Update dependency @cloudflare/vitest-pool-workers to v0.21.1

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
@cloudflare/vitest-pool-workers (source)	0.20.3 → 0.21.1

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Release Notes

cloudflare/workers-sdk (@​cloudflare/vitest-pool-workers)

v0.21.1

Compare Source

Patch Changes

• #​14882 ab9132d Thanks @​petebacondarwin! - Report built-in modules that a Worker's compatibility settings don't provide as module errors, instead of crashing workerd

  Previously, a Worker whose module graph statically reached a compatibility-gated built-in that wasn't enabled — for example import "node:child_process" without nodejs_compat — took down the runtime with *** Received signal #​11: Segmentation fault before any test ran. Vitest reported only Worker exited unexpectedly, naming neither the module nor the file that imported it, which made the cause very hard to find. The import didn't even have to be called; being reachable from the entrypoint was enough.

  The module fallback service answered these specifiers with a redirect to the modules root, but workerd already resolves node:/cloudflare:/workerd: specifiers there, so the redirect pointed back at the module workerd was in the middle of resolving and it recursed until the stack overflowed. Such a specifier only reaches the fallback service when workerd's own registry has already missed, so it's now reported as not found: workerd raises No such module "node:child_process", matching what wrangler dev does for the same Worker. The accompanying pool error names the module and points at compatibility flags rather than suggesting you bundle it, which can't help for a module built into the runtime.

• Updated dependencies [15cad03, 026e058, 731b33a, e1b5b4b, 5b1b930, 6e7d37d, d669088, 15cad03, c7aede7, 0aa8fa5]:

  • wrangler@​4.121.0
  • miniflare@5.20260804.1-alpha

v0.21.0

Compare Source

Minor Changes

• #​14994 2194f88 Thanks @​emily-shen! - Update the Workers Vitest pool for Miniflare's config-based options

  The Workers Vitest pool now converts the Miniflare options it creates for test sessions to Miniflare's config-based workers shape.

  For the most part, users should not expect to notice any changes.

  However, while miniflare.modulesRules is preserved for common text and WASM fixture imports, it is not a full replacement for Miniflare's old modules: true module graph collection and you may notice some differences in behaviour.

Patch Changes

• Updated dependencies [6dbd192, 2194f88, 2194f88, 2194f88, 2194f88, 2194f88, 2194f88, 2194f88]:
  • miniflare@5.20260804.0-alpha
  • wrangler@​4.120.1

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Summary by cubic

Update @cloudflare/vitest-pool-workers from 0.20.3 to 0.21.1 to adopt Miniflare’s config-based options and improve test stability. Previously, gated built-in imports could crash the runtime; now they surface clear module errors tied to missing compatibility flags.

• Tests may resolve modules slightly differently than with Miniflare’s old modules: true; adjust miniflare.modulesRules or fixtures if you see changes.
• CI and local testing must use Node 22+ due to transitive wrangler and miniflare engine requirements.
• If tests import Node built-ins, enable the appropriate compatibility flags (for example, nodejs_compat) instead of bundling; these imports now fail fast with explicit errors.

^{Written for commit 184484d. Summary will update on new commits.}

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