Provide fallbacks for assertions in production (#2141)

Closes #2109
#skip-changelog

Sources/Sentry/SentryClient.m

@@ -468,6 +468,10 @@ - (SentryEvent *_Nullable)prepareEvent:(SentryEvent *)event
                           isCrashEvent:(BOOL)isCrashEvent
 {
     NSParameterAssert(event);
+    if (event == nil) {
+        return nil;
+    }
+
     if ([self isDisabled]) {
         [self logDisabledMessage];
         return nil;

Sources/Sentry/SentrySerialization.m

@@ -163,6 +163,7 @@ + (SentryEnvelope *_Nullable)envelopeWithData:(NSData *)data
     SentryEnvelopeHeader *envelopeHeader = nil;
     const unsigned char *bytes = [data bytes];
     int envelopeHeaderIndex = 0;
+
     for (int i = 0; i < data.length; ++i) {
         if (bytes[i] == '\n') {
             envelopeHeaderIndex = i;
@@ -208,12 +209,19 @@ + (SentryEnvelope *_Nullable)envelopeWithData:(NSData *)data
             break;
         }
     }
+
     if (nil == envelopeHeader) {
         [SentryLog logWithMessage:[NSString stringWithFormat:@"Invalid envelope. No header found."]
                          andLevel:kSentryLevelError];
         return nil;
     }
+
     NSAssert(envelopeHeaderIndex > 0, @"EnvelopeHeader was parsed, its index is expected.");
+    if (envelopeHeaderIndex == 0) {
+        NSLog(@"EnvelopeHeader was parsed, its index is expected.");
+        return nil;
+    }
+
     // Parse items
     NSInteger itemHeaderStart = envelopeHeaderIndex + 1;
 

Sources/Sentry/SentrySwizzle.m

@@ -19,7 +19,11 @@ @implementation SentrySwizzleInfo
 
 - (SentrySwizzleOriginalIMP)getOriginalImplementation
 {
-    NSAssert(_impProviderBlock, nil);
+    NSAssert(_impProviderBlock, @"_impProviderBlock can't be missing");
+    if (!_impProviderBlock) {
+        NSLog(@"_impProviderBlock can't be missing");
+        return NULL;
+    }
 
 #if TEST
     @synchronized(self) {
@@ -136,9 +140,14 @@ + (BOOL)swizzleInstanceMethod:(SEL)selector
                          mode:(SentrySwizzleMode)mode
                           key:(const void *)key
 {
-    NSAssert(!(NULL == key && SentrySwizzleModeAlways != mode),
+    NSAssert(!(key == NULL && mode != SentrySwizzleModeAlways),
         @"Key may not be NULL if mode is not SentrySwizzleModeAlways.");
 
+    if (key == NULL && mode != SentrySwizzleModeAlways) {
+        NSLog(@"Key may not be NULL if mode is not SentrySwizzleModeAlways.");
+        return NO;
+    }
+
     @synchronized(swizzledClassesDictionary()) {
         if (key) {
             NSSet<Class> *swizzledClasses = swizzledClassesForKey(key);

Sources/SentryCrash/Recording/Tools/SentryCrashJSONCodecObjC.m

@@ -126,6 +126,10 @@ - (id)initWithEncodeOptions:(SentryCrashJSONEncodeOption)encodeOptions
         self.callbacks = malloc(sizeof(*self.callbacks));
         // Unlikely malloc failure.
         NSAssert(self.callbacks != NULL, @"Could not allocate callbacks");
+        if (self.callbacks == NULL) {
+            NSLog(@"Could not allocate callbacks");
+            return NULL;
+        }
 
         self.callbacks->onBeginArray = onBeginArray;
         self.callbacks->onBeginObject = onBeginObject;