fix(fetch): rename globalThis.fetch wrapper from "value" to "fetch"#8406
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`globalThis.fetch`'s wrapper carries the name `value`, so every stack frame that flows through fetch surfaces as `at value` instead of `at fetch`. Renaming the wrapper makes frames blend with bundled-undici fetch. The diff also renames the inner `let fetch` slot. A named function expression `function fetch (...)` binds `fetch` to itself inside its body; without the slot rename the wrapper calls itself and stack-overflows on first invocation. Retiring the wrap is blocked on upstream undici PR #2701: bundled undici in Node 18+ exposes only `undici:request:*` channels, and the existing undici plugin already subscribes to those. Architecture review (baseline -> proposal, 1-10): 1. Drift prevention 7 -> 7 2. Coupling at module boundary 8 -> 8 3. Explicit contracts 7 -> 7 4. Testability at boundaries 5 -> 8 (spec pins the name and the recursion-safety invariant) 5. Extensibility 7 -> 7 6. Hot-path fitness 8 -> 8 Refs: nodejs/undici#2701
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Overall package sizeSelf size: 5.81 MB Dependency sizes| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 3.0.1 | 82.56 kB | 817.39 kB | | dc-polyfill | 0.1.11 | 25.74 kB | 25.74 kB |🤖 This report was automatically generated by heaviest-objects-in-the-universe |
🎉 All green!❄️ No new flaky tests detected 🎯 Code Coverage (details) 🔗 Commit SHA: e1e6c3c | Docs | Datadog PR Page | Give us feedback! |
BenchmarksBenchmark execution time: 2026-05-11 00:14:06 Comparing candidate commit e1e6c3c in PR branch Found 0 performance improvements and 0 performance regressions! Performance is the same for 1739 metrics, 105 unstable metrics. |
pabloerhard
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May 11, 2026
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May 13, 2026
…8406) `globalThis.fetch`'s wrapper carries the name `value`, so every stack frame that flows through fetch surfaces as `at value` instead of `at fetch`. Renaming the wrapper makes frames blend with bundled-undici fetch. The diff also renames the inner `let fetch` slot. A named function expression `function fetch (...)` binds `fetch` to itself inside its body; without the slot rename the wrapper calls itself and stack-overflows on first invocation. Retiring the wrap is blocked on upstream undici PR #2701: bundled undici in Node 18+ exposes only `undici:request:*` channels, and the existing undici plugin already subscribes to those. Architecture review (baseline -> proposal, 1-10): 1. Drift prevention 7 -> 7 2. Coupling at module boundary 8 -> 8 3. Explicit contracts 7 -> 7 4. Testability at boundaries 5 -> 8 (spec pins the name and the recursion-safety invariant) 5. Extensibility 7 -> 7 6. Hot-path fitness 8 -> 8 Refs: nodejs/undici#2701
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Summary
globalThis.fetch's wrapper carries the namevalue, so every stack frame that flows through fetch surfaces asat valueinstead ofat fetch. Rename the wrapper -- and the innerlet fetchslot it forwards to, since the named function expression's name shadows the outer binding and would self-recurse otherwise -- so frames blend with bundled-undici fetch.Test plan
New
packages/datadog-instrumentations/test/fetch.spec.jspinsglobalThis.fetch.name === 'fetch'after the instrumentation loads and that the wrapper forwards calls without self-recursion:nycon the file reports 87.5% line / statement coverage. The uncovered region is the pre-existing serverless-only stub path (lines 9-11); the rename on those lines is identity-preserving.Refs: nodejs/undici#2701