[sophiecarreras]

list[X] is a types.GenericAlias and cannot take a __pydantic_config__ attribute, so every JSON option typed list[...] (e.g. --lifecycle-rules) raised AttributeError: 'types.GenericAlias' object has no attribute '__pydantic_config__' when pydantic (the full extra) is installed. type_with_config now catches the AttributeError and uses the type unchanged; pydantic applies its defaults in that case.

No upstream issue exists for this; its text is below instead.

Reproduce on v5.0.2 / master 9ea898a (Python 3.12, pydantic 2.12.5):

pip install -e . pydantic==2.12.5 pytest ...
pytest test/unit/test_console_tool.py -k lifecycle_rules

Fails: test_create_bucket__with_lifecycle_rules, test_create_bucket__mutually_exclusive_lifecycle_rules_options. The default nox -s unit does not install the full extra, so CI does not see it.

Verification (Python 3.12, pydantic 2.12.5):

• Before the fix the two lifecycle-rule tests and two new tests in test/unit/_cli/test_obj_loads.py fail; after it all pass.
• The rest of test/unit gives the same results as before. 8 autocomplete/shell-install tests fail identically with and without the change in my environment.
• ruff check and ruff format --check pass. The new pydantic-specific test is skipped when pydantic is not installed, like the existing one next to it.

Includes changelog fragment changelog.d/+pydantic-generic-alias.fixed.md.

🤖 Generated with Claude Code

[sophiecarreras]

Code review (independent pass).

Important (fixed in the follow-up commit)

• obj_loads.py: the first version of the fix dropped extra='allow' for list[X], so --lifecycle-rules silently discarded unknown keys while --lifecycle-rule kept them. The config is now passed to TypeAdapter(..., config=...) when the type cannot carry it as an attribute.
• test_obj_loads.py: the generic test did not cover extra keys. It now includes one and expects it preserved.
• Changelog fragment named --lifecycle-rule; the affected option is --lifecycle-rules (create and update). Corrected.

Nit (not changed)

• The new pydantic tests are skipped in the default nox -s unit (no full extra), so CI does not exercise them. Running a unit session with the full extra would close this gap.
• The legacy __config__ branch in type_with_config is untested and untouched by this PR.
• Commit subject is longer than 72 characters.