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
96 use Debian::Dgit qw(:DEFAULT $wa);
101 my @cmd = qw(git config -z);
102 push @cmd, qw(--get-all) if wantarray;
104 my $out = cmdoutput @cmd;
105 return split /\0/, $out;
112 my ($type,$data) = git_cat_file $objid;
113 die unless $type eq 'commit';
114 $data =~ m/(?<=\n)\n/;
118 sub D_DEB () { return 0x1; } # debian/ (not including debian/patches/)
119 sub D_UPS () { return 0x2; } # upstream files
120 sub D_PAT_ADD () { return 0x4; } # debian/patches/ extra patches at end
121 sub D_PAT_OTH () { return 0x8; } # debian/patches other changes
123 our $rd = ".git/git-debrebase";
124 our $ud = "$rd/work";
126 sub commit_pr_info ($) {
128 return Data::Dumper->dump([$r], [qw(commit)]);
131 sub calculate_committer_authline () {
132 my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
133 'DUMMY COMMIT (git-debrebase)', "$basis:";
134 my ($h,$m) = get_commit $c;
135 $h =~ m/^committer .*$/m or confess "($h) ?";
139 # classify returns an info hash like this
141 # Hdr => # commit headers, including 1 final newline
142 # Msg => # commit message (so one newline is dropped)
144 # Type => (see below)
146 # Ix => $index # ie 0, 1, 2, ...
148 # Differs => return value from get_differs
150 # IsDggitImport => 'orig' 'tarball' 'unpatched' 'package' (as from dgit)
152 # NewMsg => # commit message, but with any [dgit import ...] edited
153 # # to say "[was: ...]"
163 # has additional entres in classification result
164 # Overwritten = [ subset of Parents ]
165 # Contributor = $the_remaining_Parent
167 # DgitImportUnpatched
168 # has additional entry in classification result
169 # OrigParents = [ subset of Parents ]
171 # BreakwaterUpstreamMerge
172 # has additional entry in classification result
173 # OrigParents = [ subset of Parents ]
178 my ($h,$m) = get_commit $objid;
180 my ($t) = $h =~ m/^tree (\w+)$/m or die $cur;
181 my (@ph) = $h =~ m/^parent (\w+)$/m;
192 foreach my $ph (@ph) {
196 Differs => (get_differs $t, $ph),
201 my ($type, @rest) = @_;
202 $r = { %r, Type => $type, @rest };
207 $r = { %r, Type => Unknown };
212 my $d = $r->{Parents}[0]{Differs};
213 if ($d == D_DPAT_ADD) {
214 return $classify->(qw(AddPatches));
215 } elsif ($d & (D_DPAT_ADD|D_DPAT_OTH)) {
216 return $unknown->("edits debian/patches");
217 } elsif ($d == D_DEB) {
218 return $classify->(qw(Packaging));
219 } elsif ($d == D_UPS) {
220 return $classify->(qw(Upstream));
221 } elsif ($d == D_DEB|D_UPS) {
222 return $classify->(qw(Mixed));
224 return $unknown->("no changes");
226 confess "internal error $objid ?";
230 return $unknown->("origin commit");
233 my @identical = grep { !$_->{Differs} } @p;
234 if (@p == 2 && @identical == 1) {
235 my @overwritten = grep { $_->{Differs} } @p;
236 confess "internal error $objid ?" unless @overwritten==1;
237 return $classify->(qw(Pseudomerge),
238 Overwritten => $overwritten[0],
239 Contributor => $identical[0]);
241 if (@p == 2 && @identical == 2) {
242 my @bytime = nsort_by {
243 my ($ph,$pm) = get_commit $_->{CommitId};
244 $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
247 return $classify->(qw(Pseudomerge),
248 SubType => qw(Ambiguous),
249 Overwritten => $bytime[0],
250 Contributor => $bytime[1]);
253 my ($p_h, $p_m) = get_commit $p;
254 $p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
255 ($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
257 my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' };
259 if (!(grep { !$_->{IsOrigin} } @p) and
260 (@origs >= @p - 1) and
261 $m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
263 return $classify->(qw(DgitImportUnpatched),
264 OrigParents => \@orig_ps);
267 my ($stype, $series) = git_cat_file "$t:debian/patches/series";
268 my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
270 # How to decide about l/r ordering of breakwater merges ? git
271 # --topo-order prefers to expand 2nd parent first. There's
272 # already an easy rune to look for debian/ history anyway (git log
273 # debian/) so debian breakwater branch should be 1st parent; that
274 # way also there's also an easy rune to look for the upstream
275 # patches (--topo-order).
278 !$p[0]{IsOrigin} && # breakwater merge never starts with an origin
279 !($p[0]{Differs} & ~D_DEB) &&
280 !($p[1]{Differs} & ~D_UPS)) {
281 return $classify->(qw(BreakwaterUpstreamMerge),
282 OrigParents => [ $p[1] ]);
284 # xxx multi-.orig upstreams
286 return $unknown->("complex merge");
290 my ($input, $pseudos_must_overwrite_this, $wantdebonly) = @_;
291 # go through commits backwards
292 # we generate two lists of commits to apply
293 my (@deb_cl, @ups_cl, @processed);
299 my ($appendinfo) = @_;
302 $ms .= "\n\n[git-debrebase $appendinfo]\n";
305 my $rewrite_from_here = sub {
306 push @processed, { SpecialMethod => 'StartRewrite' };
313 my $ty = $cl->{Type};
314 my $st = $cl->{SubType};
315 $found{$ty. ( defined($st) ? "-$st" : '' )}++;
316 my $p0 = $cl->{Parents}[0]{CommitId};
317 if ($ty eq 'AddPatches') {
319 $rewrite_from_here->();
321 } elsif ($ty eq 'Packaging') {
323 push @processed, $cl;
326 } elsif ($ty eq 'Upstream') {
328 push @processed, $cl;
331 } elsif ($ty eq 'Mixed') {
334 my $cls = { $cl, $xmsg->("split mixed commit: $wh part") };
337 $queue->(\@deb_cl, "debian");
338 $queue->(\@ups_cl, "upstream");
339 $rewrite_from_here->();
341 } elsif ($ty eq 'Pseudomerge') {
342 if (defined $pseudos_must_overwrite_this) {
344 is_fast_fwd $pseudos_must_overwrite_this, $_->{CommitId}
346 @{ $cl->{Overwritten} }
348 die "Pseudomerge $cl->{CommitId} does not overwrite ".
349 "$pseudos_must_overwrite_this as expected.";
351 push @pseudomerges, $cl;
352 $rewrite_from_here->();
353 $cur = $ty->{Contributor};
355 } elsif ($ty eq 'BreakwaterUpstreamMerge') {
358 } elsif ($ty eq 'DgitImportUnpatched' &&
359 @pseudomerges == 1) {
360 # This import has a tree which is just like a breakwater
361 # tree, but it has the wrong history. Its ought to have
362 # the previous breakwater (which dgit ought to have
363 # generated a pseudomerge to overwrite) as an ancestor.
364 # That will make the history of the debian/ files correct.
365 # As for the upstream version: either it's the same upstream
366 # as the previous breakwater, in which case that history is
367 # precisely right. Otherwise, it was a non-gitish upload
368 # of a new upstream version. We can tell these apart
369 # by looking at the tree of the supposed upstream.
370 if ($differs & D_UPS) {
373 SpecialMethod => 'DgitImportUpstreamUpdate',
374 $xmsg->("convert dgit import: debian changes")
379 SpecialMethod => 'DgitImportDebianUpdate',
380 $xmsg->("convert dgit import: upstream changes")
382 my $differs = get_differs $previous_breakwater, $cl->{Tree};
383 $basis = launder $pseudomerges[0]{Overwritten}, undef, 1;
384 $rewrite_from_here->();
387 die "Reached difficult commit $cur: ".Dumper($cl);
390 # Now we build it back up again
393 in_workarea sub { xxx attributes xxx };
399 my $rm_tree_cached = sub {
401 runcmd @git, qw(rm --quiet -rf --cached), $subdir;
403 my $read_tree_debian = sub {
405 $rm_tree_cached->(qw(debian));
406 runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
408 my $read_tree_upstream = sub {
410 runcmd @git, qw(read-tree), $treeish;
411 $read_tree_debian->($build);
414 my $committer_authline = calculate_committer_authline();
417 mkdir $rd or $!==EEXIST or die $!;
419 foreach my $cl (qw(Debian), (reverse @deb_cl),
420 { SpecialMethod => 'RecordBreakwaterTip' },
421 qw(Upstream), (reverse @ups_cl)) {
423 $current_method = $cl;
426 $method = $cl->{SpecialMethod} // $current_method;
427 my @parents = ($build);
428 my $cltree = $cl->{CommitId}
429 if ($method eq 'Debian') {
430 $read_tree_debian->($cltree);
431 } elsif ($method eq 'Upstream') {
432 $read_tree_upstream->($cltree);
433 } elsif ($method eq 'StartRewrite') {
436 } elsif ($method eq 'RecordBreakwaterTip') {
437 last if $wantdebonly;
438 $breakwater = $build;
440 } elsif ($method eq 'DgitImportDebianUpdate') {
441 $read_tree_debian->($cltree);
442 $rm_tree_cached(qw(debian/patches));
443 } elsif ($method eq 'DgitImportUpstreamUpdate') {
444 $read_tree_upstream->($cltree);
445 push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
449 $rewriting ||= $cl ne pop @processed;
450 my $newtree = cmdoutput @git, qw(write-tree);
452 $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
453 $ch =~ s{^parent .*\n}{}m;
454 $ch =~ s{(?=^author}{
455 map { "parent $_\n" } @parents
456 }me or confess "$ch ?";
458 $ch =~ s{^committer .*$}{$committer_authline}m
461 my $cf = "$rd/m$rewrite"
462 open CD, ">", $cf or die $!;
463 print CD $ch, "\n", $cl->{Msg}; or die $!;
465 my @cmd = (@git, qw(hash-object));
466 push @cmd, qw(-w) if $rewrite;
467 push @cmd, qw(-t commit), $cf;
468 my $newcommit = cmdoutput @cmd;
469 confess "$ch ?" unless $rewrite or $newcommit eq $cl->{CommitId};
474 runcmd @git, qw(diff-tree --quiet),
475 map { $wantdebonly ? "$_:debian" : $_ },
478 return ($build, $breakwater);
481 sub get_head () { return git_rev_parse qw(HEAD); }
483 sub update_head ($$) {
484 my ($old, $new, $mrest) = @_;
485 runcmd @git, qw(update-ref -m), "git-debrebase $mrest", $new, $old;
489 my $old = get_head();
490 my ($tip,$breakwater) = launder $old, 0, undef, 0;
491 update_head $old, $tip, 'launder'; # no tree changes! xxx debian/patches
492 printf "# breakwater tip:\n%s\n", $breakwater;
495 my $toplevel = runcmd @git, qw(rev-parse --show-toplevel);
496 chdir $toplevel or die "chdir $toplevel: $!";
498 my $cmd = shift @ARGV;
501 $cmdfn = ${*::}{"cmd_$cmdfn"};
503 $cmdfn or badusage "unknown git-debrebase sub-operation $cmd";