`get_component_priority_dict_with_base()` normalizes every key of a
component priority dictionary by calling `load_object()` on it, including
keys whose value is `None`, i.e. components the user is disabling.
`normalize_key()` only guarded against `(NameError, TypeError, ValueError)`,
the three exceptions `load_object()` raises itself, but not against the
`ImportError` raised by the `import_module()` call it makes. A stale entry
disabling a component whose module no longer exists, e.g.
`{"scrapy.webservice.WebService": None}`, therefore aborted settings
resolution with `ModuleNotFoundError` instead of being ignored.
Add `ImportError` to the guard so that an unimportable key falls back to its
raw string form. Since its value is `None`, it is then dropped by the
existing `if v is not None` filter, and disabling by import path keeps
working. Enabled components with an unimportable path are unaffected:
`MiddlewareManager.from_crawler()` calls `load_object()` on them again and
still fails there.
Fixes#7820
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
* Restore 2.14 getwithbase, add a new method for class key deduplication
* Use the original getwithbase code, not some equivalent
* Fix mocking
* Test key exceptions
* Fix test for getwithbase() to ensure class-keyed overrides with None are handled correctly
* Test actual import paths from default_settings
* Improvements
* Remove unused logger
* Run pre-commit
* Restore and improve duplicate key handling and warning
* type → object
---------
Co-authored-by: Adrian Chaves <adrian@zyte.com>
* Deprecate spider args of spider middleware methods.
* Deprecate the spider arg of pipeline process_item().
* Fix a typing issue.
* Deprecate the spider arg of pipeline {open,close}_spider().
* Cleanup.
* Update docs.
* Add pragma: no cover to some deprecated code.
* More tests.
* More tests.
* More tests.
* Simplify _process_parallel().
* Switch to pytest.raises().
* Add matches= to broad pytest.raises().
* Adjust the test_nonserializable_object() regex for Python <= 3.11.
* Adjust the test_nonserializable_object() regex for PyPy.
* Adjust other test exception regexes for PyPy.
* Cleanup.