Fix crash in receiveEmail when no R2 bucket binding is found

[G4brym]

Summary

• Adds a missing null check in receiveEmail() to prevent a TypeError crash when no R2 bucket binding is available
• If neither emailRouting.targetBucket resolves to a valid bucket nor any R2-like binding is found in the environment, the handler now throws a descriptive Error instead of crashing on bucket.put() with an opaque TypeError: Cannot read properties of undefined

What changed

In packages/worker/src/modules/emails/receiveEmail.ts, after the two bucket discovery attempts (explicit config and environment scan), a guard clause was added:

if (!bucket) {
    throw new Error(
        "No R2 bucket binding found for email routing. Configure emailRouting.targetBucket or add an R2 bucket binding.",
    );
}

Why

Without this check, if a worker has email routing enabled but no R2 bucket binding configured, incoming emails would crash the worker with an unhelpful TypeError. The new error message tells the operator exactly what's wrong and how to fix it.

Test plan

• All 78 worker tests pass (7 skipped — same as baseline)
• All 110 dashboard tests pass
• Linter passes with no issues

🤖 Generated with Claude Code

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	r2-explorer-docs	705622c	Commit Preview URL Branch Preview URL	Mar 08 2026, 01:08 AM

[G4brym]

Automated Code Review — APPROVED ✅

Review Scores: 5/5 reviewers approved

Summary

Reviewed the addition of a null guard for the R2 bucket binding in receiveEmail(). This is a clean, minimal defensive fix that replaces an opaque TypeError crash with a descriptive, actionable error message. The change is correctly placed after both bucket discovery attempts and before any bucket usage.

Review Perspectives

1. Correctness: ✅ Guard is in the right position, covers the exact gap between discovery and usage
2. Security: ✅ Static error string, no user input in the message, no exposure risks
3. Performance: ✅ Single boolean check, zero overhead
4. Code Quality: ✅ Follows existing patterns, clear error message, proper changeset
5. Testing: ✅ All 188 tests pass; the guard replaces one crash with a better one

Minor notes (non-blocking)

• A unit test covering the no-bucket-binding scenario would be a nice addition in the future, but is not required for this defensive fix.

🤖 Automated review by prodboard