fix(backend): scope PEP 440 prerelease detection to Python backends by jdx · Pull Request #9558 · jdx/mise

jdx · 2026-05-03T09:47:25Z

Summary

Two regressions visible in the release PR (#9485):

mise install go:.../@latest returns "no versions found" when the latest is a Go pseudo-version (e.g. go:github.com/go-kratos/kratos/cmd/kratos/v2) — the e2e-0 / backend/test_go_install_slow failure.
(After narrowing the rule too aggressively in earlier revs of this PR: mise latest python returned 3.15.0a8 instead of a stable. Fixed below.)

Cause

The ([abc])[0-9]+ alternative in the shared VERSION_REGEX was unanchored, so it false-positived on any a/b/c followed by a digit anywhere in a string — including the random hex hash inside Go pseudo-versions (e.g. c1 inside f149714c1d54).

#9500 enabled mark_prereleases_from_version_pattern: true for the go backend on May 1, which is what made it user-visible — the regex was already over-permissive but no Go-flavored input had been feeding it before.

Fix

The rule is PEP 440-specific (Python's separator-less alpha/beta/rc shorthand). Move it out of the general regex into PEP440_PRERELEASE_REGEX and consult it only from Python-flavored backends.

VERSION_REGEX (in src/plugins/mod.rs): drop the ([abc])[0-9]+ alternative.
PEP440_PRERELEASE_REGEX (new): (?i)[0-9](?:a|b|c|rc)[0-9]+(?:\$|[^a-z0-9]) — grounded in PEP 440's canonical grammar [N!]N(.N)*[{a|b|rc}N][.postN][.devN]. The leading digit anchors the prerelease segment to follow the release segment (so it can't trigger inside arbitrary identifiers); c is included as PEP 440's recognized alternate spelling for rc; the trailing boundary stops it from matching inside hex hashes even when those start with a digit.
pipx:
- Stamps PEP 440 prereleases on VersionInfo in _list_remote_versions so the cache reflects it.
- Overrides fuzzy_match_filter to drop them from match results.
python core plugin: same fuzzy_match_filter override (python-build returns 3.15.0a8-style alphas).
Both share a new fuzzy_match_versions_pep440 helper in src/backend/mod.rs so the override is one line each.

Test plan

cargo test test_pep440_prerelease_regex (new) — Python suffixes match, Go pseudo-versions and bare-b identifiers don't, .post doesn't.
cargo test test_version_regex_filters_prerelease — confirms PEP 440 cases now negative on the general regex.
cargo test test_mark_prerelease_flags_regex_matches — added a Go pseudo-version case and a PEP 440 case (both should not be flagged by the general path).
cargo test test_fuzzy_match_versions_*, test_filter_cached_prereleases_*, pipx::tests::*.
Local repro: mise ls-remote 'go:github.com/go-kratos/kratos/cmd/kratos/v2' returns 2.0.0-20260404020628-f149714c1d54.
Local repro: mise latest python returns 3.14.4 (was 3.15.0a8 after the earlier rev of this PR).
Wait on CI for e2e-0 / test_go_install_slow and e2e-6 / test_latest.

🤖 Generated with Claude Code

Note

Medium Risk
Adjusts prerelease detection and fuzzy version resolution logic, which can change what versions are considered installable/latest across multiple backends; mistakes could hide valid versions or surface prereleases unexpectedly.

Overview
Fixes prerelease filtering regressions by removing the unanchored ([abc])[0-9]+ clause from the shared VERSION_REGEX (which was incorrectly flagging strings like Go pseudo-versions) and introducing a new Python-scoped PEP440_PRERELEASE_REGEX.

Python-flavored backends (pipx and the core python plugin) now apply PEP 440 prerelease handling explicitly: pipx stamps PEP 440 alphas/betas/rcs onto cached VersionInfo.prerelease, and both backends override fuzzy matching via a new shared helper fuzzy_match_versions_pep440 so latest/prefix queries skip 3.15.0a8-style versions unless explicitly requested.

Adds focused tests to ensure Go pseudo-versions are not filtered by the general regex and that PEP 440 prerelease detection works only where intended.

^{Reviewed by Cursor Bugbot for commit 287f01d. Bugbot is set up for automated code reviews on this repo. Configure here.}

greptile-apps · 2026-05-03T09:48:53Z

Greptile Summary

This PR fixes two regressions by scoping PEP 440 separator-less prerelease detection (aN/bN/cN/rcN) out of the shared VERSION_REGEX and into a new PEP440_PRERELEASE_REGEX that is only consulted by Python-flavored backends (pipx, python). The root cause was an unanchored ([abc])[0-9]+ alternative in VERSION_REGEX that false-positived on hex substrings in Go pseudo-version hashes (e.g. c1 in f149714c1d54), causing mise install go:.../@latest to return "no versions found".

Confidence Score: 5/5

Safe to merge — the fix is tightly scoped, regression-tested, and does not change behaviour for any non-Python backend.

No P0/P1 issues found. The regex change is correct and well-anchored, the two-layer filtering (VersionInfo stamp + fuzzy_match_filter override) is complementary rather than duplicative, the exact-match bypass is preserved, and the test suite covers Python prereleases, stable versions, Go pseudo-versions, and bare identifiers.

No files require special attention.

Important Files Changed

Filename	Overview
src/plugins/mod.rs	Removes `([abc])[0-9]+` from `VERSION_REGEX` and introduces the new `PEP440_PRERELEASE_REGEX` constant with correct leading-digit anchor and trailing boundary; new unit tests cover Python prereleases, stable releases, Go pseudo-versions, and bare identifiers.
src/backend/mod.rs	Adds `fuzzy_match_versions_pep440` helper that pre-filters PEP 440 prereleases before delegating to the shared `fuzzy_match_versions`; includes an exact-match bypass so explicit prerelease requests still resolve; well-tested.
src/backend/pipx.rs	Refactors `_list_remote_versions` to stamp PEP 440 prerelease flags on cached `VersionInfo` entries and overrides `fuzzy_match_filter` to drop them from query resolution; clean structural simplification alongside the new behaviour.
src/plugins/core/python.rs	Adds `fuzzy_match_filter` override to delegate to `fuzzy_match_versions_pep440`, ensuring `python-build`-style alphas (`3.15.0a8`) are excluded from `latest` resolution without touching any other logic.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Backend calls fuzzy_match_filter] --> B{Python-flavored backend?}
    B -- "Yes (pipx / python)" --> C[fuzzy_match_versions_pep440]
    B -- No --> D[fuzzy_match_versions]
    C --> E{filter_prereleases?}
    E -- Yes --> F["Pre-filter: drop PEP440_PRERELEASE_REGEX matches\n(except exact query match)"]
    E -- No --> G[Keep all versions]
    F --> D
    G --> D
    D --> H{filter_prereleases?}
    H -- Yes --> I["Drop VERSION_REGEX matches\n(-rc1, -dev, -alpha …)\nexact match preserved"]
    H -- No --> J[Keep all versions]
    I --> K[Pattern match against query]
    J --> K
    K --> L[Return matched versions]

_{Reviews (7): Last reviewed commit: "fix(backend): scope PEP 440 prerelease d..." | Re-trigger Greptile}

gemini-code-assist

Code Review

This pull request updates the VERSION_REGEX in src/plugins/mod.rs to prevent false positives when matching version strings, specifically addressing issues where hex hashes in Go pseudo-versions were incorrectly identified as prerelease suffixes. It also adds comprehensive test cases to verify the new regex behavior against Python-style suffixes and Go pseudo-versions. I have no feedback to provide.

github-actions · 2026-05-03T10:44:40Z

Hyperfine Performance

`mise x -- echo`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.4.28 x -- echo`	23.1 ± 0.8	21.6	30.5	1.00
`mise x -- echo`	24.0 ± 0.8	22.5	28.9	1.04 ± 0.05

`mise env`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.4.28 env`	22.9 ± 0.9	21.2	29.6	1.00
`mise env`	23.1 ± 0.6	21.8	25.6	1.01 ± 0.05

`mise hook-env`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.4.28 hook-env`	23.0 ± 0.6	22.0	29.2	1.00
`mise hook-env`	24.3 ± 0.8	22.6	27.5	1.05 ± 0.05

`mise ls`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.4.28 ls`	20.7 ± 0.7	19.4	25.1	1.00
`mise ls`	21.3 ± 0.7	19.8	25.3	1.03 ± 0.05

`xtasks/test/perf`

Command	mise-2026.4.28	mise	Variance
install (cached)	154ms	160ms	-3%
ls (cached)	78ms	81ms	-3%
bin-paths (cached)	83ms	85ms	-2%
task-ls (cached)	856ms	811ms	+5%

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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The `([abc])[0-9]+` alternative in the shared `VERSION_REGEX` was unanchored, so it false-positived on any `a`/`b`/`c` followed by a digit anywhere in a version string — including the random hex hash inside Go pseudo-versions (e.g. `c1` inside `f149714c1d54`). After #9500 enabled `mark_prereleases_from_version_pattern: true` for the `go` backend, this caused `mise install go:.../@latest` to filter out the only available version for paths whose latest is a pseudo-version, e.g. `go:github.com/go-kratos/kratos/cmd/kratos/v2`. The rule itself is PEP 440-specific (Python's separator-less alpha/beta/rc shorthand) and shouldn't have been in the general regex. Move it into a new `PEP440_PRERELEASE_REGEX` consulted only by the Python-flavored backends — `pipx` and the `python` core plugin. Other backends would otherwise false-positive on hex hashes / short SHAs. The new regex is grounded in the canonical PEP 440 grammar, `[N!]N(.N)*[{a|b|rc}N][.postN][.devN]`: the prerelease segment must follow the release segment, so the regex requires a leading digit. `c` is included as PEP 440's recognized alternate spelling for `rc`. A trailing `(?:$|[^a-z0-9])` boundary keeps it from matching inside hex identifiers even when those start with a digit. Both Python-flavored backends share the logic via a new `fuzzy_match_versions_pep440` helper. `pipx` additionally stamps the flag on its `VersionInfo` cache entries so `prerelease=true` reflects upstream metadata as well as fuzzy-match filtering. Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

@jdx

### 🚀 Features - **(conda)** graduate conda backend out of experimental by @jdx in [#9544](#9544) - **(deps)** Add dart and flutter providers by @tjarvstrand in [#9505](#9505) - **(registry)** add neo4j by @mnm364 in [#9525](#9525) - **(registry)** add rustfs by @mnm364 in [#9530](#9530) - **(task)** support exclusion patterns in task sources by @jlarmstrongiv in [#9496](#9496) - **(vfox)** add stat function to lua file module by @esteve in [#9497](#9497) ### 🐛 Bug Fixes - **(backend)** flag regex prerelease versions by @jdx in [#9500](#9500) - **(backend)** mark -nightly/-canary/-experimental as prereleases by @jdx in [#9523](#9523) - **(backend)** suppress no-versions warning for unresolved-latest backends by @jdx in [#9548](#9548) - **(backend)** include dotnet prereleases from package flags by @jdx in [#9551](#9551) - **(backend)** scope PEP 440 prerelease detection to Python backends by @jdx in [#9558](#9558) - **(cargo)** Apply install_env during cargo install by @c22 in [#9502](#9502) - **(copr)** drop epel-9 chroots since rust >= 1.91 is unavailable by @jdx in [#9484](#9484) - **(github)** skip attestations on non-default api_url by @jdx in [#9486](#9486) - **(github)** retry ip allow list errors without auth by @risu729 in [#9506](#9506) - **(http)** update versions host tracking endpoint by @jdx in [#9527](#9527) - **(install)** don't warn for configured tools when version is passed via CLI by @jdx in [#9522](#9522) - **(install)** refresh latest before installing missing tools by @jdx in [#9545](#9545) - **(install)** don't cache nonexistent install paths by @jdx in [#9553](#9553) - **(lockfile)** don't propagate ad-hoc CLI overrides into the project lockfile by @jdx in [#9562](#9562) - **(plugin)** detect plugin types after cloning by @risu729 in [#9540](#9540) - **(release)** pass --no-git-checks to aube publish by @jdx in [#9483](#9483) - **(task)** convert PATH to MSYS Unix form when spawning POSIX shells on Windows by @JamBalaya56562 in [#9547](#9547) ### 📚 Documentation - **(contributing)** require popularity check for registry PRs by @jdx in [7bbeebe](7bbeebe) - **(watch)** update pitchfork domain to en.dev by @risu729 in [#9536](#9536) - document ghtkn GitHub token setup by @jdx in [#9546](#9546) - clarify registry backend acceptance policy by @jdx in [#9543](#9543) - Change exec command to use bash for variable echo by @kuboon in [#9567](#9567) ### 🧪 Testing - **(e2e)** run test-tool targets in parallel by @jdx in [#9564](#9564) - **(e2e)** run tests in parallel by @jdx in [#9563](#9563) - **(e2e)** bind-mount /tmp on disk and surface failed tests in CI summary by @jdx in [#9570](#9570) - **(tasks)** migrate test_task_help atask to usage field by @jdx in [#9549](#9549) ### 📦️ Dependency Updates - update fedora:45 docker digest to 8b838b3 by @renovate[bot] in [#9507](#9507) - update ghcr.io/jdx/mise:deb docker digest to f02194c by @renovate[bot] in [#9509](#9509) - update taiki-e/install-action digest to 7769b73 by @renovate[bot] in [#9512](#9512) - update ghcr.io/jdx/mise:alpine docker digest to 581f8a8 by @renovate[bot] in [#9508](#9508) - update rust crate ctor to v0.10.1 by @renovate[bot] in [#9515](#9515) - update ghcr.io/jdx/mise:rpm docker digest to a5c9655 by @renovate[bot] in [#9510](#9510) - update rust docker digest to a9cfb75 by @renovate[bot] in [#9511](#9511) - update rust crate age to v0.11.3 by @renovate[bot] in [#9514](#9514) - update rust crate jiff to v0.2.24 by @renovate[bot] in [#9516](#9516) - update dependency vitepress-plugin-tabs to ^0.9.0 by @renovate[bot] in [#9518](#9518) - update autofix-ci/action action to v1.3.4 by @renovate[bot] in [#9513](#9513) - update rust crate usage-lib to v3.2.1 by @renovate[bot] in [#9517](#9517) - update apple-actions/import-codesign-certs action to v7 by @renovate[bot] in [#9519](#9519) - update taiki-e/install-action digest to 51cd0b8 by @renovate[bot] in [#9531](#9531) - exclude taiki-e/install-action from renovate by @jdx in [#9532](#9532) - update rust crate blake3 to v1.8.5 by @renovate[bot] in [#9533](#9533) ### 📦 Registry - enable shellcheck on windows by @zeitlinger in [#9487](#9487) - add google-java-format by @zeitlinger in [#9488](#9488) - add expert ([aqua:expert-lsp/expert](https://github.com/expert-lsp/expert)) by @AlternateRT in [#9498](#9498) - update entry for checkmake by @eread in [#9504](#9504) - add systemctl-tui ([aqua:rgwood/systemctl-tui](https://github.com/rgwood/systemctl-tui)) by @2xdevv in [#9521](#9521) - add codon by @3w36zj6 in [#9538](#9538) - add tool yr (backend:github:VirusTotal/yara-x) by @adam-moss in [#9542](#9542) - add tool betterleaks (backend:aqua/betterleaks/betterleaks) by @adam-moss in [#9541](#9541) - add `git-filter-repo` by @garysassano in [#9550](#9550) - add umoci ([aqua:opencontainers/umoci](https://github.com/opencontainers/umoci)) by @2xdevv in [#9555](#9555) - add aqua backend for elixir-ls by @AlternateRT in [#9557](#9557) - deny inline backend options by @risu729 in [#9565](#9565) ### Chore - **(ci)** fail registry tests without summary by @jdx in [#9559](#9559) - **(ci)** use !cancelled() instead of always() for test-ci aggregator by @jdx in [#9569](#9569) - **(ci)** use namespace runners for ci jobs by @jdx in [#9561](#9561) - **(config)** deprecate shorthands_file setting by @risu729 in [#9534](#9534) - **(docs)** remove shrill.en.dev analytics script by @jdx in [#9539](#9539) - **(release)** replace bc with awk in release-plz star formatting by @jdx in [d7f177f](d7f177f) - bump hk to 1.44.3 by @jdx in [#9493](#9493) - invert CLAUDE.md/AGENTS.md so AGENTS.md is canonical by @jdx in [#9560](#9560) - set dev profile debug to 1 by @jdx in [#9572](#9572) ### New Contributors - @kuboon made their first contribution in [#9567](#9567) - @AlternateRT made their first contribution in [#9557](#9557) - @2xdevv made their first contribution in [#9555](#9555) - @adam-moss made their first contribution in [#9541](#9541) - @jlarmstrongiv made their first contribution in [#9496](#9496) - @tjarvstrand made their first contribution in [#9505](#9505)

gemini-code-assist Bot reviewed May 3, 2026

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jdx force-pushed the fix/version-regex-go-pseudo-versions branch from cfff9d8 to a3ba126 Compare May 3, 2026 10:01

jdx changed the title ~~fix(backend): don't flag Go pseudo-versions as prereleases~~ fix(backend): scope PEP 440 prerelease detection to pipx only May 3, 2026

jdx force-pushed the fix/version-regex-go-pseudo-versions branch from a3ba126 to 2be0505 Compare May 3, 2026 10:06

jdx enabled auto-merge (squash) May 3, 2026 10:20

jdx force-pushed the fix/version-regex-go-pseudo-versions branch from 29cc81a to 0919ec8 Compare May 3, 2026 11:01

jdx changed the title ~~fix(backend): scope PEP 440 prerelease detection to pipx only~~ fix(backend): scope PEP 440 prerelease detection to Python backends May 3, 2026

cursor Bot reviewed May 3, 2026

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Comment thread src/backend/mod.rs

jdx disabled auto-merge May 3, 2026 11:13

jdx force-pushed the fix/version-regex-go-pseudo-versions branch from 0919ec8 to 287f01d Compare May 3, 2026 11:14

jdx enabled auto-merge (squash) May 3, 2026 11:26

jdx merged commit 2e66f3e into main May 3, 2026
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jdx deleted the fix/version-regex-go-pseudo-versions branch May 3, 2026 11:29

mise-en-dev mentioned this pull request May 3, 2026

chore: release 2026.5.0 #9485

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BrewTestBot mentioned this pull request May 3, 2026

mise 2026.5.0 Homebrew/homebrew-core#280712

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fix(backend): scope PEP 440 prerelease detection to Python backends#9558

fix(backend): scope PEP 440 prerelease detection to Python backends#9558
jdx merged 1 commit intomainfrom
fix/version-regex-go-pseudo-versions

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Summary

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Greptile Summary

Confidence Score: 5/5

Important Files Changed

Flowchart

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Hyperfine Performance

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`mise x -- echo`

`mise env`

`mise hook-env`

`mise ls`

`xtasks/test/perf`