Improve support for deprecated builders without env arg (#10702)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

sphinx/builders/__init__.py

@@ -89,10 +89,11 @@ def __init__(self, app: "Sphinx", env: BuildEnvironment = None) -> None:
             self.env: BuildEnvironment = env
             self.env.set_versioning_method(self.versioning_method,
                                            self.versioning_compare)
-        elif env is not Ellipsis:
+        else:
             # ... is passed by SphinxComponentRegistry.create_builder to not show two warnings.
             warnings.warn("The 'env' argument to Builder will be required from Sphinx 7.",
                           RemovedInSphinx70Warning, stacklevel=2)
+            self.env = None
         self.events: EventManager = app.events
         self.config: Config = app.config
         self.tags: Tags = app.tags

sphinx/registry.py

@@ -166,7 +166,7 @@ def create_builder(self, app: "Sphinx", name: str,
                 f"'env'argument. Report this bug to the developers of your custom builder, "
                 f"this is likely not a issue with Sphinx. The 'env' argument will be required "
                 f"from Sphinx 7.", RemovedInSphinx70Warning, stacklevel=2)
-            builder = self.builders[name](app, env=...)  # type: ignore[arg-type]
+            builder = self.builders[name](app)
             if env is not None:
                 builder.set_environment(env)
             return builder