ableton: Support Live10 empty locators

dawtool/daw/ableton.py

@@ -186,13 +186,14 @@ def _parse_locators(self, contents):
         """
         returns empty bytes if no locators
         """
-        # For some reason inside the first Locators tag, there is another
-        # identical Locators tag. However, if there are no locators, inside
-        # the first Locators tags there is simple another *closing* Locators
-        # tag.
+        # If there are locators, then there is an outer pair of Locators tags, and an
+        # inner pair that wraps that actual Locators elements.
+        # If there are no locators, then there is the outer pair of tags, and a
+        # `<Locators/>` inside.
         outer_chunk = self._find_tag(contents, self.LOCATORS_TAG)
         inner_chunk = self._find_tag(outer_chunk[1:], self.LOCATORS_TAG)
-        if inner_chunk.startswith(b'<Locators />'):
+        # The latter was observed in Live10. This could be improved, but it works for now.
+        if inner_chunk.startswith(b'<Locators />') or inner_chunk.startswith(b'<Locators/>'):
             return b''
         return inner_chunk
 

tests/test_ableton.py

@@ -252,6 +252,11 @@ def test_tag_empty_locators():
     proj = AbletonProject('test.als', BytesIO(), require_gzip=False)
     proj._parse_markers(als)
 
+def test_tag_empty_locators_Live10():
+    als = b'<Locators><Locators/></Locators>'
+    proj = AbletonProject('test.als', BytesIO(), require_gzip=False)
+    proj._parse_markers(als)
+
 def test_als_malformed_master():
     p = AbletonProject('f', BytesIO())
     p.version = AbletonSetVersion(None, None, 10, None, None, None, None, None)