[RUM-14471] Add predicate to filter Activities for TTID reporting by hamorillo · Pull Request #3173 · DataDog/dd-sdk-android

hamorillo · 2026-02-11T15:45:29Z

What does this PR do?

Adds AppStartupActivityPredicate to RumConfiguration allowing customers to filter out interstitial Activities (e.g., auth screens) from TTID (Time To Initial Display) reporting.

Example of use:

RumConfiguration.Builder(applicationId)
      .setAppStartupActivityPredicate { activity ->
          // Exclude splash activity from TTID measurement
          activity !is SplashActivity
      }
      .build()

Rum.enable(rumConfiguration)

Motivation

TTID was not being reported when interstitial Activities that launch another Activity in onCreate() and finish themselves never draw a frame. This allows customers to exclude such Activities from startup detection and get the right TTID.

Additional Notes

Introduces new public API: AppStartupActivityPredicate interface
Provides DefaultAppStartupActivityPredicate that includes all Activities (backward compatible)

Review checklist (to be filled by reviewers)

Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
Make sure you discussed the feature or bugfix with the maintaining team in an Issue
Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)

codecov-commenter · 2026-02-11T16:20:42Z

Codecov Report

❌ Patch coverage is 84.21053% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.26%. Comparing base (18b420c) to head (faf2b5e).

Files with missing lines	Patch %	Lines
...kotlin/com/datadog/android/rum/RumConfiguration.kt	0.00%	2 Missing ⚠️
.../rum/internal/startup/RumAppStartupDetectorImpl.kt	88.89%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3173      +/-   ##
===========================================
- Coverage    71.30%   71.26%   -0.04%     
===========================================
  Files          928      929       +1     
  Lines        34444    34457      +13     
  Branches      5812     5813       +1     
===========================================
- Hits         24558    24553       -5     
- Misses        8252     8263      +11     
- Partials      1634     1641       +7

Files with missing lines	Coverage Δ
...lin/com/datadog/android/rum/internal/RumFeature.kt	`89.28% <100.00%> (+0.31%)`	⬆️
...rnal/startup/DefaultAppStartupActivityPredicate.kt	`100.00% <100.00%> (ø)`
...roid/rum/internal/startup/RumAppStartupDetector.kt	`100.00% <100.00%> (ø)`
.../rum/internal/startup/RumAppStartupDetectorImpl.kt	`94.00% <88.89%> (+0.82%)`	⬆️
...kotlin/com/datadog/android/rum/RumConfiguration.kt	`92.31% <0.00%> (-2.07%)`	⬇️

... and 43 files with indirect coverage changes

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hamorillo · 2026-02-12T07:51:20Z

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...id-rum/src/main/kotlin/com/datadog/android/rum/internal/startup/RumAppStartupDetectorImpl.kt

...c/main/kotlin/com/datadog/android/rum/internal/startup/DefaultAppStartupActivityPredicate.kt

...id-rum/src/main/kotlin/com/datadog/android/rum/internal/startup/RumAppStartupDetectorImpl.kt

0xnm

It would be nice maybe to add some instrumented test here to make sure that:

logic added indeed does what it is intended to do in the real application
there is no regression

I understand that it will be hard to assert the output of such test, because I guess we want to validate TTID which may go left-right from run to run. But having something like this would be nice.

Not a blocker though, just an additional safety measure.

hamorillo · 2026-02-12T13:30:36Z

It would be nice maybe to add some instrumented test here

Nice suggestion @0xnm. Thanks! I've added a couple of integration tests.

0xnm

I briefly went through PRs and left some comments. For the logic details I let @aleksandr-gringauz do the judgement :)

0xnm · 2026-02-13T08:50:17Z

features/dd-sdk-android-rum/api/apiSurface

  override fun reset()
  override fun close()
+interface com.datadog.android.rum.startup.AppStartupActivityPredicate
+  fun shouldTrackStartup(android.app.Activity): Boolean


very nit: all other predicate interfaces in RUM module have similar method called accept. Doesn't matter much though since it is a functional interface, so it most probably will be used as lambda.

...st/kotlin/com/datadog/android/sdk/integration/rum/startup/AppStartupActivityPredicateTest.kt

aleksandr-gringauz

I left some comments. Overall - LGTM.

Before merging I suggest we spend some time investigating a "just-works" approach. We might discover something that could lead to changes in the proposed API of the predicate. Unlikely, but I think there is no need to rush.

Also I'd like to avoid telling customers to use the predicate to fix the case of "Activity launches another Activity in onCreate" if we manage to come up with a better solution.

aleksandr-gringauz · 2026-02-13T09:45:24Z

...k-android-rum/src/main/kotlin/com/datadog/android/rum/startup/AppStartupActivityPredicate.kt

+ * Use this to exclude "interstitial Activities" - Activities that are launched during
+ * app startup but immediately launch another Activity in their `onCreate()` method
+ * and call `finish()` on themselves (e.g., splash screens, authentication screens).
+ *
+ * These interstitial Activities may never draw a frame, which can prevent TTID from
+ * being reported when the actual main Activity is displayed.


and call finish() on themselves (e.g., splash screens, authentication screens).

If you implement a splash screen as activity, it probably draws a frame and doesn't call finish in Activity.onCreate.

I suggest we change this phrase a bit like this:

During application launch the SDK tracks the first Activity that is created and uses the time it draws its first frame to compute the TTID value. Use this if you want to skip some Activities and instead make the SDK consider the 2nd, 3rd Activity's first frame. Example use cases are:

Splash screens implemented as Activity.

Activities that launch another Activity in their onCreate() method and call finish() on themselves.

Also if we come up with a "just-works" solution we don't want to tell customers to use AppStartupActivityPredicate for the case of "Activities that launch another Activity in their onCreate() method and call finish() on themselves.".

I think all suggestions have been implemented. Let's pause this PR until I finish with the "just-works" approach.

...id-rum/src/main/kotlin/com/datadog/android/rum/internal/startup/RumAppStartupDetectorImpl.kt

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/RumConfiguration.kt

...integration/src/androidTest/kotlin/com/datadog/android/sdk/integration/rum/ExpectedEvents.kt

aleksandr-gringauz · 2026-02-13T14:28:45Z

...mented/integration/src/androidTest/kotlin/com/datadog/android/sdk/integration/rum/RumTest.kt

+    @After
+    fun tearDown() {
+        // Ensure SDK is stopped and wait for cleanup to complete
+        Datadog.stopInstance()
+        InstrumentationRegistry.getInstrumentation().waitForIdleSync()
+    }


FYI this change affects some other tests as well. Not that I'm against it though, seems fine. Just a heads-up.

...id-rum/src/main/kotlin/com/datadog/android/rum/internal/startup/RumAppStartupDetectorImpl.kt

Introduce AppStartupActivityPredicate to allow customers to exclude interstitial Activities (e.g., auth screens) that launch another Activity in onCreate() and finish themselves. This fixes TTID not being reported when such Activities never draw a frame.

Use WeakHashMap to cache shouldTrackStartup() result at activity creation and reuse it at destruction, ensuring symmetric counter increment/decrement. This prevents counter corruption when predicates depend on mutable state (e.g., activity flags, runtime toggles) that may change between lifecycle callbacks.

…leton

…interstitial activities from TTID measurement

@after

Problem: When running multiple startup tests together, Datadog.stopInstance() in afterActivityFinished() triggered async cleanup operations that didn't complete before the next test initialized. This caused RumSessionScopeStartupManager state (ttidSentForSession = true) to leak between tests, preventing TTID from being reported in subsequent tests. Solution: Added @after tearDown() method in RumTest base class that: 1. Calls Datadog.stopInstance() to trigger cleanup 2. Calls InstrumentationRegistry.getInstrumentation().waitForIdleSync() to ensure main thread becomes idle before proceeding The waitForIdleSync() approach is superior to sleep() because it waits for actual completion rather than an arbitrary timeout. This ensures: - All pending UI operations complete - Main thread work finishes - Async cleanup operations have time to complete - Proper test isolation The double-stop (once in @after, once in afterActivityFinished) is safe due to Datadog.stopInstance() being idempotent. Verified: Both AppStartupActivityPredicateTest and AppStartupMainActivityDirectTest pass reliably when run together.

Added viewArguments parameter to ExpectedVitalAppLaunchEvent to allow verifying view attributes in vital app launch events. Updated startup tests to verify that TTID and TTFD events originate from MainContentActivity by checking the view name attribute using type-safe class references.

…king behavior and use cases

…rImpl and add safe methods to "detetk_custom_safe_call.yml"

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hamorillo marked this pull request as ready for review February 12, 2026 07:50

hamorillo requested a review from a team as a code owner February 12, 2026 07:50

chatgpt-codex-connector bot reviewed Feb 12, 2026

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ambushwork previously approved these changes Feb 12, 2026

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hamorillo dismissed ambushwork’s stale review via 8fd800a February 12, 2026 13:28

hamorillo requested review from 0xnm, aleksandr-gringauz and ambushwork February 12, 2026 17:51

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hamorillo dismissed stale reviews from ambushwork and 0xnm via 8794580 February 13, 2026 12:58

hamorillo force-pushed the hector.morilloprieto/RUM-14471 branch from cbbc8d5 to 8794580 Compare February 13, 2026 12:58

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hamorillo force-pushed the hector.morilloprieto/RUM-14471 branch 4 times, most recently from a9af87b to 5538b89 Compare February 18, 2026 21:14

hamorillo added 2 commits February 24, 2026 14:37

[RUM-14471] Add unit tests for DefaultAppStartupActivityPredicate

145f4ea

hamorillo added 10 commits February 24, 2026 14:37

Refactor DefaultAppStartupActivityPredicate from class to object sing…

97ad11f

…leton

Add instrumented tests verifying AppStartupActivityPredicate filters …

7bd41b5

…interstitial activities from TTID measurement

Add @ExperimentalRumApi annotation to setAppStartupActivityPredicate

ee2e8d7

Update AppStartupActivityPredicate documentation to clarify TTID trac…

d4be97d

…king behavior and use cases

Refactor RumAppStartupDetectorImpl to use Set instead of manual counter

139712e

Suppress UnsafeThirdPartyFunctionCall warning in RumAppStartupDetecto…

78ac478

…rImpl and add safe methods to "detetk_custom_safe_call.yml"

Add OptIn to use the setAppStartupActivityPredicate on integration tests

faf2b5e

hamorillo force-pushed the hector.morilloprieto/RUM-14471 branch from 5538b89 to faf2b5e Compare February 24, 2026 14:16

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hamorillo commented Feb 11, 2026

What does this PR do?

Motivation

Additional Notes

Review checklist (to be filled by reviewers)

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