Merge pull request #1237 from bugsnag/PLAT-6493/fix-thread-capture-npe

Prevent rare NPE when capturing thread traces

CHANGELOG.md

@@ -7,6 +7,9 @@
  * Fix bug that terminated the app when multiple ANRs occur
    [#1235](https://github.com/bugsnag/bugsnag-android/pull/1235)
 
+* Prevent rare NPE when capturing thread traces
+  [#1237](https://github.com/bugsnag/bugsnag-android/pull/1237)
+
 ## 5.9.1 (2021-04-22)
 
 ### Bug fixes

bugsnag-android-core/src/main/java/com/bugsnag/android/ThreadState.kt

@@ -60,10 +60,16 @@ internal class ThreadState @JvmOverloads constructor(
         val currentThreadId = currentThread.id
         return stackTraces.keys
             .sortedBy { it.id }
-            .map {
-                val stacktrace = Stacktrace.stacktraceFromJavaTrace(stackTraces[it]!!, projectPackages, logger)
-                val errorThread = it.id == currentThreadId
-                Thread(it.id, it.name, ThreadType.ANDROID, errorThread, stacktrace, logger)
+            .mapNotNull { thread ->
+                val trace = stackTraces[thread]
+
+                if (trace != null) {
+                    val stacktrace = Stacktrace.stacktraceFromJavaTrace(trace, projectPackages, logger)
+                    val errorThread = thread.id == currentThreadId
+                    Thread(thread.id, thread.name, ThreadType.ANDROID, errorThread, stacktrace, logger)
+                } else {
+                    null
+                }
             }.toMutableList()
     }
 

bugsnag-android-core/src/test/java/com/bugsnag/android/ThreadStateMissingTraceTest.kt

@@ -0,0 +1,34 @@
+package com.bugsnag.android
+
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import java.lang.RuntimeException
+import java.lang.Thread
+import java.util.Collections
+
+class ThreadStateMissingTraceTest {
+
+    @Test
+    fun handleNullThreadTraces() {
+        val currentThread = Thread.currentThread()
+        val traces = Thread.getAllStackTraces()
+
+        // make all stacktraces null
+        traces.keys.forEach {
+            traces[it] = null
+        }
+
+        val state = ThreadState(
+            RuntimeException(),
+            false,
+            ThreadSendPolicy.ALWAYS,
+            Collections.emptyList(),
+            NoopLogger,
+            currentThread,
+            traces
+        )
+        assertNotNull(state)
+        assertTrue(state.threads.isEmpty())
+    }
+}