Bug hunt ledger: uv #310

[agent] 2026-09-30: handover from the Poetry bug-hunt routine (ledger #311)

While checking Poetry mode switches I hit the same defect on a uv project. I filed it as #328 with the Poetry evidence. Here's the uv side so you can add a uv comment to that issue, or file a uv-specific one if the root cause differs.

hosted → vendored on a uv project is refused as a "user-authored" source.

main f6b7fb9, uv 0.8.17, Linux. Local mock of the patch API serving a patched six-1.16.0 wheel.

printf '[project]\nname = "uvp"\nversion = "0.1.0"\nrequires-python = ">=3.9"\ndependencies = ["six==1.16.0"]\n' > pyproject.toml
uv lock && uv sync
socket-patch scan --mode hosted --json --yes     # redirected: 1
uv sync
socket-patch scan --mode vendored --json --yes
# -> failed pypi_uv_source_already_exists "[tool.uv.sources] already declares a source for six; refusing to overwrite a user-authored source"
#    uv.lock still: source = { url = "http://127.0.0.1:18080/patch/pypi/six/1.16.0/<token>/<uuid>/six-1.16.0-py2.py3-none-any.whl" }

Root cause (shared): crates/socket-patch-core/src/patch/redirect/takeover.rs:79 redirect_revert_supported only covers cargo, npm and golang, so the vendored run never reverts the hosted redirect for pkg:pypi/.

Not yet checked for uv: vendored → hosted, and lock-only hosted → vendored (on Poetry that fails vendor_fetch_unverifiable because the lock pins the patched wheel's hash).

Also unconfirmed for uv: on Poetry, vendored repair on a lock-only checkout whose committed wheel was deleted fails vendor_artifact_unrepairable, even though the vendor ledger's wiring[].original fragment keeps the pristine hash (see the Poetry ledger backlog). Worth checking on uv.lock.

[agent] 2026-09-30: uv bug-hunt run

This is the first run. The ledger started empty and there were no pm:uv issues, so there was nothing to re-triage. Picked up the Poetry handover (entries/uv/20260930T151432Z-from-poetry.md).

Tested: main f6b7fb9 (CLI 4.0.0). Latest release is 4.0.0, which predates the current uv rewriter (#238 / #239), so it can't be used for first-bad checks on these paths. uv binaries: 0.2.37, 0.4.30, 0.5.31, 0.8.17 and 0.12.21 (latest).

Setup: the sandbox blocks the Socket patch hosts, so a local mock of the authenticated patch API (/v0/orgs/<org>/patches/{batch,by-package,package,view}, blob, and the hosted wheel with HEAD) served a deterministic patched six-1.16.0 wheel. The mock and drivers are embedded in both probe workflows. Every install check is a fresh clone plus an empty-cache uv sync --locked / --frozen / plain, followed by a sha256 of the installed six.py.

Cells (Linux unless noted)

Issues

• Filed Hosted uv rollback and remove are stuck after any unrelated pyproject.toml edit or uv add, and the suggested re-scan doesn't fix it #379: Hosted uv rollback and remove are stuck after any unrelated pyproject.toml edit or uv add, and the suggested re-scan doesn't fix it #379
• Filed Vendored uv repair can't rebuild a missing wheel once uv sync has installed it, because it rebuilds from the patched installed copy and the hash never matches #381: Vendored uv repair can't rebuild a missing wheel once uv sync has installed it, because it rebuilds from the patched installed copy and the hash never matches #381
• Commented on Poetry hosted ⇄ vendored mode switch is refused, and blames a "user-authored" source that socket-patch wrote itself #328 with uv 0.12.21 evidence and the reverse direction: Poetry hosted ⇄ vendored mode switch is refused, and blames a "user-authored" source that socket-patch wrote itself #328 (comment)

False positives ruled out

• vendor_fetch_failed for files.pythonhosted.org during a lock-only repair is the sandbox TLS artifact (rustls vs the proxy CA). It passes in CI.
• The sidecar socket-patch.vendor.json being removed on a failed repair is the documented "nothing kept" contract. vendor --revert still restores the registry lock from state.json.
• Rollback with .socket/vendor/redirect-state.json deleted reports Manifest not found. The ledger is required by design.
• The Windows mock wheel sha differs from Linux/macOS (zlib output), which is a harness artifact, not a CLI bug.

Probe runs

• https://github.com/SocketDev/socket-patch/actions/runs/36774452940 (hosted rollback drift)
• https://github.com/SocketDev/socket-patch/actions/runs/36776160780 (vendored repair)

I couldn't delete either probe branch: the git proxy silently ignores ref deletes ("Everything up-to-date"), the same as for the siblings. A maintainer needs to delete bughunt/uv/20260930-rollback-drift and bughunt/uv/20260930-vendored-repair. Each one only adds .github/workflows/bughunt-uv.yml.

Next

1. Isolate the Windows + uv 0.2.37 lock-only repair mismatch: is the vendor-time wheel built from the installed dist?
2. [[distribution]]-grammar hosted locks (0.1.45 / 0.2.5 / 0.2.18 / 0.2.34): rollback after uv lock or re-save, and uv sync --locked after hosted.
3. [[tool.uv.index]] explicit / non-default index (lock source = { registry = "<mirror>" }), plus { index = … } pins with a transitive target.
4. Hosted uv pip compile --generate-hashes requirements + uv pip sync --require-hashes, then uv pip compile --upgrade and rollback.
5. CRLF uv.lock + uv add on Windows (probe), and multi-version resolution-markers forks refusal vs VEX.

[agent] 2026-09-30: handover from the PDM bug-hunt routine (ledger #312)

While filing #382 (hosted PDM rollback/remove stuck once the patched package leaves pdm.lock), I ran the same flow on uv as a comparison. On main f6b7fb9: a native uv project with dependencies = ["urllib3==1.26.18", "six"], then uv lock, then scan --mode hosted (redirected 1), then uv remove --no-sync urllib3. After that rollback --json --yes exits 1 with uv.lock: content matches neither the redirected nor the original fragment for redirect_uv_lock_wheel — the file drifted; re-run scan --mode hosted to normalize (pyproject.toml, uv.lock). uv.lock and pyproject.toml no longer mention urllib3 at all.

This may already be covered by #379 (uv drift after uv add / pyproject edits). If not, it's the uv sibling of #382: the shared refusal is at crates/socket-patch-core/src/patch/redirect/replay.rs:803-811. I didn't file it, because it's uv's call.