💥 always collect early requests by BenoitZugmeyer · Pull Request #4285 · DataDog/browser-sdk

BenoitZugmeyer · 2026-03-05T18:14:02Z

Motivation

Resources initiated early in the page lifecycle (before the SDK is fully initialized) were
previously missed unless trackEarlyRequests was explicitly enabled. This change makes that
behavior the default, ensuring all requests are captured regardless of when they start.

Changes

Remove the legacy matchRequestResourceEntry path (polling performance.getEntriesByName)
— the registry-based approach is now the only path
Remove trackEarlyRequests option (now always enabled, option is a breaking removal)
Remove ResponseBodyAction.WAIT — no longer needed since timing always comes from PerformanceResourceTiming
Unify RumFetchResourceEventDomainContext, RumXhrResourceEventDomainContext, and RumOtherResourceEventDomainContext
into a single RumResourceEventDomainContext

Test instructions

yarn dev-server start
yarn dev-server intake clear

Create sandbox/test-early-requests.html:

<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Test early requests</title>
    <script>fetch('/ok')</script>
    <script src="/datadog-rum.js"></script>
    <script>
      window.domainContexts = []
      DD_RUM.init({
        clientToken: 'xxx', applicationId: 'xxx', trackResources: true, proxy: '/proxy',
        beforeSend(event, context) {
          if (event.type === 'resource') window.domainContexts.push({ url: event.resource.url, context })
        },
      })
    </script>
  </head>
  <body>
    <button id="fetch-btn" onclick="fetch('/ok')">Make fetch</button>
    <button id="xhr-btn" onclick="var x=new XMLHttpRequest();x.open('GET','/ok');x.send()">Make XHR</button>
  </body>
</html>

agent-browser open http://localhost:8080/test-early-requests.html
agent-browser click '#fetch-btn'
agent-browser click '#xhr-btn'
agent-browser tab new

# 1. Verify pre-init fetch is collected (method: null = no request context = pre-init)
yarn dev-server intake rum-resources | jq '[.resource.url, .resource.type, .resource.method]'
# Expected: includes ["http://localhost:8080/ok","fetch",null] (pre-init), ["http://localhost:8080/ok","fetch","GET"], ["http://localhost:8080/ok","xhr","GET"]

# 2. Verify unified domain context shape
agent-browser tab 0
agent-browser eval 'window.domainContexts.map(({url,context})=>({url,keys:Object.keys(context).sort(),isManual:context.isManual,xhrIsXMLHttpRequest:context.xhr instanceof XMLHttpRequest,handlingStackType:typeof context.handlingStack}))'
# Expected: all resources share keys [error,handlingStack,isAborted,isManual,performanceEntry,requestInit,requestInput,response,xhr]
# XHR resource has xhrIsXMLHttpRequest:true, post-init fetch has handlingStackType:"string"

yarn dev-server stop
rm sandbox/test-early-requests.html

Checklist

Tested locally
Tested on staging
Added unit tests for this change.
Added e2e/integration tests for this change.
Updated documentation and/or relevant AGENTS.md file

datadog-datadog-prod-us1 · 2026-03-05T18:15:56Z

⚠️ Tests

✨ Fix all issues with BitsAI or with Cursor

⚠️ Warnings

🧪 2 Tests failed

rum resources › fetch abort support › track aborted fetch from rum/resources.scenario.ts (Datadog) (Fix with Cursor)

resources.scenario.ts:199:15 track aborted fetch

[Webkit] › rum/resources.scenario.ts:199:15 › rum resources › fetch abort support › track aborted fetch 

    Error: expect(received).toBeTruthy()

    Received: undefined

      217 |
      218 |         const resourceEvent = intakeRegistry.rumResourceEvents.find((event) => event.resource.type === 'fetch')
...

rum resources › XHR abort support › track aborted XHR from rum/resources.scenario.ts (Datadog) (Fix with Cursor)

resources.scenario.ts:96:15 track aborted XHR

[Webkit] › rum/resources.scenario.ts:96:15 › rum resources › XHR abort support › track aborted XHR 

    Error: expect(received).toBeTruthy()

    Received: undefined

      182 |     function expectXHR(intakeRegistry: IntakeRegistry) {
      183 |       const resourceEvent = intakeRegistry.rumResourceEvents.find((event) => event.resource.type === 'xhr')
...

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 85.71%
• Overall Coverage: 77.30% (+0.09%)

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: 5aa1db1 | Docs | Datadog PR Page | Was this helpful? React with 👍/👎 or give us feedback!}

cit-pr-commenter-54b7da · 2026-03-05T18:16:38Z

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	170.95 KiB	169.91 KiB	-1.04 KiB	-0.61%	✅
Rum Profiler	6.18 KiB	6.18 KiB	0 B	0.00%	✅
Rum Recorder	27.48 KiB	27.48 KiB	0 B	0.00%	✅
Logs	56.51 KiB	56.42 KiB	-89 B	-0.15%	✅
Rum Slim	128.19 KiB	127.16 KiB	-1.03 KiB	-0.80%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base CPU Time (ms)	Local CPU Time (ms)	𝚫%
RUM - add global context	0.0069	0.0041	-40.58%
RUM - add action	0.019	0.0144	-24.21%
RUM - add error	0.0167	0.014	-16.17%
RUM - add timing	0.0033	0.0026	-21.21%
RUM - start view	0.0154	0.0126	-18.18%
RUM - start/stop session replay recording	0.001	0.0007	-30.00%
Logs - log message	0.0223	0.0189	-15.25%

🧠 Memory Performance

Action Name	Base Memory Consumption	Local Memory Consumption	𝚫
RUM - add global context	27.55 KiB	32.38 KiB	+4.83 KiB
RUM - add action	51.99 KiB	57.33 KiB	+5.34 KiB
RUM - add timing	26.39 KiB	34.20 KiB	+7.81 KiB
RUM - add error	55.79 KiB	61.45 KiB	+5.66 KiB
RUM - start/stop session replay recording	25.34 KiB	33.90 KiB	+8.56 KiB
RUM - start view	462.57 KiB	468.61 KiB	+6.03 KiB
Logs - log message	44.62 KiB	48.70 KiB	+4.08 KiB

🔗 RealWorld

the old `matchRequestResourceEntry` approach (polling `performance.getEntriesByName` on request completion) is superseded by the registry-based path that was behind the `trackEarlyRequests` flag. remove the flag and always use the registry, which also drops the `pageStateHistory` dependency and the frozen-state duration workaround.

The WAIT action was introduced so that fetch request duration could be derived from waiting for the response body to be fully consumed. Now that resource timing always comes from PerformanceResourceTiming (early request collection is the only path), waiting for the body before reporting a resource is no longer necessary. This also simplifies readBytesFromStream, which is now always called to collect bytes (never just to wait).

Early request collection is now always enabled, making this option a no-op. Remove it from the public API, internal configuration, and telemetry.

now that fetch and xhr resources always have a performance entry and may or may not have request information, separate context types per request type make less sense. replace RumFetchResourceEventDomainContext, RumXhrResourceEventDomainContext and RumOtherResourceEventDomainContext with a single RumResourceEventDomainContext.

chatgpt-codex-connector

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chatgpt-codex-connector · 2026-03-17T17:00:51Z

packages/rum-core/src/domain/resource/resourceCollection.ts

  const performanceResourceSubscription = createPerformanceObservable(configuration, {
    type: RumPerformanceEntryType.RESOURCE,
    buffered: true,
  }).subscribe((entries) => {


Restore request fallback when resource timings are unavailable

This change makes resource collection depend exclusively on PerformanceObserver entries, so when a fetch/xhr timing is missing or filtered out (for example the negative-duration entries explicitly dropped in packages/rum-core/src/browser/performanceObservable.ts:306-310), no resource event is emitted even though REQUEST_COMPLETED was observed. Prior to this commit, the request-based path still produced a resource in that scenario, so this regresses resource/tracing/GraphQL data completeness in affected browsers and edge cases.

Useful? React with 👍 / 👎.

- mention reviewing all PR commits, not just the latest diff - document `agent-browser tab 0` + `agent-browser eval` for inspecting window state

BenoitZugmeyer added 4 commits March 17, 2026 17:50

🔥 remove the trackEarlyRequests option

1282068

Early request collection is now always enabled, making this option a no-op. Remove it from the public API, internal configuration, and telemetry.

BenoitZugmeyer force-pushed the benoit/enable-early-request-collection branch from 8c3d1f0 to c99a9b7 Compare March 17, 2026 16:53

BenoitZugmeyer marked this pull request as ready for review March 17, 2026 16:54

BenoitZugmeyer requested a review from a team as a code owner March 17, 2026 16:54

chatgpt-codex-connector bot reviewed Mar 17, 2026

View reviewed changes

🔧 improve manual-testing skill instructions

5aa1db1

- mention reviewing all PR commits, not just the latest diff - document `agent-browser tab 0` + `agent-browser eval` for inspecting window state

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💥 always collect early requests#4285

💥 always collect early requests#4285
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