Fix intermittent crash in sanitizedStringFromString and a potential solution

Author: benski

Branch-SDK/BNCPreferenceHelper.h

@@ -83,6 +83,7 @@ NSURL* /* _Nonnull */ BNCURLForBranchDirectory(void);
 
 - (void)addInstrumentationDictionaryKey:(NSString *)key value:(NSString *)value;
 - (NSMutableDictionary *)instrumentationDictionary;
+- (NSDictionary *)instrumentationParameters; // a safe copy to use in a POST body
 - (void)clearInstrumentationDictionary;
 
 - (void)saveBranchAnalyticsData:(NSDictionary *)analyticsData;

Branch-SDK/BNCPreferenceHelper.m

@@ -492,6 +492,15 @@ - (void)setRequestMetadataKey:(NSString *)key value:(NSObject *)value {
     }
 }
 
+- (NSDictionary *)instrumentationParameters {
+    @synchronized (self) {
+        if (_instrumentationDictionary.count == 0) {
+            return nil; // this avoids the .count check in prepareParamDict
+        }
+        return [[NSDictionary alloc] initWithDictionary:_instrumentationDictionary];
+    }
+}
+
 - (NSMutableDictionary *)instrumentationDictionary {
     @synchronized (self) {
         if (!_instrumentationDictionary) {

Branch-SDK/BNCServerInterface.m

@@ -453,10 +453,12 @@ - (NSMutableDictionary *)prepareParamDict:(NSDictionary *)params
         fullParamDict[BRANCH_REQUEST_KEY_STATE] = metadata;
     }
     // we only send instrumentation info in the POST body request
-    if (self.preferenceHelper.instrumentationDictionary.count && [reqType isEqualToString:@"POST"]) {
-        fullParamDict[BRANCH_REQUEST_KEY_INSTRUMENTATION] = self.preferenceHelper.instrumentationDictionary;
+    if ([reqType isEqualToString:@"POST"]) {
+        NSDictionary *instrumentationDictionary = self.preferenceHelper.instrumentationParameters;
+        if (instrumentationDictionary) {
+            fullParamDict[BRANCH_REQUEST_KEY_INSTRUMENTATION] = instrumentationDictionary;
+        }
     }
-    
     return fullParamDict;
 }