Add support for worker connect handler in miniflare

[fhanau]

This is needed to add initial support for the connect handler in workerd (experimental-only for now).

Part of EW-9330. Updates miniflare so that the connect handler is marked as reserved. This is needed for cloudflare/workerd#6059 to land, additional changes are included in #12802 which needs the workerd PR to be merged first. This PR should be sufficient for allowing the workerd PR to land: Reordering the steps in workerd CI shows that while miniflare tests are failing, vite and vitest tests are not so this one change should be sufficient to allow merging the workerd PR.

---

• Tests
  • Tests included/updated: Intended to be tested with EW-9330 Implement connect() handler workerd#6059
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because:
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: Feature is behind experimental compat flag for now.

---

[changeset-bot]

🦋 Changeset detected

Latest commit: e3d301d

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

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commit: 103460e

[workers-devprod]

Codeowners approval required for this PR:

• ✅ @cloudflare/wrangler

Show detailed file reviewers

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 2 additional findings.

[jamesopstad]

Please could you add a changeset. It can just describe the change very briefly.

[fhanau]

Please could you add a changeset. It can just describe the change very briefly.

This is a one-line change for a test to enable a feature in another repo that won't be available externally for now. I can add a change set, but wouldn't this be the kind of PR that doesn't require one?

[jamesopstad]

Please could you add a changeset. It can just describe the change very briefly.

This is a one-line change for a test to enable a feature in another repo that won't be available externally for now. I can add a change set, but wouldn't this be the kind of PR that doesn't require one?

What do you mean about it being a "change for a test"? CREATE_PROXY_PROTOTYPE_CLASS_HELPER_SCRIPT isn't only used for testing, or am I misunderstanding?

We generally add changesets for any change that should trigger a version bump and release.

[fhanau]

Right, the change here isn't test-only, that's case with the follow-up change in #12802. Corrected the PR and commit title and added a change set.

[github-actions]

⚠️ Issues found

File: .changeset/ten-dancers-know.md

1. Missing body: The changeset contains only a title with no body. The README requires "one or more paragraphs explaining the reason for the change and anything notable about the approach." A description like "Add support for worker connect handler in miniflare" tells users what changed but not why it was needed, how it works, or what users can do with it.

2. Version type (minor consideration): The description says "Add support for..." which indicates new functionality. Per the README, new features should be minor. If this is adding a new capability to miniflare (e.g., implementing a previously unsupported Workers runtime handler), it likely warrants minor rather than patch. Please confirm whether this is a bug fix/alignment with existing behavior (patch) or genuinely new functionality (minor).

[fhanau]

⚠️ Issues found

File: .changeset/ten-dancers-know.md

1. Missing body: The changeset contains only a title with no body. The README requires "one or more paragraphs explaining the reason for the change and anything notable about the approach." A description like "Add support for worker connect handler in miniflare" tells users what changed but not why it was needed, how it works, or what users can do with it.
2. Version type (minor consideration): The description says "Add support for..." which indicates new functionality. Per the README, new features should be minor. If this is adding a new capability to miniflare (e.g., implementing a previously unsupported Workers runtime handler), it likely warrants minor rather than patch. Please confirm whether this is a bug fix/alignment with existing behavior (patch) or genuinely new functionality (minor).

• missing body? There is precedent for having a one-line change set description, see e.g .changeset/late-humans-win.md.
• This does not introduce any new user-facing functionality since connect() will be behind the "experimental" compat flag, so patch should be appropriate.