potiuk opened a new pull request, #71186: URL: https://github.com/apache/airflow/pull/71186
`flit build` has no PEP 517 build isolation — `flit/wheel.py` does `import flit_core.wheel as core_wheel`, so the backend is whichever `flit_core` is installed. That makes the `flit_core==` pin every provider declares inert on the path we release from, and leaves breeze's own dependency as the only thing deciding it. The specifiers were capped below 4 so that backend could not change by accident; this takes the cap off deliberately. ### Validation Built `apache-airflow-providers-imap` with 3.12.0 and with 4.0.2, same `SOURCE_DATE_EPOCH`, `--use-vcs` passed explicitly in both: - wheel members identical — 13 files - sdist members identical — 33 entries - `METADATA` differs only by the intended additions: ```diff -Metadata-Version: 2.4 +Metadata-Version: 2.5 +Import-Name: airflow.providers.imap +Import-Namespace: airflow +Import-Namespace: airflow.providers ``` The metadata parses cleanly, so the 4.0.1 defect that cost `METADATA` its header/body separator is confirmed fixed in 4.0.2. ### Floors, not bumped caps The issue notes the hazard: `upgrade_important_versions.py` rewrites these by version number, so bumping `flit>=3.12.0,<4` would have produced `flit>=4.0.2,<4`. `flit`, `flit-core` and the 104 per-provider `flit_core==` pins now all move together at `4.0.2`, and the tracking comment at the cap site is removed. ### One addition the issue does not mention flit 4.0.2 was published 2026-08-04, inside the `"4 days"` `exclude-newer` window, so `uv` refuses it and the adoption would not take effect. A temporary per-package cutoff is added in both `[tool.uv.exclude-newer-package]` and `[tool.uv.pip.exclude-newer-package]`, following the existing `pydantic-ai-skills` precedent, with a note to remove it once the rolling window advances past 2026-08-04. closes: #71121 ##### Was generative AI tooling used to co-author this PR? - [X] Yes — Claude Opus 5 (1M context) Generated-by: Claude Opus 5 (1M context) following [the guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#gen-ai-assisted-contributions) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
