[Vadman97]

Summary

Fixes how the Android SDK handles sampling regex rules. It now matches the way the Go SDK does it and the way the Java plugin was fixed in #381, following Andrey's review comment there.

• Substring matching: CustomSampler called Regex.matches, which only matches the whole string. Every other SDK checks whether the pattern appears anywhere in the value. It now calls containsMatchIn, so health matches GET /health-check. ^ and $ still work when a rule needs a full match.
• Invalid patterns no longer throw: patterns were compiled lazily from inside the span/log processors. A bad pattern from the backend threw PatternSyntaxException out of EventSpanProcessor.onEnd / SamplingLogProcessor.onEmit. Nothing upstream catches it, including the OpenTelemetry SDK's SdkSpan.end / SdkLogRecordBuilder.emit, so it reached the app's span.end() or log call. Now each pattern's compile result is cached, failures included. A bad pattern logs one warning through the SDK's ObserveLogger and its rule never matches. Other rules in the same config still apply.
• ObservabilityService passes its logger to CustomSampler through a new optional logger parameter (defaults to null, so the constructor stays source-compatible).

Note: the cache is cleared on setConfig, so a bad pattern is warned about once each time a config is loaded, not on every span or log.

How did you test this change?

• Added Regex Matching Tests to CustomSamplerTest:
  • substring match for span names and log messages
  • ^, $ and ^...$ anchors are still respected
  • an invalid pattern doesn't throw and never matches
  • an invalid-regex rule is skipped while later rules in the same config still apply (spans and logs)
  • the warning is logged exactly once over repeated spans
  • no warning for a valid pattern
• Ran ./gradlew :lib:testDebugUnitTest locally in sdk/@launchdarkly/observability-android (JDK 21, Android SDK platform 35): 544 tests, 0 failures, 2 skipped (already skipped before this change).
• Checked the tests against the old behavior: with matches and no exception handling put back, 7 of the 9 new tests fail.
• No existing tests relied on full-match semantics, so none needed changing.

🤖 Generated with Claude Code

_{Opened from termag}

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Note

Overview
Aligns Android sampling regex behavior with other LaunchDarkly observability SDKs and hardens error handling when remote rules are malformed.

CustomSampler now uses containsMatchIn instead of Regex.matches, so patterns match when they appear anywhere in span names or log messages (e.g. health matches GET /health-check); ^ / $ still enforce full-string matches when needed. Invalid patterns are compiled through a cached CompiledRegex path: compile failures log one warning via optional ObserveLogger, never throw into span/log export, and that rule never matches while later rules in the same config still apply.

ObservabilityService passes its logger into CustomSampler. Unit tests add a Regex Matching suite for substring/anchor behavior, invalid-regex safety, and one-time warnings.

^{Reviewed by Cursor Bugbot for commit 71a5b05. Bugbot is set up for automated code reviews on this repo. Configure here.}

[abelonogov-ld]

Cool! It is even compiled!