⬆️ Increase lower bound to `pydantic >=2.9.0.` and fix the test suite by svlandeg · Pull Request #15139 · fastapi/fastapi

svlandeg · 2026-03-17T17:05:34Z

Our CI is intended to test the lowest ranges of our dependency pins as well as the highest, but it turns out this wasn't actually working well for Pydantic, and our lowest "supported" version wasn't actually being tested. Cf more digging by Yurii here.

This PR ensures that the lowest Pydantic supported version is installed when we're testing the lower bounds. From the first commit on this PR, you can see that it fails for the current master, which means that we weren't actually supporting the lower versions included in our dependency range.

Some of the issues include:

AttributeError: Config has no attribute val_json_bytes (only introduced in Pydantic 2.9)
- This is easily fixed by bumping to lower bound 2.9, solving most issues in one sweep
Comparison assert failures in test_schema_pydantic.v2.py.
- One is caused by additionalProperties being set to True always since Pydantic 2.11
- Bumping to lower bound 2.11 feels a bit much right now, so I've opted to fix these tests instead, allowing multiple versions of the schema.

codspeed-hq · 2026-03-17T17:08:07Z

Merging this PR will not alter performance

✅ 20 untouched benchmarks

_{Comparing svlandeg:fix/ci_pydantic (cf6054d) with master (64feaec)}

github-actions · 2026-03-17T18:35:57Z

📝 Docs preview

Last commit cf6054d at: https://396957b8.fastapitiangolo.pages.dev

YuriiMotov

LGTM!

I only suggest we specify exact version number in the comments. So that it would be easier to track when we can remove this.

With Pydantic 2.7 we have 70 tests failing with various reasons:

Details

FAILED tests/test_no_schema_split.py::test_openapi_schema - AssertionError: assert {'components'...e Message'}}}} == {'components'...e Message'}}}}
FAILED tests/test_openapi_examples.py::test_openapi_schema - AssertionError: assert {'components'...ples'}}, ...}} == {'components'...ples'}}, ...}}
FAILED tests/test_regex_deprecated_body.py::test_openapi_schema - AssertionError: assert {'components'...ead Items'}}}} == {'components'...ead Items'}}}}
FAILED tests/test_request_params/test_body/test_optional_str.py::test_optional_str_alias_schema[/optional-alias] - KeyError: ''
FAILED tests/test_request_params/test_body/test_optional_list.py::test_optional_list_str_alias_schema[/optional-list-alias] - KeyError: ''
FAILED tests/test_request_params/test_body/test_optional_list.py::test_optional_list_alias_and_validation_alias_schema[/optional-list-alias-and-validation-alias] - KeyError: ''
FAILED tests/test_request_params/test_body/test_optional_list.py::test_optional_list_validation_alias_schema[/optional-list-validation-alias] - KeyError: ''
FAILED tests/test_request_params/test_body/test_optional_list.py::test_optional_list_str_schema[/optional-list-str] - KeyError: ''
FAILED tests/test_request_params/test_body/test_optional_str.py::test_optional_str_schema[/optional-str] - KeyError: ''
FAILED tests/test_request_params/test_body/test_optional_str.py::test_optional_alias_and_validation_alias_schema[/optional-alias-and-validation-alias] - KeyError: ''
FAILED tests/test_request_params/test_body/test_optional_str.py::test_optional_validation_alias_schema[/optional-validation-alias] - KeyError: ''
FAILED tests/test_request_params/test_file/test_list.py::test_list_alias_schema[/list-uploadfile-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_list.py::test_list_schema[/list-uploadfile] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_list.py::test_list_alias_schema[/list-bytes-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_list.py::test_list_schema[/list-bytes] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_list.py::test_list_alias_and_validation_alias_schema[/list-uploadfile-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_schema[/optional-bytes] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_alias_schema[/optional-bytes-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_list.py::test_list_validation_alias_schema[/list-uploadfile-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_list.py::test_list_alias_and_validation_alias_schema[/list-bytes-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_schema[/optional-uploadfile] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_alias_schema[/optional-uploadfile-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_list.py::test_list_validation_alias_schema[/list-bytes-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_validation_alias_schema[/optional-bytes-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_alias_and_validation_alias_schema[/optional-bytes-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_alias_and_validation_alias_schema[/optional-uploadfile-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_list_schema[/optional-list-bytes] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_required.py::test_required_schema[/required-bytes] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_list_schema[/optional-list-uploadfile] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_list_alias_schema[/optional-list-uploadfile-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_list_alias_and_validation_alias_schema[/optional-list-bytes-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_validation_alias_schema[/optional-list-uploadfile-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_list_alias_and_validation_alias_schema[/optional-list-uploadfile-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_validation_alias_schema[/optional-list-bytes-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_required.py::test_required_alias_schema[/required-uploadfile-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_required.py::test_required_validation_alias_schema[/required-bytes-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_required.py::test_required_validation_alias_schema[/required-uploadfile-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_optional.py::test_optional_validation_alias_schema[/optional-uploadfile-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_form/test_optional_list.py::test_optional_list_str_schema[/optional-list-str] - KeyError: ''
FAILED tests/test_request_params/test_form/test_optional_list.py::test_optional_list_str_alias_schema[/optional-list-alias] - KeyError: ''
FAILED tests/test_request_params/test_file/test_required.py::test_required_alias_schema[/required-bytes-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_form/test_optional_list.py::test_optional_list_validation_alias_schema[/optional-list-validation-alias] - KeyError: ''
FAILED tests/test_request_params/test_form/test_optional_list.py::test_optional_list_alias_and_validation_alias_schema[/optional-list-alias-and-validation-alias] - KeyError: ''
FAILED tests/test_request_params/test_file/test_optional_list.py::test_optional_list_alias_schema[/optional-list-bytes-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_file/test_required.py::test_required_schema[/required-uploadfile] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_form/test_optional_str.py::test_optional_str_schema[/optional-str] - KeyError: ''
FAILED tests/test_request_params/test_file/test_required.py::test_required_alias_and_validation_alias_schema[/required-bytes-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_form/test_optional_str.py::test_optional_str_alias_schema[/optional-alias] - KeyError: ''
FAILED tests/test_request_params/test_file/test_required.py::test_required_alias_and_validation_alias_schema[/required-uploadfile-alias-and-validation-alias] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_request_params/test_form/test_optional_str.py::test_optional_validation_alias_schema[/optional-validation-alias] - KeyError: ''
FAILED tests/test_request_params/test_form/test_optional_str.py::test_optional_alias_and_validation_alias_schema[/optional-alias-and-validation-alias] - KeyError: ''
FAILED tests/test_schema_extra_examples.py::test_openapi_schema - AssertionError: assert {'components'...mple'}}, ...}} == {'components'...mple'}}, ...}}
FAILED tests/test_tutorial/test_json_base64_bytes/test_tutorial001.py::test_post_data_in_out[tutorial001_py310] - AssertionError: assert {'data': 'U0d...: 'A plumbus'} == {'data': 'SGV...: 'A plumbus'}
FAILED tests/test_tutorial/test_json_base64_bytes/test_tutorial001.py::test_post_data[tutorial001_py310] - AssertionError: assert {'content': '...on': 'A file'} == {'content': '...on': 'A file'}
FAILED tests/test_tutorial/test_request_files/test_tutorial001.py::test_openapi_schema[tutorial001_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial001.py::test_openapi_schema[tutorial001_an_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial001_03.py::test_openapi_schema[tutorial001_03_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial001_03.py::test_openapi_schema[tutorial001_03_an_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial002.py::test_openapi_schema[tutorial002_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial002.py::test_openapi_schema[tutorial002_an_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial003.py::test_openapi_schema[tutorial003_an_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_schema_extra_example/test_tutorial003.py::test_openapi_schema[tutorial003_py310] - AssertionError: assert {'components'...or'}}, ...}}}} == {'components'...or'}}, ...}}}}
FAILED tests/test_tutorial/test_schema_extra_example/test_tutorial003.py::test_openapi_schema[tutorial003_an_py310] - AssertionError: assert {'components'...or'}}, ...}}}} == {'components'...or'}}, ...}}}}
FAILED tests/test_tutorial/test_request_forms_and_files/test_tutorial001.py::test_openapi_schema[tutorial001_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial001_02.py::test_openapi_schema[tutorial001_02_an_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_forms_and_files/test_tutorial001.py::test_openapi_schema[tutorial001_an_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_schema_extra_example/test_tutorial004.py::test_openapi_schema[tutorial004_py310] - AssertionError: assert {'components'...or'}}, ...}}}} == {'components'...or'}}, ...}}}}
FAILED tests/test_tutorial/test_schema_extra_example/test_tutorial004.py::test_openapi_schema[tutorial004_an_py310] - AssertionError: assert {'components'...or'}}, ...}}}} == {'components'...or'}}, ...}}}}
FAILED tests/test_tutorial/test_request_files/test_tutorial001_02.py::test_openapi_schema[tutorial001_02_py310] - AttributeError: Config has no attribute 'val_json_bytes'
FAILED tests/test_tutorial/test_request_files/test_tutorial003.py::test_openapi_schema[tutorial003_py310] - AttributeError: Config has no attribute 'val_json_bytes'

Co-authored-by: Motov Yurii <[email protected]>

svlandeg · 2026-03-23T08:51:38Z

Note: once we merge this, we can remove the # pragma: no cover from evaluate_forwardref introduced in #15101

YuriiMotov · 2026-03-23T09:07:37Z

Note: once we merge this, we can remove the # pragma: no cover from evaluate_forwardref introduced in #15101

I think we can do it right in this PR)

svlandeg · 2026-03-23T09:14:11Z

Note: once we merge this, we can remove the # pragma: no cover from evaluate_forwardref introduced in #15101

I think we can do it right in this PR)

We can't, because that PR isn't merged yet. Whichever merges first, we can update the other one.

tiangolo

Great, thank you! 🙌

svlandeg added 2 commits March 17, 2026 17:53

add explicit test for lowest supported pydantic version

25c1db5

cleanup

e78d68d

svlandeg self-assigned this Mar 17, 2026

svlandeg added the upgrade label Mar 17, 2026

github-actions Bot added the internal label Mar 17, 2026

svlandeg removed the internal label Mar 17, 2026

bump lower pin to pydantic 2.9.0

338ab78

svlandeg mentioned this pull request Mar 17, 2026

⬆️ Update Pydantic v2 code to address deprecations #15101

Merged

update uv lock

c856921

svlandeg added 2 commits March 17, 2026 22:03

upgrade further to Pydantic 2.10

8afefc8

one more fix for uv lock

54b65bc

svlandeg changed the title ~~⬆️ Update lower Pydantic pin~~ ⬆️ Update lower Pydantic pin to pydantic >=2.10.0. Mar 17, 2026

svlandeg changed the title ~~⬆️ Update lower Pydantic pin to pydantic >=2.10.0.~~ ⬆️ Update lower Pydantic pin to pydantic >=2.9.0. and fix the test suite Mar 17, 2026

svlandeg changed the title ~~⬆️ Update lower Pydantic pin to pydantic >=2.9.0. and fix the test suite~~ ⬆️ Increase lower bound to pydantic >=2.9.0. and fix the test suite Mar 17, 2026

svlandeg added 3 commits March 17, 2026 22:37

allow multiple versions of the schema

7665c15

bump back to 2.9

357ba64

allow enum variation for python 3.9

daa5590

svlandeg marked this pull request as ready for review March 18, 2026 10:37

Merge branch 'master' into fix/ci_pydantic

18c4631

svlandeg removed their assignment Mar 18, 2026

svlandeg requested a review from YuriiMotov March 18, 2026 10:38

Merge branch 'master' into fix/ci_pydantic

b2d6e12

YuriiMotov approved these changes Mar 20, 2026

View reviewed changes

Comment thread tests/test_schema_compat_pydantic_v2.py Outdated

Comment thread tests/test_schema_compat_pydantic_v2.py Outdated

Comment thread .github/workflows/test.yml

svlandeg and others added 2 commits March 23, 2026 09:48

Apply suggestions from Yurii

d482539

Co-authored-by: Motov Yurii <[email protected]>

Merge branch 'master' into fix/ci_pydantic

cf6054d

tiangolo approved these changes Mar 23, 2026

View reviewed changes

tiangolo merged commit aeb9f4b into fastapi:master Mar 23, 2026
38 checks passed

svlandeg deleted the fix/ci_pydantic branch March 23, 2026 12:40

gilesperiencia-del approved these changes Mar 26, 2026

View reviewed changes

jackleeio mentioned this pull request Mar 27, 2026

Review: compatibility and contract risks around Pydantic >=2.9.0 floor bump #15236

Closed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

⬆️ Increase lower bound to `pydantic >=2.9.0.` and fix the test suite#15139

⬆️ Increase lower bound to `pydantic >=2.9.0.` and fix the test suite#15139
tiangolo merged 13 commits intofastapi:masterfrom
svlandeg:fix/ci_pydantic

svlandeg commented Mar 17, 2026 •

edited

Loading

Uh oh!

codspeed-hq Bot commented Mar 17, 2026 •

edited

Loading

Uh oh!

github-actions Bot commented Mar 17, 2026 •

edited

Loading

Uh oh!

YuriiMotov left a comment •

edited

Loading

Uh oh!

Uh oh!

Uh oh!

Uh oh!

svlandeg commented Mar 23, 2026

Uh oh!

YuriiMotov commented Mar 23, 2026

Uh oh!

svlandeg commented Mar 23, 2026

Uh oh!

tiangolo left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Uh oh!

Conversation

svlandeg commented Mar 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

codspeed-hq Bot commented Mar 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merging this PR will not alter performance

Uh oh!

github-actions Bot commented Mar 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

📝 Docs preview

Uh oh!

YuriiMotov left a comment • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

svlandeg commented Mar 23, 2026

Uh oh!

YuriiMotov commented Mar 23, 2026

Uh oh!

svlandeg commented Mar 23, 2026

Uh oh!

tiangolo left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

svlandeg commented Mar 17, 2026 •

edited

Loading

codspeed-hq Bot commented Mar 17, 2026 •

edited

Loading

github-actions Bot commented Mar 17, 2026 •

edited

Loading

YuriiMotov left a comment •

edited

Loading