Fix serious performance regression.

In Repository::commit, don't call startFastImport() if we have nothing to
write to the fastImport stream. startFastImport() may start new
git-fast-import processes if they were previously killed, so it may be
extremely slow to call it frequently if it's not necessary.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/repository.cpp b/src/repository.cpp
index b362bdf..7baf995 100644
--- a/src/repository.cpp
+++ b/src/repository.cpp
@@ -374,6 +374,9 @@ int Repository::resetBranch(const QString &branch, int revnum, int mark, const Q
 
 void Repository::commit()
 {
+    if (deletedBranches.isEmpty() && resetBranches.isEmpty()) {
+        return;
+    }
     startFastImport();
     fastImport.write(deletedBranches);
     fastImport.write(resetBranches);