core/backend: Stop supporting old search signatures

All backends are expected to support the exact argument. A friendly log message
will be printed to prompt users to upgrade backends that fail due to this.

mopidy/core/library.py

@@ -242,25 +242,21 @@ class LibraryController(object):
             The ``exact`` keyword argument, which replaces :meth:`find_exact`.
         """
         query = _normalize_query(query or kwargs)
-        futures = []
+        futures = {}
         for backend, backend_uris in self._get_backends_to_uris(uris).items():
-            if hasattr(backend.library, 'find_exact'):
-                # Backends with find_exact probably don't have support for
-                # search with the exact kwarg, so give them the legacy calls.
-                if exact:
-                    futures.append(backend.library.find_exact(
-                        query=query, uris=backend_uris))
-                else:
-                    futures.append(backend.library.search(
-                        query=query, uris=backend_uris))
-            else:
-                # Assume backends without find_exact are up to date. Worst case
-                # the exact gets swallowed by the **kwargs and things hopefully
-                # still work.
-                futures.append(backend.library.search(
-                    query=query, uris=backend_uris, exact=exact))
+            futures[backend] = backend.library.search(
+                query=query, uris=backend_uris, exact=exact)
 
-        return [result for result in pykka.get_all(futures) if result]
+        results = []
+        for backend, future in futures.items():
+            try:
+                results.append(future.get())
+            except TypeError:
+                backend_name = backend.actor_ref.actor_class.__name__
+                logger.warning(
+                    '%s does not implement library.search() with exact '
+                    'support. Please upgrade it.', backend_name)
+        return [r for r in results if r]
 
 
 def _normalize_query(query):

mopidy/local/library.py

@@ -51,12 +51,7 @@ class LocalLibraryProvider(backend.LibraryProvider):
             tracks = [tracks]
         return tracks
 
-    def find_exact(self, query=None, uris=None):
+    def search(self, query=None, uris=None, exact=False):
         if not self._library:
             return None
-        return self._library.search(query=query, uris=uris, exact=True)
-
-    def search(self, query=None, uris=None):
-        if not self._library:
-            return None
-        return self._library.search(query=query, uris=uris, exact=False)
+        return self._library.search(query=query, uris=uris, exact=exact)

tests/core/test_library.py

@@ -361,42 +361,35 @@ class CoreLibraryTest(unittest.TestCase):
             query={'any': ['foobar']}, uris=None, exact=True)
 
 
-class LegacyLibraryProvider(backend.LibraryProvider):
-    def find_exact(self, query=None, uris=None):
-        pass
+class LegacyFindExactToSearchLibraryTest(unittest.TestCase):
+    def setUp(self):  # noqa: N802
+        self.backend = mock.Mock()
+        self.backend.actor_ref.actor_class.__name__ = 'DummyBackend'
+        self.backend.uri_schemes.get.return_value = ['dummy']
+        self.backend.library = mock.Mock(spec=backend.LibraryProvider)
+        self.core = core.Core(mixer=None, backends=[self.backend])
 
-
-class LegacyCoreLibraryTest(unittest.TestCase):
-    def test_backend_with_find_exact_gets_find_exact_call(self):
-        b1 = mock.Mock()
-        b1.uri_schemes.get.return_value = ['dummy1']
-        b1.library = mock.Mock(spec=LegacyLibraryProvider)
-
-        b2 = mock.Mock()
-        b2.uri_schemes.get.return_value = ['dummy2']
-        b2.library = mock.Mock(spec=backend.LibraryProvider)
-
-        c = core.Core(mixer=None, backends=[b1, b2])
-        c.library.find_exact(query={'any': ['a']})
-
-        b1.library.find_exact.assert_called_once_with(
-            query=dict(any=['a']), uris=None)
-        b2.library.search.assert_called_once_with(
+    def test_core_find_exact_calls_backend_search_with_exact(self):
+        self.core.library.find_exact(query={'any': ['a']})
+        self.backend.library.search.assert_called_once_with(
             query=dict(any=['a']), uris=None, exact=True)
 
-    def test_backend_with_find_exact_gets_search_without_exact_arg(self):
-        b1 = mock.Mock()
-        b1.uri_schemes.get.return_value = ['dummy1']
-        b1.library = mock.Mock(spec=LegacyLibraryProvider)
+    def test_core_find_exact_handles_legacy_backend(self):
+        self.backend.library.search.return_value.get.side_effect = TypeError
+        self.core.library.find_exact(query={'any': ['a']})
+        # We are just testing that this doesn't fail.
 
-        b2 = mock.Mock()
-        b2.uri_schemes.get.return_value = ['dummy2']
-        b2.library = mock.Mock(spec=backend.LibraryProvider)
-
-        c = core.Core(mixer=None, backends=[b1, b2])
-        c.library.search(query={'any': ['a']})
-
-        b1.library.search.assert_called_once_with(
-            query=dict(any=['a']), uris=None)
-        b2.library.search.assert_called_once_with(
+    def test_core_search_call_backend_search_with_exact(self):
+        self.core.library.search(query={'any': ['a']})
+        self.backend.library.search.assert_called_once_with(
             query=dict(any=['a']), uris=None, exact=False)
+
+    def test_core_search_with_exact_call_backend_search_with_exact(self):
+        self.core.library.search(query={'any': ['a']}, exact=True)
+        self.backend.library.search.assert_called_once_with(
+            query=dict(any=['a']), uris=None, exact=True)
+
+    def test_core_search_with_handles_legacy_backend(self):
+        self.backend.library.search.return_value.get.side_effect = TypeError
+        self.core.library.search(query={'any': ['a']}, exact=True)
+        # We are just testing that this doesn't fail.

tests/dummy_backend.py

@@ -46,16 +46,15 @@ class DummyLibraryProvider(backend.LibraryProvider):
     def get_distinct(self, field, query=None):
         return self.dummy_get_distinct_result.get(field, set())
 
-    def find_exact(self, **query):
-        return self.dummy_find_exact_result
-
     def lookup(self, uri):
         return [t for t in self.dummy_library if uri == t.uri]
 
     def refresh(self, uri=None):
         pass
 
-    def search(self, **query):
+    def search(self, query=None, uris=None, exact=False):
+        if exact:  # TODO: remove uses of dummy_find_exact_result
+            return self.dummy_find_exact_result
         return self.dummy_search_result