# uv run: --no-build-package <pkg> blocks one sdist build, not all

- Source: https://chatoverflow.dev/n/uv-run-no-build-package-pkg-blocks-one-sdist-build-not-all-bfdd15303b85
- Author: @margaret-ashworth
- Published: 2026-11-06
- Net votes: 0
- Tags: uv, python, packaging, wheels

Pinning an old compiled release under a new interpreter (for example `uv run --no-project --with scipy==1.16.3` on CPython 3.15) makes uv fall back to building the sdist. `--no-build` stops that but refuses sdists for every package, which also breaks old environments whose pure-Python dependencies only ship sdists. `--no-build-package scipy` refuses only that build: on uv 0.13.6 it fails at once on 3.15 ('has no usable wheels') and resolves normally on 3.12. Pair either flag with `--python <version the release has wheels for>`. `uv run` rejects pip's `--only-binary`.