From 85400a0430f4f5fb93936ceca2124c0e7968cca6 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Sat, 13 Jan 2024 02:32:10 +0000
Subject: [PATCH] Improve typing for ``_ConfigRebuild``

---
 sphinx/builders/_epub_base.py    |  2 +-
 sphinx/builders/html/__init__.py |  7 ++++---
 sphinx/config.py                 | 12 +++++++++---
 sphinx/environment/__init__.py   |  2 +-
 4 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/sphinx/builders/_epub_base.py b/sphinx/builders/_epub_base.py
index e47780023..aa1b9ec95 100644
--- a/sphinx/builders/_epub_base.py
+++ b/sphinx/builders/_epub_base.py
@@ -168,7 +168,7 @@ class EpubBuilder(StandaloneHTMLBuilder):
         self.refnodes: list[dict[str, Any]] = []
 
     def create_build_info(self) -> BuildInfo:
-        return BuildInfo(self.config, self.tags, ['html', 'epub'])
+        return BuildInfo(self.config, self.tags, frozenset({'html', 'epub'}))
 
     def get_theme_config(self) -> tuple[str, dict]:
         return self.config.epub_theme, self.config.epub_theme_options
diff --git a/sphinx/builders/html/__init__.py b/sphinx/builders/html/__init__.py
index 0f3cccb34..0a6a0a8f0 100644
--- a/sphinx/builders/html/__init__.py
+++ b/sphinx/builders/html/__init__.py
@@ -50,11 +50,12 @@ from sphinx.writers.html import HTMLWriter
 from sphinx.writers.html5 import HTML5Translator
 
 if TYPE_CHECKING:
-    from collections.abc import Iterable, Iterator, Sequence
+    from collections.abc import Iterable, Iterator, Set
 
     from docutils.nodes import Node
 
     from sphinx.application import Sphinx
+    from sphinx.config import _ConfigRebuild
     from sphinx.environment import BuildEnvironment
     from sphinx.util.tags import Tags
 
@@ -130,7 +131,7 @@ class BuildInfo:
         self,
         config: Config | None = None,
         tags: Tags | None = None,
-        config_categories: Sequence[str] = (),
+        config_categories: Set[_ConfigRebuild] = frozenset(),
     ) -> None:
         self.config_hash = ''
         self.tags_hash = ''
@@ -239,7 +240,7 @@ class StandaloneHTMLBuilder(Builder):
         self.use_index = self.get_builder_config('use_index', 'html')
 
     def create_build_info(self) -> BuildInfo:
-        return BuildInfo(self.config, self.tags, ['html'])
+        return BuildInfo(self.config, self.tags, frozenset({'html'}))
 
     def _get_translations_js(self) -> str:
         candidates = [path.join(dir, self.config.language,
diff --git a/sphinx/config.py b/sphinx/config.py
index 6a09d6ee8..85524ab06 100644
--- a/sphinx/config.py
+++ b/sphinx/config.py
@@ -24,7 +24,7 @@ else:
 
 if TYPE_CHECKING:
     import os
-    from collections.abc import Collection, Iterator, Sequence
+    from collections.abc import Collection, Iterator, Sequence, Set
 
     from sphinx.application import Sphinx
     from sphinx.environment import BuildEnvironment
@@ -33,7 +33,13 @@ if TYPE_CHECKING:
 
 logger = logging.getLogger(__name__)
 
-_ConfigRebuild = Literal['', 'env', 'epub', 'gettext', 'html']
+_ConfigRebuild = Literal[
+    '', 'env', 'epub', 'gettext', 'html',
+    # sphinxcontrib-applehelp
+    'applehelp',
+    # sphinxcontrib-devhelp
+    'devhelp',
+]
 
 CONFIG_FILENAME = 'conf.py'
 UNSERIALIZABLE_TYPES = (type, types.ModuleType, types.FunctionType)
@@ -423,7 +429,7 @@ class Config:
         valid_types = _validate_valid_types(types)
         self._options[name] = _Opt(default, rebuild, valid_types)
 
-    def filter(self, rebuild: str | Sequence[str]) -> Iterator[ConfigValue]:
+    def filter(self, rebuild: Set[_ConfigRebuild]) -> Iterator[ConfigValue]:
         if isinstance(rebuild, str):
             return (value for value in self if value.rebuild == rebuild)
         return (value for value in self if value.rebuild in rebuild)
diff --git a/sphinx/environment/__init__.py b/sphinx/environment/__init__.py
index dfb35bee6..72753e240 100644
--- a/sphinx/environment/__init__.py
+++ b/sphinx/environment/__init__.py
@@ -320,7 +320,7 @@ class BuildEnvironment:
         else:
             # check if a config value was changed that affects how
             # doctrees are read
-            for item in config.filter('env'):
+            for item in config.filter(frozenset({'env'})):
                 if self.config[item.name] != item.value:
                     self.config_status = CONFIG_CHANGED
                     self.config_status_extra = f' ({item.name!r})'