[PATCH ssoma] extractor: do not needlessly update config file

[Eric Wong]

No reason to trigger excessive writes when nothing is done.
---
 lib/Ssoma/Extractor.pm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/Ssoma/Extractor.pm b/lib/Ssoma/Extractor.pm
index 7e2b5d1..baf9adb 100644
--- a/lib/Ssoma/Extractor.pm
+++ b/lib/Ssoma/Extractor.pm
@@ -47,6 +47,7 @@ sub _extract {
 
        my $lkey = "target.$target.last-imported";
        my $last = $cfg->{$lkey};
+       my $last_imported = $last;
 
        my $ref = $self->{ref};
        my $tip = $git->qx_sha1("git rev-parse $ref^0");
@@ -106,7 +107,7 @@ sub _extract {
        }
 
        # update the last-imported var
-       {
+       if (!defined($last_imported) || $last_imported ne $tip) {
                # This state file is important, and git does not fsync it.
                if (open my $st, '<', $state) {
                        # clobber existing backup
-- 
EW