python: Replace NamedTuple with dataclass.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

requirements/common.in

@@ -8,6 +8,9 @@ Django==2.2.*
 # needed for Literal, TypedDict
 typing-extensions
 
+# Backport of @dataclass
+dataclasses;python_version<"3.7"
+
 # Needed for rendering backend templates
 Jinja2
 

requirements/dev.txt

@@ -243,6 +243,10 @@ cssutils==1.0.2 \
     --hash=sha256:a2fcf06467553038e98fea9cfe36af2bf14063eb147a70958cfcaa8f5786acaf \
     --hash=sha256:c74dbe19c92f5052774eadb15136263548dd013250f1ed1027988e7fef125c8d \
     # via premailer
+dataclasses==0.7 ; python_version < "3.7" \
+    --hash=sha256:3459118f7ede7c8bea0fe795bff7c6c2ce287d01dd226202f7c9ebc0610a7836 \
+    --hash=sha256:494a6dcae3b8bcf80848eea2ef64c0cc5cd307ffc263e17cdf42f3e5420808e6 \
+    # via -r requirements/common.in
 decorator==4.4.2 \
     --hash=sha256:41fa54c2a0cc4ba648be4fd43cff00aedf5b9465c9bf18d64325bc225f08f760 \
     --hash=sha256:e3a62f0520172440ca0dcc823749319382e377f37f140a0b99ef45fecb84bfe7 \

requirements/prod.txt

@@ -154,6 +154,10 @@ cssutils==1.0.2 \
     --hash=sha256:a2fcf06467553038e98fea9cfe36af2bf14063eb147a70958cfcaa8f5786acaf \
     --hash=sha256:c74dbe19c92f5052774eadb15136263548dd013250f1ed1027988e7fef125c8d \
     # via premailer
+dataclasses==0.7 ; python_version < "3.7" \
+    --hash=sha256:3459118f7ede7c8bea0fe795bff7c6c2ce287d01dd226202f7c9ebc0610a7836 \
+    --hash=sha256:494a6dcae3b8bcf80848eea2ef64c0cc5cd307ffc263e17cdf42f3e5420808e6 \
+    # via -r requirements/common.in
 decorator==4.4.2 \
     --hash=sha256:41fa54c2a0cc4ba648be4fd43cff00aedf5b9465c9bf18d64325bc225f08f760 \
     --hash=sha256:e3a62f0520172440ca0dcc823749319382e377f37f140a0b99ef45fecb84bfe7 \

version.py

@@ -44,4 +44,4 @@ API_FEATURE_LEVEL = 12
 #   historical commits sharing the same major version, in which case a
 #   minor version bump suffices.
 
-PROVISION_VERSION = '86.3'
+PROVISION_VERSION = '86.4'

zerver/lib/bugdown/__init__.py

@@ -1,6 +1,6 @@
 # Zulip's main markdown implementation.  See docs/subsystems/markdown.md for
 # detailed documentation on our markdown syntax.
-from typing import (Any, Callable, Dict, Generic, Iterable, List, NamedTuple,
+from typing import (Any, Callable, Dict, Generic, Iterable, List,
                     Optional, Set, Tuple, TypeVar, Union)
 from typing.re import Match, Pattern
 from typing_extensions import TypedDict
@@ -15,6 +15,7 @@ import os
 import html
 import time
 import functools
+from dataclasses import dataclass
 from io import StringIO
 import dateutil.parser
 import dateutil.tz
@@ -291,12 +292,12 @@ def walk_tree(root: Element,
 
     return results
 
-ElementFamily = NamedTuple('ElementFamily', [
-    ('grandparent', Optional[Element]),
-    ('parent', Element),
-    ('child', Element),
-    ('in_blockquote', bool),
-])
+@dataclass
+class ElementFamily:
+    grandparent: Optional[Element]
+    parent: Element
+    child: Element
+    in_blockquote: bool
 
 T = TypeVar("T")
 
@@ -1517,6 +1518,11 @@ class BlockQuoteProcessor(markdown.blockprocessors.BlockQuoteProcessor):
         # And then run the upstream processor's code for removing the '>'
         return super().clean(line)
 
+@dataclass
+class Fence:
+    fence_str: str
+    is_code: bool
+
 class BugdownListPreprocessor(markdown.preprocessors.Preprocessor):
     """ Allows list blocks that come directly after another block
         to be rendered as a list.
@@ -1529,11 +1535,6 @@ class BugdownListPreprocessor(markdown.preprocessors.Preprocessor):
 
     def run(self, lines: List[str]) -> List[str]:
         """ Insert a newline between a paragraph and ulist if missing """
-        Fence = NamedTuple('Fence', [
-            ('fence_str', str),
-            ('is_code', bool),
-        ])
-
         inserts = 0
         in_code_fence: bool = False
         open_fences: List[Fence] = []

zerver/lib/integrations.py

@@ -1,5 +1,6 @@
 import os
 
+from dataclasses import dataclass
 from typing import Dict, List, Optional, Any, Tuple
 from django.conf.urls import url
 from django.contrib.staticfiles.storage import staticfiles_storage
@@ -201,22 +202,17 @@ def split_fixture_path(path: str) -> Tuple[str, str]:
     integration_name = os.path.split(os.path.dirname(path))[-1]
     return integration_name, fixture_name
 
-# FIXME: Change to namedtuple if we drop Python3.6: No default values support on namedtuples (or dataclass)
+@dataclass
 class ScreenshotConfig:
-    def __init__(self, fixture_name: str, image_name: str='001.png',
-                 image_dir: Optional[str]=None, bot_name: Optional[str]=None,
-                 payload_as_query_param: bool=False, payload_param_name: str='payload',
-                 extra_params: Optional[Dict[str, str]]=None,
-                 use_basic_auth: bool=False, custom_headers: Optional[Dict[str, str]]=None):
-        self.fixture_name = fixture_name
-        self.image_name = image_name
-        self.image_dir = image_dir
-        self.bot_name = bot_name
-        self.payload_as_query_param = payload_as_query_param
-        self.payload_param_name = payload_param_name
-        self.extra_params = extra_params
-        self.use_basic_auth = use_basic_auth
-        self.custom_headers = custom_headers
+    fixture_name: str
+    image_name: str = '001.png'
+    image_dir: Optional[str] = None
+    bot_name: Optional[str] = None
+    payload_as_query_param: bool = False
+    payload_param_name: str = 'payload'
+    extra_params: Optional[Dict[str, str]] = None
+    use_basic_auth: bool = False
+    custom_headers: Optional[Dict[str, str]] = None
 
 def get_fixture_and_image_paths(integration: WebhookIntegration,
                                 screenshot_config: ScreenshotConfig) -> Tuple[str, str]: