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);
116 my @cmd = qw(git config -z);
117 push @cmd, qw(--get-all) if wantarray;
119 my $out = cmdoutput @cmd;
120 return split /\0/, $out;
127 my ($type,$data) = git_cat_file $objid;
128 die unless $type eq 'commit';
129 $data =~ m/(?<=\n)\n/;
133 sub D_DEB () { return 0x1; } # debian/ (not including debian/patches/)
134 sub D_UPS () { return 0x2; } # upstream files
135 sub D_PAT_ADD () { return 0x4; } # debian/patches/ extra patches at end
136 sub D_PAT_OTH () { return 0x8; } # debian/patches other changes
138 our $rd = ".git/git-debrebase";
139 our $ud = "$rd/work";
142 sub commit_pr_info ($) {
144 return Data::Dumper->dump([$r], [qw(commit)]);
147 sub calculate_committer_authline () {
148 my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
149 'DUMMY COMMIT (git-debrebase)', "HEAD:";
150 my ($h,$m) = get_commit $c;
151 $h =~ m/^committer .*$/m or confess "($h) ?";
155 # classify returns an info hash like this
157 # Hdr => # commit headers, including 1 final newline
158 # Msg => # commit message (so one newline is dropped)
160 # Type => (see below)
162 # Ix => $index # ie 0, 1, 2, ...
164 # Differs => return value from get_differs
166 # IsDggitImport => 'orig' 'tarball' 'unpatched' 'package' (as from dgit)
168 # NewMsg => # commit message, but with any [dgit import ...] edited
169 # # to say "[was: ...]"
179 # has additional entres in classification result
180 # Overwritten = [ subset of Parents ]
181 # Contributor = $the_remaining_Parent
183 # DgitImportUnpatched
184 # has additional entry in classification result
185 # OrigParents = [ subset of Parents ]
187 # BreakwaterUpstreamMerge
188 # has additional entry in classification result
189 # OrigParents = [ subset of Parents ]
194 my ($h,$m) = get_commit $objid;
196 my ($t) = $h =~ m/^tree (\w+)$/m or die $objid;
197 my (@ph) = $h =~ m/^parent (\w+)$/m;
208 foreach my $ph (@ph) {
212 Differs => (get_differs $t, $ph),
217 my ($type, @rest) = @_;
218 $r = { %$r, Type => $type, @rest };
223 $r = { %$r, Type => qw(Unknown) };
228 my $d = $r->{Parents}[0]{Differs};
229 if ($d == D_PAT_ADD) {
230 return $classify->(qw(AddPatches));
231 } elsif ($d & (D_PAT_ADD|D_PAT_OTH)) {
232 return $unknown->("edits debian/patches");
233 } elsif ($d == D_DEB) {
234 return $classify->(qw(Packaging));
235 } elsif ($d == D_UPS) {
236 return $classify->(qw(Upstream));
237 } elsif ($d == (D_DEB|D_UPS)) {
238 return $classify->(qw(Mixed));
240 return $unknown->("no changes");
242 confess "internal error $objid ?";
246 return $unknown->("origin commit");
249 my @identical = grep { !$_->{Differs} } @p;
250 if (@p == 2 && @identical == 1) {
251 my @overwritten = grep { $_->{Differs} } @p;
252 confess "internal error $objid ?" unless @overwritten==1;
253 return $classify->(qw(Pseudomerge),
254 Overwritten => $overwritten[0],
255 Contributor => $identical[0]);
257 if (@p == 2 && @identical == 2) {
258 my @bytime = nsort_by {
259 my ($ph,$pm) = get_commit $_->{CommitId};
260 $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
263 return $classify->(qw(Pseudomerge),
264 SubType => qw(Ambiguous),
265 Overwritten => $bytime[0],
266 Contributor => $bytime[1]);
269 my ($p_h, $p_m) = get_commit $p;
270 $p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
271 ($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
273 my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' } @p;
275 if (!(grep { !$_->{IsOrigin} } @p) and
276 (@orig_ps >= @p - 1) and
277 $m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
279 return $classify->(qw(DgitImportUnpatched),
280 OrigParents => \@orig_ps);
283 my ($stype, $series) = git_cat_file "$t:debian/patches/series";
284 my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
286 # How to decide about l/r ordering of breakwater merges ? git
287 # --topo-order prefers to expand 2nd parent first. There's
288 # already an easy rune to look for debian/ history anyway (git log
289 # debian/) so debian breakwater branch should be 1st parent; that
290 # way also there's also an easy rune to look for the upstream
291 # patches (--topo-order).
294 !$p[0]{IsOrigin} && # breakwater merge never starts with an origin
295 !($p[0]{Differs} & ~D_DEB) &&
296 !($p[1]{Differs} & ~D_UPS)) {
297 return $classify->(qw(BreakwaterUpstreamMerge),
298 OrigParents => [ $p[1] ]);
300 # xxx multi-.orig upstreams
302 return $unknown->("complex merge");
309 $wantdebonly,$depth) = @_;
310 # go through commits backwards
311 # we generate two lists of commits to apply
312 # => ($tip, $breakwater_tip)
313 my (@deb_cl, @ups_cl, @processed);
321 my ($appendinfo) = @_;
324 $ms .= "\n\n[git-debrebase $appendinfo]\n";
327 my $rewrite_from_here = sub {
328 push @processed, { SpecialMethod => 'StartRewrite' };
335 my $prprdelim = sub { print $report $prdelim if $report; $prdelim=""; };
339 my $ty = $cl->{Type};
340 my $st = $cl->{SubType};
342 print $report $prdelim, "$cl->{CommitId} $cl->{Type}";
345 $found{$ty. ( defined($st) ? "-$st" : '' )}++;
346 push @processed, $cl;
347 my $p0 = $cl->{Parents}[0]{CommitId};
348 if ($ty eq 'AddPatches') {
350 $rewrite_from_here->();
352 } elsif ($ty eq 'Packaging') {
356 } elsif ($ty eq 'Upstream') {
360 } elsif ($ty eq 'Mixed') {
363 my $cls = { $cl, $xmsg->("split mixed commit: $wh part") };
366 $queue->(\@deb_cl, "debian");
367 $queue->(\@ups_cl, "upstream");
368 $rewrite_from_here->();
370 } elsif ($ty eq 'Pseudomerge') {
371 print $report " Contributor=$ty->{Contributor}" if $report;
372 push @pseudomerges, $cl;
373 $rewrite_from_here->();
374 $cur = $ty->{Contributor};
376 } elsif ($ty eq 'BreakwaterUpstreamMerge') {
379 } elsif ($ty eq 'DgitImportUnpatched' &&
380 @pseudomerges == 1) {
381 # This import has a tree which is just like a breakwater
382 # tree, but it has the wrong history. Its ought to have
383 # the previous breakwater (which dgit ought to have
384 # generated a pseudomerge to overwrite) as an ancestor.
385 # That will make the history of the debian/ files correct.
386 # As for the upstream version: either it's the same upstream
387 # as the previous breakwater, in which case that history is
388 # precisely right. Otherwise, it was a non-gitish upload
389 # of a new upstream version. We can tell these apart
390 # by looking at the tree of the supposed upstream.
391 my $differs = get_differs $previous_breakwater, $cl->{Tree};
392 printf $report " Differs=%#x", $differs if $report;
393 if ($differs & D_UPS) {
394 printf $report " D_UPS" if $report;
397 SpecialMethod => 'DgitImportUpstreamUpdate',
398 $xmsg->("convert dgit import: debian changes")
403 SpecialMethod => 'DgitImportDebianUpdate',
404 $xmsg->("convert dgit import: upstream changes")
408 $pseudomerges[0]{Overwritten},
409 $nogenerate, $report,
411 $rewrite_from_here->();
414 print $report " Unprocessable" if $report;
417 return (undef,undef);
419 die "commit $cur: Cannot cope with this commit";
424 return (undef, $basis);
427 # Now we build it back up again
435 my $rm_tree_cached = sub {
437 runcmd @git, qw(rm --quiet -rf --cached), $subdir;
439 my $read_tree_debian = sub {
441 $rm_tree_cached->(qw(debian));
442 runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
444 my $read_tree_upstream = sub {
446 runcmd @git, qw(read-tree), $treeish;
447 $read_tree_debian->($build);
450 my $committer_authline = calculate_committer_authline();
453 mkdir $rd or $!==EEXIST or die $!;
455 foreach my $cl (qw(Debian), (reverse @deb_cl),
456 { SpecialMethod => 'RecordBreakwaterTip' },
457 qw(Upstream), (reverse @ups_cl)) {
459 $current_method = $cl;
462 my $method = $cl->{SpecialMethod} // $current_method;
463 my @parents = ($build);
464 my $cltree = $cl->{CommitId};
465 if ($method eq 'Debian') {
466 $read_tree_debian->($cltree);
467 } elsif ($method eq 'Upstream') {
468 $read_tree_upstream->($cltree);
469 } elsif ($method eq 'StartRewrite') {
472 } elsif ($method eq 'RecordBreakwaterTip') {
473 last if $wantdebonly;
474 $breakwater = $build;
476 } elsif ($method eq 'DgitImportDebianUpdate') {
477 $read_tree_debian->($cltree);
478 $rm_tree_cached->(qw(debian/patches));
479 } elsif ($method eq 'DgitImportUpstreamUpdate') {
480 $read_tree_upstream->($cltree);
481 push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
485 $rewriting ||= $cl ne pop @processed;
486 my $newtree = cmdoutput @git, qw(write-tree);
488 $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
489 $ch =~ s{^parent .*\n}{}m;
490 $ch =~ s{(?=^author}{
491 map { "parent $_\n" } @parents
492 }me or confess "$ch ?";
494 $ch =~ s{^committer .*$}{$committer_authline}m
497 my $cf = "$rd/m$rewrite"
498 open CD, ">", $cf or die $!;
499 print CD $ch, "\n", $cl->{Msg}; or die $!;
501 my @cmd = (@git, qw(hash-object));
502 push @cmd, qw(-w) if $rewrite;
503 push @cmd, qw(-t commit), $cf;
504 my $newcommit = cmdoutput @cmd;
505 confess "$ch ?" unless $rewrite or $newcommit eq $cl->{CommitId};
510 runcmd @git, qw(diff-tree --quiet),
511 map { $wantdebonly ? "$_:debian" : $_ },
514 return ($build, $breakwater);
517 sub get_head () { return git_rev_parse qw(HEAD); }
519 sub update_head ($$) {
520 my ($old, $new, $mrest) = @_;
521 runcmd @git, qw(update-ref -m), "git-debrebase $mrest", $new, $old;
525 badusage "no arguments to launder allowed";
526 my $old = get_head();
527 my ($tip,$breakwater) = walk $old;
528 update_head $old, $tip, 'launder';
529 # no tree changes except debian/patches
530 runcmd @git, qw(rm --quiet -rf debian/patches);
531 printf "# breakwater tip\n%s\n", $breakwater;
535 die if ($ARGV[0]//'') =~ m/^-/;
536 badusage "too many arguments to analyse" if @ARGV>1;
539 $old = git_rev_parse $old;
543 my ($dummy,$breakwater) = walk $old, 1,*STDOUT;
544 print "$breakwater BREAKWATER\n";
545 STDOUT->error and die $!;
548 my $toplevel = runcmd @git, qw(rev-parse --show-toplevel);
549 chdir $toplevel or die "chdir $toplevel: $!";
551 my $cmd = shift @ARGV;
554 $cmdfn = ${*::}{"cmd_$cmdfn"};
556 $cmdfn or badusage "unknown git-debrebase sub-operation $cmd";