mypy: strict optional fixes.

zerver/lib/ccache.py

@@ -103,11 +103,11 @@ def der_encode_octet_string(val):
     return der_encode_tlv(0x04, val)
 
 def der_encode_sequence(tlvs, tagged=True):
-    # type: (List[bytes], Optional[bool]) -> bytes
+    # type: (List[Optional[bytes]], Optional[bool]) -> bytes
     body = []
     for i, tlv in enumerate(tlvs):
         # Missing optional elements represented as None.
-        if not tlv:
+        if tlv is None:
             continue
         if tagged:
             # Assume kerberos-style explicit tagging of components.

zerver/lib/message.py

@@ -203,6 +203,7 @@ class MessageDict(object):
 
         if last_edit_time is not None:
             obj['last_edit_timestamp'] = datetime_to_timestamp(last_edit_time)
+            assert edit_history is not None
             obj['edit_history'] = ujson.loads(edit_history)
 
         if apply_markdown:
@@ -220,6 +221,7 @@ class MessageDict(object):
                     # TODO: see #1379 to eliminate bugdown dependencies
                     message = Message.objects.select_related().get(id=message_id)
 
+                assert message is not None  # Hint for mypy.
                 # It's unfortunate that we need to have side effects on the message
                 # in some cases.
                 rendered_content = render_markdown(message, content, realm=message.get_realm())

zerver/lib/utils.py

@@ -163,6 +163,7 @@ def query_chunker(queries, id_collector=None, chunk_size=1000, db_chunk_size=Non
         q = q.order_by('id')
         min_id = -1
         while True:
+            assert db_chunk_size is not None  # Hint for mypy, but also workaround for mypy bug #3442.
             rows = list(q.filter(id__gt=min_id)[0:db_chunk_size])
             if len(rows) == 0:
                 break

zerver/lib/webhooks/git.py

@@ -192,9 +192,9 @@ def get_commits_content(commits_data, is_truncated=False):
     commits_content = u''
     for commit in commits_data[:COMMITS_LIMIT]:
         commits_content += COMMIT_ROW_TEMPLATE.format(
-            commit_short_sha=get_short_sha(commit.get('sha')),
+            commit_short_sha=get_short_sha(commit['sha']),
             commit_url=commit.get('url'),
-            commit_msg=commit.get('message').partition('\n')[0]
+            commit_msg=commit['message'].partition('\n')[0]
         )
 
     if len(commits_data) > COMMITS_LIMIT: