Subject: [PATCH] Don't checkout the full tree if avoidable

From: Steven Walter <[email-masked]>
Date: Fri, 28 Sep 2007 13:24:19 -0400

In most cases of branching, the tree is copied unmodified from the trunk
to the branch.  When that is done, we can simply start with the parent's
index and apply the changes on the branch as usual.

Signed-off-by: Steven Walter <[email-masked]>
---
 git-svn.perl |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/git-svn.perl b/git-svn.perl
index 484b057..2ca2042 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -1847,6 +1847,13 @@ sub find_parent_branch {
 			$gs->ra->gs_do_switch($r0, $rev, $gs,
 					      $self->full_url, $ed)
 			  or die "SVN connection failed somewhere...\n";
+		} elsif ($self->trees_match($new_url, $r0,
+			                    $self->full_url, $rev)) {
+			$self->tmp_index_do(sub {
+			    command_noisy('read-tree', $parent);
+			});
+			$self->{last_commit} = $parent;
+			# Assume copy with no changes
 		} else {
 			print STDERR "Following parent with do_update\n";
 			$ed = SVN::Git::Fetcher->new($self);
@@ -1859,6 +1866,17 @@ sub find_parent_branch {
 	return undef;
 }
 
+sub trees_match {
+    my ($self, $url1, $rev1, $url2, $rev2) = @_;
+    
+    my $ret=1;
+    open(my $fh, "svn diff $url1\@$rev1 $url2\@$rev2 |");
+    $ret=0 if (<$fh>);
+    close($fh);
+
+    return $ret;
+}
+
 sub do_fetch {
 	my ($self, $paths, $rev) = @_;
 	my $ed;
-- 
1.5.3.1