3 # Script helping make fast-forwarding histories while still rebasing
4 # upstream deltas when working on Debian packaging
6 # Copyright (C)2017 Ian Jackson
8 # This program 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.
13 # This program 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.
18 # You should have received a copy of the GNU General Public License
19 # along with this program. If not, see <http://www.gnu.org/licenses/>.
21 # git-debrebase new-upstreams-v0 \
22 # NEW-VERSION ORIG-COMMITISH
23 # [EXTRA-ORIG-NAME EXTRA-ORIG-COMMITISH ...]
26 # git-debrebase status
27 # git-debrebase start # like ffqrebase start + debrebase launder
28 # git-debrebase new-upstream [stuff] # see below
29 # git-debrebase <git-rebase options> # does debrebase start if necessary
31 # git-debrebase analyse
32 # git-debrebase launder # prints breakwater tip
33 # git-debrebase create-new-upstream-breakwater [-f] <upstreaminfo>...
36 # [,][<subdir>:][+]<commitid>[,...]
38 # if initial comma is supplied, entries are not positional. Unspecified
39 # <subdir> means root (and there may be only one).
40 # xxx want auto branch names
43 # [+]<commit> [<subdir/> [+]<commit>...]
45 # --new-upstream-different-subtrees
48 # git-debrebase new-upstream
49 # - previous breakwater merge must be gdr-generated
50 # - orig set is the same as before
51 # - implicitly uses upstream branches according to orig set
52 # - not all upstream branches need be updated
53 # - insists on fast-forward of each branch, unless
54 # --force (or --force=<subdir>[/])
55 # branch set adjustments
56 # git-debrebase new-upstream --add <subdir>/
57 # git-debrebase new-upstream --rm <subdir>/
58 # git-debrebase new-upstream / [<subdir>/ ...]
59 # - orig set is adjusted
60 # - otherwise like auto (--add is not checked for ffness, obv)
61 # - multiple --add and --rm may be specified
62 # - --add makes new upstream the last contributor
64 # git-debrebase / [<rootcommitid>] [<subdir>/ [<commitid>] ...]
65 # - orig set is precisely as specified now
66 # - previous breakwater merge is irrelevant
67 # - no fast forward checks
68 # for now only explicit with commitids
70 # implicitly uses `upstream'
71 # # (or multiple other branches)
72 # git-debrebase new-upstream \
73 # [<subdir>/]=<commitid>
75 # UPSTREAM[,[[SUBDIR:]SUBUPSTREAM]
76 # default for SUBDIR: is from previous upstream merge[xxx terminology]
80 # when starting must record original start (for ff)
81 # and new rebase basis
83 # git-ffqrebase start [BASE]
84 # # records previous HEAD so it can be overwritten
85 # # records base for future git-ffqrebase
86 # git-ffqrebase set-base BASE
87 # git-ffqrebase <git-rebase options>
88 # git-ffqrebase finish
89 # git-ffqrebase status [BRANCH]
91 # refs/ffqrebase-prev/BRANCH BRANCH may be refs/...; if not it means
92 # refs/ffqrebase-base/BRANCH refs/heads/BRANCH
93 # zero, one, or both of these may exist
95 # git-debrebase without start, if already started, is willing
96 # to strip pseudomerges provided that they overwrite exactly
98 # xxxx is this right ? what matters is have we pushed
99 # I think in fact the right answer is:
100 # git-debrebase always strips out pseudomerges from its branch
101 # a pseudomerge is put in at the time we want to push
102 # at that time, we make a pseudomerge of the remote tracking
103 # branch (if raw git) or the dgit view (if dgit)
104 # for raw git git-ffqrebase, do want preciseley to record
105 # value of remote tracking branch or our branch, on start, so we
106 # overwrite only things we intend to
107 # the previous pseudomerge check for tags and remote branches ?
111 use Debian::Dgit qw(:DEFAULT :playground);
118 use Getopt::Long qw(:config posix_default gnu_compat bundling);
122 die "bad usage: $m\n";
128 my @cmd = qw(git config -z);
129 push @cmd, qw(--get-all) if wantarray;
131 my $out = cmdoutput @cmd;
132 return split /\0/, $out;
139 my $data = git_cat_file $objid, 'commit';
140 $data =~ m/(?<=\n)\n/ or die "$objid ($data) ?";
144 sub D_UPS () { 0x02; } # upstream files
145 sub D_PAT_ADD () { 0x04; } # debian/patches/ extra patches at end
146 sub D_PAT_OTH () { 0x08; } # debian/patches other changes
147 sub D_DEB_CLOG () { 0x10; } # debian/ (not patches/ or changelog)
148 sub D_DEB_OTH () { 0x20; } # debian/changelog
149 sub DS_DEB () { D_DEB_CLOG | D_DEB_OTH; } # debian/ (not patches/)
151 our $playprefix = 'debrebase';
157 sub in_workarea ($) {
160 my $r = eval { $sub->(); };
161 { local $@; changedir $maindir; }
165 sub fresh_workarea () {
166 $workarea = fresh_playground "$playprefix/work";
167 in_workarea sub { playtree_setup };
170 sub get_differs ($$) {
172 # This resembles quiltify_trees_differ, in dgit, a bit.
173 # But we don't care about modes, or dpkg-source-unrepresentable
174 # changes, and we don't need the plethora of different modes.
175 # Conversely we need to distinguish different kinds of changes to
176 # debian/ and debian/patches/.
181 my ($opts, $limits, $fn) = @_;
182 my @cmd = (@git, qw(diff-tree -z --no-renames));
184 push @cmd, "$_:" foreach $x, $y;
186 my $diffs = cmdoutput @cmd;
187 foreach (split /\0/, $diffs) { $fn->(); }
190 $rundiff->([qw(--name-only)], [], sub {
191 $differs |= $_ eq 'debian' ? DS_DEB : D_UPS;
194 if ($differs & DS_DEB) {
196 $rundiff->([qw(--name-only -r)], [qw(debian)], sub {
198 m{^debian/patches/} ? D_PAT_OTH :
199 $_ eq 'debian/changelog' ? D_DEB_CLOG :
202 die "mysterious debian changes $x..$y"
203 unless $differs & (D_PAT_OTH|DS_DEB);
206 if ($differs & D_PAT_OTH) {
208 $differs &= ~D_PAT_OTH;
210 $differs |= D_PAT_OTH;
211 no warnings qw(exiting); last;
213 $rundiff->([qw(--name-status -r)], [qw(debian/patches/)], sub {
214 no warnings qw(exiting);
215 if (!defined $mode) {
218 die unless s{^debian/patches/}{};
220 if ($mode eq 'A' && !m/\.series$/s) {
222 } elsif ($mode eq 'M' && $_ eq 'series') {
223 my $x_s = git_cat_file "$x:debian/patches/series", 'blob';
224 my $y_s = git_cat_file "$y:debian/patches/series", 'blob';
225 chomp $x_s; $x_s .= "\n";
226 $ok = $x_s eq substr($y_s, 0, length $x_s);
231 $differs |= $ok ? D_PAT_ADD : D_PAT_OTH;
233 die "mysterious debian/patches changes $x..$y"
234 unless $differs & (D_PAT_ADD|D_PAT_OTH);
237 printdebug sprintf "get_differs %s, %s = %#x\n", $x, $y, $differs;
242 sub commit_pr_info ($) {
244 return Data::Dumper->dump([$r], [qw(commit)]);
247 sub calculate_committer_authline () {
248 my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
249 'DUMMY COMMIT (git-debrebase)', "HEAD:";
250 my ($h,$m) = get_commit $c;
251 $h =~ m/^committer .*$/m or confess "($h) ?";
255 # classify returns an info hash like this
257 # Hdr => # commit headers, including 1 final newline
258 # Msg => # commit message (so one newline is dropped)
260 # Type => (see below)
262 # Ix => $index # ie 0, 1, 2, ...
264 # Differs => return value from get_differs
266 # IsDggitImport => 'orig' 'tarball' 'unpatched' 'package' (as from dgit)
268 # NewMsg => # commit message, but with any [dgit import ...] edited
269 # # to say "[was: ...]"
280 # has additional entres in classification result
281 # Overwritten = [ subset of Parents ]
282 # Contributor = $the_remaining_Parent
284 # DgitImportUnpatched
285 # has additional entry in classification result
286 # OrigParents = [ subset of Parents ]
288 # BreakwaterUpstreamMerge
289 # has additional entry in classification result
290 # OrigParents = [ subset of Parents ] # singleton list
292 sub parsecommit ($;$) {
293 my ($objid, $p_ref) = @_;
294 # => hash with CommitId Hdr Msg Tree Parents
295 # Parents entries have only Ix CommitId
296 # $p_ref, if provided, must be [] and is used as a base for Parents
301 my ($h,$m) = get_commit $objid;
303 my ($t) = $h =~ m/^tree (\w+)$/m or die $objid;
304 my (@ph) = $h =~ m/^parent (\w+)$/mg;
314 foreach my $ph (@ph) {
328 my $r = parsecommit($objid, \@p);
332 $p->{Differs} => (get_differs $p->{CommitId}, $t),
335 printdebug "classify $objid \$t=$t \@p",
336 (map { sprintf " %s/%#x", $_->{CommitId}, $_->{Differs} } @p),
340 my ($type, @rest) = @_;
341 $r = { %$r, Type => $type, @rest };
343 my $dd = new Data::Dumper [ $r ];
344 Terse $dd 1; Indent $dd 0; Useqq $dd 1;
345 printdebug " = $type ".(Dump $dd)."\n";
351 $r = { %$r, Type => qw(Unknown) };
352 printdebug " ** Unknown\n";
357 my $d = $r->{Parents}[0]{Differs};
358 if ($d == D_PAT_ADD) {
359 return $classify->(qw(AddPatches));
360 } elsif ($d & (D_PAT_ADD|D_PAT_OTH)) {
361 return $unknown->("edits debian/patches");
362 } elsif ($d & DS_DEB and !($d & ~DS_DEB)) {
363 my ($ty,$dummy) = git_cat_file "$ph[0]:debian";
365 if ($d == D_DEB_CLOG) {
366 return $classify->(qw(Changelog));
368 return $classify->(qw(Packaging));
370 } elsif ($ty eq 'missing') {
371 return $classify->(qw(BreakwaterStart));
373 return $unknown->("parent's debian is not a directory");
375 } elsif ($d == D_UPS) {
376 return $classify->(qw(Upstream));
377 } elsif ($d & DS_DEB and $d & D_UPS and !($d & ~(DS_DEB|D_UPS))) {
378 return $classify->(qw(Mixed));
380 return $unknown->("no changes");
382 confess "internal error $objid ?";
386 return $unknown->("origin commit");
389 my @identical = grep { !$_->{Differs} } @p;
390 if (@p == 2 && @identical == 1) {
391 my @overwritten = grep { $_->{Differs} } @p;
392 confess "internal error $objid ?" unless @overwritten==1;
393 return $classify->(qw(Pseudomerge),
394 Overwritten => $overwritten[0],
395 Contributor => $identical[0]);
397 if (@p == 2 && @identical == 2) {
398 my @bytime = nsort_by {
399 my ($ph,$pm) = get_commit $_->{CommitId};
400 $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
403 return $classify->(qw(Pseudomerge),
404 SubType => qw(Ambiguous),
405 Overwritten => $bytime[0],
406 Contributor => $bytime[1]);
409 my ($p_h, $p_m) = get_commit $p->{CommitId};
410 $p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
411 ($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
413 my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' } @p;
415 if (!(grep { !$_->{IsOrigin} } @p) and
416 (@orig_ps >= @p - 1) and
417 $m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
419 return $classify->(qw(DgitImportUnpatched),
420 OrigParents => \@orig_ps);
423 my ($stype, $series) = git_cat_file "$t:debian/patches/series";
424 my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
426 # How to decide about l/r ordering of breakwater merges ? git
427 # --topo-order prefers to expand 2nd parent first. There's
428 # already an easy rune to look for debian/ history anyway (git log
429 # debian/) so debian breakwater branch should be 1st parent; that
430 # way also there's also an easy rune to look for the upstream
431 # patches (--topo-order).
433 # The above tells us which way *we* will generate them. But we
434 # might encounter ad-hoc breakwater merges generated manually,
435 # which might be the other way around. In principle, in some odd
436 # situations, a breakwater merge might have two identical parents.
437 # In that case we guess which way round it is (ie, which parent
438 # has the upstream history). The order of the 2-iteration loop
439 # controls which guess we make.
441 foreach my $prevbrw (qw(0 1)) {
444 !$p[$prevbrw]{IsOrigin} && # breakwater never starts with an origin
445 !($p[$prevbrw]{Differs} & ~DS_DEB) &&
446 !($p[!$prevbrw]{Differs} & ~D_UPS)) {
447 return $classify->(qw(BreakwaterUpstreamMerge),
448 OrigParents => [ $p[!$prevbrw] ]);
452 # multi-orig upstreams are represented with a breakwater merge
453 # from a single upstream commit which combines the orig tarballs
455 return $unknown->("complex merge");
461 $nogenerate,$report) = @_;
462 # => ($tip, $breakwater_tip)
463 # (or nothing, if $nogenerate)
465 # go through commits backwards
466 # we generate two lists of commits to apply:
467 # breakwater branch and upstream patches
468 my (@brw_cl, @upp_cl, @processed);
475 my ($appendinfo) = @_;
478 $ms .= "\n\n[git-debrebase $appendinfo]\n";
481 my $rewrite_from_here = sub {
482 my $sp_cl = { SpecialMethod => 'StartRewrite' };
483 push @brw_cl, $sp_cl;
484 push @processed, $sp_cl;
489 my $prprdelim = sub { print $report $prdelim if $report; $prdelim=""; };
492 return unless $report;
493 print $report $prdelim, @_;
497 my $bomb = sub { # usage: return $bomb->();
498 print $report " Unprocessable" if $report;
501 return (undef,undef);
503 die "commit $cur: Cannot cope with this commit (d.".
504 (join ' ', map { sprintf "%#x", $_->{Differs} }
505 @{ $cl->{Parents} }). ")";
511 my $build_start = sub {
512 my ($msg, $parent) = @_;
515 no warnings qw(exiting); last;
520 my $ty = $cl->{Type};
521 my $st = $cl->{SubType};
522 $prline->("$cl->{CommitId} $cl->{Type}");
523 $found{$ty. ( defined($st) ? "-$st" : '' )}++;
524 push @processed, $cl;
525 my $p0 = @{ $cl->{Parents} }==1 ? $cl->{Parents}[0]{CommitId} : undef;
526 if ($ty eq 'AddPatches') {
528 $rewrite_from_here->();
530 } elsif ($ty eq 'Packaging' or $ty eq 'Changelog') {
534 } elsif ($ty eq 'BreakwaterStart') {
535 $build_start->('FirstPackaging', $cur);
536 } elsif ($ty eq 'Upstream') {
540 } elsif ($ty eq 'Mixed') {
543 my $cls = { %$cl, $xmsg->("split mixed commit: $wh part") };
546 $queue->(\@brw_cl, "debian");
547 $queue->(\@upp_cl, "upstream");
548 $rewrite_from_here->();
551 } elsif ($ty eq 'Pseudomerge') {
552 my $contrib = $cl->{Contributor}{CommitId};
553 print $report " Contributor=$contrib" if $report;
554 push @pseudomerges, $cl;
555 $rewrite_from_here->();
558 } elsif ($ty eq 'BreakwaterUpstreamMerge') {
559 $build_start->("PreviousBreakwater", $cur);
560 } elsif ($ty eq 'DgitImportUnpatched') {
561 my $pm = $pseudomerges[-1];
563 # To an extent, this is heuristic. Imports don't have
564 # a useful history of the debian/ branch. We assume
565 # that the first pseudomerge after an import has a
566 # useful history of debian/, and ignore the histories
567 # from later pseudomerges. Often the first pseudomerge
568 # will be the dgit import of the upload to the actual
569 # suite intended by the non-dgit NMUer, and later
570 # pseudomerges may represent in-archive copies.
571 my $ovwrs = $pm->{Overwritten};
572 printf $report " PM=%s \@Overwr:%d", $pm, (scalar @$ovwrs)
577 my $ovwr = $ovwrs->[0]{CommitId};
578 printf $report " Overwr=%s", $ovwr if $report;
579 # This import has a tree which is just like a
580 # breakwater tree, but it has the wrong history. It
581 # ought to have the previous breakwater (which the
582 # pseudomerge overwrote) as an ancestor. That will
583 # make the history of the debian/ files correct. As
584 # for the upstream version: either it's the same as
585 # was ovewritten (ie, same as the previous
586 # breakwater), in which case that history is precisely
587 # right; or, otherwise, it was a non-gitish upload of a
588 # new upstream version. We can tell these apart by
589 # looking at the tree of the supposed upstream.
592 SpecialMethod => 'DgitImportDebianUpdate',
593 $xmsg->("convert dgit import: debian changes")
595 my $differs = (get_differs $ovwr, $cl->{Tree});
596 printf $report " Differs=%#x", $differs if $report;
597 if ($differs & D_UPS) {
598 printf $report " D_UPS" if $report;
599 # This will also trigger if a non-dgit git-based NMU
600 # deleted .gitignore (which is a thing that some of
601 # the existing git tools do if the user doesn't
602 # somehow tell them not to). Ah well.
605 SpecialMethod => 'DgitImportUpstreamUpdate',
606 $xmsg->("convert dgit import: upstream changes")
609 $prline->(" Import");
610 $rewrite_from_here->();
611 $upp_limit //= $#upp_cl; # further, deeper, patches discarded
615 # Everything is from this import. This kind of import
616 # is already in valid breakwater format, with the
617 # patches as commits.
618 printf $report " NoPM" if $report;
619 # last thing we processed will have been the first patch,
620 # if there is one; which is fine, so no need to rewrite
621 # on account of this import
622 $build_start->("ImportOrigin", $cur);
630 return if $nogenerate;
632 # Now we build it back up again
638 my $rm_tree_cached = sub {
640 runcmd @git, qw(rm --quiet -rf --cached --ignore-unmatch), $subdir;
642 my $read_tree_debian = sub {
644 $rm_tree_cached->(qw(debian));
645 runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
647 my $read_tree_upstream = sub {
649 runcmd @git, qw(read-tree), $treeish;
650 $read_tree_debian->($build);
653 my $committer_authline = calculate_committer_authline();
655 printdebug "WALK REBUILD $build ".(scalar @processed)."\n";
657 confess "internal error" unless $build eq (pop @processed)->{CommitId};
660 mkdir $rd or $!==EEXIST or die $!;
662 runcmd @git, qw(read-tree), $build;
663 foreach my $cl (qw(Debian), (reverse @brw_cl),
664 { SpecialMethod => 'RecordBreakwaterTip' },
665 qw(Upstream), (reverse @upp_cl)) {
667 $current_method = $cl;
670 my $method = $cl->{SpecialMethod} // $current_method;
671 my @parents = ($build);
672 my $cltree = $cl->{CommitId};
673 printdebug "WALK BUILD ".($cltree//'undef').
674 " $method (rewriting=$rewriting)\n";
675 if ($method eq 'Debian') {
676 $read_tree_debian->($cltree);
677 } elsif ($method eq 'Upstream') {
678 $read_tree_upstream->($cltree);
679 } elsif ($method eq 'StartRewrite') {
682 } elsif ($method eq 'RecordBreakwaterTip') {
683 $breakwater = $build;
685 } elsif ($method eq 'DgitImportDebianUpdate') {
686 $read_tree_debian->($cltree);
687 $rm_tree_cached->(qw(debian/patches));
688 } elsif ($method eq 'DgitImportUpstreamUpdate') {
689 $read_tree_upstream->($cltree);
690 push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
695 my $procd = (pop @processed) // 'UNDEF';
698 printdebug "WALK REWRITING NOW cl=$cl procd=$procd\n";
701 my $newtree = cmdoutput @git, qw(write-tree);
703 $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
704 $ch =~ s{^parent .*\n}{}m;
705 $ch =~ s{(?=^author)}{
706 join '', map { "parent $_\n" } @parents
707 }me or confess "$ch ?";
709 $ch =~ s{^committer .*$}{$committer_authline}m
712 my $cf = "$rd/m$rewriting";
713 open CD, ">", $cf or die $!;
714 print CD $ch, "\n", $cl->{Msg} or die $!;
716 my @cmd = (@git, qw(hash-object));
717 push @cmd, qw(-w) if $rewriting;
718 push @cmd, qw(-t commit), $cf;
719 my $newcommit = cmdoutput @cmd;
720 confess "$ch ?" unless $rewriting or $newcommit eq $cl->{CommitId};
725 my $final_check = get_differs $build, $input;
726 die sprintf "internal error %#x %s %s", $final_check, $build, $input
727 if $final_check & ~D_PAT_ADD;
729 return ($build, $breakwater);
732 sub get_head () { return git_rev_parse qw(HEAD); }
734 sub update_head ($$$) {
735 my ($old, $new, $mrest) = @_;
736 runcmd @git, qw(update-ref -m), "debrebase: $mrest", 'HEAD', $new, $old;
739 sub update_head_checkout ($$$) {
740 my ($old, $new, $mrest) = @_;
741 my $symref = git_get_symref();
742 runcmd @git, qw(checkout), $new, qw(.);
743 update_head $old, $new, $mrest;
747 badusage "no arguments to launder allowed" if @ARGV;
748 my $old = get_head();
749 my ($tip,$breakwater) = walk $old;
750 update_head $old, $tip, 'launder';
751 # no tree changes except debian/patches
752 runcmd @git, qw(rm --quiet --ignore-unmatch -rf debian/patches);
753 printf "# breakwater tip\n%s\n", $breakwater;
754 printf "# working tip\n%s\n", $tip;
758 die if ($ARGV[0]//'') =~ m/^-/;
759 badusage "too many arguments to analyse" if @ARGV>1;
762 $old = git_rev_parse $old;
766 my ($dummy,$breakwater) = walk $old, 1,*STDOUT;
767 STDOUT->error and die $!;
770 sub cmd_new_upstream_v0 () {
772 "need NEW-VERSION ORIG-COMMITISH [EXTRA-ORIG-NAME EXTRA-ORIG-COMMITISH...]"
773 unless @ARGV % 2 == 0 and @ARGV >= 2;
774 # tree should be clean and this is not checked
775 # automatically and unconditionally launders before rebasing
776 # if rebase --abort is used, laundering has still been done
778 # parse args - low commitment
779 my $new_version = new Dpkg::Version scalar(shift @ARGV), 1;
780 my $new_upstream_version = $new_version->version();
781 my $new_orig_commitish = git_rev_parse shift @ARGV;
786 New => git_rev_parse shift @ARGV,
788 die unless $xo->{Name} =~ m/^$extra_orig_namepart_re$/;
789 push @extra_origs, $xo;
792 # now we need to investigate the branch this generates the
793 # laundered version but we don't switch to it yet
794 my $old = get_head();
795 my ($laundered_tip,$breakwater) = walk $old;
797 my $breakwater_cl = classify $breakwater;
798 my $old_orig_pi = $breakwater_cl->{OrigParents}[0];
807 print STDERR "upstream not fast forward: $msg\n";
811 # check fast forward, and make new combined-orig commit
812 my $old_orig_ci = parsecommit $old_orig_pi->{CommitId};
813 my $n_old_origs = scalar @{ $old_orig_cp->{Parents} };
814 @{ $n_old_origs } == @extra_origs+1 or
816 "previous breakwater upstream has %d parents".
817 " but new upstream has %d pieces, cannot check ff",
819 (1 + scalar @extra_origs));
822 my @upstream_merge_parents;
824 foreach my $piece_ix (0..$n_old_origs-1) {
825 my $prevpc = $breakwater.'^'.($old_orig_pi->{Ix} + 1);
827 $prevpc .= '^'.($piece_ix + 1);
829 die unless $ git_rev_parse $prevpc;
830 my ($newpc,$newdesc,$pcname);
832 $newpc = $new_orig_commitish;
833 $newdesc = 'new main upstream piece';
835 $newpc = $extra_origs[$piece_ix+1]{New};
836 $pcname = $extra_origs[$piece_ix-1]{Name}
837 $newdesc = "new upstream extra piece \`$pcname";
839 $ffwant->($prevpc, "previous upstream piece ($prevpc)",
840 $newpc, "newdesc ($newpc)");
842 push @upstream_merge_parents, $newpc;
844 my @cmd = @git, qw(read-tree);
845 if (defined $pcname) {
846 push @cmd, "-prefix=$pcname/";
847 runcmd @git, qw(rm --cached -f --ignore-unmatch), $pcname;
853 # index now contains the new upstream
855 die "upstreams not fast forward, stopping".
856 " (xxx should be an override option)";
860 # need to make the upstream subtree merge commit
861 my $us_tree = cmdoutput @git, qw(write-tree);
862 my @cmd = @git, qw(commit-tree), $us_tree;
866 die 'do we want to make ff from previous upstream comb?"';
868 push @cmd, qw(-p), $_ foreach @upstream_merge_parents;
869 push @cmd, qw(-m), "Combine upstreams for $new_upstream_version";
871 "[git-debrebase combine-upstreams . ".
872 (join " ", map { $_->{Name} } @extra_upstreams)."]";
873 my $combined = cmdoutput @cmd;
881 xxx check new orig version is reasonable;
882 xxx decorate new orig version to get new debian version;
885 sub cmd_downstream_rebase_launder_v0 () {
886 badusage "needs 1 argument, the baseline" unless @ARGV==1;
888 $base = git_rev_parse $base;
889 my $old_head = get_head();
890 my $current = $old_head;
893 if ($current eq $base) {
894 $topmost_keep //= $current;
895 print " $current BASE stop\n";
898 my $cl = classify $current;
899 print " $current $cl->{Type}";
901 my $p0 = $cl->{Parents}[0]{CommitId};
903 if ($cl->{Type} eq 'Pseudomerge') {
904 print " ^".($cl->{Contributor}{Ix}+1);
905 $next = $cl->{Contributor}{CommitId};
906 } elsif ($cl->{Type} eq 'AddPatches' or
907 $cl->{Type} eq 'Changelog') {
917 $topmost_keep //= $current;
919 die "to-be stripped changes not on top of the branch\n"
924 if ($topmost_keep eq $old_head) {
927 print "updating to $topmost_keep\n";
929 $old_head, $topmost_keep,
930 'downstream-rebase-launder-v0';
934 GetOptions("D+" => \$debuglevel) or die badusage "bad options\n";
935 initdebug('git-debrebase ');
936 enabledebug if $debuglevel;
938 my $toplevel = cmdoutput @git, qw(rev-parse --show-toplevel);
939 chdir $toplevel or die "chdir $toplevel: $!";
941 $rd = fresh_playground "$playprefix/misc";
943 my $cmd = shift @ARGV;
946 $cmdfn = ${*::}{"cmd_$cmdfn"};
948 $cmdfn or badusage "unknown git-debrebase sub-operation $cmd";