path: root/gitweb/gitweb.perl
diff options
authorJakub Narebski <>2009-07-24 22:44:03 (GMT)
committerJunio C Hamano <>2009-07-25 08:39:16 (GMT)
commit11930423d11c1256014e10b940c4ee8f12328739 (patch)
tree7278a50732f9b8d77812506c4411e5bc175da439 /gitweb/gitweb.perl
parent6de9433fd0525632094f3cc172a606f217fa2097 (diff)
gitweb: Use "previous" header of git-blame -p in 'blame' view
Luben Tuikov changed 'lineno' link (line number link) from pointing to 'blame' view at given line at blamed commit, to the one at parent of blamed commit in 244a70e (Blame "linenr" link jumps to previous state at "orig_lineno", 2007-01-04). This made it possible to do data mining using 'blame' view, by going through history of a line using mentioned line number link. Original implementation called "git rev-parse <commit>^" to find SHA-1 of a parent of a given commit once per each blamed line. In 39c19ce (gitweb: cache $parent_commit info in git_blame(), 2008-12-11) this was improved so rev-parse was called once per each unique commit in git-blame output. Alternate solution would be to relax validation for 'hb' parameter by allowing extended SHA-1 syntax of the form <rev>^ (perhaps redirecting to gitweb URL with <rev>^ resolved, in practice moving call to rev-parse to 'the other side of link'). This solution had a bug that it didn't work for boundary commits. Boundary commits don't have parents, so "git rev-parse <commit>^" returned literal "<commit>^" (which didn't exists). Gitweb didn't detect this situation and passed this result literally as 'hb' parameter in 'linenr' link. Following such link currently gives 400 - Invalid hash base parameter error; 'hb' parameter is restricted via validate_refname to correct refnames and doesn't allow for extended SHA-1 syntax. This bug could have been fixed alternatively by checking if commit is boundary commit, or check if rev-parse result is unchanged (still ends in '^' prefix). The solution employing rev-parse to find parent of commit had inherent problem if blamed commit renamed file; then name of file would be different in its parent. Solving this outside git-blame would be difficult and costly (at least cost of additional fork for extra git command). Currently gitweb uses information in "previous" header, which was introduced by Junio C Hamano in 96e1170 (blame: show "previous" information in --porcelain/--incremental format, 2008-06-04) This (currently undocumented) header has the following format: "previous <sha1 of parent commit> <filename at parent>" Using "previous" header solves both problem of performance and the problem that blamed commit could have renaming blamed file. Because "previous" header can be repeated for the same commit when blamed commit is merge (has more than one parent), and we are interested usually in _first_ parent, currently we store only first value if blame header repeats. Using first parent (first "previous" line) was what gitweb did before; without this change gitweb would use last parent instead. If there is no previous commit 'linenr' link points to blamed commit and blamed filename, making it work correctly for boundary commits. Acked-by: Luben Tuikov <> Signed-off-by: Jakub Narebski <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'gitweb/gitweb.perl')
1 files changed, 15 insertions, 14 deletions
diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 3078b92..b8a121b 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -4827,7 +4827,7 @@ HTML
chomp $data;
last if ($data =~ s/^\t//); # contents of line
if ($data =~ /^(\S+)(?: (.*))?$/) {
- $meta->{$1} = $2;
+ $meta->{$1} = $2 unless exists $meta->{$1};
my $short_rev = substr($full_rev, 0, 8);
@@ -4852,20 +4852,21 @@ HTML
print "</td>\n";
- my $parent_commit;
- if (!exists $meta->{'parent'}) {
- open (my $dd, "-|", git_cmd(), "rev-parse", "$full_rev^")
- or die_error(500, "Open git-rev-parse failed");
- $parent_commit = <$dd>;
- close $dd;
- chomp($parent_commit);
- $meta->{'parent'} = $parent_commit;
- } else {
- $parent_commit = $meta->{'parent'};
- }
+ # 'previous' <sha1 of parent commit> <filename at commit>
+ if (exists $meta->{'previous'} &&
+ $meta->{'previous'} =~ /^([a-fA-F0-9]{40}) (.*)$/) {
+ $meta->{'parent'} = $1;
+ $meta->{'file_parent'} = unquote($2);
+ }
+ my $linenr_commit =
+ exists($meta->{'parent'}) ?
+ $meta->{'parent'} : $full_rev;
+ my $linenr_filename =
+ exists($meta->{'file_parent'}) ?
+ $meta->{'file_parent'} : unquote($meta->{'filename'});
my $blamed = href(action => 'blame',
- file_name => $meta->{'filename'},
- hash_base => $parent_commit);
+ file_name => $linenr_filename,
+ hash_base => $linenr_commit);
print "<td class=\"linenr\">";
print $cgi->a({ -href => "$blamed#l$orig_lineno",
-class => "linenr" },