Issue Review: cloudflare/workers-sdk#5860

Summary

Redirects in local dev mode produce malformed URLs with multiple ports (e.g., localhost:8787:8787:3000).

Findings

• Created: 2024-05-17
• Updated: 2025-10-30
• Version: wrangler 3.56.0 → wrangler 4.61.0
• Component: wrangler (dev)
• Labels: bug
• Comments: 9

Key Evidence

• Reproduction: https://stackblitz.com/edit/stackblitz-starters-vjsh9a
• Two issues reported:
  1. unstable_dev fetch throws error when following redirects
  2. Redirect Location header contains malformed URL: http://localhost:8787:8787:3000/redirected
• Issue tracked separately in #5221 for the malformed URL
• Worked correctly in wrangler v2 (both local and remote mode)
• User @mariusGundersen confirmed "still a problem a year later" (May 2025)
• User @seankovacs confirmed issue persists with wrangler 4.24.0 (July 2025)

Recommendation

Status: KEEP OPEN

Reasoning: This is a regression from wrangler v2 that affects local development with redirects. The malformed URL issue is tracked in #5221. Multiple users confirm the issue persists in recent versions.

Action: Fix the URL construction logic when generating redirect Location headers in local dev mode.

Suggested Comment

N/A - Issue is being tracked, related to #5221.