Only assign errors if parameter is non-NULL. (#4168)

* Only assign errors if parameter is non-NULL.

This fixes #4164.

* Remove unnecessary commenting.

* Remove other unnecessary comment.

Author: ryanwilson

Functions/CHANGELOG.md

@@ -1,3 +1,6 @@
+# Unreleased
+- [fixed] Fix internal analyzer issue with error assignment (#4164).
+
 # v2.4.0
 - [added] Introduce community support for tvOS and macOS (#2506).
 

Functions/FirebaseFunctions/FUNSerializer.m

@@ -153,7 +153,9 @@ - (nullable id)decodeWrappedType:(NSDictionary *)wrapped error:(NSError **)error
     NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
     NSNumber *n = [formatter numberFromString:value];
     if (n == nil) {
-      *error = FUNInvalidNumberError(value, wrapped);
+      if (error != NULL) {
+        *error = FUNInvalidNumberError(value, wrapped);
+      }
       return nil;
     }
     return n;
@@ -164,12 +166,16 @@ - (nullable id)decodeWrappedType:(NSDictionary *)wrapped error:(NSError **)error
     unsigned long long n = strtoull(str, &end, 10);
     if (errno == ERANGE) {
       // This number was actually too big for an unsigned long long.
-      *error = FUNInvalidNumberError(value, wrapped);
+      if (error != NULL) {
+        *error = FUNInvalidNumberError(value, wrapped);
+      }
       return nil;
     }
     if (*end) {
       // The whole string wasn't parsed.
-      *error = FUNInvalidNumberError(value, wrapped);
+      if (error != NULL) {
+        *error = FUNInvalidNumberError(value, wrapped);
+      }
       return nil;
     }
     return @(n);
@@ -202,7 +208,9 @@ - (nullable id)decode:(id)object error:(NSError **)error {
           decoded[key] = decodedItem;
         }];
     if (decodeError) {
-      *error = decodeError;
+      if (error != NULL) {
+        *error = decodeError;
+      }
       return nil;
     }
     return decoded;