Compile-time Error: control may reach end of non-void function with Xcode 10.2

TL;DR

Thanks @AidenMontgomery.

1. Open the source file at ${RN_PROJ}/node_modules/realm/src/jsc/jsc_value.hpp.
2. Find the switch-case segment at THERE.
3. Replace the whole switch-case segment with the following code.

    switch (JSValueGetType(ctx, value)) {
        case kJSTypeNull: return "null";
        case kJSTypeNumber: return "number";
        case kJSTypeObject: return "object";
        case kJSTypeString: return "string";
        case kJSTypeBoolean: return "boolean";
        case kJSTypeUndefined: return "undefined";
        case kJSTypeSymbol: return "symbol";
    }

Goals

When I were compiling the React Native Project with Xcode, the compiler prompts an error.

Expected Results

No error.

Actual Results

/Users/***/***/***/node_modules/realm/src/jsc/jsc_value.hpp:54:1: error: control may reach end of non-void function [-Werror,-Wreturn-type]

Version of Realm and Tooling

• Realm JS SDK Version: 2.25.0
• React Native: 0.58.6
• Node: 10.15.2
• Client OS & Version: iOS 12.2.0

Temp Solution

1. Open the source code: ${RN_PROJ}/node_modules/realm/src/jsc/jsc_value.hpp;
2. Add return "null"; between line 33 and 34.

I know this is not a good solution. So I am looking forward to the official solution.

[HengCC]

temp solution :

add default: return "null"; between line 52 and 53,

template<>
inline const char *jsc::Value::typeof(JSContextRef ctx, const JSValueRef &value) {
    switch (JSValueGetType(ctx, value)) {
        case kJSTypeNull: return "null";
        case kJSTypeNumber: return "number";
        case kJSTypeObject: return "object";
        case kJSTypeString: return "string";
        case kJSTypeBoolean: return "boolean";
        case kJSTypeUndefined: return "undefined";
        default: return "null";
    }
    
}

this working for me, waiting for the official solution

[AidenMontgomery]

From what I can tell, and I’m probably wrong, there is a new entry in the JSType Enum kJSTypeSymbol which is not being handled in the switch statement. Therefore the switch is not handling all of the possible values returned by JSValueGetType

I don’t know what the effect of doing this will be, but I think that the solution is as follows…

inline const char *jsc::Value::typeof(JSContextRef ctx, const JSValueRef &value) {
    switch (JSValueGetType(ctx, value)) {
        case kJSTypeNull: return "null";
        case kJSTypeNumber: return "number";
        case kJSTypeObject: return "object";
        case kJSTypeString: return "string";
        case kJSTypeBoolean: return "boolean";
        case kJSTypeUndefined: return "undefined";
        case kJSTypeSymbol: return "symbol";
    }
}

This does mean that when/if a new value is added to the Enum again we will see the same issue, unless there is a default added, I just don’t know what that should do.