annotate: Fix bug when parsing merges with differing real and logical parents.

Signed-off-by: Ryan Anderson <ryan@michonline.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-annotate.perl b/git-annotate.perl
index 505b5ccb280e16e4279569810ed1f41cf247e570..215ed26f3aff4b12139359ca841a9a80c567a6e6 100755 (executable)
--- a/git-annotate.perl
+++ b/git-annotate.perl
@@ -147,7 +147,7 @@ sub init_claim {
 
 
 sub handle_rev {
-       my $i = 0;
+       my $revseen = 0;
        my %seen;
        while (my $rev = shift @revqueue) {
                next if $seen{$rev}++;
@@ -247,22 +247,129 @@ sub git_find_parent {
        return $parent;
 }
 
+sub git_find_all_parents {
+       my ($rev) = @_;
+
+       my $revparent = open_pipe("git-rev-list","--remove-empty", "--parents","--max-count=1","$rev")
+               or die "Failed to open git-rev-list to find a single parent: $!";
+
+       my $parentline = <$revparent>;
+       chomp $parentline;
+       my ($origrev, @parents) = split m/\s+/, $parentline;
+
+       close($revparent);
+
+       return @parents;
+}
+
+sub git_merge_base {
+       my ($rev1, $rev2) = @_;
+
+       my $mb = open_pipe("git-merge-base", $rev1, $rev2)
+               or die "Failed to open git-merge-base: $!";
+
+       my $base = <$mb>;
+       chomp $base;
+
+       close($mb);
+
+       return $base;
+}
+
+# Construct a set of pseudo parents that are in the same order,
+# and the same quantity as the real parents,
+# but whose SHA1s are as similar to the logical parents
+# as possible.
+sub get_pseudo_parents {
+       my ($all, $fake) = @_;
+
+       my @all = @$all;
+       my @fake = @$fake;
+
+       my @pseudo;
+
+       my %fake = map {$_ => 1} @fake;
+       my %seenfake;
+
+       my $fakeidx = 0;
+       foreach my $p (@all) {
+               if (exists $fake{$p}) {
+                       if ($fake[$fakeidx] ne $p) {
+                               die sprintf("parent mismatch: %s != %s\nall:%s\nfake:%s\n",
+                                           $fake[$fakeidx], $p,
+                                           join(", ", @all),
+                                           join(", ", @fake),
+                                          );
+                       }
+
+                       push @pseudo, $p;
+                       $fakeidx++;
+                       $seenfake{$p}++;
+
+               } else {
+                       my $base = git_merge_base($fake[$fakeidx], $p);
+                       if ($base ne $fake[$fakeidx]) {
+                               die sprintf("Result of merge-base doesn't match fake: %s,%s != %s\n",
+                                      $fake[$fakeidx], $p, $base);
+                       }
+
+                       # The details of how we parse the diffs
+                       # mean that we cannot have a duplicate
+                       # revision in the list, so if we've already
+                       # seen the revision we would normally add, just use
+                       # the actual revision.
+                       if ($seenfake{$base}) {
+                               push @pseudo, $p;
+                       } else {
+                               push @pseudo, $base;
+                               $seenfake{$base}++;
+                       }
+               }
+       }
+
+       return @pseudo;
+}
+
 
 # Get a diff between the current revision and a parent.
 # Record the commit information that results.
 sub git_diff_parse {
        my ($parents, $rev, %revinfo) = @_;
 
+       my @pseudo_parents;
+       my @command = ("git-diff-tree");
+       my $revision_spec;
+
+       if (scalar @$parents == 1) {
+
+               $revision_spec = join("..", $parents->[0], $rev);
+               @pseudo_parents = @$parents;
+       } else {
+               my @all_parents = git_find_all_parents($rev);
+
+               if (@all_parents !=  @$parents) {
+                       @pseudo_parents = get_pseudo_parents(\@all_parents, $parents);
+               } else {
+                       @pseudo_parents = @$parents;
+               }
+
+               $revision_spec = $rev;
+               push @command, "-c";
+       }
+
        my @filenames = ( $revs{$rev}{'filename'} );
+
        foreach my $parent (@$parents) {
                push @filenames, $revs{$parent}{'filename'};
        }
 
-       my $diff = open_pipe("git-diff-tree","-M","-p","-c",$rev,"--",
-                               @filenames )
+       push @command, "-p", "-M", $revision_spec, "--", @filenames;
+
+
+       my $diff = open_pipe( @command )
                or die "Failed to call git-diff for annotation: $!";
 
-       _git_diff_parse($diff, $parents, $rev, %revinfo);
+       _git_diff_parse($diff, \@pseudo_parents, $rev, %revinfo);
 
        close($diff);
 }
@@ -283,6 +390,7 @@ sub _git_diff_parse {
        $diff_header_regexp .= "@" x @$parents;
        $diff_header_regexp .= ' -\d+,\d+' x @$parents;
        $diff_header_regexp .= ' \+(\d+),\d+';
+       $diff_header_regexp .= " " . ("@" x @$parents);
 
        my %claim_regexps;
        my $allparentplus = '^' . '\\+' x @$parents . '(.*)$';
@@ -311,6 +419,7 @@ sub _git_diff_parse {
        DIFF:
        while(<$diff>) {
                chomp;
+               #printf("%d:%s:\n", $gotheader, $_);
                if (m/$diff_header_regexp/) {
                        $remstart = $1 - 1;
                        # (0-based arrays)
@@ -391,10 +500,17 @@ sub _git_diff_parse {
                                                printf("parent %s is on line %d\n", $parent, $pi{$parent});
                                        }
 
+                                       my @context;
+                                       for (my $i = -2; $i < 2; $i++) {
+                                               push @context, get_line($slines, $ri + $i);
+                                       }
+                                       my $context = join("\n", @context);
+
+                                       my $justline = substr($_, scalar @$parents);
                                        die sprintf("Line %d, does not match:\n|%s|\n|%s|\n%s\n",
                                                    $ri,
-                                               substr($_,scalar @$parents),
-                                               get_line($slines,$ri), $rev);
+                                                   $justline,
+                                                   $context);
                                }
                                foreach my $parent (@$parents) {
                                        $plines{$parent}[$pi{$parent}++] = $slines->[$ri];