An 'outside the range of int' bug found in cJSON_CreateNumber about cjson HOT 2 OPEN

You are reading a string value using cJSON_GetNumberValue, which will return a NAN(link).

It's designed to be like this. I don't think this is an error.

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For easier reference, a boiled down POC:

const char* input = "{ \"Width\": \"100\" }";
cJSON* root = cJSON_Parse(input);

cJSON* widthObj = cJSON_GetObjectItem(root, "Width");
double width = cJSON_GetNumberValue(widthObj);  // Trying to read a string object as number value

printf("%f\n", width);                          // width == NAN

cJSON_AddNumberToObject(root, "Width2", width); // UBSAN reports error here

I agree, this looks like expected behaviour.

But the runtime error seems to be explicitly about the cast to int in cJSON_CreateNumber, which is necessary for the assignment to valueint.
From what I understand, casting NAN to integer should be undefined behaviour with C89.

Overall this would be another argument for future versions to drop valueint completely, as discussed for example in #63

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