Add rationale comment for globalThis double-cast

andreiborza · andreiborza · commit 985f4ba720a3 · 2026-07-17T17:56:57.000+02:00
diff --git a/packages/node/src/sdk/initOtel.ts b/packages/node/src/sdk/initOtel.ts
@@ -48,6 +48,8 @@ function registerGlobalTracerProvider(provider: TracerProvider): boolean {
     return true;
   }
 
+  // @opentelemetry/api stores the registry under a `Symbol.for` key that no public type
+  // describes, so `typeof globalThis` can only be narrowed to it by casting through `unknown`.
   const otelGlobal = globalThis as unknown as Record<symbol, { trace?: unknown } | undefined>;
   const registry = otelGlobal[OTEL_API_GLOBAL_KEY];
   if (registry && !registry.trace) {

Original file line number	Diff line number	Diff line change
`@@ -48,6 +48,8 @@ function registerGlobalTracerProvider(provider: TracerProvider): boolean {`
`48`	`48`	`return true;`
`49`	`49`	`}`
`50`	`50`
	`51`	+ // @opentelemetry/api stores the registry under a `Symbol.for` key that no public type
	`52`	+ // describes, so `typeof globalThis` can only be narrowed to it by casting through `unknown`.
`51`	`53`	`const otelGlobal = globalThis as unknown as Record<symbol, { trace?: unknown } \| undefined>;`
`52`	`54`	`const registry = otelGlobal[OTEL_API_GLOBAL_KEY];`
`53`	`55`	`if (registry && !registry.trace) {`