[PATCHv2/RFC 2/3] gitweb: Harden parse_commit and parse_commits

[Jakub Narebski <jnareb@gmail.com>]

Gitweb has problems and gives errors when repository it shows is on
unborn branch (HEAD doesn't point to a valid commit), but there exist
other branches.

One of errors that shows in gitweb logs is undefined $commit_id in
parse_commits() subroutine.  Therefore we harden both parse_commit()
and parse_commits() against undefined $commit_id, and against no
output from git-rev-list because HEAD doesn't point to a commit.

Reported-by: rajesh boyapati <boyapatisrajesh@gmail.com>
Signed-off-by: Jakub Narebski <jnareb@gmail.com>
---
This patch first appeared on git mailing list in "Fwd: Git-web error"
thread as

  [PATCH] gitweb: Harden parse_commit and parse_commits
  Message-Id: <201202081604.17187.jnareb@gmail.com>
  http://article.gmane.org/gmane.comp.version-control.git/190237

More prevention of generating warnings, rather than real fix.

 gitweb/gitweb.perl |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 0fdca5b..2eaf585 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -3334,6 +3334,8 @@ sub parse_commit {
 	my ($commit_id) = @_;
 	my %co;
 
+	return unless defined $commit_id;
+
 	local $/ = "\0";
 
 	open my $fd, "-|", git_cmd(), "rev-list",
@@ -3343,7 +3345,9 @@ sub parse_commit {
 		$commit_id,
 		"--",
 		or die_error(500, "Open git-rev-list failed");
-	%co = parse_commit_text(<$fd>, 1);
+	my $commit_text = <$fd>;
+	%co = parse_commit_text($commit_text, 1)
+		if defined $commit_text;
 	close $fd;
 
 	return %co;
@@ -3353,6 +3357,7 @@ sub parse_commits {
 	my ($commit_id, $maxcount, $skip, $filename, @args) = @_;
 	my @cos;
 
+	return unless defined $commit_id;
 	$maxcount ||= 1;
 	$skip ||= 0;
 
-- 
1.7.9