Potential UB of illegal String in `source_url`

[shinmao]

Hi, I am wondering whether this code might create an illegal string, which contains any non-utf8 value.

rusty_v8/src/wasm.rs

Lines 158 to 164 in 6b12ea1

	pub fn source_url(&self) -> &str {
	let mut len = 0;
	unsafe {
	let ptr = v8__CompiledWasmModule__SourceUrl(self.0, &mut len);
	let bytes = std::slice::from_raw_parts(ptr as _, len);
	std::str::from_utf8_unchecked(bytes)
	}

Based on the pointer passed by v8__CompiledWasmModule__SourceUrl

rusty_v8/src/binding.cc

Lines 3737 to 3741 in 6b12ea1

	const char* v8__CompiledWasmModule__SourceUrl(v8::CompiledWasmModule* self,
	size_t* length) {
	const std::string& source_url = self->source_url();
	*length = source_url.size();
	return source_url.data();

As I know, string in C++ is not required to be utf8 only. Therefore, the function source_url might incorrectly assume that the string should also be legal in Rust.

refer to the documentation (https://v8.github.io/api/head/classv8_1_1CompiledWasmModule.html), there is also no guarantee of utf8 encoding in the definition.