Add reproduction for sentry-javascript#19367

.gitignore

@@ -7,6 +7,8 @@ node_modules/
 dist/
 out/
 build/
+.next/
+next-env.d.ts
 *.tsbuildinfo
 
 # Environment files

sentry-javascript/19367/README.md

@@ -0,0 +1,227 @@
+# Reproduction for sentry-javascript#19367
+
+**Issue:** https://github.com/getsentry/sentry-javascript/issues/19367
+
+## Description
+
+Next.js 16 Turbopack bundles `@opentelemetry/api` into **separate chunks** for the
+instrumentation hook (Sentry SDK init) and each route handler. This creates multiple
+module instances that share the global context manager via `Symbol.for("opentelemetry.js.api.1")`,
+but have separate `ContextAPI` singletons and module closures.
+
+In `@sentry/nextjs` 10.38.0, `_startSpan()` nests 3 `context.with()` calls:
+```
+context.with(suppressedCtx)           <- copy A's ContextAPI
+  -> tracer.startActiveSpan()
+    -> api.context.with(ctxWithSpan)   <- copy B's ContextAPI
+      -> context.with(activeCtx)       <- copy A's ContextAPI
+        -> callback
+```
+
+With duplicated module instances, the `SentryContextManager`'s scope cloning and
+re-entry through the async context strategy can spiral into infinite recursion,
+causing `RangeError: Maximum call stack size exceeded`.
+
+This did not happen with `@sentry/nextjs` 10.8.0 because `startSpan()` only had
+**1** `context.with()` call (inside `tracer.startActiveSpan()`), keeping the
+re-entry depth bounded.
+
+## Steps to Reproduce
+
+1. Install dependencies:
+   ```bash
+   npm install
+   ```
+
+2. Build with Turbopack (the default for Next.js 16):
+   ```bash
+   npm run build
+   ```
+
+3. **Verify the duplication in build output:**
+   ```bash
+   npm run check-otel-dedup
+   ```
+   This analyzes which chunks each route and the instrumentation hook load,
+   confirming they get **different** copies of `@opentelemetry/api`.
+
+4. Start the production server:
+   ```bash
+   npm start
+   ```
+
+5. Test the diagnostic endpoint:
+   ```bash
+   curl http://localhost:3000/api/otel-check | python3 -m json.tool
+   ```
+
+6. Test the realistic route with nested Sentry spans:
+   ```bash
+   curl http://localhost:3000/api/test | python3 -m json.tool
+   ```
+
+7. Load test to attempt triggering the crash (intermittent):
+   ```bash
+   for i in $(seq 1 500); do curl -s http://localhost:3000/api/test > /dev/null & done; wait
+   ```
+
+## What the check script shows
+
+`npm run check-otel-dedup` maps the exact chunk loading for each entry point:
+
+```
+=== @opentelemetry/api duplication analysis ===
+
+Instrumentation OTel chunks:
+  [root-of-the-server]__963c8309._.js (8KB) -- Symbol.for: true, ContextAPI: false
+  _0066dbbb._.js (4684KB) -- Symbol.for: false, ContextAPI: true
+
+/api/test OTel chunks:
+  [root-of-the-server]__3f199e61._.js (9KB) -- Symbol.for: true, ContextAPI: false
+  [root-of-the-server]__8f25289d._.js (161KB) -- Symbol.for: false, ContextAPI: true
+
+  *** DUPLICATION DETECTED for /api/test ***
+  Instrumentation-only OTel chunks: __963c8309, _0066dbbb
+  Route-only OTel chunks: __3f199e61, __8f25289d
+  -> Different module instances with separate ContextAPI singletons
+```
+
+## Routes
+
+| Route | Purpose |
+|---|---|
+| `/api/otel-check` | Diagnostic: tests `context.with()` (single + 3-deep nested), reports global OTel registry state |
+| `/api/test` | Realistic: nested `Sentry.startSpan()` calls simulating DB queries + external API calls |
+
+## Investigation Findings
+
+### Structural Evidence (Confirmed)
+
+After `npm run build`, the `check-otel-dedup` script confirms that the instrumentation
+hook and each route handler load **different chunks** containing `@opentelemetry/api`.
+Every route gets its own copy. The instrumentation hook and route handlers never share
+OTel chunks.
+
+**Two ContextAPI class definitions in the same chunk:** The route handler chunk contains
+two separate `ContextAPI` class definitions -- one Turbopack ESM-style (used by route
+handler code) and one CJS-style (bundled from `@prisma/instrumentation`'s nested
+`@opentelemetry/instrumentation` dependency). Both call `_getContextManager()` which
+reads from `globalThis[Symbol.for("opentelemetry.js.api.1")]`, so they share the same
+context manager but are separate JavaScript objects with separate closures, singletons,
+and prototype chains.
+
+**Version-independent:** The duplication occurs identically with both `@sentry/nextjs`
+10.8.0 and 10.38.0 (8 chunks with OTel `Symbol.for`, 2 with `ContextAPI` in both).
+
+**`prismaIntegration()` makes no difference:** Removing `Sentry.prismaIntegration()`
+produces identical chunk structure. The `@prisma/instrumentation` package is bundled
+because it is a direct dependency of `@sentry/node`, not because of the integration call.
+
+### Runtime Behavior (Crash Not Reproduced)
+
+| Test | Result |
+|---|---|
+| Single `context.with()` call | Passes |
+| 3-deep nested `context.with()` (mimicking `_startSpan`) | Passes |
+| Alternating Copy A / Copy B `context.with()` | Passes |
+| 1000 concurrent mixed A/B `context.with()` calls | Passes |
+| `Sentry.startSpan()` with nested spans + Copy B `context.with()` | Passes |
+| 500 concurrent HTTP requests to `/api/test` | Server survives |
+| `--stack-size=128` with concurrent load | Server survives |
+| Monkey-patching instrumentation's `ContextAPI.with()` | Never triggered by routes (confirming separate singletons) |
+
+**Why the crash doesn't reproduce locally:** The `SentryContextManager.with()` calls
+`super.with()` which ends at `asyncLocalStorage.run(ctx, fn)` -- it does **not** call
+back to any `ContextAPI.with()`. So there is no direct recursive loop between the two
+ContextAPI singletons.
+
+**Remaining hypotheses for the crash:**
+- Node.js v24 runtime differences (different ALS behavior or stack limits)
+- Actual Prisma DB queries creating deeper instrumentation chains
+- pnpm workspace resolution causing different module nesting
+- `next-intl` middleware adding wrapping to the Next.js config
+- Sustained production traffic ("minutes to hours" under load)
+- Duplicate copies of `require-in-the-middle`/`import-in-the-middle` both patching
+  the same modules, creating re-entrant wrapping chains
+
+### Turbopack's Behavior Is By Design
+
+Per-route self-contained bundles are intentional. A Turbopack contributor (lukesandberg)
+confirmed on [vercel/next.js#89192](https://github.com/vercel/next.js/issues/89192):
+
+> "Bundling the module into multiple different output chunks is expected. The different
+> routes may end up in different lambdas in production and so need to be self-contained."
+
+However, the runtime deduplication layer that is supposed to compensate is not working
+correctly for `@opentelemetry/api`. The Turbopack runtime uses a shared `moduleCache`
+but the build output shows separate module definitions with different module IDs across
+chunks.
+
+**Known gaps:**
+- [vercel/next.js#89192](https://github.com/vercel/next.js/issues/89192) -- Duplicate
+  class definitions across route chunks, breaking `instanceof` (same root cause)
+- [vercel/next.js#89252](https://github.com/vercel/next.js/issues/89252) -- Related
+  chunking issue where unused CSS is included across routes
+- Turbopack status page lists "Production Optimized JS Chunking" as still in progress
+- Webpack does not have this problem (SplitChunksPlugin deduplicates shared deps)
+
+### The `serverExternalPackages` Workaround
+
+Adding `@opentelemetry/api` to `serverExternalPackages` in `next.config.js` forces
+Node.js native `require()` resolution at runtime, bypassing Turbopack's bundling:
+
+```js
+const nextConfig = {
+  serverExternalPackages: ["@opentelemetry/api"],
+};
+```
+
+This guarantees a single module instance because Node.js `require()` caches modules.
+`@opentelemetry/api` is **not** on Next.js's built-in auto-externalized packages list,
+though `@sentry/profiling-node` and `import-in-the-middle` are. Adding it upstream
+would be a reasonable fix.
+
+### OTel's Singleton Design vs Bundler Reality
+
+`@opentelemetry/api` uses `Symbol.for("opentelemetry.js.api.1")` to store a global
+registry on `globalThis`. This design was intended for the npm/yarn flat `node_modules`
+world where multiple _versions_ might coexist. It was not designed for bundler-created
+duplicate instances of the _same version_ in the same process.
+
+**What the `Symbol.for` pattern protects:** global context manager registration,
+global tracer provider registration, version compatibility checks.
+
+**What it does NOT protect:** class identity (`instanceof` fails across copies),
+module closures (each copy has its own), singleton instances (`ContextAPI.getInstance()`
+returns a different object per copy), instrumentation registration (two copies may
+both try to hook into the same Node.js modules).
+
+## Conclusions
+
+**Confirmed:**
+1. Turbopack creates separate `@opentelemetry/api` module instances -- reproducible and deterministic
+2. This is a known Turbopack limitation -- runtime deduplication does not work correctly here
+3. Webpack does not have this problem
+4. The duplication is SDK-version-independent (10.8.0 and 10.38.0 identical)
+5. `prismaIntegration()` is irrelevant -- duplication comes from `@sentry/node`'s bundled `@prisma/instrumentation`
+
+**Not confirmed:**
+1. The actual infinite recursion mechanism -- could not trigger `RangeError` in any test
+2. Why 10.38.0 crashes but 10.8.0 doesn't -- structural duplication is identical
+3. The exact conditions -- likely requires Node.js v24, real Prisma queries, pnpm, or sustained production traffic
+
+**Recommended actions:**
+
+| Action | Owner | Priority |
+|---|---|---|
+| Add `@opentelemetry/api` to `serverExternalPackages` | Users (workaround) | Immediate |
+| Add `@opentelemetry/api` to Next.js built-in externals list | Next.js team | Short-term |
+| Fix Turbopack runtime module deduplication | Turbopack team | Medium-term |
+| Track [vercel/next.js#89192](https://github.com/vercel/next.js/issues/89192) | All | Ongoing |
+
+## Environment
+
+- `@sentry/nextjs`: 10.38.0
+- `next`: 16.1.6 (Turbopack)
+- `@prisma/instrumentation`: ^7.4.0
+- Node.js: v20+ (reporter uses v24)

sentry-javascript/19367/app/api/otel-check/route.ts

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+import { NextResponse } from "next/server";
+import { context, trace } from "@opentelemetry/api";
+
+/**
+ * Diagnostic route that proves @opentelemetry/api is duplicated at runtime.
+ *
+ * When Turbopack bundles this route, it gets its OWN copy of @opentelemetry/api
+ * (separate module instance from the one Sentry loaded in the instrumentation hook).
+ * Both copies share the same globalThis[Symbol.for("opentelemetry.js.api.1")]
+ * registry, but they are different JavaScript objects with different closures.
+ *
+ * This is the root cause of sentry-javascript#19367: the duplicated ContextAPI
+ * creates a re-entrant loop through the shared global context manager.
+ */
+export async function GET() {
+  const diagnostics: Record<string, unknown> = {};
+
+  // 1. Check the global OTel registry (shared across all copies via Symbol.for)
+  const globalKey = Symbol.for("opentelemetry.js.api.1");
+  const globalRegistry = (globalThis as any)[globalKey];
+  diagnostics.globalOtelRegistry = {
+    exists: !!globalRegistry,
+    version: globalRegistry?.version,
+    hasContextManager: !!globalRegistry?.context,
+    hasTracerProvider: !!globalRegistry?.trace,
+    hasDiag: !!globalRegistry?.diag,
+  };
+
+  // 2. Check the context manager registered by Sentry
+  const ctxManager = globalRegistry?.context;
+  if (ctxManager) {
+    diagnostics.contextManager = {
+      constructor: ctxManager.constructor.name,
+      hasWithMethod: typeof ctxManager.with === "function",
+    };
+  }
+
+  // 3. Test context.with() — the method that causes the infinite recursion
+  let contextWithResult: string;
+  try {
+    const result = context.with(context.active(), () => {
+      return "context.with() succeeded (single call)";
+    });
+    contextWithResult = result;
+  } catch (err: any) {
+    contextWithResult = `CRASH: ${err.message}`;
+  }
+  diagnostics.singleContextWith = contextWithResult;
+
+  // 4. Test nested context.with() — mimics what _startSpan() does in SDK 10.38.0
+  //
+  // In 10.38.0, _startSpan() wraps the call like:
+  //   context.with(suppressedCtx, () =>           // call 1
+  //     tracer.startActiveSpan(name, ctx, span =>  // call 2 (inside startActiveSpan)
+  //       context.with(activeCtx, () =>            // call 3
+  //         callback(span)
+  //       )
+  //     )
+  //   )
+  //
+  // With duplicated modules, each context.with() may go through a different
+  // ContextAPI singleton, and the Sentry context manager's scope cloning
+  // triggers re-entry through the async context strategy.
+  let nestedResult: string;
+  try {
+    context.with(context.active(), () => {
+      return context.with(context.active(), () => {
+        const tracer = trace.getTracer("repro-test");
+        return tracer.startActiveSpan("nested-test", (span) => {
+          span.end();
+          return "nested context.with() succeeded (3-deep, same as _startSpan in 10.38.0)";
+        });
+      });
+    });
+    nestedResult = "3-deep nested context.with() succeeded";
+  } catch (err: any) {
+    nestedResult = `CRASH: ${err.message}`;
+  }
+  diagnostics.nestedContextWith = nestedResult;
+
+  // 5. The build-time evidence
+  diagnostics.buildTimeEvidence =
+    "Run `npm run check-otel-dedup` on the build output to confirm that " +
+    "the instrumentation hook and route handlers load DIFFERENT chunks " +
+    "containing @opentelemetry/api. Turbopack creates separate module " +
+    "instances instead of deduplicating into a single shared chunk.";
+
+  return NextResponse.json(diagnostics, {
+    status: contextWithResult.startsWith("CRASH") ? 500 : 200,
+  });
+}

sentry-javascript/19367/app/api/test/route.ts

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+import { NextResponse } from "next/server";
+import * as Sentry from "@sentry/nextjs";
+
+/**
+ * Simulates a realistic API route that creates nested Sentry spans.
+ *
+ * In production, auto-instrumentation (HTTP, Prisma, etc.) creates spans
+ * around every request and DB query. Each Sentry.startSpan() call in 10.38.0
+ * internally calls context.with() THREE times (suppressed ctx → startActiveSpan
+ * → active ctx). With Turbopack's duplicate @opentelemetry/api modules, this
+ * 3-deep nesting × N nested spans can spiral into infinite recursion.
+ *
+ * The crash is intermittent because it depends on Node.js event loop timing
+ * and which module copy's ContextAPI handles each context.with() call.
+ */
+export async function GET() {
+  // Outer span — simulates the HTTP instrumentation auto-span
+  return Sentry.startSpan({ name: "GET /api/test" }, async () => {
+    // Inner span — simulates a DB query (e.g., Prisma)
+    const dbResult = await Sentry.startSpan(
+      { name: "prisma:query SELECT" },
+      async () => {
+        await new Promise((resolve) => setTimeout(resolve, 2));
+        return { users: 42 };
+      }
+    );
+
+    // Another inner span — simulates a second DB query
+    const cacheResult = await Sentry.startSpan(
+      { name: "redis:get session" },
+      async () => {
+        await new Promise((resolve) => setTimeout(resolve, 1));
+        return { cached: true };
+      }
+    );
+
+    // Deeply nested span — simulates calling an external API
+    const apiResult = await Sentry.startSpan(
+      { name: "http:POST /external-api" },
+      async () => {
+        // Nested span inside the external call
+        return Sentry.startSpan(
+          { name: "serialize:response" },
+          async () => {
+            await new Promise((resolve) => setTimeout(resolve, 1));
+            return { ok: true };
+          }
+        );
+      }
+    );
+
+    return NextResponse.json({
+      status: "ok",
+      dbResult,
+      cacheResult,
+      apiResult,
+      timestamp: Date.now(),
+    });
+  });
+}