Maximum call stack size exceeded when SignalsPlugin and DataDog RUM are both active

[bwhiting2356]

When using SignalsPlugin alongside DataDog RUM (@datadog/browser-rum), the app crashes with:

RangeError: Maximum call stack size exceeded

This is caused by infinite recursion between the two libraries’ fetch instrumentation.

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❗ Error

RangeError: Maximum call stack size exceeded
    at interceptedFetch (@segment/analytics-signals)
    at instrumentation (@datadog/browser-rum)
    at interceptedFetch (@segment/analytics-signals)
    at instrumentation (@datadog/browser-rum)
    ... (repeats infinitely)

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🔁 Steps to Reproduce

1. Install Segment packages:

    npm install @segment/analytics-next @segment/analytics-signals
   

2. Install DataDog RUM:

    npm install @datadog/browser-rum
   

3. Initialize both:

Segment with SignalsPlugin

    const analytics = new AnalyticsBrowser();

    await analytics.load({
      writeKey: 'xxx',
      plugins: [new SignalsPlugin()],
    });

DataDog RUM

    datadogRum.init({
      applicationId: 'xxx',
      clientToken: 'xxx',
      trackResources: true, // default
    });

4. App crashes immediately with a stack overflow.

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🔍 Root Cause

Both libraries wrap the global fetch API.
When a fetch call is made, each wrapper calls the other in an infinite loop.

The NetworkGenerator is registered unconditionally in the Signals constructor:

    void this.registerGenerator([...domGenerators, new NetworkGenerator()]);

The existing config options (networkSignalsAllowSameDomain, networkSignalsAllowList, etc.) only filter which signals are emitted — the fetch wrapper is still installed and causes the conflict.

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🛠️ Workaround

We’re using patch-package to remove NetworkGenerator from the registered generators:

    - void this.registerGenerator([...domGenerators, new NetworkGenerator()]);
    + void this.registerGenerator([...domGenerators]);

This disables network signals but keeps interaction and navigation signals working.

---

💡 Suggested Fix

Add a configuration option to disable network signal generation entirely:

    new SignalsPlugin({
      disableNetworkSignals: true,
    });

This would skip registering NetworkGenerator, avoiding conflicts with other tools that instrument fetch (DataDog, Sentry, New Relic, etc.).

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🧪 Environment

• @segment/analytics-signals: 2.4.4
• @segment/analytics-next: 1.76.0
• @datadog/browser-rum: 5.x