Enable no_implicit_reexport for core files [mypy] (#63820)

script/hassfest/mypy_config.py

@@ -81,6 +81,12 @@ IGNORED_MODULES: Final[list[str]] = [
     "homeassistant.components.zwave.*",
 ]
 
+# Component modules which should set no_implicit_reexport = true.
+NO_IMPLICIT_REEXPORT_MODULES: set[str] = {
+    "homeassistant.components",
+    "homeassistant.components.diagnostics.*",
+}
+
 HEADER: Final = """
 # Automatically generated by hassfest.
 #
@@ -165,7 +171,12 @@ def generate_and_validate(config: Config) -> str:
             )
 
     # Validate that all modules exist.
-    all_modules = strict_modules + strict_core_modules + IGNORED_MODULES
+    all_modules = (
+        strict_modules
+        + strict_core_modules
+        + IGNORED_MODULES
+        + list(NO_IMPLICIT_REEXPORT_MODULES)
+    )
     for module in all_modules:
         if module.endswith(".*"):
             module_path = Path(module[:-2].replace(".", os.path.sep))
@@ -193,6 +204,12 @@ def generate_and_validate(config: Config) -> str:
     for key in STRICT_SETTINGS:
         mypy_config.set(general_section, key, "true")
 
+    # By default enable no_implicit_reexport only for homeassistant.*
+    # Disable it afterwards for all components
+    components_section = "mypy-homeassistant.*"
+    mypy_config.add_section(components_section)
+    mypy_config.set(components_section, "no_implicit_reexport", "true")
+
     for core_module in strict_core_modules:
         core_section = f"mypy-{core_module}"
         mypy_config.add_section(core_section)
@@ -204,12 +221,20 @@ def generate_and_validate(config: Config) -> str:
     mypy_config.add_section(components_section)
     for key in STRICT_SETTINGS:
         mypy_config.set(components_section, key, "false")
+    mypy_config.set(components_section, "no_implicit_reexport", "false")
 
     for strict_module in strict_modules:
         strict_section = f"mypy-{strict_module}"
         mypy_config.add_section(strict_section)
         for key in STRICT_SETTINGS:
             mypy_config.set(strict_section, key, "true")
+        if strict_module in NO_IMPLICIT_REEXPORT_MODULES:
+            mypy_config.set(strict_section, "no_implicit_reexport", "true")
+
+    for reexport_module in NO_IMPLICIT_REEXPORT_MODULES.difference(strict_modules):
+        reexport_section = f"mypy-{reexport_module}"
+        mypy_config.add_section(reexport_section)
+        mypy_config.set(reexport_section, "no_implicit_reexport", "true")
 
     # Disable strict checks for tests
     tests_section = "mypy-tests.*"