[amortemousque]

Motivation

Automatic click actions do not have an application handling stack identifying their microfrontend. Implement the recommended API from the click action attribution RFC.

Changes

• Record static attach-element-stack API usage telemetry. Schema dependency: rum-events-format #456.

• Add DD_RUM.attachElementStack(element) to RUM and RUM Slim. Capture the caller's stack at the public API entry point and immediately register it in an instance-owned WeakMap, including before init(). Registrations survive startup without buffering or retaining detached elements strongly.

• Snapshot the closest registered target/ancestor stack at pointerdown, crossing shadow roots. Re-registration affects future actions; ongoing actions and rage-click groups retain their initial stack.

• Resolve service/version through existing source-code metadata and expose context.elementStack in beforeSend for manual attribution. Keep stacks out of serialized events and preserve shell fallback.

• Add unit and real build-plugin integration coverage, including registration before initialization, RUM Slim, shell fallback, and manual overrides. Implementation and tests were developed with AI assistance and independently reviewed.

Test instructions

• Full unit suite: 5,301 passed; focused feature suites: 226 passed.
• Chromium/Firefox microfrontend regression: 111 passed, 3 existing skips.
• All 18 new scenarios passed across Chromium, Firefox, and WebKit, covering RUM and RUM Slim.
• Typecheck, all TypeScript compatibility modes, changed-file ESLint/Prettier, and git diff --check passed.
• Independent whole-branch review: no actionable findings.

The new scenarios can be run after building the SDK and test apps:

yarn build
yarn build:apps --app microfrontend --app vanilla
yarn test:e2e microfrontend.scenario.ts -g 'with element stacks' --project chromium --project firefox --project webkit

WebKit's existing unload-triggered intake delivery failure was reproduced with the pre-existing custom-action scenario. Diagnostics confirmed correct automatic attribution and normal periodic delivery. The new WebKit cases await regular intake delivery before navigating; production transport behavior is unchanged.

Local E2E validation used built SDK bundles and a temporary configuration that omits unrelated framework servers and allows validated fixture paths under the hidden .codex worktree. That configuration is not part of this PR.

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 (API JSDoc and approved design)

[datadog-prod-us1-6]

✅ All CI checks and tests passed.

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 76.47%
• Overall Coverage: 77.32% (-0.00%)

_{This comment will be updated automatically if new data arrives.
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[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum Salesforce	N/A	188.48 KiB	N/A	N/A	N/A
Rum	188.07 KiB	188.46 KiB	+395 B	+0.21%	✅
Rum-salesforce Profiler	N/A	8.35 KiB	N/A	N/A	N/A
Rum Profiler	8.35 KiB	8.35 KiB	0 B	0.00%	✅
Rum-salesforce Recorder	N/A	32.04 KiB	N/A	N/A	N/A
Rum Recorder	32.04 KiB	32.04 KiB	0 B	0.00%	✅
Logs	59.31 KiB	59.31 KiB	0 B	0.00%	✅
Rum Slim	145.69 KiB	146.06 KiB	+376 B	+0.25%	✅
Worker	22.96 KiB	22.96 KiB	0 B	0.00%	✅
Rum Shopify	N/A	218.90 KiB	N/A	N/A	N/A
Rum-shopify Profiler	N/A	8.35 KiB	N/A	N/A	N/A
Rum-shopify Recorder	N/A	4.85 KiB	N/A	N/A	N/A

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-16T12:07:38.569642Z	c13ff7b	New commits
🔒 Security Review	✅ Completed 2026-10-16T12:08:21.425886Z	c13ff7b	New commits

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[chatgpt-codex-connector]

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Reviewed commit: 65086b87d4

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[chatgpt-codex-connector]

Record attachElementStack API usage

issue: Whenever a customer calls this new public API, the registration is performed without invoking addTelemetryUsage, so usage telemetry cannot report adoption of attachElementStack while the surrounding public methods report their calls. Add a dedicated static usage feature for this API so these calls are observable.

AGENTS.md reference: AGENTS.md:L120-L123

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[datadog-prod-us1-6]

More details

Element stacks are stored per SDK instance and snapshotted at pointerdown, preserving attribution for ongoing actions while keeping stacks out of serialized events. The completed static review found no reportable defects.

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