getobj $1, 'commit';
+ $parent =~ m/^(?:.+\n)+(author .*\ncommitter .*\n)/;
+ m/\n$/ or die "$obj ?";
+ $_ .= $1;
+ $count{'fix import'}++;
+ }
+ my $newdata = $_.$msg;
+ my $newobj;
+ if ($newdata eq $olddata) {
+ $newobj = $obj;
+ $count{unchanged}++;
+ } else {
+ $newobj = hashobj $newdata, 'commit';
+ }
+ $$m= $newobj;
+ return $newobj;
+}
+
+sub rewrite_tag ($) {
+ my ($obj) = @_;
+ $_ = getobj $obj, 'tag';
+ m/^type (\w+)\n/m or die "$obj ?";
+ if ($1 ne 'commit') {
+ $count{"oddtags $1"}++;
+ return $obj;
+ }
+ m/^object (\w+)\n/m or die "$obj ?";
+ my $oldref = $1;
+ my $newref = rewrite_commit $oldref;
+ if ($oldref eq $newref) {
+ return $obj;
+ }
+ s/^(object )\w+$/ $1.$newref /me or die "$obj ($_) ?";
+ s/^-----BEGIN PGP SIGNATURE-----\n.*^-----END PGP SIGNATURE-----\n$//sm;
+ return hashobj $_, 'tag';
+}
+
+$!=0; $?=0;
+my $refs=`git for-each-ref`;
+die "$? $!" if $?;
+
+chomp $refs;
+
+our @updates;
+
+foreach my $rline (split /\n/, $refs) {
+ my ($obj, $type, $refname) =
+ $rline =~ m/^(\w+)\s+(\w+)\s+(\S.*)/
+ or die "$_ ?";
+ my $rewrite;
+ if ($type eq 'commit') {
+ $rewrite = rewrite_commit($obj);
+ } elsif ($type eq 'tag') {
+ $rewrite = rewrite_tag($obj);
+ } else {
+ warn "ref $refname refers to $type\n";
+ next;
+ }
+ next if $rewrite eq $obj;
+ push @updates, [ $refname, $obj, $rewrite ];
+}
+
+open U, "|git update-ref -m 'dgit bad commit fixup' --stdin" or die $!;
+
+if ($real) {
+ $!=0; $?=0;
+ my $bare = `git rev-parse --is-bare-repository`;
+ die "$? $!" if $?;
+ if ($bare eq 'false') {
+ print "detaching your HEAD\n" or die $!;
+ system 'git checkout --detach' and die "$! $?";
+ }
+}
+
+for my $up (@updates) {
+ my ($ref, $old, $new) = @$up;
+ my $otherref = $ref;
+ $otherref =~ s{^refs/}{};
+ if ($real) {
+ print U <<END or die $!;
+create refs/dgit-badcommit/$otherref $old
+update $ref $new $old
+END
+ } else {
+ print U <<END or die $!;
+update refs/dgit-badfixuptest/$otherref $new
+END
+ }
+}
+
+$?=0; $!=0;
+close U or die "$? $!";
+die $? if $?;
+
+print Dumper(\%count);
+
+if ($real) {
+ print "old values saved in refs/dgit-badcommit/\n" or die $!;
+} else {
+ print "testing output saved in refs/dgit-badfixuptest/\n" or die $!;
+}