Parse notable addresses for Swift Assertion failure messages

Source/BugsnagCrashReport.h

@@ -187,4 +187,11 @@ initWithErrorName:(NSString *_Nonnull)name
  *  Device state such as oreground status and run duration
  */
 @property(nonatomic, readwrite, copy, nullable) NSDictionary *appState;
+
+
+/**
+ * Returns the enhanced error message for the thread, or nil if none exists.
+ */
+- (NSString *_Nullable)enhancedErrorMessageForThread:(NSDictionary *_Nullable)thread;
+
 @end

Source/BugsnagCrashReport.m

@@ -540,8 +540,15 @@ - (NSArray *)serializeThreadsWithException:(NSMutableDictionary *)exception {
     for (NSDictionary *thread in [self threads]) {
         NSArray *backtrace = thread[@"backtrace"][@"contents"];
         BOOL stackOverflow = [thread[@"stack"][@"overflow"] boolValue];
-
-        if ([thread[@"crashed"] boolValue]) {
+        BOOL isCrashedThread = [thread[@"crashed"] boolValue];
+
+        if (isCrashedThread) {
+            NSString *errMsg = [self enhancedErrorMessageForThread:thread];
+
+            if (errMsg) { // use enhanced error message (currently swift assertions)
+                BSGDictInsertIfNotNil(exception, errMsg, @"message");
+            }
+
             NSUInteger seen = 0;
             NSMutableArray *stacktrace = [NSMutableArray array];
 
@@ -587,4 +594,53 @@ - (NSArray *)serializeThreadsWithException:(NSMutableDictionary *)exception {
     return bugsnagThreads;
 }
 
+/**
+ * Returns the enhanced error message for the thread, or nil if none exists.
+ *
+ * This relies very heavily on heuristics rather than any documented APIs.
+ */
+- (NSString *)enhancedErrorMessageForThread:(NSDictionary *)thread {
+    NSDictionary *notableAddresses = thread[@"notable_addresses"];
+    NSMutableArray *msgBuffer = [NSMutableArray new];
+    BOOL hasReservedWord = NO;
+
+    if (notableAddresses) {
+        for (NSString *key in notableAddresses) {
+            if (![key hasPrefix:@"stack"]) { // skip stack frames, only use register values
+                NSDictionary *data = notableAddresses[key];
+                NSString *contentValue = data[@"value"];
+
+                hasReservedWord = hasReservedWord || [self isReservedWord:contentValue];
+
+                // must be a string that isn't a reserved word and isn't a filepath
+                if ([@"string" isEqualToString:data[@"type"]]
+                    && ![self isReservedWord:contentValue]
+                    && !([[contentValue componentsSeparatedByString:@"/"] count] > 2)) {
+
+                    [msgBuffer addObject:contentValue];
+                }
+            }
+        }
+        [msgBuffer sortUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
+    }
+
+    if (hasReservedWord && [msgBuffer count] > 0) { // needs to have a reserved word used + a message
+        return [msgBuffer componentsJoinedByString:@" | "];
+    } else {
+        return nil;
+    }
+}
+
+/**
+ * Determines whether a string is a "reserved word" that identifies it as a known value.
+ *
+ * For fatalError, preconditionFailure, and assertionFailure, "fatal error" will be in one of the registers.
+ *
+ * For assert, "assertion failed" will be in one of the registers.
+ */
+- (BOOL)isReservedWord:(NSString *)contentValue {
+    return [@"assertion failed" isEqualToString:contentValue]
+    || [@"fatal error" isEqualToString:contentValue];
+}
+
 @end

Source/BugsnagCrashSentry.m

@@ -23,8 +23,7 @@ - (void)install:(BugsnagConfiguration *)config
 
     BugsnagSink *sink = [[BugsnagSink alloc] initWithApiClient:apiClient];
     [BSG_KSCrash sharedInstance].sink = sink;
-    // We don't use this feature yet, so we turn it off
-    [BSG_KSCrash sharedInstance].introspectMemory = NO;
+    [BSG_KSCrash sharedInstance].introspectMemory = YES;
     [BSG_KSCrash sharedInstance].deleteBehaviorAfterSendAll =
         BSG_KSCDeleteOnSucess;
     [BSG_KSCrash sharedInstance].onCrash = onCrash;

Tests/BugsnagCrashReportTests.m

@@ -127,4 +127,73 @@ - (void)testNotifyReleaseStagesSkipsSendFromConfig {
     XCTAssertFalse([report shouldBeSent]);
 }
 
+- (void)testEnhancedErrorMessage {
+    BugsnagCrashReport *errorReport = [BugsnagCrashReport new];
+    NSMutableDictionary *thread = [NSMutableDictionary new];
+
+    // nil for empty threads
+    XCTAssertNil([errorReport enhancedErrorMessageForThread:thread]);
+    NSMutableDictionary *addresses = [NSMutableDictionary new];
+
+    // nil for empty notable addresses
+    thread[@"notable_addresses"] = addresses;
+    XCTAssertNil([errorReport enhancedErrorMessageForThread:thread]);
+
+    // nil for "fatal error" with no additional dict present
+
+    for (NSString *reservedWord in @[@"fatal error", @"assertion failed"]) {
+        addresses[@"r14"] = @{
+                              @"address": @4511089532,
+                              @"type": @"string",
+                              @"value": reservedWord
+                              };
+        XCTAssertNil([errorReport enhancedErrorMessageForThread:thread]);
+    }
+
+    // returns msg for "fatal error" with additional dict present
+    addresses[@"r12"] = @{
+                          @"address": @4511086448,
+                          @"type": @"string",
+                          @"value": @"Whoops - fatalerror"
+                          };
+    XCTAssertEqualObjects(@"Whoops - fatalerror", [errorReport enhancedErrorMessageForThread:thread]);
+
+
+    // ignores additional dict if more than 2 "/" present
+    addresses[@"r24"] = @{
+                          @"address": @4511084983,
+                          @"type": @"string",
+                          @"value": @"/usr/include/lib/something.swift"
+                          };
+    XCTAssertEqualObjects(@"Whoops - fatalerror", [errorReport enhancedErrorMessageForThread:thread]);
+
+    // ignores dict if not type string
+    addresses[@"r25"] = @{
+                          @"address": @4511084983,
+                          @"type": @"long",
+                          @"value": @"Swift is hard"
+                          };
+    XCTAssertEqualObjects(@"Whoops - fatalerror", [errorReport enhancedErrorMessageForThread:thread]);
+
+    // sorts and concatenates multiple multiple messages
+    addresses[@"r26"] = @{
+                          @"address": @4511082095,
+                          @"type": @"string",
+                          @"value": @"Swift is hard"
+                          };
+    XCTAssertEqualObjects(@"Swift is hard | Whoops - fatalerror", [errorReport enhancedErrorMessageForThread:thread]);
+
+    // ignores stack frames
+    addresses[@"stack523409"] = @{
+                          @"address": @4511080001,
+                          @"type": @"string",
+                          @"value": @"Not a register"
+                          };
+    XCTAssertEqualObjects(@"Swift is hard | Whoops - fatalerror", [errorReport enhancedErrorMessageForThread:thread]);
+
+    // ignores values if no reserved word used
+    addresses[@"r14"] = nil;
+    XCTAssertNil([errorReport enhancedErrorMessageForThread:thread]);
+}
+
 @end

examples/swift-ios/Podfile.lock

@@ -1,5 +1,5 @@
 PODS:
-  - Bugsnag (5.11.2)
+  - Bugsnag (5.12.1)
 
 DEPENDENCIES:
   - Bugsnag (from `../..`)
@@ -9,7 +9,7 @@ EXTERNAL SOURCES:
     :path: ../..
 
 SPEC CHECKSUMS:
-  Bugsnag: daab816e964545823e9f9b826486bd30c67f22da
+  Bugsnag: c8b1ccbb22acf100ce5b496bdc223be3184c7a57
 
 PODFILE CHECKSUM: 2107babfbfdb18f0288407b9d9ebd48cbee8661c