X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=git-debrebase;h=c240d88b44ca7c6f7d8fe52ccfec5f8bd9982370;hb=e64f34c55170943aa35bb806700c8ba3e99c50a7;hp=482c432de9d0f6af2d3603b0965a45b27c422035;hpb=d62795ff059d1c5854f49d6ea84e2bfebf94e621;p=dgit.git

diff --git a/git-debrebase b/git-debrebase
index 482c432d..c240d88b 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -50,9 +50,11 @@ usages:
 See git-debrebase(1), git-debrebase(5), dgit-maint-debrebase(7) (in dgit).
 END
 
-our ($opt_force, $opt_noop_ok, @opt_anchors);
+our ($opt_force, $opt_careful, $opt_noop_ok, @opt_anchors);
 our ($opt_defaultcmd_interactive);
 
+$opt_careful = 0;
+
 our $us = qw(git-debrebase);
 
 our $wrecknoteprefix = 'refs/debrebase/wreckage';
@@ -181,6 +183,62 @@ sub run_deferred_updates ($) {
     @deferred_update_messages = ();
 }
 
+sub get_tree ($) {
+    # tree object name => ([ $name, $info ], ...)
+    # where $name is the sort key, ie has / at end for subtrees
+    # $info is the LHS from git-ls-tree (<mode> <type> <hash>)
+    # will crash if $x does not exist, so don't do that
+    my ($x) = @_;
+    our (@get_tree_memo, %get_tree_memo);
+    my $memo = $get_tree_memo{$x};
+    return @$memo if $memo;
+
+    local $debugcmd_when_debuglevel = 3;
+    my @l;
+    my @cmd = (qw(git ls-tree -z --full-tree --), $x);
+    my $o = cmdoutput @cmd;
+    $o =~ s/\0$//s;
+    my $last = '';
+    foreach my $l (split /\0/, $o) {
+	my ($i, $n) = split /\t/, $l, 2;
+	$n .= '/' if $i =~ m/^\d+ tree /;
+	push @l, [ $n, $i ];
+	confess "$x need $last < $n ?" unless $last lt $n;
+    }
+    $get_tree_memo{$x} = \@l;
+    push @get_tree_memo, $x;
+    if (@get_tree_memo > 10) {
+	delete $get_tree_memo{ shift @get_tree_memo };
+    }
+    return @l;
+}
+
+sub trees_diff_walk ($$$;$) {
+    # trees_diff_walk [$all,] $x, $y, sub {... }
+    # calls sub->($name, $ix, $iy) for each difference (with $all, each name)
+    # $x and $y are as for get_tree
+    # where $name, $ix, $iy are $name and $info from get_tree
+    my $all = shift @_ if @_>=4;
+    my ($x,$y,$call) = @_;
+    return if !$all and $x eq $y;
+    my @x = get_tree $x;
+    my @y = get_tree $y;
+    while (@x || @y) {
+	my $cmp = !@x       <=> !@y          # eg @y empty? $cmp=-1, use x
+ 	     ||    $x[0][0] cmp  $y[0][0];   # eg, x lt y ? $cmp=-1, use x
+	my ($n, $ix, $iy);                   # all same? $cmp=0, use both
+	$ix=$iy='';
+	($n, $ix) = @{ shift @x } if $cmp <= 0;
+	($n, $iy) = @{ shift @y } if $cmp >= 0;
+	next if !$all and $ix eq $iy;
+	printdebug sprintf
+	    "trees_diff_walk(%d,'%s','%s') call('%s','%s','%s')\n",
+	    !!$all,$x,$y, $n,$ix,$iy
+	    if $debuglevel >= 2;
+	$call->($n, $ix, $iy);
+    }
+}
+
 sub get_differs ($$) {
     my ($x,$y) = @_;
     # This resembles quiltify_trees_differ, in dgit, a bit.
@@ -1423,11 +1481,6 @@ sub walk ($;$$$) {
 
     my $rewriting = 0;
 
-    my $read_tree_upstream = sub {
-	my ($treeish) = @_;
-	read_tree_upstream $treeish, 0, $build;
-    };
-
     $#upp_cl = $upp_limit if defined $upp_limit;
  
     my $committer_authline = calculate_committer_authline();
@@ -1439,7 +1492,12 @@ sub walk ($;$$$) {
     in_workarea sub {
 	mkdir $rd or $!==EEXIST or die $!;
 	my $current_method;
-	runcmd @git, qw(read-tree), $build;
+	my $want_debian = $build;
+	my $want_upstream = $build;
+
+	my $read_tree_upstream = sub { ($want_upstream) = @_; };
+	my $read_tree_debian = sub { ($want_debian) = @_; };
+
 	foreach my $cl (qw(Debian), (reverse @brw_cl),
 			{ SpecialMethod => 'RecordBreakwaterTip' },
 			qw(Upstream), (reverse @upp_cl)) {
@@ -1453,7 +1511,7 @@ sub walk ($;$$$) {
 	    printdebug "WALK BUILD ".($cltree//'undef').
 		" $method (rewriting=$rewriting)\n";
 	    if ($method eq 'Debian') {
-		read_tree_debian($cltree);
+		$read_tree_debian->($cltree);
 	    } elsif ($method eq 'Upstream') {
 		$read_tree_upstream->($cltree);
 	    } elsif ($method eq 'StartRewrite') {
@@ -1463,7 +1521,7 @@ sub walk ($;$$$) {
 		$breakwater = $build;
 		next;
 	    } elsif ($method eq 'DgitImportDebianUpdate') {
-		read_tree_debian($cltree);
+		$read_tree_debian->($cltree);
 	    } elsif ($method eq 'DgitImportUpstreamUpdate') {
  		confess unless $rewriting;
 		my $differs = (get_differs $build, $cltree);
@@ -1474,7 +1532,7 @@ sub walk ($;$$$) {
 		print "Found a general merge, will try to tidy it up.\n";
 		$rewriting = 1;
 		$read_tree_upstream->($cl->{MergeBestAnchor});
-		read_tree_debian($cltree);
+		$read_tree_debian->($cltree);
 		@parents = map { $_->{Breakwater} } @{ $cl->{Parents} };
 	    } elsif ($method eq 'MergeMergeSeries') {
 		my $cachehit = reflog_cache_lookup
@@ -1527,27 +1585,46 @@ sub walk ($;$$$) {
 		    printdebug "WALK REWRITING NOW cl=$cl procd=$procd\n";
 		}
 	    }
-	    my $newtree = cmdoutput @git, qw(write-tree);
-	    my $ch = $cl->{Hdr};
-	    $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
-	    $ch =~ s{^parent .*\n}{}mg;
-	    $ch =~ s{(?=^author)}{
-		join '', map { "parent $_\n" } @parents
-	    }me or confess "$ch ?";
-	    if ($rewriting) {
-		$ch =~ s{^committer .*$}{$committer_authline}m
-		    or confess "$ch ?";
+	    if ($rewriting || $opt_careful) {
+		read_tree_upstream $want_upstream, 0, $want_debian;
+
+		my $newtree = cmdoutput @git, qw(write-tree);
+		my $ch = $cl->{Hdr};
+		$ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
+		$ch =~ s{^parent .*\n}{}mg;
+		$ch =~ s{(?=^author)}{
+		    join '', map { "parent $_\n" } @parents
+		}me or confess "$ch ?";
+		if ($rewriting) {
+		    $ch =~ s{^committer .*$}{$committer_authline}m
+			or confess "$ch ?";
+		}
+		my $cf = "$rd/m$rewriting";
+		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 $rewriting;
+		push @cmd, qw(-t commit), $cf;
+		my $newcommit = cmdoutput @cmd;
+		confess "$ch ?" unless $rewriting
+		    or $newcommit eq $cl->{CommitId};
+		$build = $newcommit;
+	    } else {
+		$build = $cl->{CommitId};
+		trees_diff_walk "$want_upstream:", "$build:", sub {
+		    my ($n) = @_;
+		    no warnings qw(exiting);
+		    next if $n eq 'debian/';
+		    confess "mismatch @_ ?";
+		};
+		trees_diff_walk "$want_debian:debian", "$build:debian", sub {
+		    confess "mismatch @_ ?";
+		};
+		my @old_parents = map { $_->{CommitId} } @{ $cl->{Parents} };
+		confess "mismatch @parents != @old_parents ?"
+		    unless "@parents" eq "@old_parents";
 	    }
-	    my $cf = "$rd/m$rewriting";
-	    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 $rewriting;
-	    push @cmd, qw(-t commit), $cf;
-	    my $newcommit = cmdoutput @cmd;
-	    confess "$ch ?" unless $rewriting or $newcommit eq $cl->{CommitId};
-	    $build = $newcommit;
             if (grep { $method eq $_ } qw(DgitImportUpstreamUpdate)) {
                 $last_anchor = $cur;
             }