[mod] addition of various type hints / tbc

- pyright configuration [1]_
- stub files: types-lxml [2]_
- addition of various type hints
- enable use of new type system features on older Python versions [3]_
- ``.tool-versions`` - set python to lowest version we support (3.10.18) [4]_:
  Older versions typically lack some typing features found in newer Python
  versions.  Therefore, for local type checking (before commit), it is necessary
  to use the older Python interpreter.

.. [1] https://docs.basedpyright.com/v1.20.0/configuration/config-files/
.. [2] https://pypi.org/project/types-lxml/
.. [3] https://typing-extensions.readthedocs.io/en/latest/#
.. [4] https://mise.jdx.dev/configuration.html#tool-versions

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Format: reST

searx/engines/__init__.py

@@ -51,8 +51,8 @@ ENGINE_DEFAULT_ARGS: dict[str, int | str | list[t.Any] | dict[str, t.Any] | bool
 # set automatically when an engine does not have any tab category
 DEFAULT_CATEGORY = 'other'
 
-categories: dict[str, list[str]] = {'general': []}
-engines: dict[str, Engine | types.ModuleType] = {}
+categories: "dict[str, list[Engine|types.ModuleType]]" = {'general': []}
+engines: "dict[str, Engine | types.ModuleType]" = {}
 engine_shortcuts = {}
 """Simple map of registered *shortcuts* to name of the engine (or ``None``).
 
@@ -76,7 +76,7 @@ def check_engine_module(module: types.ModuleType):
         raise TypeError(msg)
 
 
-def load_engine(engine_data: dict[str, t.Any]) -> Engine | types.ModuleType | None:
+def load_engine(engine_data: dict[str, t.Any]) -> "Engine | types.ModuleType | None":
     """Load engine from ``engine_data``.
 
     :param dict engine_data:  Attributes from YAML ``settings:engines/<engine>``
@@ -151,7 +151,7 @@ def load_engine(engine_data: dict[str, t.Any]) -> Engine | types.ModuleType | No
     return engine
 
 
-def set_loggers(engine, engine_name):
+def set_loggers(engine: "Engine|types.ModuleType", engine_name: str):
     # set the logger for engine
     engine.logger = logger.getChild(engine_name)
     # the engine may have load some other engines
@@ -170,7 +170,7 @@ def set_loggers(engine, engine_name):
             module.logger = logger.getChild(module_engine_name)  # type: ignore
 
 
-def update_engine_attributes(engine: Engine | types.ModuleType, engine_data):
+def update_engine_attributes(engine: "Engine | types.ModuleType", engine_data: dict[str, t.Any]):
     # set engine attributes from engine_data
     for param_name, param_value in engine_data.items():
         if param_name == 'categories':
@@ -188,13 +188,13 @@ def update_engine_attributes(engine: Engine | types.ModuleType, engine_data):
             setattr(engine, arg_name, copy.deepcopy(arg_value))
 
 
-def update_attributes_for_tor(engine: Engine | types.ModuleType):
+def update_attributes_for_tor(engine: "Engine | types.ModuleType"):
     if using_tor_proxy(engine) and hasattr(engine, 'onion_url'):
         engine.search_url = engine.onion_url + getattr(engine, 'search_path', '')  # type: ignore
         engine.timeout += settings['outgoing'].get('extra_proxy_timeout', 0)  # type: ignore
 
 
-def is_missing_required_attributes(engine):
+def is_missing_required_attributes(engine: "Engine | types.ModuleType"):
     """An attribute is required when its name doesn't start with ``_`` (underline).
     Required attributes must not be ``None``.
 
@@ -207,12 +207,12 @@ def is_missing_required_attributes(engine):
     return missing
 
 
-def using_tor_proxy(engine: Engine | types.ModuleType):
+def using_tor_proxy(engine: "Engine | types.ModuleType"):
     """Return True if the engine configuration declares to use Tor."""
     return settings['outgoing'].get('using_tor_proxy') or getattr(engine, 'using_tor_proxy', False)
 
 
-def is_engine_active(engine: Engine | types.ModuleType):
+def is_engine_active(engine: "Engine | types.ModuleType"):
     # check if engine is inactive
     if engine.inactive is True:
         return False
@@ -224,7 +224,7 @@ def is_engine_active(engine: Engine | types.ModuleType):
     return True
 
 
-def register_engine(engine: Engine | types.ModuleType):
+def register_engine(engine: "Engine | types.ModuleType"):
     if engine.name in engines:
         logger.error('Engine config error: ambiguous name: {0}'.format(engine.name))
         sys.exit(1)
@@ -239,7 +239,7 @@ def register_engine(engine: Engine | types.ModuleType):
         categories.setdefault(category_name, []).append(engine)
 
 
-def load_engines(engine_list):
+def load_engines(engine_list: list[dict[str, t.Any]]):
     """usage: ``engine_list = settings['engines']``"""
     engines.clear()
     engine_shortcuts.clear()