python dev-server: check cache *before* doing entrypoint detection by msullivan · Pull Request #15365 · vercel/vercel

msullivan · 2026-03-04T02:10:29Z

The potential downside here is that if the entrypoint implicitly changes,
then we won't pick that up.

The upside is that we skip doing a bunch of work.

(Currently on one django repo I was looking at, it was 700ms! I'm
going to look into that and fix it but I expect it will remain at 10s
of ms, which is worth avoiding.)

Note

Low Risk Change

This PR reorders cache checks to run before entrypoint detection and changes the server cache key to exclude the entry parameter, which could cause incorrect server reuse if entrypoints change.

Cache key changed from workPath::entry::framework to workPath::framework, removing entry from key
Cache lookup moved before entrypoint detection logic to skip work on subsequent requests
Potential for stale server reuse if entrypoint changes without framework/workPath change

^{Risk assessment for commit 924bb7d.}

changeset-bot · 2026-03-04T02:10:36Z

🦋 Changeset detected

Latest commit: 924bb7d

The changes in this PR will be included in the next version bump.

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Name	Type
@vercel/python	Minor
vercel	Patch

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github-actions · 2026-03-04T02:11:27Z

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github-actions · 2026-03-04T02:12:09Z

🧪 Unit Test Strategy

Comparing: 415ee0b → 924bb7d (view diff)

Strategy: Affected packages only

✅ Only testing packages that have been modified or depend on modified packages.

Affected packages - 2 (5%)

@vercel/python
vercel

Unaffected packages - 38 (95%)

@vercel-internals/get-package-json
@vercel/backends
@vercel/build-utils
@vercel/cervel
@vercel/cli-auth
@vercel/client
@vercel/config
@vercel/detect-agent
@vercel/edge
@vercel/elysia
@vercel/error-utils
@vercel/express
@vercel/fastify
@vercel/firewall
@vercel/frameworks
@vercel/fs-detectors
@vercel/functions
@vercel/gatsby-plugin-vercel-builder
@vercel/go
@vercel/h3
@vercel/hono
@vercel/hydrogen
@vercel/koa
@vercel/nestjs
@vercel/next
@vercel/node
@vercel/oidc
@vercel/oidc-aws-credentials-provider
@vercel/python-analysis
@vercel/redwood
@vercel/related-projects
@vercel/remix-builder
@vercel/routing-utils
@vercel/ruby
@vercel/rust
@vercel/static-build
@vercel/static-config
examples

Results

Unit tests: Only affected packages will run unit tests
E2E tests: Running in parallel via E2E Tests workflow
Type checks: Only affected packages will run type checks

This comment is automatically generated based on the affected testing strategy

The potential downside here is that if the entrypoint implicitly changes, then we won't pick that up. The upside is that we skip doing a bunch of work. Currently on one django repo I was looking at, it was 700ms! I'm going to look into that and fix it but I expect it will remain at 10s of ms, which is worth avoiding.

ricardo-agz

Nice! How slow/fast is Django now?

msullivan · 2026-03-05T22:10:20Z

Nice! How slow/fast is Django now?

This makes the latency on the test project I was using ~10ms.

msullivan · 2026-03-05T22:22:46Z

(Though I have also tracked down why django introspection is so slow and will fix it)

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @vercel/build-utils@13.7.0 ### Minor Changes - [python] add support for module-based entrypoints for cron jobs ([#15393](#15393)) - For the django frontend, dynamically load settings.py instead of parsing it ([#15367](#15367)) ### Patch Changes - Updated dependencies \[[`83e804013528fc54de31082960ae31f58339bd71`](83e8040), [`921314f958c4ec85adb09e020310a5becb7f866c`](921314f)]: - @vercel/python-analysis@0.9.0 ## vercel@50.29.0 ### Minor Changes - Add interactive mode to `webhooks create` and change warning prefix from `WARN!` to `WARNING!` ([#15406](#15406)) ### Patch Changes - Updated dependencies \[[`32e8ba5f593fdeddeb63d241d7806d6c12fffe76`](32e8ba5), [`83e804013528fc54de31082960ae31f58339bd71`](83e8040), [`0f1fa86770a35d0192d64d36cb46d932e1d2a12a`](0f1fa86), [`813f3d324404237e3806530b465625ea33816370`](813f3d3), [`0a78892b1e155eb4b587a8b84c4e6814f750697f`](0a78892), [`9a973a704b7350e19d0c3ac8e110ce55eea795b2`](9a973a7), [`c6f5ac6c11fb7f431b5fb634a7fb321b10c829af`](c6f5ac6), [`921314f958c4ec85adb09e020310a5becb7f866c`](921314f)]: - @vercel/next@4.15.42 - @vercel/build-utils@13.7.0 - @vercel/python@6.21.0 - @vercel/detect-agent@1.1.1 - @vercel/static-build@2.8.46 - @vercel/backends@0.0.42 - @vercel/elysia@0.1.45 - @vercel/express@0.1.54 - @vercel/fastify@0.1.48 - @vercel/go@3.4.3 - @vercel/h3@0.1.54 - @vercel/hono@0.2.48 - @vercel/hydrogen@1.3.5 - @vercel/koa@0.1.28 - @vercel/nestjs@0.2.49 - @vercel/node@5.6.12 - @vercel/redwood@2.4.9 - @vercel/remix-builder@5.6.0 - @vercel/ruby@2.3.2 - @vercel/rust@1.0.5 ## @vercel/fs-detectors@5.9.0 ### Minor Changes - [python] add support for module-based entrypoints for cron jobs ([#15393](#15393)) ### Patch Changes - [python] add support for Python worker services with Django tasks ([#15396](#15396)) ## @vercel/python@6.21.0 ### Minor Changes - [python] add support for module-based entrypoints for cron jobs ([#15393](#15393)) - Avoid doing entry point detection on every request to a python dev server ([#15365](#15365)) - For the django frontend, dynamically load settings.py instead of parsing it ([#15367](#15367)) ### Patch Changes - speed up python entrypoint detection ([#15402](#15402)) - Add Python builder cache preparation for Build Output API v3 cache globs, the builder virtualenv, and the repo-local uv cache. ([#15407](#15407)) - Updated dependencies \[[`83e804013528fc54de31082960ae31f58339bd71`](83e8040), [`921314f958c4ec85adb09e020310a5becb7f866c`](921314f)]: - @vercel/python-analysis@0.9.0 ## @vercel/python-analysis@0.9.0 ### Minor Changes - [python] add support for module-based entrypoints for cron jobs ([#15393](#15393)) - For the django frontend, dynamically load settings.py instead of parsing it ([#15367](#15367)) ## @vercel/backends@0.0.42 ### Patch Changes - Updated dependencies \[[`83e804013528fc54de31082960ae31f58339bd71`](83e8040), [`921314f958c4ec85adb09e020310a5becb7f866c`](921314f)]: - @vercel/build-utils@13.7.0 ## @vercel/cervel@0.0.29 ### Patch Changes - Updated dependencies \[]: - @vercel/backends@0.0.42 ## @vercel/client@17.2.54 ### Patch Changes - Updated dependencies \[[`83e804013528fc54de31082960ae31f58339bd71`](83e8040), [`921314f958c4ec85adb09e020310a5becb7f866c`](921314f)]: - @vercel/build-utils@13.7.0 ## @vercel/config@0.0.38 ### Patch Changes - Fix type generation ([#15386](#15386)) ## @vercel/detect-agent@1.1.1 ### Patch Changes - Add Antigravity agent detection via `ANTIGRAVITY_AGENT` environment variable ([#15413](#15413)) - Detect Codex when `CODEX_CI` or `CODEX_THREAD_ID` is present. ([#15412](#15412)) ## @vercel/elysia@0.1.45 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.6.12 ## @vercel/express@0.1.54 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.6.12 - @vercel/cervel@0.0.29 ## @vercel/fastify@0.1.48 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.6.12 ## @vercel/gatsby-plugin-vercel-builder@2.0.144 ### Patch Changes - Updated dependencies \[[`83e804013528fc54de31082960ae31f58339bd71`](83e8040), [`921314f958c4ec85adb09e020310a5becb7f866c`](921314f)]: - @vercel/build-utils@13.7.0 ## @vercel/h3@0.1.54 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.6.12 ## @vercel/hono@0.2.48 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.6.12 ## @vercel/koa@0.1.28 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.6.12 ## @vercel/nestjs@0.2.49 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.6.12 ## @vercel/next@4.15.42 ### Patch Changes - Revert "[next] vary fallback allowQuery for partial fallback shells" ([#15418](#15418)) ## @vercel/node@5.6.12 ### Patch Changes - Updated dependencies \[[`83e804013528fc54de31082960ae31f58339bd71`](83e8040), [`921314f958c4ec85adb09e020310a5becb7f866c`](921314f)]: - @vercel/build-utils@13.7.0 ## @vercel/static-build@2.8.46 ### Patch Changes - Updated dependencies \[]: - @vercel/gatsby-plugin-vercel-builder@2.0.144 ## @vercel/python-runtime@0.6.0 ### Minor Changes - [python] add support for Python worker services with Django tasks ([#15396](#15396)) - [python] add support for module-based entrypoints for cron jobs ([#15393](#15393))  > [!NOTE] > Low Risk Change > > This PR is an automated Changesets release that only updates version numbers in package.json files, CHANGELOG.md files, and deletes changeset markdown files — no functional code changes. > > - Version bumps across ~30 packages (patch/minor) > - Changelog and changeset file updates only > - Single constant update: VERCEL_RUNTIME_VERSION = '0.6.0' > > <sup>Risk assessment for [commit d3cf7ea](https://github.com/vercel/vercel/commit/d3cf7ea8deab73a058f4228f0346317fcf3e3dbc).</sup>  Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

msullivan requested a review from ricardo-agz March 4, 2026 02:10

msullivan requested review from a team as code owners March 4, 2026 02:10

vercel bot deployed to Preview March 4, 2026 02:11 View deployment

msullivan force-pushed the py-dev-server-cache branch from d6b9cd9 to 6ef2e24 Compare March 4, 2026 18:57

vercel bot deployed to Preview March 4, 2026 18:59 View deployment

msullivan force-pushed the py-dev-server-cache branch from 6ef2e24 to 2775d97 Compare March 4, 2026 19:01

msullivan force-pushed the py-dev-server-cache branch from 2775d97 to 924bb7d Compare March 4, 2026 19:35

vercel bot deployed to Preview March 4, 2026 19:36 View deployment

ricardo-agz approved these changes Mar 5, 2026

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ricardo-agz reviewed Mar 5, 2026

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msullivan merged commit 0a78892 into main Mar 6, 2026
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msullivan deleted the py-dev-server-cache branch March 6, 2026 00:42

vercel-release-bot mentioned this pull request Mar 6, 2026

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python dev-server: check cache before doing entrypoint detection#15365

python dev-server: check cache before doing entrypoint detection#15365
msullivan merged 1 commit intomainfrom
py-dev-server-cache

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