Don't update already up to date branches

2 files changed, 31 insertions, 9 deletions

diff --git a/gbp-pull b/gbp-pull
index 71f6c0bf..6f23dbe5 100755
--- a/gbp-pull
+++ b/gbp-pull
@@ -29,22 +29,38 @@ from gbp.errors import GbpError
 from gbp.git import (GitRepositoryError, GitRepository)
 
 def fast_forward_branch(branch, repo, options):
+    """
+    update branch to its remote branch, fail on non fast forward updates
+    unless --force is given
+    @return: branch updated or already up to date
+    @rtype: boolean
+    """
+    update = False
+
     remote = repo.get_merge_branch(branch)
     if not remote:
         print >>sys.stderr, "Warning: no branch tracking '%s' found - skipping." % branch
-        return
-    fast_forward = repo.is_fast_forward(branch, remote)
-    if not fast_forward:
+        return False
+
+    can_fast_forward, up_to_date = repo.is_fast_forward(branch, remote)
+
+    if up_to_date: # Great, we're done
+        print "Branch '%s' is already up to date." % branch
+        return True
+
+    if can_fast_forward:
+        update = True
+    else:
         if options.force:
             print "Non-fast forwarding '%s' due to --force" % branch
-            fast_forward = True
+            update = True
         else:
             print >>sys.stderr, "Warning: Skipping non-fast forward of '%s' - use --force" % branch
 
-    if fast_forward:
+    if update:
         repo.set_branch(branch)
         GitMerge(remote)()
-    return fast_forward
+    return update
 
 def main(argv):
     changelog = 'debian/changelog'
diff --git a/gbp/git.py b/gbp/git.py
index c09ce1ea..4f7ba989 100644
--- a/gbp/git.py
+++ b/gbp/git.py
@@ -118,13 +118,19 @@ class GitRepository(object):
         return remote
 
     def is_fast_forward(self, from_branch, to_branch):
-        """check if an update from from_branch to to_branch would be a fast forward"""
+        """check if an update from from_branch to to_branch would be a fast
+           forward or if the branch is uptodate already"""
         out = self.__git_getoutput('rev-list', ["--left-right",
                                    "%s...%s" % (from_branch, to_branch)])[0]
+
+        if not out: # already up to date
+            return True, True
+
         for line in out:
             if line.startswith("<"):
-                return False
-        return True
+                return False, False
+
+        return True, False
 
     def set_branch(self, branch):
         """switch to branch 'branch'"""