lib should not allow named branches

Author: studavekar

mbed/mbed.py

@@ -1058,6 +1058,12 @@ def fromlib(cls, lib=None):
         m_local = re.match(regex_local_ref, ref.strip().replace('\\', '/'))
         m_repo_ref = re.match(regex_url_ref, ref.strip().replace('\\', '/'))
         m_bld_ref = re.match(regex_build_url, ref.strip().replace('\\', '/'))
+
+        if m_repo_ref:
+            rev = m_repo_ref.group(3)
+            if rev and not re.match(r'^([a-fA-F0-9]{6,40})$', rev):
+                error('named branches not allowed in .lib, offending lib is {} '.format(os.path.basename(lib)))
+
         if not (m_local or m_bld_ref or m_repo_ref):
             warning(
                 "File \"%s\" in \"%s\" uses a non-standard .lib file extension, which is not compatible with the mbed build tools.\n" % (os.path.basename(lib), os.path.split(lib)[0]))