Using `@sentry/nextjs` and `@sentry/cloudflare` together crashes every request with `context.getValue is not a function`

Start with packages/server-utils/src/async-context.ts and packages/opentelemetry/src/asyncContextStrategy.ts, comparing how each strategy discovers and reuses AsyncLocalStorage. Run both reproduction snippets and verify that mismatched stores no longer cause getCurrentScope or trace.getSpan to crash; the unsupported combined SDK behavior should remain explicit.

Description

A Next.js app on Cloudflare Workers that initializes @sentry/nextjs in instrumentation.ts and also wraps the Worker entry with @sentry/cloudflare's withSentry fails on every request:

TypeError: e.getValue is not a function
    at getScopesFromContext
    at getScopes
    ...
    at _onSpanEnded
    at end

Seen with @sentry/nextjs@11.0.0-rc.1 and @sentry/cloudflare@11.0.0-rc.1, which share the same @sentry/core.

Root cause

The two SDKs install different async context strategies, and the second one reuses the AsyncLocalStorage of the first even though the two strategies put different things into it:

Both pick up an existing store like this, without checking which strategy created it (added in #22889):

const existing = getAsyncContextStrategy(getMainCarrier()).getTracingChannelBinding?.()?.asyncLocalStorage;
const asyncLocalStorage = existing ?? new AsyncLocalStorage();

Once the stores are shared, api.context.active() returns the plain { scope, isolationScope } object, and getScopesFromContext(ctx) (or trace.getSpan(ctx)) calls ctx.getValue() on it. It fails in both install orders.

Reproduction

No framework needed:

import { getCurrentScope, withIsolationScope } from '@sentry/core';
import { setAsyncLocalStorageAsyncContextStrategy } from '@sentry/cloudflare';
import { setOpenTelemetryContextAsyncContextStrategy } from '@sentry/opentelemetry';

setAsyncLocalStorageAsyncContextStrategy();
withIsolationScope(() => {
  setOpenTelemetryContextAsyncContextStrategy();
  getCurrentScope(); // TypeError: context.getValue is not a function
});

The reverse order fails the same way:

import { context, trace } from '@opentelemetry/api';

setOpenTelemetryContextAsyncContextStrategy();
setAsyncLocalStorageAsyncContextStrategy();
withIsolationScope(() => {
  trace.getSpan(context.active()); // TypeError: context.getValue is not a function
});

Expected

A strategy only reuses an AsyncLocalStorage that holds the store shape it expects, for example by tagging the binding with its store type and creating a fresh ALS on a mismatch.

This only stops the crash. Two SDKs in one runtime still end up with one active strategy and one current client, so combining @sentry/nextjs and @sentry/cloudflare stays unsupported. It would still be better to fail soft than to break every request. The same clash can happen with any other pair of SDKs that use different strategies.