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/>.
22 # git-debrebase status
23 # git-debrebase start # like ffqrebase start + debrebase launder
24 # git-debrebase new-upstream [stuff] # see below
25 # git-debrebase <git-rebase options> # does debrebase start if necessary
27 # git-debrebase analyse
28 # git-debrebase launder # prints breakwater tip
29 # git-debrebase create-new-upstream-breakwater [-f] <upstreaminfo>...
32 # [,][<subdir>:][+]<commitid>[,...]
34 # if initial comma is supplied, entries are not positional. Unspecified
35 # <subdir> means root (and there may be only one).
36 # xxx want auto branch names
39 # [+]<commit> [<subdir/> [+]<commit>...]
41 # --new-upstream-different-subtrees
44 # git-debrebase new-upstream
45 # - previous breakwater merge must be gdr-generated
46 # - orig set is the same as before
47 # - implicitly uses upstream branches according to orig set
48 # - not all upstream branches need be updated
49 # - insists on fast-forward of each branch, unless
50 # --force (or --force=<subdir>[/])
51 # branch set adjustments
52 # git-debrebase new-upstream --add <subdir>/
53 # git-debrebase new-upstream --rm <subdir>/
54 # git-debrebase new-upstream / [<subdir>/ ...]
55 # - orig set is adjusted
56 # - otherwise like auto (--add is not checked for ffness, obv)
57 # - multiple --add and --rm may be specified
58 # - --add makes new upstream the last contributor
60 # git-debrebase / [<rootcommitid>] [<subdir>/ [<commitid>] ...]
61 # - orig set is precisely as specified now
62 # - previous breakwater merge is irrelevant
63 # - no fast forward checks
64 # for now only explicit with commitids
66 # implicitly uses `upstream'
67 # # (or multiple other branches)
68 # git-debrebase new-upstream \
69 # [<subdir>/]=<commitid>
71 # UPSTREAM[,[[SUBDIR:]SUBUPSTREAM]
72 # default for SUBDIR: is from previous upstream merge[xxx terminology]
76 # when starting must record original start (for ff)
77 # and new rebase basis
79 # git-ffqrebase start [BASE]
80 # # records previous HEAD so it can be overwritten
81 # # records base for future git-ffqrebase
82 # git-ffqrebase set-base BASE
83 # git-ffqrebase <git-rebase options>
84 # git-ffqrebase finish
85 # git-ffqrebase status [BRANCH]
87 # refs/ffqrebase-prev/BRANCH BRANCH may be refs/...; if not it means
88 # refs/ffqrebase-base/BRANCH refs/heads/BRANCH
89 # zero, one, or both of these may exist
91 # git-debrebase without start, if already started, is willing
92 # to strip pseudomerges provided that they overwrite exactly
94 # xxxx is this right ? what matters is have we pushed
95 # I think in fact the right answer is:
96 # git-debrebase always strips out pseudomerges from its branch
97 # a pseudomerge is put in at the time we want to push
98 # at that time, we make a pseudomerge of the remote tracking
99 # branch (if raw git) or the dgit view (if dgit)
100 # for raw git git-ffqrebase, do want preciseley to record
101 # value of remote tracking branch or our branch, on start, so we
102 # overwrite only things we intend to
103 # the previous pseudomerge check for tags and remote branches ?
112 use Debian::Dgit qw(:DEFAULT $wa);
116 die "bad usage: $m\n";
122 my @cmd = qw(git config -z);
123 push @cmd, qw(--get-all) if wantarray;
125 my $out = cmdoutput @cmd;
126 return split /\0/, $out;
133 my ($type,$data) = git_cat_file $objid;
134 die unless $type eq 'commit';
135 $data =~ m/(?<=\n)\n/;
139 sub D_DEB () { return 0x1; } # debian/ (not including debian/patches/)
140 sub D_UPS () { return 0x2; } # upstream files
141 sub D_PAT_ADD () { return 0x4; } # debian/patches/ extra patches at end
142 sub D_PAT_OTH () { return 0x8; } # debian/patches other changes
144 our $rd = ".git/git-debrebase";
145 our $ud = "$rd/work";
148 sub get_differs ($$) {
150 # This resembles quiltify_trees_differ, in dgit, a bit. But: we
151 # don't care about modes, or dpkg-source-unrepresentable changes,
152 # and we don't need the plethora of different modes.
159 my @cmd = (@git, qw(diff-tree -z --name-only));
160 push @cmd "$_:$sfx" foreach $x, $y;
161 my $diffs = cmdoutput @bcmd, $x, $y;
162 foreach $f (split /\0/, $diffs) { $fn->(); }
166 $differs |= $f eq 'debian' ? D_DEB : D_UPS;
169 if ($differs & D_DEB) {
171 $rundiff(':debian', sub {
172 $differs |= $f eq 'patches' ? D_PAT_OTH : D_DEB;
176 if ($differs & D_PAT_OTH) {
184 sub commit_pr_info ($) {
186 return Data::Dumper->dump([$r], [qw(commit)]);
189 sub calculate_committer_authline () {
190 my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
191 'DUMMY COMMIT (git-debrebase)', "HEAD:";
192 my ($h,$m) = get_commit $c;
193 $h =~ m/^committer .*$/m or confess "($h) ?";
197 # classify returns an info hash like this
199 # Hdr => # commit headers, including 1 final newline
200 # Msg => # commit message (so one newline is dropped)
202 # Type => (see below)
204 # Ix => $index # ie 0, 1, 2, ...
206 # Differs => return value from get_differs
208 # IsDggitImport => 'orig' 'tarball' 'unpatched' 'package' (as from dgit)
210 # NewMsg => # commit message, but with any [dgit import ...] edited
211 # # to say "[was: ...]"
221 # has additional entres in classification result
222 # Overwritten = [ subset of Parents ]
223 # Contributor = $the_remaining_Parent
225 # DgitImportUnpatched
226 # has additional entry in classification result
227 # OrigParents = [ subset of Parents ]
229 # BreakwaterUpstreamMerge
230 # has additional entry in classification result
231 # OrigParents = [ subset of Parents ]
236 my ($h,$m) = get_commit $objid;
238 my ($t) = $h =~ m/^tree (\w+)$/m or die $objid;
239 my (@ph) = $h =~ m/^parent (\w+)$/m;
250 foreach my $ph (@ph) {
254 Differs => (get_differs $t, $ph),
259 my ($type, @rest) = @_;
260 $r = { %$r, Type => $type, @rest };
265 $r = { %$r, Type => qw(Unknown) };
270 my $d = $r->{Parents}[0]{Differs};
271 if ($d == D_PAT_ADD) {
272 return $classify->(qw(AddPatches));
273 } elsif ($d & (D_PAT_ADD|D_PAT_OTH)) {
274 return $unknown->("edits debian/patches");
275 } elsif ($d == D_DEB) {
276 my ($ty,$dummy) = git_cat_file "$ph[0]:debian";
278 return $classify->(qw(Packaging));
279 } elsif ($ty eq 'missing') {
280 return $classify->(qw(BreakwaterStart));
282 return $unknown->("parent's debian is not a directory");
284 } elsif ($d == D_UPS) {
285 return $classify->(qw(Upstream));
286 } elsif ($d == (D_DEB|D_UPS)) {
287 return $classify->(qw(Mixed));
289 return $unknown->("no changes");
291 confess "internal error $objid ?";
295 return $unknown->("origin commit");
298 my @identical = grep { !$_->{Differs} } @p;
299 if (@p == 2 && @identical == 1) {
300 my @overwritten = grep { $_->{Differs} } @p;
301 confess "internal error $objid ?" unless @overwritten==1;
302 return $classify->(qw(Pseudomerge),
303 Overwritten => $overwritten[0],
304 Contributor => $identical[0]);
306 if (@p == 2 && @identical == 2) {
307 my @bytime = nsort_by {
308 my ($ph,$pm) = get_commit $_->{CommitId};
309 $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
312 return $classify->(qw(Pseudomerge),
313 SubType => qw(Ambiguous),
314 Overwritten => $bytime[0],
315 Contributor => $bytime[1]);
318 my ($p_h, $p_m) = get_commit $p;
319 $p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
320 ($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
322 my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' } @p;
324 if (!(grep { !$_->{IsOrigin} } @p) and
325 (@orig_ps >= @p - 1) and
326 $m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
328 return $classify->(qw(DgitImportUnpatched),
329 OrigParents => \@orig_ps);
332 my ($stype, $series) = git_cat_file "$t:debian/patches/series";
333 my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
335 # How to decide about l/r ordering of breakwater merges ? git
336 # --topo-order prefers to expand 2nd parent first. There's
337 # already an easy rune to look for debian/ history anyway (git log
338 # debian/) so debian breakwater branch should be 1st parent; that
339 # way also there's also an easy rune to look for the upstream
340 # patches (--topo-order).
343 !$p[0]{IsOrigin} && # breakwater merge never starts with an origin
344 !($p[0]{Differs} & ~D_DEB) &&
345 !($p[1]{Differs} & ~D_UPS)) {
346 return $classify->(qw(BreakwaterUpstreamMerge),
347 OrigParents => [ $p[1] ]);
349 # xxx multi-.orig upstreams
351 return $unknown->("complex merge");
357 $nogenerate,$report) = @_;
358 # => ($tip, $breakwater_tip)
359 # (or nothing, if $nogenerate)
361 # go through commits backwards
362 # we generate two lists of commits to apply:
363 # breakwater branch and upstream patches
364 my (@brw_cl, @upp_cl, @processed);
371 my ($appendinfo) = @_;
374 $ms .= "\n\n[git-debrebase $appendinfo]\n";
377 my $rewrite_from_here = sub {
378 my $sp_cl = { SpecialMethod => 'StartRewrite' };
379 push @brw_cl, $sp_cl;
380 push @processed, $sp_cl;
385 my $prprdelim = sub { print $report $prdelim if $report; $prdelim=""; };
388 return unless $report;
389 print $report $prdelim, @_;
393 my $bomb = sub { # usage: return $bomb->();
394 print $report " Unprocessable" if $report;
397 return (undef,undef);
399 die "commit $cur: Cannot cope with this commit";
405 my $build_start = sub {
406 my ($msg, $parent) = @_;
409 no warnings qw(exiting); last;
414 my $ty = $cl->{Type};
415 my $st = $cl->{SubType};
416 $prline->("$cl->{CommitId} $cl->{Type}");
417 $found{$ty. ( defined($st) ? "-$st" : '' )}++;
418 push @processed, $cl;
419 my $p0 = @{ $cl->{Parents} }==1 ? $cl->{Parents}[0]{CommitId} : undef;
420 if ($ty eq 'AddPatches') {
422 $rewrite_from_here->();
424 } elsif ($ty eq 'Packaging') {
428 } elsif ($ty eq 'BreakwaterStart') {
429 $build_start->('FirstPackaging', $cur);
430 } elsif ($ty eq 'Upstream') {
434 } elsif ($ty eq 'Mixed') {
437 my $cls = { $cl, $xmsg->("split mixed commit: $wh part") };
440 $queue->(\@brw_cl, "debian");
441 $queue->(\@upp_cl, "upstream");
442 $rewrite_from_here->();
445 } elsif ($ty eq 'Pseudomerge') {
446 print $report " Contributor=$ty->{Contributor}" if $report;
447 push @pseudomerges, $cl;
448 $rewrite_from_here->();
449 $cur = $ty->{Contributor};
451 } elsif ($ty eq 'BreakwaterUpstreamMerge') {
452 $build_start->("PreviousBreakwater", $cur);
453 } elsif ($ty eq 'DgitImportUnpatched') {
454 my $pm = $pseudomerges[-1];
456 # To an extent, this is heuristic. Imports don't have
457 # a useful history of the debian/ branch. We assume
458 # that the first pseudomerge after an import has a
459 # useful history of debian/, and ignore the histories
460 # from later pseudomerges. Often the first pseudomerge
461 # will be the dgit import of the upload to the actual
462 # suite intended by the non-dgit NMUer, and later
463 # pseudomerges may represent in-archive copies.
464 my $ovwrs = $pm->{Overwritten};
465 printf $report " PM=%s \@Overwr:%d", $pm, (scalar @$ovwrs)
470 my $ovwr = $ovwrs->[0]{CommitId};
471 printf $report " Overwr=%s", $ovwr if $report;
472 # This import has a tree which is just like a
473 # breakwater tree, but it has the wrong history. It
474 # ought to have the previous breakwater (which the
475 # pseudomerge overwrote) as an ancestor. That will
476 # make the history of the debian/ files correct. As
477 # for the upstream version: either it's the same as
478 # was ovewritten (ie, same as the previous
479 # breakwater), in which case that history is precisely
480 # right; or, otherwise, it was a non-gitish upload of a
481 # new upstream version. We can tell these apart by
482 # looking at the tree of the supposed upstream.
485 SpecialMethod => 'DgitImportDebianUpdate',
486 $xmsg->("convert dgit import: debian changes")
488 my $differs = (get_differs $ovwr, $cl->{Tree});
489 printf $report " Differs=%#x", $differs if $report;
490 if ($differs & D_UPS) {
491 printf $report " D_UPS" if $report;
492 # This will also trigger if a non-dgit git-based NMU
493 # deleted .gitignore (which is a thing that some of
494 # the existing git tools do if the user doesn't
495 # somehow tell them not to). Ah well.
498 SpecialMethod => 'DgitImportUpstreamUpdate',
499 $xmsg->("convert dgit import: upstream changes")
502 $prline->(" Import");
503 $rewrite_from_here->();
504 $upp_limit //= $#upp_cl; # further, deeper, patches discarded
508 # Everything is from this import. This kind of import
509 # is already in valid breakwater format, with the
510 # patches as commits.
511 printf $report " NoPM" if $report;
512 # last thing we processed will have been the first patch,
513 # if there is one; which is fine, so no need to rewrite
514 # on account of this import
515 $build_start->("ImportOrigin", $cur);
523 return if $nogenerate;
525 # Now we build it back up again
531 my $rm_tree_cached = sub {
533 runcmd @git, qw(rm --quiet -rf --cached), $subdir;
535 my $read_tree_debian = sub {
537 $rm_tree_cached->(qw(debian));
538 runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
540 my $read_tree_upstream = sub {
542 runcmd @git, qw(read-tree), $treeish;
543 $read_tree_debian->($build);
546 my $committer_authline = calculate_committer_authline();
549 mkdir $rd or $!==EEXIST or die $!;
551 foreach my $cl (qw(Debian), (reverse @brw_cl),
552 { SpecialMethod => 'RecordBreakwaterTip' },
553 qw(Upstream), (reverse @upp_cl)) {
555 $current_method = $cl;
558 my $method = $cl->{SpecialMethod} // $current_method;
559 my @parents = ($build);
560 my $cltree = $cl->{CommitId};
561 if ($method eq 'Debian') {
562 $read_tree_debian->($cltree);
563 } elsif ($method eq 'Upstream') {
564 $read_tree_upstream->($cltree);
565 } elsif ($method eq 'StartRewrite') {
568 } elsif ($method eq 'RecordBreakwaterTip') {
569 $breakwater = $build;
571 } elsif ($method eq 'DgitImportDebianUpdate') {
572 $read_tree_debian->($cltree);
573 $rm_tree_cached->(qw(debian/patches));
574 } elsif ($method eq 'DgitImportUpstreamUpdate') {
575 $read_tree_upstream->($cltree);
576 push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
580 $rewriting ||= $cl ne pop @processed;
581 my $newtree = cmdoutput @git, qw(write-tree);
583 $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
584 $ch =~ s{^parent .*\n}{}m;
585 $ch =~ s{(?=^author)}{
586 map { "parent $_\n" } @parents
587 }me or confess "$ch ?";
589 $ch =~ s{^committer .*$}{$committer_authline}m
592 my $cf = "$rd/m$rewriting";
593 open CD, ">", $cf or die $!;
594 print CD $ch, "\n", $cl->{Msg} or die $!;
596 my @cmd = (@git, qw(hash-object));
597 push @cmd, qw(-w) if $rewriting;
598 push @cmd, qw(-t commit), $cf;
599 my $newcommit = cmdoutput @cmd;
600 confess "$ch ?" unless $rewriting or $newcommit eq $cl->{CommitId};
605 runcmd @git, qw(diff-tree --quiet), $input, $build;
607 return ($build, $breakwater);
610 sub get_head () { return git_rev_parse qw(HEAD); }
612 sub update_head ($$$) {
613 my ($old, $new, $mrest) = @_;
614 runcmd @git, qw(update-ref -m), "git-debrebase $mrest", $new, $old;
618 badusage "no arguments to launder allowed";
619 my $old = get_head();
620 my ($tip,$breakwater) = walk $old;
621 update_head $old, $tip, 'launder';
622 # no tree changes except debian/patches
623 runcmd @git, qw(rm --quiet -rf debian/patches);
624 printf "# breakwater tip\n%s\n", $breakwater;
628 die if ($ARGV[0]//'') =~ m/^-/;
629 badusage "too many arguments to analyse" if @ARGV>1;
632 $old = git_rev_parse $old;
636 my ($dummy,$breakwater) = walk $old, 1,*STDOUT;
637 print "$breakwater BREAKWATER\n";
638 STDOUT->error and die $!;
641 my $toplevel = cmdoutput @git, qw(rev-parse --show-toplevel);
642 chdir $toplevel or die "chdir $toplevel: $!";
644 my $cmd = shift @ARGV;
647 $cmdfn = ${*::}{"cmd_$cmdfn"};
649 $cmdfn or badusage "unknown git-debrebase sub-operation $cmd";