perf(anr): make anr stack matching more specific

added early exits for method and file parsing by excluding
separator characters ('.' and ':')

skip string trim in favor of what should be a fairly quick and
performant match on exactly whitespace + 'at'

extra docs for the regex itself for future travelers

Author: kattrali

platform/jvm/capture/src/main/kotlin/io/bitdrift/capture/reports/processor/AppExitAnrTraceProcessor.kt

@@ -25,8 +25,16 @@ import java.io.InputStreamReader
  */
 internal object AppExitAnrTraceProcessor {
     private const val ANR_MAIN_THREAD_IDENTIFIED = "\"main\""
-    private const val ANR_STACKTRACE_PREFIX = "at "
-    private val ANR_STACK_TRACE_REGEX = Regex("^\\s+at\\s+(.*)\\.(.*)\\((.*):(\\d+)\\)$")
+
+    // matcher for lines like `    at some.pkg.ClassName.doSomething(ClassName.kt:732)`
+    // * class  - fully-qualified class
+    // * method - method within class
+    // * file   - class source file
+    // * line   - line number
+    private val ANR_STACK_TRACE_REGEX =
+        Regex(
+            "^\\s+at\\s+(?<class>.+)\\.(?<method>[^.]+)\\((?<file>[^:]+):(?<line>\\d+)\\)\$",
+        )
     private val mainStackTraceFrames = mutableListOf<Int>()
     private var isProcessingMainThreadTrace = false
 
@@ -69,8 +77,6 @@ internal object AppExitAnrTraceProcessor {
         )
     }
 
-    private fun isStackTraceLine(currentLine: String) = currentLine.trim().startsWith(ANR_STACKTRACE_PREFIX)
-
     private fun setIsMainThreadStackTrace(line: String) {
         if (line.startsWith(ANR_MAIN_THREAD_IDENTIFIED)) {
             isProcessingMainThreadTrace = true
@@ -85,7 +91,6 @@ internal object AppExitAnrTraceProcessor {
         currentLine: String,
     ) {
         setIsMainThreadStackTrace(currentLine)
-        if (!isStackTraceLine(currentLine)) return
 
         ANR_STACK_TRACE_REGEX.find(currentLine)?.destructured?.let { (className, symbolName, fileName, lineNumber) ->
             if (!isProcessingMainThreadTrace) {

platform/jvm/capture/src/test/kotlin/io/bitdrift/capture/FatalIssueReporterProcessorTest.kt

@@ -120,15 +120,15 @@ class FatalIssueReporterProcessorTest {
 
     @Test
     fun persistAppExitReport_whenUserPerceivedAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "Input Dispatching Timed Out",
             expectedMessage = "User Perceived ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenBroadcastReceiverAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit =
                 "Broadcast of Intent { act=android.intent.action.MAIN " +
                     "cmp=com.example.app/.MainActivity}",
@@ -138,7 +138,7 @@ class FatalIssueReporterProcessorTest {
 
     @Test
     fun persistAppExitReport_whenExecutingServiceAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit =
                 "Executing service. { act=android.intent.action.MAIN \" +\n" +
                     "                    \"cmp=com.example.app/.MainActivity}",
@@ -148,71 +148,71 @@ class FatalIssueReporterProcessorTest {
 
     @Test
     fun persistAppExitReport_whenStartServiceForegroundAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "Service.StartForeground() not called.{ act=android.intent.action.MAIN}",
             expectedMessage = "Service.startForeground() Not Called ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenContentProviderTimeoutAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "My Application. Content Provider Timeout",
             expectedMessage = "Content Provider ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenAppRegisteredTimeoutAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "My Application. App Registered Timeout",
             expectedMessage = "App Registered ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenShortFgsTimeoutAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "Foreground service ANR. Short FGS Timeout. Duration=5000ms",
             expectedMessage = "Short Foreground Service Timeout ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenSystemJobServiceTimeoutAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "SystemJobService. Job Service Timeout",
             expectedMessage = "Job Service ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenAppStartupTimeOut_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "App start timeout. Timeout=5000ms",
             expectedMessage = "App Start ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenServiceStartTimeout_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "Service start timeout. Timeout=5000ms",
             expectedMessage = "Service Start ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenBackgroundAnr_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit = "It's full moon ANR",
             expectedMessage = "Undetermined ANR",
         )
     }
 
     @Test
     fun persistAppExitReport_whenGenericAnrTimeout_shouldMatchAnrReason() {
-        assertAnrReason(
+        assertAnrContents(
             descriptionFromAppExit =
                 "bg anr: Process " +
                     "ProcessRecord{9707291 4609:io.bitdrift.gradletestapp/u0a207} " +
@@ -259,7 +259,7 @@ class FatalIssueReporterProcessorTest {
             .persistFatalIssue(any(), any(), any())
     }
 
-    private fun assertAnrReason(
+    private fun assertAnrContents(
         descriptionFromAppExit: String,
         expectedMessage: String,
     ) {
@@ -279,6 +279,12 @@ class FatalIssueReporterProcessorTest {
         assertThat(report.errors(0)).isNotNull
         report.errors(0)?.let { error ->
             assertThat(error.name).isEqualTo(expectedMessage)
+            val frame = error.stackTrace(0)
+            assertThat(frame).isNotNull
+            assertThat(frame!!.sourceFile!!.line).isEqualTo(106)
+            assertThat(frame.sourceFile!!.path).isEqualTo("FatalIssueGenerator.kt")
+            assertThat(frame.symbolName).isEqualTo("startProcessing")
+            assertThat(frame.className).isEqualTo("io.bitdrift.capture.FatalIssueGenerator")
         }
     }