[wrangler] Enable new config for cf dev

[penalosa]

Projects started through cf dev now enable Wrangler's new configuration format, so dev loads cloudflare.config.ts and optional wrangler.config.ts in the same way as the delegate's build path.

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• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because: this forwards an existing, tested Wrangler option; the existing 26 cf-wrangler tests pass.
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: this aligns the experimental delegate's dev and build configuration behaviour.

A picture of a cute animal (not mandatory, but encouraged)

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[changeset-bot]

🦋 Changeset detected

Latest commit: 3aba61d

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

This PR includes changesets to release 3 packages

Name	Type
wrangler	Patch
@cloudflare/vite-plugin	Patch
@cloudflare/vitest-pool-workers	Patch

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[workers-devprod]

Codeowners approval required for this PR:

• ✅ @cloudflare/wrangler

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[github-actions]

✅ All changesets look good

[ask-bonk]

The plumbing is consistent: experimentalNewConfig flows from the options literal → startDev → ConfigController, gating the new-config load path. The change is minimal, coherent, and aligns dev with the already-new-config build path in the same experimental delegate.

I reviewed the change thoroughly:

• The single functional change adds experimentalNewConfig: true to the dev options literal, alongside the existing config: undefined (so the --config-not-supported guard in readNewConfig is satisfied).
• The option is correctly consumed via args.experimentalNewConfig in start-dev.ts:279 → ConfigController.
• Behavior now requires cloudflare.config.ts, but this matches the build verb (which already forces the new-config BOS path) — intentional and consistent for this experimental delegate.
• Changeset is present, correctly scoped to wrangler as a patch.
• No existing tests assert against the old options shape.

No logic bugs, security issues, backward-compat violations, or incorrect API behavior. This is a small, well-scoped, internally consistent change.

LGTM

github run

[pkg-pr-new]

@cloudflare/autoconfig

npm i https://pkg.pr.new/@cloudflare/autoconfig@15082

@cloudflare/build-output-utils

npm i https://pkg.pr.new/@cloudflare/build-output-utils@15082

@cloudflare/config

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create-cloudflare

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@cloudflare/deploy-helpers

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@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@15082

miniflare

npm i https://pkg.pr.new/miniflare@15082

@cloudflare/pages-functions

npm i https://pkg.pr.new/@cloudflare/pages-functions@15082

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@15082

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@15082

@cloudflare/vite-plugin

npm i https://pkg.pr.new/@cloudflare/vite-plugin@15082

@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@15082

@cloudflare/workers-auth

npm i https://pkg.pr.new/@cloudflare/workers-auth@15082

@cloudflare/workers-editor-shared

npm i https://pkg.pr.new/@cloudflare/workers-editor-shared@15082

@cloudflare/workers-utils

npm i https://pkg.pr.new/@cloudflare/workers-utils@15082

wrangler

npm i https://pkg.pr.new/wrangler@15082

commit: 3aba61d

[workers-devprod]

Codeowners reviews satisfied

[workers-devprod]

Codeowners approval required for this PR:

• ✅ @cloudflare/wrangler

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