Added test for branch changes - it appears to work well, at least as far as the restricted tests are concerned

Author: Byron

lib/git/objects/submodule.py

@@ -41,7 +41,7 @@ def wrapper(self, *args, **kwargs):
 	wrapper.__name__ = func.__name__
 	return wrapper
 
-def find_remote_branch(remotes, branch):
+def find_first_remote_branch(remotes, branch):
 	"""Find the remote branch matching the name of the given branch or raise InvalidGitRepositoryError"""
 	for remote in remotes:
 		try:
@@ -394,7 +394,7 @@ def update(self, recursive=False, init=True, to_latest_revision=False):
 			# see whether we have a valid branch to checkout
 			try:
 				# find  a remote which has our branch - we try to be flexible
-				remote_branch = find_remote_branch(mrepo.remotes, self.branch)
+				remote_branch = find_first_remote_branch(mrepo.remotes, self.branch)
 				local_branch = self.branch
 				if not local_branch.is_valid():
 					# Setup a tracking configuration - branch doesn't need to 
@@ -1078,14 +1078,23 @@ def update(self, previous_commit=None, recursive=True, force_remove=False, init=
 					# new remote branch
 					smm = sm.module()
 					smmr = smm.remotes
-					tbr = git.Head.create(smm, sm.branch.name)
-					tbr.set_tracking_branch(find_remote_branch(smmr, sm.branch))
+					try:
+						tbr = git.Head.create(smm, sm.branch.name)
+					except git.GitCommandError, e:
+						if e.status != 128:
+							raise
+						#END handle something unexpected
+						
+						# ... or reuse the existing one
+						tbr = git.Head(smm, git.Head.to_full_path(sm.branch.name))
+					#END assure tracking branch exists
 
+					tbr.set_tracking_branch(find_first_remote_branch(smmr, sm.branch))
 					# figure out whether the previous tracking branch contains
 					# new commits compared to the other one, if not we can 
 					# delete it.
 					try:
-						tbr = find_remote_branch(smmr, psm.branch)
+						tbr = find_first_remote_branch(smmr, psm.branch)
 						if len(smm.git.cherry(tbr, psm.branch)) == 0:
 							psm.branch.delete(smm, psm.branch)
 						#END delete original tracking branch if there are no changes

test/git/test_submodule.py

@@ -437,16 +437,34 @@ def test_root_module(self, rwrepo):
 		# head changed, as the remote url and its commit changed
 		assert prev_commit != nsm.module().head.commit
 
-		assert False
+		# add the submodule's changed commit to the index, which is what the
+		# user would do
+		# beforehand, update our instance's binsha with the new one
+		nsm.binsha = nsm.module().head.commit.binsha
+		rwrepo.index.add([nsm])
 
 		# change branch
 		#=================
-		nsm.set_parent_commit(csmpathchange)
-		# the branch used here is an old failure branch which should ideally stay ... lets see how long that works ;)
-		nbn = 'pack_offset_cache'
-		assert nsm.branch.name != nbn
-		nsm.config_writer().set_value(Submodule.k_head_option, nbn)
-		csmbranchchange = rwrepo.index.commit("changed branch")
+		# we only have one branch, so we switch to a virtual one, and back 
+		# to the current one to trigger the difference
+		cur_branch = nsm.branch
+		nsmm = nsm.module()
+		prev_commit = nsmm.head.commit
+		for branch in ("some_virtual_branch", cur_branch.name):
+			nsm.config_writer().set_value(Submodule.k_head_option, branch)
+			csmbranchchange = rwrepo.index.commit("changed branch to %s" % branch)
+			nsm.set_parent_commit(csmbranchchange)
+		# END for each branch to change
+		
+		# Lets remove our tracking branch to simulate some changes
+		nsmmh = nsmm.head
+		assert nsmmh.ref.tracking_branch() is None					# never set it up until now
+		assert not nsmmh.is_detached
+		
+		rm.update(recursive=False)
+		
+		assert nsmmh.ref.tracking_branch() is not None
+		assert not nsmmh.is_detached
 
 
 		# recursive update