openclaw - 💡(How to fix) Fix bug: undici 8.2.0 Content-Length validation fails when dispatcher is replaced via setGlobalDispatcher [1 comments, 2 participants]

Description

When OpenClaw Gateway replaces the global undici dispatcher via setGlobalDispatcher() (see undici-global-dispatcher-CxFhjJy5.js), all fetch() calls dispatched through Node.js internal undici → OpenClaw bundled undici v8.2.0 Agent → Dispatcher1Wrapper → Client chain fail with:

TypeError: fetch failed
  cause: InvalidArgumentError: invalid content-length header

The error occurs in isValidContentLengthHeaderValue() at undici/lib/core/request.js:503.

Root Cause

Node.js internal undici passes headers to the OpenClaw bundled undici Client via dispatch(opts, handler). The Content-Length header value arrives in a format that undici v8.2.0's isValidContentLengthHeaderValue() rejects.

Format analysis

Debug logging revealed Content-Length values passing validation include formats like:

• "66, 66" (comma-separated, multi-value)
• "183, 183" (comma-separated, multi-value)
• "35735" (single value - passes)

The validation function isValidContentLengthHeaderValue() only accepts pure digit strings. Values like "66, 66" contain commas and spaces, causing the function to return false.

This suggests that the Dispatcher1Wrapper or Node.js internal undici → OpenClaw undici 8.2.0 handoff converts single Content-Length values into multi-value format for certain request types.

Stack trace

InvalidArgumentError: invalid content-length header
    at processHeader (undici/lib/core/request.js:503:13)
    at new Request (undici/lib/core/request.js:264:11)
    at Client.[dispatch] (undici/lib/dispatcher/client.js:340:21)
    at Client.dispatch (undici/lib/dispatcher/dispatcher-base.js:171:29)
    at Pool.[dispatch] (undici/lib/dispatcher/pool-base.js:163:28)
    at Pool.dispatch (undici/lib/dispatcher/dispatcher-base.js:171:29)
    at Agent.[dispatch] (undici/lib/dispatcher/agent.js:138:23)
    at Agent.dispatch (undici/lib/dispatcher/dispatcher-base.js:171:29)
    at Dispatcher1Wrapper.dispatch (undici/lib/dispatcher/dispatcher1-wrapper.js:95:29)
    at node:internal/deps/undici/undici:13616:55

Impact

• All external HTTPS requests made via fetch() within the Gateway process fail if they carry a Content-Length header
• Affects any channel plugin (weixin, feishu, etc.) that makes HTTP API calls
• Error occurs immediately (< 2s), not a timeout

Environment

• OpenClaw: 2026.5.5 (b1abf9d)
• Node.js: v25.9.0
• OS: macOS (Darwin arm64)
• Bundled undici: 8.2.0 (at /opt/homebrew/lib/node_modules/openclaw/node_modules/undici/)

Workaround

Patching isValidContentLengthHeaderValue() in undici/lib/core/request.js to return true bypasses the validation issue. The parseInt(val, 10) call on the next line (line 505) correctly handles both single and multi-value formats via JS coercion.

But this is only a temporary workaround since it affects node_modules.

Reproduction

1. Start an OpenClaw gateway with any channel plugin that makes external fetch() calls (e.g., openclaw-weixin)
2. Observe fetch() calls from the channel subprocess fail with "invalid content-length header"
3. Compare: same fetch() call from a standalone Node.js process (not through OpenClaw's dispatcher) works fine

Expected Behavior

Content-Length header values passed from Node.js internal undici to OpenClaw bundled undici 8.2.0 should be accepted without validation errors, regardless of the value format (single value, multi-value, or array).