Runtime Breaking Change: Cannot assign to read only property 'console'

[handfuloflight]

Bug Report: Runtime Breaking Change - Cannot assign to read only property 'console'

Summary

Starting approximately 8:26 PM UTC on November 5, 2025, all workflow executions began failing with a TypeError: Cannot assign to read only property 'console' error during environment setup. This affects both stable and alpha versions of @convex-dev/workflow.

Error Details

Full Error Message

Uncaught TypeError: Cannot assign to read only property 'console' of object '#<ii>'
    at setupEnvironment (../../../../node_modules/@convex-dev/workflow/src/client/environment.ts:81:6)
    at handler (../../../../node_modules/@convex-dev/workflow/src/client/workflowMutation.ts:106:6)
    at async handler (../../../../node_modules/@convex-dev/workflow/src/component/workflow.ts:55:8)
    at async start [as start] (../../../../node_modules/@convex-dev/workflow/src/client/index.ts:144:6)

Error Location

The error occurs in setupEnvironment() when attempting to replace the global console object:

// environment.ts:81 (0.2.7) or line 103 (0.2.8-alpha.11)
global.console = createConsole(global.console as Console, getGenerationState);

Affected Versions

• ✅ Confirmed broken: @convex-dev/workflow@0.2.7 (stable)
• ✅ Confirmed broken: @convex-dev/workflow@0.2.8-alpha.11 (alpha)
• 🔍 Likely affected: All versions that use setupEnvironment() with console patching

Environment

• Convex Runtime Version: Appears to be a backend runtime change (no client version bump)
• Client Library: convex@1.28.0
• Started: ~November 5, 2025, 8:26 PM UTC
• Node.js Runtime: Default (Node 18)
• Deployment: Convex Cloud

Root Cause Analysis

The Convex runtime environment has changed global.console to have writable: false in its property descriptor. This prevents the workflow library from replacing it with a wrapped Proxy version needed for deterministic logging.

Before: Object.getOwnPropertyDescriptor(global, 'console').writable === true
After: Object.getOwnPropertyDescriptor(global, 'console').writable === false

This appears to be a security hardening change or side effect of a runtime update that was not communicated or documented.

Impact

Critical Production Impact

• All workflow executions fail immediately during initialization
• In-progress workflows cannot resume from saved state
• Any API calls that trigger workflows fail completely
• Applications using workflows for orchestration are completely broken

Production Impact

Applications using workflows for multi-step orchestration and durable execution are completely non-functional.

Steps to Reproduce

1. Install @convex-dev/workflow@0.2.7 or @convex-dev/workflow@0.2.8-alpha.11
2. Define any workflow using WorkflowManager
3. Attempt to start the workflow via workflow.start()
4. Observe TypeError: Cannot assign to read only property 'console'

Expected Behavior

Workflows should initialize successfully and execute as designed.

Actual Behavior

All workflows crash during environment setup with a console property assignment error.

Workaround Attempts

• ❌ Downgrading to 0.2.7 - Still fails
• ❌ Upgrading to 0.2.8-alpha.11 - Still fails
• ⚠️ Only option: Disable all workflows (not viable for production)

Potential Solutions

Option 1: Revert Runtime Change (Quick Fix)

Make global.console writable again in the Convex runtime environment.

Option 2: Update Workflow Library (Proper Fix)

Use Object.defineProperty() instead of direct assignment:

Object.defineProperty(global, 'console', {
  value: createConsole(global.console as Console, getGenerationState),
  writable: true,
  enumerable: true,
  configurable: true
});

Option 3: Provide Alternative API

Expose a Convex-native console wrapper that workflows can use without patching globals.

Additional Context

• No GitHub issues filed by other users yet (we may be first to hit this)
• Convex Status page shows no incidents on Nov 5
• No release notes or changelogs documenting this change
• Timing suggests silent backend runtime rollout

Request for Convex Team

1. Immediate: Can you confirm this is a known runtime change?
2. Urgent: What is the timeline for a fix or workaround?
3. Communication: Please document breaking runtime changes in release notes

This is a critical production blocker for any application using workflows.

---

Time Started: November 5, 2025, ~8:26 PM UTC
Affected: Production application using workflows

[nim442]

Running into the same issue. Coincides with Node 18 deprecation?

[handfuloflight]

RESOLVED ✅

Solution: Upgrade to Node 20 runtime + update Convex client

Steps to Fix:

1. Update Convex client to latest patch version:

bun update convex@1.28.2
# or: npm install convex@1.28.2

2. Create convex/convex.json with Node 20 configuration:

{
  "node": {
    "nodeVersion": "20"
  }
}

3. Restart Convex dev server:

npx convex dev

Root Cause

The issue was caused by Node 18's end-of-life deprecation. The Convex runtime made global.console read-only in Node 18, breaking the workflow library's environment setup. Node 20 doesn't have this restriction.

Confirmed working with:

• convex@1.28.2
• @convex-dev/workflow@0.2.7
• nodeVersion: "20" in convex.json

[goffrie]

Hi, thank you for the report. This was an unintended change in the Convex runtime and we have reverted it.