git-svn: improve repository URL matching when following parents

Warning! This patch isn't heavily-tested against remote servers, it only helped me limp by on a server I was having trouble with tonight. I was barely awake when working on this and have been living in a different timezone for more than a week, so don't trust it too much unless you're already having difficulty with some servers.

This way we can avoid the spawning of a new SVN::Ra session by reusing the existing one.

The most problematic issue is that some svn servers disallow too many connections from a single IP, so this will allow git-svn to fetch from those repositories with a higher success rate by using fewer connections.

This sometimes showed up as a new (and redundant) [svn-remote "$parent_refname"] entry in $GIT_DIR/svn/.metadata.

---

Note: there are still cases where git-svn can open more than one connection to the SVN server, which can make some SVN setups/administrators unhappy. Unfortunately, I'm pretty sure I won't have time to properly fix all of these in the next few days.

For now, if you get "connection closed unexpectedly" messages while fetching (and following parents), just restart git-svn and it'll pick up where it left off.

 git-svn.perl |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

index 75e97cc..7ba8c8f 100755
@@ -2226,7 +2226,12 @@ sub find_parent_branch {
 		# just grow a tail if we're not unique enough :x
 		$ref_id .= '-' while find_ref($ref_id);
 		print STDERR "Initializing parent: $ref_id\n";
-		$gs = Git::SVN->init($new_url, '', $ref_id, $ref_id, 1);
+		my ($u, $p) = ($new_url, '');
+		if ($u =~ s#^\Q$url\E(/|$)##) {
+			$p = $u;
+			$u = $url;
+		}
+		$gs = Git::SVN->init($u, $p, $self->{repo_id}, $ref_id, 1);
 	}
 	my ($r0, $parent) = $gs->find_rev_before($r, 1);
 	if (!defined $r0 || !defined $parent) {

Eric Wong

Warning lifted, please apply to master.

It may be a while before I have time to fix this. If anybody else is willing to step up, please do.

Some notes:

Most of this is related to svn:// (and possibly svn+ssh://) sessions, and definitely doesn't apply to file:// servers.

I couldn't find an explicit way to close the socket using the SVN API. However, the socket does seem to get closed when the refcount of the SVN::Ra object hits zero.

It seems only one SVN::Ra can be active at a time. Even though it's possible to hold multiple sockets open to an SVN server within the same process (with svn://), the SVN library code doesn't work well with multiple sessions active.

Eric Wong