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 ?
110 use Debian::Dgit qw(:DEFAULT $wa);
115 my @cmd = qw(git config -z);
116 push @cmd, qw(--get-all) if wantarray;
118 my $out = cmdoutput @cmd;
119 return split /\0/, $out;
126 my ($type,$data) = git_cat_file $objid;
127 die unless $type eq 'commit';
128 $data =~ m/(?<=\n)\n/;
132 sub D_DEB () { return 0x1; } # debian/ (not including debian/patches/)
133 sub D_UPS () { return 0x2; } # upstream files
134 sub D_PAT_ADD () { return 0x4; } # debian/patches/ extra patches at end
135 sub D_PAT_OTH () { return 0x8; } # debian/patches other changes
137 our $rd = ".git/git-debrebase";
138 our $ud = "$rd/work";
140 sub commit_pr_info ($) {
142 return Data::Dumper->dump([$r], [qw(commit)]);
145 sub calculate_committer_authline () {
146 my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
147 'DUMMY COMMIT (git-debrebase)', "$basis:";
148 my ($h,$m) = get_commit $c;
149 $h =~ m/^committer .*$/m or confess "($h) ?";
153 # classify returns an info hash like this
155 # Hdr => # commit headers, including 1 final newline
156 # Msg => # commit message (so one newline is dropped)
158 # Type => (see below)
160 # Ix => $index # ie 0, 1, 2, ...
162 # Differs => return value from get_differs
164 # IsDggitImport => 'orig' 'tarball' 'unpatched' 'package' (as from dgit)
166 # NewMsg => # commit message, but with any [dgit import ...] edited
167 # # to say "[was: ...]"
177 # has additional entres in classification result
178 # Overwritten = [ subset of Parents ]
179 # Contributor = $the_remaining_Parent
181 # DgitImportUnpatched
182 # has additional entry in classification result
183 # OrigParents = [ subset of Parents ]
185 # BreakwaterUpstreamMerge
186 # has additional entry in classification result
187 # OrigParents = [ subset of Parents ]
192 my ($h,$m) = get_commit $objid;
194 my ($t) = $h =~ m/^tree (\w+)$/m or die $cur;
195 my (@ph) = $h =~ m/^parent (\w+)$/m;
206 foreach my $ph (@ph) {
210 Differs => (get_differs $t, $ph),
215 my ($type, @rest) = @_;
216 $r = { %r, Type => $type, @rest };
221 $r = { %r, Type => Unknown };
226 my $d = $r->{Parents}[0]{Differs};
227 if ($d == D_DPAT_ADD) {
228 return $classify->(qw(AddPatches));
229 } elsif ($d & (D_DPAT_ADD|D_DPAT_OTH)) {
230 return $unknown->("edits debian/patches");
231 } elsif ($d == D_DEB) {
232 return $classify->(qw(Packaging));
233 } elsif ($d == D_UPS) {
234 return $classify->(qw(Upstream));
235 } elsif ($d == D_DEB|D_UPS) {
236 return $classify->(qw(Mixed));
238 return $unknown->("no changes");
240 confess "internal error $objid ?";
244 return $unknown->("origin commit");
247 my @identical = grep { !$_->{Differs} } @p;
248 if (@p == 2 && @identical == 1) {
249 my @overwritten = grep { $_->{Differs} } @p;
250 confess "internal error $objid ?" unless @overwritten==1;
251 return $classify->(qw(Pseudomerge),
252 Overwritten => $overwritten[0],
253 Contributor => $identical[0]);
255 if (@p == 2 && @identical == 2) {
256 my @bytime = nsort_by {
257 my ($ph,$pm) = get_commit $_->{CommitId};
258 $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
261 return $classify->(qw(Pseudomerge),
262 SubType => qw(Ambiguous),
263 Overwritten => $bytime[0],
264 Contributor => $bytime[1]);
267 my ($p_h, $p_m) = get_commit $p;
268 $p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
269 ($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
271 my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' };
273 if (!(grep { !$_->{IsOrigin} } @p) and
274 (@origs >= @p - 1) and
275 $m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
277 return $classify->(qw(DgitImportUnpatched),
278 OrigParents => \@orig_ps);
281 my ($stype, $series) = git_cat_file "$t:debian/patches/series";
282 my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
284 # How to decide about l/r ordering of breakwater merges ? git
285 # --topo-order prefers to expand 2nd parent first. There's
286 # already an easy rune to look for debian/ history anyway (git log
287 # debian/) so debian breakwater branch should be 1st parent; that
288 # way also there's also an easy rune to look for the upstream
289 # patches (--topo-order).
292 !$p[0]{IsOrigin} && # breakwater merge never starts with an origin
293 !($p[0]{Differs} & ~D_DEB) &&
294 !($p[1]{Differs} & ~D_UPS)) {
295 return $classify->(qw(BreakwaterUpstreamMerge),
296 OrigParents => [ $p[1] ]);
298 # xxx multi-.orig upstreams
300 return $unknown->("complex merge");
306 $wantdebonly,$depth) = @_;
307 # go through commits backwards
308 # we generate two lists of commits to apply
309 # => ($tip, $breakwater_tip)
310 my (@deb_cl, @ups_cl, @processed);
318 my ($appendinfo) = @_;
321 $ms .= "\n\n[git-debrebase $appendinfo]\n";
324 my $rewrite_from_here = sub {
325 push @processed, { SpecialMethod => 'StartRewrite' };
331 my $prprdelim = sub { print $report $prdelim if $report; $prdelim=""; }
335 my $ty = $cl->{Type};
336 my $st = $cl->{SubType};
338 print $report $prdelim, "$cl->{CommitId} $cl->{Type}";
341 $found{$ty. ( defined($st) ? "-$st" : '' )}++;
342 push @processed, $cl;
343 my $p0 = $cl->{Parents}[0]{CommitId};
344 if ($ty eq 'AddPatches') {
346 $rewrite_from_here->();
348 } elsif ($ty eq 'Packaging') {
352 } elsif ($ty eq 'Upstream') {
356 } elsif ($ty eq 'Mixed') {
359 my $cls = { $cl, $xmsg->("split mixed commit: $wh part") };
362 $queue->(\@deb_cl, "debian");
363 $queue->(\@ups_cl, "upstream");
364 $rewrite_from_here->();
366 } elsif ($ty eq 'Pseudomerge') {
367 print $report " Contributor=$ty->{Contributor}" if $report;
368 push @pseudomerges, $cl;
369 $rewrite_from_here->();
370 $cur = $ty->{Contributor};
372 } elsif ($ty eq 'BreakwaterUpstreamMerge') {
375 } elsif ($ty eq 'DgitImportUnpatched' &&
376 @pseudomerges == 1) {
377 # This import has a tree which is just like a breakwater
378 # tree, but it has the wrong history. Its ought to have
379 # the previous breakwater (which dgit ought to have
380 # generated a pseudomerge to overwrite) as an ancestor.
381 # That will make the history of the debian/ files correct.
382 # As for the upstream version: either it's the same upstream
383 # as the previous breakwater, in which case that history is
384 # precisely right. Otherwise, it was a non-gitish upload
385 # of a new upstream version. We can tell these apart
386 # by looking at the tree of the supposed upstream.
387 my $differs = get_differs $previous_breakwater, $cl->{Tree};
388 printf $report " Differs=%#x", $differs if $report;
389 if ($differs & D_UPS) {
390 printf $report " D_UPS" if $report;
393 SpecialMethod => 'DgitImportUpstreamUpdate',
394 $xmsg->("convert dgit import: debian changes")
399 SpecialMethod => 'DgitImportDebianUpdate',
400 $xmsg->("convert dgit import: upstream changes")
404 $pseudomerges[0]{Overwritten},
405 $nogenerate, $report,
407 $rewrite_from_here->();
410 print $report " Unprocessable" if $report;
413 return (undef,undef);
415 die "commit $cur: Cannot cope with this commit";
420 return (undef, $basis);
423 # Now we build it back up again
431 my $rm_tree_cached = sub {
433 runcmd @git, qw(rm --quiet -rf --cached), $subdir;
435 my $read_tree_debian = sub {
437 $rm_tree_cached->(qw(debian));
438 runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
440 my $read_tree_upstream = sub {
442 runcmd @git, qw(read-tree), $treeish;
443 $read_tree_debian->($build);
446 my $committer_authline = calculate_committer_authline();
449 mkdir $rd or $!==EEXIST or die $!;
451 foreach my $cl (qw(Debian), (reverse @deb_cl),
452 { SpecialMethod => 'RecordBreakwaterTip' },
453 qw(Upstream), (reverse @ups_cl)) {
455 $current_method = $cl;
458 $method = $cl->{SpecialMethod} // $current_method;
459 my @parents = ($build);
460 my $cltree = $cl->{CommitId}
461 if ($method eq 'Debian') {
462 $read_tree_debian->($cltree);
463 } elsif ($method eq 'Upstream') {
464 $read_tree_upstream->($cltree);
465 } elsif ($method eq 'StartRewrite') {
468 } elsif ($method eq 'RecordBreakwaterTip') {
469 last if $wantdebonly;
470 $breakwater = $build;
472 } elsif ($method eq 'DgitImportDebianUpdate') {
473 $read_tree_debian->($cltree);
474 $rm_tree_cached(qw(debian/patches));
475 } elsif ($method eq 'DgitImportUpstreamUpdate') {
476 $read_tree_upstream->($cltree);
477 push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
481 $rewriting ||= $cl ne pop @processed;
482 my $newtree = cmdoutput @git, qw(write-tree);
484 $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
485 $ch =~ s{^parent .*\n}{}m;
486 $ch =~ s{(?=^author}{
487 map { "parent $_\n" } @parents
488 }me or confess "$ch ?";
490 $ch =~ s{^committer .*$}{$committer_authline}m
493 my $cf = "$rd/m$rewrite"
494 open CD, ">", $cf or die $!;
495 print CD $ch, "\n", $cl->{Msg}; or die $!;
497 my @cmd = (@git, qw(hash-object));
498 push @cmd, qw(-w) if $rewrite;
499 push @cmd, qw(-t commit), $cf;
500 my $newcommit = cmdoutput @cmd;
501 confess "$ch ?" unless $rewrite or $newcommit eq $cl->{CommitId};
506 runcmd @git, qw(diff-tree --quiet),
507 map { $wantdebonly ? "$_:debian" : $_ },
510 return ($build, $breakwater);
513 sub get_head () { return git_rev_parse qw(HEAD); }
515 sub update_head ($$) {
516 my ($old, $new, $mrest) = @_;
517 runcmd @git, qw(update-ref -m), "git-debrebase $mrest", $new, $old;
521 badusage "no arguments to launder allowed";
522 my $old = get_head();
523 my ($tip,$breakwater) = walk $old;
524 update_head $old, $tip, 'launder';
525 # no tree changes except debian/patches
526 runcmd @git, qw(rm --quiet -rf debian/patches);
527 printf "# breakwater tip\n%s\n", $breakwater;
531 die if ($ARGV[0]//'') =~ m/^-/;
532 badusage "too many arguments to analyse" if @ARGV>1;
535 $old = git_rev_parse $old;
539 my ($dummy,$breakwater) = walk $old, 1,*STDOUT;
540 print "$breakwater BREAKWATER\n";
541 STDOUT->error and die $!;
544 my $toplevel = runcmd @git, qw(rev-parse --show-toplevel);
545 chdir $toplevel or die "chdir $toplevel: $!";
547 my $cmd = shift @ARGV;
550 $cmdfn = ${*::}{"cmd_$cmdfn"};
552 $cmdfn or badusage "unknown git-debrebase sub-operation $cmd";