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 ?
111 use Debian::Dgit qw(:DEFAULT $wa);
115 die "bad usage: $m\n";
121 my @cmd = qw(git config -z);
122 push @cmd, qw(--get-all) if wantarray;
124 my $out = cmdoutput @cmd;
125 return split /\0/, $out;
132 my ($type,$data) = git_cat_file $objid;
133 die unless $type eq 'commit';
134 $data =~ m/(?<=\n)\n/;
138 sub D_DEB () { return 0x1; } # debian/ (not including debian/patches/)
139 sub D_UPS () { return 0x2; } # upstream files
140 sub D_PAT_ADD () { return 0x4; } # debian/patches/ extra patches at end
141 sub D_PAT_OTH () { return 0x8; } # debian/patches other changes
143 our $rd = ".git/git-debrebase";
144 our $ud = "$rd/work";
147 sub commit_pr_info ($) {
149 return Data::Dumper->dump([$r], [qw(commit)]);
152 sub calculate_committer_authline () {
153 my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
154 'DUMMY COMMIT (git-debrebase)', "HEAD:";
155 my ($h,$m) = get_commit $c;
156 $h =~ m/^committer .*$/m or confess "($h) ?";
160 # classify returns an info hash like this
162 # Hdr => # commit headers, including 1 final newline
163 # Msg => # commit message (so one newline is dropped)
165 # Type => (see below)
167 # Ix => $index # ie 0, 1, 2, ...
169 # Differs => return value from get_differs
171 # IsDggitImport => 'orig' 'tarball' 'unpatched' 'package' (as from dgit)
173 # NewMsg => # commit message, but with any [dgit import ...] edited
174 # # to say "[was: ...]"
184 # has additional entres in classification result
185 # Overwritten = [ subset of Parents ]
186 # Contributor = $the_remaining_Parent
188 # DgitImportUnpatched
189 # has additional entry in classification result
190 # OrigParents = [ subset of Parents ]
192 # BreakwaterUpstreamMerge
193 # has additional entry in classification result
194 # OrigParents = [ subset of Parents ]
199 my ($h,$m) = get_commit $objid;
201 my ($t) = $h =~ m/^tree (\w+)$/m or die $objid;
202 my (@ph) = $h =~ m/^parent (\w+)$/m;
213 foreach my $ph (@ph) {
217 Differs => (get_differs $t, $ph),
222 my ($type, @rest) = @_;
223 $r = { %$r, Type => $type, @rest };
228 $r = { %$r, Type => qw(Unknown) };
233 my $d = $r->{Parents}[0]{Differs};
234 if ($d == D_PAT_ADD) {
235 return $classify->(qw(AddPatches));
236 } elsif ($d & (D_PAT_ADD|D_PAT_OTH)) {
237 return $unknown->("edits debian/patches");
238 } elsif ($d == D_DEB) {
239 my ($ty,$dummy) = git_cat_file "$ph[0]:debian";
241 return $classify->(qw(Packaging));
242 } elsif ($ty eq 'missing') {
243 return $classify->(qw(BreakwaterStart));
245 return $unknown->("parent's debian is not a directory");
247 } elsif ($d == D_UPS) {
248 return $classify->(qw(Upstream));
249 } elsif ($d == (D_DEB|D_UPS)) {
250 return $classify->(qw(Mixed));
252 return $unknown->("no changes");
254 confess "internal error $objid ?";
258 return $unknown->("origin commit");
261 my @identical = grep { !$_->{Differs} } @p;
262 if (@p == 2 && @identical == 1) {
263 my @overwritten = grep { $_->{Differs} } @p;
264 confess "internal error $objid ?" unless @overwritten==1;
265 return $classify->(qw(Pseudomerge),
266 Overwritten => $overwritten[0],
267 Contributor => $identical[0]);
269 if (@p == 2 && @identical == 2) {
270 my @bytime = nsort_by {
271 my ($ph,$pm) = get_commit $_->{CommitId};
272 $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
275 return $classify->(qw(Pseudomerge),
276 SubType => qw(Ambiguous),
277 Overwritten => $bytime[0],
278 Contributor => $bytime[1]);
281 my ($p_h, $p_m) = get_commit $p;
282 $p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
283 ($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
285 my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' } @p;
287 if (!(grep { !$_->{IsOrigin} } @p) and
288 (@orig_ps >= @p - 1) and
289 $m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
291 return $classify->(qw(DgitImportUnpatched),
292 OrigParents => \@orig_ps);
295 my ($stype, $series) = git_cat_file "$t:debian/patches/series";
296 my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
298 # How to decide about l/r ordering of breakwater merges ? git
299 # --topo-order prefers to expand 2nd parent first. There's
300 # already an easy rune to look for debian/ history anyway (git log
301 # debian/) so debian breakwater branch should be 1st parent; that
302 # way also there's also an easy rune to look for the upstream
303 # patches (--topo-order).
306 !$p[0]{IsOrigin} && # breakwater merge never starts with an origin
307 !($p[0]{Differs} & ~D_DEB) &&
308 !($p[1]{Differs} & ~D_UPS)) {
309 return $classify->(qw(BreakwaterUpstreamMerge),
310 OrigParents => [ $p[1] ]);
312 # xxx multi-.orig upstreams
314 return $unknown->("complex merge");
320 $nogenerate,$report) = @_;
321 # => ($tip, $breakwater_tip)
322 # (or nothing, if $nogenerate)
324 # go through commits backwards
325 # we generate two lists of commits to apply:
326 # breakwater branch and upstream patches
327 my (@brw_cl, @upp_cl, @processed);
334 my ($appendinfo) = @_;
337 $ms .= "\n\n[git-debrebase $appendinfo]\n";
340 my $rewrite_from_here = sub {
341 my $sp_cl = { SpecialMethod => 'StartRewrite' };
342 push @brw_cl, $sp_cl;
343 push @processed, $sp_cl;
348 my $prprdelim = sub { print $report $prdelim if $report; $prdelim=""; };
351 return unless $report;
352 print $report $prdelim, @_;
356 my $build_start = sub {
357 my ($msg, $parent) = @_;
360 no warnings qw(exiting); last;
363 my $bomb = sub { # usage: return $bomb->();
364 print $report " Unprocessable" if $report;
367 return (undef,undef);
369 die "commit $cur: Cannot cope with this commit";
376 my $ty = $cl->{Type};
377 my $st = $cl->{SubType};
378 $prline->("$cl->{CommitId} $cl->{Type}");
379 $found{$ty. ( defined($st) ? "-$st" : '' )}++;
380 push @processed, $cl;
381 my $p0 = @{ $cl->{Parents} }==1 ? $cl->{Parents}[0]{CommitId} : undef;
382 if ($ty eq 'AddPatches') {
384 $rewrite_from_here->();
386 } elsif ($ty eq 'Packaging') {
390 } elsif ($ty eq 'BreakwaterStart') {
391 $build_start->('FirstPackaging', $cur);
392 } elsif ($ty eq 'Upstream') {
396 } elsif ($ty eq 'Mixed') {
399 my $cls = { $cl, $xmsg->("split mixed commit: $wh part") };
402 $queue->(\@brw_cl, "debian");
403 $queue->(\@upp_cl, "upstream");
404 $rewrite_from_here->();
407 } elsif ($ty eq 'Pseudomerge') {
408 print $report " Contributor=$ty->{Contributor}" if $report;
409 push @pseudomerges, $cl;
410 $rewrite_from_here->();
411 $cur = $ty->{Contributor};
413 } elsif ($ty eq 'BreakwaterUpstreamMerge') {
414 $build_start->("PreviousBreakwater", $cur);
415 } elsif ($ty eq 'DgitImportUnpatched') {
416 my $pm = $pseudomerges[-1];
418 # To an extent, this is heuristic. Imports don't have
419 # a useful history of the debian/ branch. We assume
420 # that the first pseudomerge after an import has a
421 # useful history of debian/, and ignore the histories
422 # from later pseudomerges. Often the first pseudomerge
423 # will be the dgit import of the upload to the actual
424 # suite intended by the non-dgit NMUer, and later
425 # pseudomerges may represent in-archive copies.
426 my $ovwrs = $pm->{Overwritten};
427 printf $report " PM=%s \@Overwr:%d", $pm, (scalar @$ovwrs)
432 my $ovwr = $ovwrs->[0]{CommitId};
433 printf $report " Overwr=%s", $ovwr if $report;
434 # This import has a tree which is just like a
435 # breakwater tree, but it has the wrong history. It
436 # ought to have the previous breakwater (which the
437 # pseudomerge overwrote) as an ancestor. That will
438 # make the history of the debian/ files correct. As
439 # for the upstream version: either it's the same as
440 # was ovewritten (ie, same as the previous
441 # breakwater), in which case that history is precisely
442 # right; or, otherwise, it was a non-gitish upload of a
443 # new upstream version. We can tell these apart by
444 # looking at the tree of the supposed upstream.
447 SpecialMethod => 'DgitImportDebianUpdate',
448 $xmsg->("convert dgit import: debian changes")
450 my $differs = (get_differs $ovwr, $cl->{Tree});
451 printf $report " Differs=%#x", $differs if $report;
452 if ($differs & D_UPS) {
453 printf $report " D_UPS" if $report;
454 # This will also trigger if a non-dgit git-based NMU
455 # deleted .gitignore (which is a thing that some of
456 # the existing git tools do if the user doesn't
457 # somehow tell them not to). Ah well.
460 SpecialMethod => 'DgitImportUpstreamUpdate',
461 $xmsg->("convert dgit import: upstream changes")
464 $prline->(" Import");
465 $rewrite_from_here->();
466 $upp_limit //= $#upp_cl; # further, deeper, patches discarded
470 # Everything is from this import. This kind of import
471 # is already in valid breakwater format, with the
472 # patches as commits.
473 printf $report " NoPM" if $report;
474 # last thing we processed will have been the first patch,
475 # if there is one; which is fine, so no need to rewrite
476 # on account of this import
477 $build_start->("ImportOrigin", $cur);
485 return if $nogenerate;
487 # Now we build it back up again
493 my $rm_tree_cached = sub {
495 runcmd @git, qw(rm --quiet -rf --cached), $subdir;
497 my $read_tree_debian = sub {
499 $rm_tree_cached->(qw(debian));
500 runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
502 my $read_tree_upstream = sub {
504 runcmd @git, qw(read-tree), $treeish;
505 $read_tree_debian->($build);
508 my $committer_authline = calculate_committer_authline();
511 mkdir $rd or $!==EEXIST or die $!;
513 foreach my $cl (qw(Debian), (reverse @brw_cl),
514 { SpecialMethod => 'RecordBreakwaterTip' },
515 qw(Upstream), (reverse @upp_cl)) {
517 $current_method = $cl;
520 my $method = $cl->{SpecialMethod} // $current_method;
521 my @parents = ($build);
522 my $cltree = $cl->{CommitId};
523 if ($method eq 'Debian') {
524 $read_tree_debian->($cltree);
525 } elsif ($method eq 'Upstream') {
526 $read_tree_upstream->($cltree);
527 } elsif ($method eq 'StartRewrite') {
530 } elsif ($method eq 'RecordBreakwaterTip') {
531 $breakwater = $build;
532 last if $wantbrwonly;
534 } elsif ($method eq 'DgitImportDebianUpdate') {
535 $read_tree_debian->($cltree);
536 $rm_tree_cached->(qw(debian/patches));
537 } elsif ($method eq 'DgitImportUpstreamUpdate') {
538 $read_tree_upstream->($cltree);
539 push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
543 $rewriting ||= $cl ne pop @processed;
544 my $newtree = cmdoutput @git, qw(write-tree);
546 $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
547 $ch =~ s{^parent .*\n}{}m;
548 $ch =~ s{(?=^author)}{
549 map { "parent $_\n" } @parents
550 }me or confess "$ch ?";
552 $ch =~ s{^committer .*$}{$committer_authline}m
555 my $cf = "$rd/m$rewriting";
556 open CD, ">", $cf or die $!;
557 print CD $ch, "\n", $cl->{Msg} or die $!;
559 my @cmd = (@git, qw(hash-object));
560 push @cmd, qw(-w) if $rewriting;
561 push @cmd, qw(-t commit), $cf;
562 my $newcommit = cmdoutput @cmd;
563 confess "$ch ?" unless $rewriting or $newcommit eq $cl->{CommitId};
568 runcmd @git, qw(diff-tree --quiet),
569 map { $wantdebonly ? "$_:debian" : $_ }
572 return ($build, $breakwater);
575 sub get_head () { return git_rev_parse qw(HEAD); }
577 sub update_head ($$) {
578 my ($old, $new, $mrest) = @_;
579 runcmd @git, qw(update-ref -m), "git-debrebase $mrest", $new, $old;
583 badusage "no arguments to launder allowed";
584 my $old = get_head();
585 my ($tip,$breakwater) = walk $old;
586 update_head $old, $tip, 'launder';
587 # no tree changes except debian/patches
588 runcmd @git, qw(rm --quiet -rf debian/patches);
589 printf "# breakwater tip\n%s\n", $breakwater;
593 die if ($ARGV[0]//'') =~ m/^-/;
594 badusage "too many arguments to analyse" if @ARGV>1;
597 $old = git_rev_parse $old;
601 my ($dummy,$breakwater) = walk $old, 1,*STDOUT;
602 print "$breakwater BREAKWATER\n";
603 STDOUT->error and die $!;
606 my $toplevel = runcmd @git, qw(rev-parse --show-toplevel);
607 chdir $toplevel or die "chdir $toplevel: $!";
609 my $cmd = shift @ARGV;
612 $cmdfn = ${*::}{"cmd_$cmdfn"};
614 $cmdfn or badusage "unknown git-debrebase sub-operation $cmd";