bug: Sentry debug ID injection causes OOM during module loading #2920

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1. ericallam commented on Jan 21, 2026

   

   ericallam

   on Jan 21, 2026

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   @claude

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2. claude commented on Jan 21, 2026

   

   claudebot

   on Jan 21, 2026 – with Claude

   Last edited by claude

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   Claude finished @ericallam's task in 3m 17s —— View job

   ---

   Analysis Complete

   • Understand the issue and codebase context
   • Locate relevant source-map-support code
   • Analyze the root cause
   • Propose solution approach

   ---

   Root Cause Analysis

   The issue is a specific interaction between Sentry's debug ID injection and source-map-support:

   1. Sentry's sourcemaps inject adds new Error().stack calls to every bundled .mjs file for debug ID mapping
   2. source-map-support hooks Error.prepareStackTrace - meaning every .stack access triggers sourcemap parsing
   3. During module loading, Sentry's injected code executes new Error().stack
   4. This causes all sourcemaps to be parsed synchronously during the import phase - before any task code runs
   5. For large projects (~2000+ files), this creates a massive memory spike that exceeds small-1x (0.5GB RAM)

   Key insight: While source-map-support is designed to be lazy (only parsing on actual errors), Sentry's injection turns every module import into an "error stack access" event.

   ---

   Proposed Solutions

   Option 1: Add config option to disable source-map-support (Recommended)

   Add a new runtime.sourceMapSupport config option to TriggerConfig:

   // In packages/core/src/v3/config.ts
   export type TriggerConfig = {
     // ...
     runtime?: {
       /**
        * Enable source-map-support for better stack traces.
        * Set to false if using tools that access Error.stack during module loading
        * (e.g., Sentry debug ID injection), which can cause OOM on memory-constrained machines.
        * 
        * @default true
        */
       sourceMapSupport?: boolean;
     };
   };

   Then conditionally install in worker entry points:

   // In entryPoints/*-worker.ts
   if (config?.runtime?.sourceMapSupport !== false) {
     sourceMapSupport.install({
       handleUncaughtExceptions: false,
       environment: "node",
       hookRequire: false,
     });
   }

   Pros: Simple, user-controlled, no performance impact
   Cons: Users lose source-mapped stack traces

   Option 2: Lazy/deferred sourcemap parsing

   Use a custom retrieveSourceMap callback that defers parsing until an actual error handler requests it:

   sourceMapSupport.install({
     handleUncaughtExceptions: false,
     environment: "node",
     hookRequire: false,
     retrieveSourceMap: (source) => {
       // Only parse sourcemaps when explicitly needed (e.g., uncaught exception handlers)
       if (!shouldParseSourceMaps()) {
         return null;
       }
       // Default behavior
       return undefined;
     },
   });

   Pros: Preserves stack traces for real errors, prevents OOM during loading
   Cons: More complex, needs careful implementation to track "real" vs "synthetic" stack access

   Option 3: Environment variable toggle (Quick fix)

   Add TRIGGER_DISABLE_SOURCE_MAP_SUPPORT=1 env var check:

   if (process.env.TRIGGER_DISABLE_SOURCE_MAP_SUPPORT !== "1") {
     sourceMapSupport.install({ ... });
   }

   Pros: Immediate fix, no config schema changes
   Cons: Less discoverable, not as clean

   ---

   Recommendation

   I'd suggest implementing Option 1 (config option) as the primary solution, with Option 3 (env var) as a quick workaround users can use immediately.

   Would you like me to implement one of these solutions?
3. ericallam commented on Jan 21, 2026

   

   ericallam

   on Jan 21, 2026

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   @claude could you investigate option 2 first and event see if thats possible?

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4. claude commented on Jan 21, 2026

   

   claudebot

   on Jan 21, 2026 – with Claude

   Last edited by claude

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   Claude finished @ericallam's task in 5m 46s —— View job

   ---

   Investigation Complete: Lazy Sourcemap Parsing (Option 2)

   • Understand how source-map-support works and its API
   • Analyze current implementation in Trigger.dev worker entry points
   • Research if lazy/deferred parsing is feasible
   • Determine implementation approach
   • Report findings

   ---

   Summary

   Yes, Option 2 (lazy/deferred sourcemap parsing) is feasible.

   The most practical approach is Phase-Based Deferred Parsing: skip sourcemap parsing during module loading, enable it once bootstrap completes.

   How it works:

   let loadingPhase = true;
   
   sourceMapSupport.install({
     handleUncaughtExceptions: false,
     environment: "node",
     hookRequire: false,
     retrieveSourceMap: (source) => {
       // Skip parsing during module loading phase
       if (loadingPhase) return null;
       // Return undefined to use default behavior
       return undefined;
     },
   });
   
   // ... later, after bootstrap() completes:
   loadingPhase = false;

   Why this works:

   • During loading: Sentry's new Error().stack calls return unmapped stacks (fast, no memory pressure)
   • During runtime: Task execution errors get full sourcemap support
   • Trade-off: Import errors won't have mapped stacks, but they already have good bundler messages

   Why V8 can't distinguish "synthetic" vs "real" errors:

   • Error.prepareStackTrace is called identically for both
   • No metadata about whether error was thrown or just had .stack accessed
   • No API to detect module loading context

   Files to modify:

   • packages/cli-v3/src/entryPoints/managed-run-worker.ts
   • packages/cli-v3/src/entryPoints/dev-run-worker.ts
   • packages/cli-v3/src/entryPoints/managed-index-worker.ts
   • packages/cli-v3/src/entryPoints/dev-index-worker.ts

   Let me know if you'd like me to implement this!

   ---
5. ericallam commented on Jan 21, 2026

   

   ericallam

   on Jan 21, 2026

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   @claude implement this and please create a reference project as well to test this

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6. claude commented on Jan 21, 2026

   

   claudebot

   on Jan 21, 2026 – with Claude

   Last edited by claude

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   Claude finished @ericallam's task in 6m 31s —— View job • claude/issue-2920-20260121-0712 • Create PR ➔

   ---

   Implementation Complete

   • Read current worker entry point implementations
   • Implement phase-based deferred sourcemap parsing in all worker entry points
   • Create reference project to test OOM fix with Sentry-like debug ID injection
   • Add changeset for the fix
   • Commit and push changes

   ---

   Summary

   Implemented phase-based deferred sourcemap parsing to fix OOM during module loading when using Sentry's debug ID injection.

   Changes:

   1. New utility module (packages/cli-v3/src/entryPoints/deferredSourceMapSupport.ts):

      • installDeferredSourceMapSupport() - Installs source-map-support with a custom retrieveSourceMap callback that returns null during loading phase
      • enableSourceMapSupport() - Enables sourcemap parsing after bootstrap completes

   2. Updated worker entry points:

      • managed-run-worker.ts - Uses deferred sourcemap support, enables after bootstrap
      • dev-run-worker.ts - Uses deferred sourcemap support, enables after bootstrap
      • managed-index-worker.ts - Uses deferred sourcemap support, enables after bootstrap
      • dev-index-worker.ts - Uses deferred sourcemap support, enables after bootstrap

   3. New reference project (references/sentry-sourcemap-oom/):

      • Contains 10 simulated modules that mimic Sentry's debug ID injection pattern
      • Each module has new Error().stack called during import (like Sentry does)
      • Can be used to test the fix works correctly

   How it works:

   • During module loading phase, retrieveSourceMap returns null, skipping all sourcemap parsing
   • After bootstrap completes, the loading phase flag is set to false, enabling normal sourcemap retrieval
   • Runtime errors during task execution get full sourcemap support as before

   Trade-off: Import errors won't have source-mapped stack traces, but bundler messages are usually sufficient for those cases.

   --- |
7. claude

   added a commit that references this issue on Jan 21, 2026

   fix(cli): defer sourcemap parsing to prevent OOM during module loading

   ...

   This issue will close once commit 3d66fee is merged into the 'main' branch.

   3d66fee
8. deepshekhardas

   added a commit that references this issue on Feb 2, 2026

   fix(cli-v3): allow disabling source-map-support to prevent OOM with S…

   ...

   ed41f0a