Add missing type hints to synapse.util (#9982)

9 files changed, 39 insertions, 25 deletions

diff --git a/changelog.d/9982.misc b/changelog.d/9982.misc
new file mode 100644
index 0000000000..f3821f61a3
--- /dev/null
+++ b/changelog.d/9982.misc
@@ -0,0 +1 @@
+Add missing type hints to `synapse.util` module.
diff --git a/mypy.ini b/mypy.ini
index 1d1d1ea0f2..062872020e 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -71,8 +71,13 @@ files =
   synapse/types.py,
   synapse/util/async_helpers.py,
   synapse/util/caches,
+  synapse/util/daemonize.py,
+  synapse/util/hash.py,
+  synapse/util/iterutils.py,
   synapse/util/metrics.py,
   synapse/util/macaroons.py,
+  synapse/util/module_loader.py,
+  synapse/util/msisdn.py,
   synapse/util/stringutils.py,
   synapse/visibility.py,
   tests/replication,
@@ -80,6 +85,7 @@ files =
   tests/handlers/test_password_providers.py,
   tests/rest/client/v1/test_login.py,
   tests/rest/client/v2_alpha/test_auth.py,
+  tests/util/test_itertools.py,
   tests/util/test_stream_change_cache.py
 
 [mypy-pymacaroons.*]
@@ -175,5 +181,8 @@ ignore_missing_imports = True
 [mypy-pympler.*]
 ignore_missing_imports = True
 
+[mypy-phonenumbers.*]
+ignore_missing_imports = True
+
 [mypy-ijson.*]
 ignore_missing_imports = True
diff --git a/synapse/config/saml2.py b/synapse/config/saml2.py
index 3d1218c8d1..05e983625d 100644
--- a/synapse/config/saml2.py
+++ b/synapse/config/saml2.py
@@ -164,7 +164,13 @@ class SAML2Config(Config):
         config_path = saml2_config.get("config_path", None)
         if config_path is not None:
             mod = load_python_module(config_path)
-            _dict_merge(merge_dict=mod.CONFIG, into_dict=saml2_config_dict)
+            config = getattr(mod, "CONFIG", None)
+            if config is None:
+                raise ConfigError(
+                    "Config path specified by saml2_config.config_path does not "
+                    "have a CONFIG property."
+                )
+            _dict_merge(merge_dict=config, into_dict=saml2_config_dict)
 
         import saml2.config
 
diff --git a/synapse/storage/databases/main/keys.py b/synapse/storage/databases/main/keys.py
index 0e86807834..6990f3ed1d 100644
--- a/synapse/storage/databases/main/keys.py
+++ b/synapse/storage/databases/main/keys.py
@@ -55,7 +55,7 @@ class KeyStore(SQLBaseStore):
         """
         keys = {}
 
-        def _get_keys(txn: Cursor, batch: Tuple[Tuple[str, str]]) -> None:
+        def _get_keys(txn: Cursor, batch: Tuple[Tuple[str, str], ...]) -> None:
             """Processes a batch of keys to fetch, and adds the result to `keys`."""
 
             # batch_iter always returns tuples so it's safe to do len(batch)
diff --git a/synapse/util/hash.py b/synapse/util/hash.py
index ba676e1762..7625ca8c2c 100644
--- a/synapse/util/hash.py
+++ b/synapse/util/hash.py
@@ -17,15 +17,15 @@ import hashlib
 import unpaddedbase64
 
 
-def sha256_and_url_safe_base64(input_text):
+def sha256_and_url_safe_base64(input_text: str) -> str:
     """SHA256 hash an input string, encode the digest as url-safe base64, and
     return
 
-    :param input_text: string to hash
-    :type input_text: str
+    Args:
+        input_text: string to hash
 
-    :returns a sha256 hashed and url-safe base64 encoded digest
-    :rtype: str
+    returns:
+        A sha256 hashed and url-safe base64 encoded digest
     """
     digest = hashlib.sha256(input_text.encode()).digest()
     return unpaddedbase64.encode_base64(digest, urlsafe=True)
diff --git a/synapse/util/iterutils.py b/synapse/util/iterutils.py
index abfdc29832..886afa9d19 100644
--- a/synapse/util/iterutils.py
+++ b/synapse/util/iterutils.py
@@ -30,12 +30,12 @@ from typing import (
 T = TypeVar("T")
 
 
-def batch_iter(iterable: Iterable[T], size: int) -> Iterator[Tuple[T]]:
+def batch_iter(iterable: Iterable[T], size: int) -> Iterator[Tuple[T, ...]]:
     """batch an iterable up into tuples with a maximum size
 
     Args:
-        iterable (iterable): the iterable to slice
-        size (int): the maximum batch size
+        iterable: the iterable to slice
+        size: the maximum batch size
 
     Returns:
         an iterator over the chunks
@@ -46,10 +46,7 @@ def batch_iter(iterable: Iterable[T], size: int) -> Iterator[Tuple[T]]:
     return iter(lambda: tuple(islice(sourceiter, size)), ())
 
 
-ISeq = TypeVar("ISeq", bound=Sequence, covariant=True)
-
-
-def chunk_seq(iseq: ISeq, maxlen: int) -> Iterable[ISeq]:
+def chunk_seq(iseq: Sequence[T], maxlen: int) -> Iterable[Sequence[T]]:
     """Split the given sequence into chunks of the given size
 
     The last chunk may be shorter than the given size.
diff --git a/synapse/util/module_loader.py b/synapse/util/module_loader.py
index 8acbe276e4..cbfbd097f9 100644
--- a/synapse/util/module_loader.py
+++ b/synapse/util/module_loader.py
@@ -15,6 +15,7 @@
 import importlib
 import importlib.util
 import itertools
+from types import ModuleType
 from typing import Any, Iterable, Tuple, Type
 
 import jsonschema
@@ -44,8 +45,8 @@ def load_module(provider: dict, config_path: Iterable[str]) -> Tuple[Type, Any]:
 
     # We need to import the module, and then pick the class out of
     # that, so we split based on the last dot.
-    module, clz = modulename.rsplit(".", 1)
-    module = importlib.import_module(module)
+    module_name, clz = modulename.rsplit(".", 1)
+    module = importlib.import_module(module_name)
     provider_class = getattr(module, clz)
 
     # Load the module config. If None, pass an empty dictionary instead
@@ -69,11 +70,11 @@ def load_module(provider: dict, config_path: Iterable[str]) -> Tuple[Type, Any]:
     return provider_class, provider_config
 
 
-def load_python_module(location: str):
+def load_python_module(location: str) -> ModuleType:
     """Load a python module, and return a reference to its global namespace
 
     Args:
-        location (str): path to the module
+        location: path to the module
 
     Returns:
         python module object
diff --git a/synapse/util/msisdn.py b/synapse/util/msisdn.py
index bbbdebf264..1046224f15 100644
--- a/synapse/util/msisdn.py
+++ b/synapse/util/msisdn.py
@@ -17,19 +17,19 @@ import phonenumbers
 from synapse.api.errors import SynapseError
 
 
-def phone_number_to_msisdn(country, number):
+def phone_number_to_msisdn(country: str, number: str) -> str:
     """
     Takes an ISO-3166-1 2 letter country code and phone number and
     returns an msisdn representing the canonical version of that
     phone number.
     Args:
-        country (str): ISO-3166-1 2 letter country code
-        number (str): Phone number in a national or international format
+        country: ISO-3166-1 2 letter country code
+        number: Phone number in a national or international format
 
     Returns:
-        (str) The canonical form of the phone number, as an msisdn
+        The canonical form of the phone number, as an msisdn
     Raises:
-            SynapseError if the number could not be parsed.
+        SynapseError if the number could not be parsed.
     """
     try:
         phoneNumber = phonenumbers.parse(number, country)
diff --git a/tests/util/test_itertools.py b/tests/util/test_itertools.py
index 1bd0b45d94..e712eb42ea 100644
--- a/tests/util/test_itertools.py
+++ b/tests/util/test_itertools.py
@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Dict, List
+from typing import Dict, Iterable, List, Sequence
 
 from synapse.util.iterutils import chunk_seq, sorted_topologically
 
@@ -44,7 +44,7 @@ class ChunkSeqTests(TestCase):
         )
 
     def test_empty_input(self):
-        parts = chunk_seq([], 5)
+        parts = chunk_seq([], 5)  # type: Iterable[Sequence]
 
         self.assertEqual(
             list(parts),