Issue 2311 - Track remote Git branches when required

ensure_dependencies.py

Index: ensure_dependencies.py
diff --git a/ensure_dependencies.py b/ensure_dependencies.py
index b6557d051f6661645dea95edfde280ea288f7533..70130b5d97e7327d07128596f3c2e7d50771dc1e 100755
--- a/ensure_dependencies.py
+++ b/ensure_dependencies.py
@@ -97,6 +97,17 @@ class Git():
     return subprocess.check_output(command, cwd=repo).strip()
 
   def pull(self, repo):
+    # First perform a fetch so we have a list of remote branch names
+    subprocess.check_call(["git", "fetch", "--quiet"], cwd=repo)
+    # Next we need to ensure all remote branches are tracked
+    remotes = subprocess.check_output(["git", "branch", "--remotes"], cwd=repo)
+    for match in re.finditer(r"origin/(\S+)", remotes):
+      remote, local = match.group(0), match.group(1)
+      if local not in ["HEAD", "master"]:
+        with open(os.devnull, "w") as devnull:
+          subprocess.call(["git", "branch", "--track", local, remote],
+                          cwd=repo, stdout=devnull, stderr=devnull)
+    # Finally we need to actually fetch all the remote branches and tags
     subprocess.check_call(["git", "fetch", "--quiet", "--all", "--tags"], cwd=repo)
 
   def update(self, repo, rev):