[PATCH] git-svn: improve repository URL matching when following parents

[PATCH] git-svn: improve repository URL matching when following parents

[Eric Wong]

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.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
---

 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(-)

diff --git a/git-svn.perl b/git-svn.perl
index 75e97cc..7ba8c8f 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -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

Re: [PATCH] git-svn: improve repository URL matching when following parents

[Eric Wong]

Eric Wong <normalperson@yhbt.net> wrote:
> 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.

Warning lifted, please apply to master.

> 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.
> 
> Signed-off-by: Eric Wong <normalperson@yhbt.net>
> ---
> 
>  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.

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.

>  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(-)
> 
> diff --git a/git-svn.perl b/git-svn.perl
> index 75e97cc..7ba8c8f 100755
> --- a/git-svn.perl
> +++ b/git-svn.perl
> @@ -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