X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=dgit.git;a=blobdiff_plain;f=git-debrebase;h=8c1dba80b881d257ca161305aa63c33e990272da;hp=0d9e936d978c38934be3476a3fd81ec90c5bf7d0;hb=60b4f46cf0a103089163736e6fbf5b2fd62960aa;hpb=d26b06ee24c7993251a00b6ab01121245d74b152

diff --git a/git-debrebase b/git-debrebase
index 0d9e936d..8c1dba80 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -18,10 +18,82 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+# usages:
+#    git-debrebase status
+#    git-debrebase start       # like ffqrebase start + debrebase launder
+#    git-debrebase new-upstream [stuff]  # see below
+#    git-debrebase <git-rebase options>  # does debrebase start if necessary
+#
+#    git-debrebase analyse
+#    git-debrebase launder     # prints breakwater tip
+#    git-debrebase create-new-upstream-breakwater [-f] <upstreaminfo>...
+#
+# <upstreaminfo> is
+#    [,][<subdir>:][+]<commitid>[,...]
+#
+# if initial comma is supplied, entries are not positional.  Unspecified
+# <subdir> means root (and there may be only one).
+# xxx want auto branch names
+# xxx too complicated
+# how about for now
+#    [+]<commit> [<subdir/> [+]<commit>...]
+# ?  plus options
+#     --new-upstream-different-subtrees
+#
+#  automatic case
+#       git-debrebase new-upstream
+#             - previous breakwater merge must be gdr-generated
+#             - orig set is the same as before
+#             - implicitly uses upstream branches according to orig set
+#             - not all upstream branches need be updated
+#             - insists on fast-forward of each branch, unless
+#                  --force (or --force=<subdir>[/])
+#  branch set adjustments
+#       git-debrebase new-upstream --add <subdir>/
+#       git-debrebase new-upstream --rm <subdir>/
+#       git-debrebase new-upstream / [<subdir>/ ...]
+#             - orig set is adjusted
+#             - otherwise like auto (--add is not checked for ffness, obv)
+#             - multiple --add and --rm may be specified
+#             - --add makes new upstream the last contributor
+#  explicit
+#       git-debrebase / [<rootcommitid>] [<subdir>/ [<commitid>] ...]
+#             - orig set is precisely as specified now
+#             - previous breakwater merge is irrelevant
+#             - no fast forward checks
+#  for now only explicit with commitids
+
+    # implicitly uses `upstream'
+#                                     # (or multiple other branches)
+#       git-debrebase new-upstream \
+#             [<subdir>/]=<commitid>
+
+#    UPSTREAM[,[[SUBDIR:]SUBUPSTREAM]
+#    default for SUBDIR: is from previous upstream merge[xxx terminology]
+#    
+#
+#xxx
+# when starting must record original start (for ff)
+# and new rebase basis
+#
+#    git-ffqrebase start [BASE]
+#                # records previous HEAD so it can be overwritten
+#                # records base for future git-ffqrebase
+#    git-ffqrebase set-base BASE
+#    git-ffqrebase <git-rebase options>
+#    git-ffqrebase finish
+#    git-ffqrebase status [BRANCH]
+#
+#  refs/ffqrebase-prev/BRANCH    BRANCH may be refs/...; if not it means
+#  refs/ffqrebase-base/BRANCH      refs/heads/BRANCH
+#                               zero, one, or both of these may exist
+
 use strict;
+
 use Memoize;
+use Data::Dumper;
 
-use Debian::Dgit;
+use Debian::Dgit qw(:DEFAULT $wa);
 
 sub cfg ($) {
     my ($k) = @_;
@@ -35,5 +107,423 @@ sub cfg ($) {
 
 memoize('cfg');
 
-use Data::Dumper;
-print Dumper(cfg('wombat.foo.bar'));
+sub get_commit ($) {
+    my ($objid) = @_;
+    my ($type,$data) = git_cat_file $objid;
+    die unless $type eq 'commit';
+    $data =~ m/(?<=\n)\n/;
+    return ($`,$');
+}
+
+sub D_DEB ()     { return 0x1; } # debian/ (not including debian/patches/)
+sub D_UPS ()     { return 0x2; } # upstream files
+sub D_PAT_ADD () { return 0x4; } # debian/patches/ extra patches at end
+sub D_PAT_OTH () { return 0x8; } # debian/patches other changes
+
+our $rd = ".git/git-debrebase";
+our $ud = "$rd/work";
+
+sub commit_pr_info ($) {
+    my ($r) = @_;
+    return Data::Dumper->dump([$r], [qw(commit)]);
+}
+
+sub calculate_committer_authline () {
+    my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
+	'DUMMY COMMIT (git-debrebase)', "$basis:";
+    my ($h,$m) = get_commit $c;
+    $h =~ m/^committer .*$/m or confess "($h) ?";
+    return $&;
+}
+
+# classify returns an info hash like this
+#   CommitId => $objid
+#   Hdr => # commit headers, including 1 final newline
+#   Msg => # commit message (so one newline is dropped)
+#   Tree => $treeobjid
+#   Type => (see below)
+#   Parents = [ {
+#       Ix => $index # ie 0, 1, 2, ...
+#       CommitId
+#       Differs => return value from get_differs
+#       IsOrigin
+#       IsDggitImport => 'orig' 'tarball' 'unpatched' 'package' (as from dgit)
+#     } ...]
+#   NewMsg => # commit message, but with any [dgit import ...] edited
+#             # to say "[was: ...]"
+#
+# Types:
+#   Packaging
+#   Upstream
+#   AddPatches
+#   Mixed
+#   Unknown
+#
+#   Pseudomerge
+#     has additional entres in classification result
+#       Overwritten = [ subset of Parents ]
+#       Contributor = $the_remaining_Parent
+#
+#   DgitImportUnpatched
+#     has additional entry in classification result
+#       OrigParents = [ subset of Parents ]
+#
+#   BreakwaterUpstreamMerge
+#     has additional entry in classification result
+#       OrigParents = [ subset of Parents ]
+
+sub classify ($) {
+    my ($objid) = @_;
+
+    my ($h,$m) = get_commit $objid;
+
+    my ($t) = $h =~ m/^tree (\w+)$/m or die $cur;
+    my (@ph) = $h =~ m/^parent (\w+)$/m;
+    my @p;
+
+    my $r = {
+	CommitId => $objid,
+	Hdr => $hdr,
+	Msg => $m,
+        Tree => $t,
+	Parents => \@p,
+    };
+
+    foreach my $ph (@ph) {
+	push @p, {
+            Ix => $#p,
+            CommitId => $ph,
+            Differs => (get_differs $t, $ph),
+        };
+    }
+
+    my $classify = sub {
+	my ($type, @rest) = @_;
+	$r = { %r, Type => $type, @rest };
+	return $r;
+    };
+    my $unknown = sub {
+	my ($why) = @_;
+	$r = { %r, Type => Unknown };
+	return $r;
+    }
+
+    if (@p == 1) {
+	my $d = $r->{Parents}[0]{Differs};
+	if ($d == D_DPAT_ADD) {
+	    return $classify->(qw(AddPatches));
+	} elsif ($d & (D_DPAT_ADD|D_DPAT_OTH)) {
+	    return $unknown->("edits debian/patches");
+	} elsif ($d == D_DEB) {
+	    return $classify->(qw(Packaging));
+	} elsif ($d == D_UPS) {
+	    return $classify->(qw(Upstream));
+	} elsif ($d == D_DEB|D_UPS) {
+	    return $classify->(qw(Mixed));
+	} elsif ($d == 0) {
+	    return $unknown->("no changes");
+	} else {
+	    confess "internal error $objid ?";
+	}
+    }
+    if (!@p) {
+	return $unknown->("origin commit");
+    }
+
+    my @identical = grep { !$_->{Differs} } @p;
+    if (@p == 2 && @identical == 1) {
+	my @overwritten = grep { $_->{Differs} } @p;
+	confess "internal error $objid ?" unless @overwritten==1;
+	return $classify->(qw(Pseudomerge),
+			   Overwritten => $overwritten[0],
+			   Contributor => $identical[0]);
+    }
+    if (@p == 2 && @identical == 2) {
+	my @bytime = nsort_by {
+	    my ($ph,$pm) = get_commit $_->{CommitId};
+	    $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
+	    $1;
+	} @p;
+	return $classify->(qw(Pseudomerge),
+			   SubType => qw(Ambiguous),
+			   Overwritten => $bytime[0],
+			   Contributor => $bytime[1]);
+    }!
+    foreach my $p (@p) {
+	my ($p_h, $p_m) = get_commit $p;
+	$p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
+	($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
+    }
+    my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' };
+    my $m2 = $m;
+    if (!(grep { !$_->{IsOrigin} } @p) and
+	(@origs >= @p - 1) and
+	$m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
+	$r->{NewMsg} = $m2;
+	return $classify->(qw(DgitImportUnpatched),
+			   OrigParents => \@orig_ps);
+    }
+
+    my ($stype, $series) = git_cat_file "$t:debian/patches/series";
+    my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
+
+    # How to decide about l/r ordering of breakwater merges ?  git
+    # --topo-order prefers to expand 2nd parent first.  There's
+    # already an easy rune to look for debian/ history anyway (git log
+    # debian/) so debian breakwater branch should be 1st parent; that
+    # way also there's also an easy rune to look for the upstream
+    # patches (--topo-order).
+    if (@p == 2 &&
+	!$haspatches &&
+	!$p[0]{IsOrigin} && # breakwater merge never starts with an origin
+	!($p[0]{Differs} & ~D_DEB) &&
+	!($p[1]{Differs} & ~D_UPS)) {
+	return $classify->(qw(BreakwaterUpstreamMerge),
+			   OrigParents => [ $p[1] ]);
+    }
+    # xxx multi-.orig upstreams
+
+    return $unknown->("complex merge");
+}
+
+sub walk ($$$;$$$) {
+    my ($input, $pseudos_must_overwrite_this, $wantdebonly,
+	$report, $depth, $report_anomaly, $nogenerate) = @_;
+    # go through commits backwards
+    # we generate two lists of commits to apply
+    # => ($tip, $breakwater_tip)
+    my (@deb_cl, @ups_cl, @processed);
+    my %found;
+    my @pseudomerges;
+
+    $report //= sub { };
+    $report_anomaly //= sub {
+	my ($cl, $msg) = @_;
+	die "commit $cl: $msg\n";
+    };
+    $depth //= 0;
+
+    my $cl;
+    my $xmsg = sub {
+	my ($appendinfo) = @_;
+	my $ms = $cl->{Msg};
+	chomp $ms;
+	$ms .= "\n\n[git-debrebase $appendinfo]\n";
+	return (Msg => $ms);
+    };
+    my $rewrite_from_here = sub {
+	push @processed, { SpecialMethod => 'StartRewrite' };
+    };
+
+    my $cur = $input;
+
+    for (;;) {
+	$cl = classify $cur;
+	my $ty = $cl->{Type};
+	my $st = $cl->{SubType};
+	$report->($cl);
+	$found{$ty. ( defined($st) ? "-$st" : '' )}++;
+	my $p0 = $cl->{Parents}[0]{CommitId};
+	$cl->{Abbrev} = lc substr $ty,0,1;
+	if ($ty eq 'AddPatches') {
+	    $cl->{Abbrev} = 'P';
+	    $cur = $p0;
+	    $rewrite_from_here->();
+	    next;
+	} elsif ($ty eq 'Packaging') {
+	    $cl->{Abbrev} = 'd';
+	    push @deb_cl, $cl;
+	    push @processed, $cl;
+	    $cur = $p0;
+	    next;
+	} elsif ($ty eq 'Upstream') {
+	    push @ups_cl, $cl;
+	    push @processed, $cl;
+	    $cur = $p0;
+	    next;
+	} elsif ($ty eq 'Mixed') {
+	    my $queue = sub {
+		my ($q, $wh) = @_;
+		my $cls = { $cl, $xmsg->("split mixed commit: $wh part") };
+		push @$q, $cls;
+	    };
+	    $queue->(\@deb_cl, "debian");
+	    $queue->(\@ups_cl, "upstream");
+	    $rewrite_from_here->();
+	    next;
+	} elsif ($ty eq 'Pseudomerge') {
+	    $cl->{Abbrev} = 'M';
+	    if (defined $pseudos_must_overwrite_this &&
+		!grep {
+		    is_fast_fwd $pseudos_must_overwrite_this, $_->{CommitId}
+		},
+		@{ $cl->{Overwritten} }) {
+		$report_anomaly->($cl,
+				  "Pseudomerge should overwrite".
+				  " $pseudos_must_overwrite_this".
+				  " but does not do so");
+	    }
+	    push @pseudomerges, $cl;
+	    $rewrite_from_here->();
+	    $cur = $ty->{Contributor};
+	    next;
+	} elsif ($ty eq 'BreakwaterUpstreamMerge') {
+	    $basis = $cur;
+	    last;
+	} elsif ($ty eq 'DgitImportUnpatched' &&
+		 @pseudomerges == 1) {
+	    $cl->{Abbrev} = 'I';
+	    # This import has a tree which is just like a breakwater
+	    # tree, but it has the wrong history.  Its ought to have
+	    # the previous breakwater (which dgit ought to have
+	    # generated a pseudomerge to overwrite) as an ancestor.
+	    # That will make the history of the debian/ files correct.
+	    # As for the upstream version: either it's the same upstream
+	    # as the previous breakwater, in which case that history is
+	    # precisely right.  Otherwise, it was a non-gitish upload
+	    # of a new upstream version.  We can tell these apart
+	    # by looking at the tree of the supposed upstream.
+	    my $differs = get_differs $previous_breakwater, $cl->{Tree};
+	    if ($differs & D_UPS) {
+		push @deb_cl, {
+                    %r,
+                    SpecialMethod => 'DgitImportUpstreamUpdate',
+                    $xmsg->("convert dgit import: debian changes")
+                };
+	    }
+	    push @deb_cl, {
+		%r,
+		SpecialMethod => 'DgitImportDebianUpdate',
+                $xmsg->("convert dgit import: upstream changes")
+	    };
+	    $basis = launder $pseudomerges[0]{Overwritten}, undef, 1,
+		$report, $depth+1, $nogenerate;
+	    $rewrite_from_here->();
+	    last;
+	} else {
+	    $report_anomaly->($cl, "Cannot cope with this commit");
+	}
+    }
+    # Now we build it back up again
+
+    if ($nogenerate) {
+	return (undef, $basis);
+    }
+
+    workarea_fresh();
+
+    my $rewriting = 1;
+
+    my $build = $basis;
+
+    my $rm_tree_cached = sub {
+	my ($subdir) = @_;
+	runcmd @git, qw(rm --quiet -rf --cached), $subdir;
+    };
+    my $read_tree_debian = sub {
+	my ($treeish) = @_;
+	$rm_tree_cached->(qw(debian));
+	runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
+    };
+    my $read_tree_upstream = sub {
+	my ($treeish) = @_;
+	runcmd @git, qw(read-tree), $treeish;
+	$read_tree_debian->($build);
+    };
+ 
+    my $committer_authline = calculate_committer_authline();
+
+    in_workarea sub {
+	mkdir $rd or $!==EEXIST or die $!;
+	my $current_method;
+	foreach my $cl (qw(Debian), (reverse @deb_cl),
+			{ SpecialMethod => 'RecordBreakwaterTip' },
+			qw(Upstream), (reverse @ups_cl)) {
+	    if (!ref $cl) {
+		$current_method = $cl;
+		next;
+	    }
+	    $method = $cl->{SpecialMethod} // $current_method;
+	    my @parents = ($build);
+	    my $cltree = $cl->{CommitId}
+	    if ($method eq 'Debian') {
+		$read_tree_debian->($cltree);
+	    } elsif ($method eq 'Upstream') {
+		$read_tree_upstream->($cltree);
+	    } elsif ($method eq 'StartRewrite') {
+		$rewriting = 1;
+		next;
+	    } elsif ($method eq 'RecordBreakwaterTip') {
+		last if $wantdebonly;
+		$breakwater = $build;
+		next;
+	    } elsif ($method eq 'DgitImportDebianUpdate') {
+		$read_tree_debian->($cltree);
+		$rm_tree_cached(qw(debian/patches));
+	    } elsif ($method eq 'DgitImportUpstreamUpdate') {
+		$read_tree_upstream->($cltree);
+		push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
+	    } else {
+		confess "$method ?";
+	    }
+	    $rewriting ||= $cl ne pop @processed;
+	    my $newtree = cmdoutput @git, qw(write-tree);
+	    my $ch = $cl->{Hdr};
+	    $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
+	    $ch =~ s{^parent .*\n}{}m;
+	    $ch =~ s{(?=^author}{
+		map { "parent $_\n" } @parents
+	    }me or confess "$ch ?";
+	    if ($rewrite) {
+		$ch =~ s{^committer .*$}{$committer_authline}m
+		    or confess "$ch ?";
+	    }
+	    my $cf = "$rd/m$rewrite"
+		open CD, ">", $cf or die $!;
+	    print CD $ch, "\n", $cl->{Msg}; or die $!;
+	    close CD or die $!;
+	    my @cmd = (@git, qw(hash-object));
+	    push @cmd, qw(-w) if $rewrite;
+	    push @cmd, qw(-t commit), $cf;
+	    my $newcommit = cmdoutput @cmd;
+	    confess "$ch ?" unless $rewrite or $newcommit eq $cl->{CommitId};
+	    $build = $newcommit;
+	}
+    };
+
+    runcmd @git, qw(diff-tree --quiet),
+	map { $wantdebonly ? "$_:debian" : $_ },
+	$input, $build;
+
+    return ($build, $breakwater);
+}
+
+sub get_head () { return git_rev_parse qw(HEAD); }
+
+sub update_head ($$) {
+    my ($old, $new, $mrest) = @_;
+    runcmd @git, qw(update-ref -m), "git-debrebase $mrest", $new, $old;
+}
+
+sub cmd_analyse () {
+    
+
+sub cmd_launder () {
+    my $old = get_head();
+    my ($tip,$breakwater) = launder $old, 0, undef, 0;
+    update_head $old, $tip, 'launder';
+    # no tree changes except debian/patches
+    runcmd @git, qw(rm --quiet -rf debian/patches);
+    printf "# breakwater tip:\n%s\n", $breakwater;
+}
+
+my $toplevel = runcmd @git, qw(rev-parse --show-toplevel);
+chdir $toplevel or die "chdir $toplevel: $!";
+
+my $cmd = shift @ARGV;
+my $cmdfn = $cmd;
+$cmdfn =~ y/-/_/;
+$cmdfn = ${*::}{"cmd_$cmdfn"};
+
+$cmdfn or badusage "unknown git-debrebase sub-operation $cmd";
+$cmdfn->();