Avoid crashes on ES module resolution when module not found (#1546)

libdeno/binding.cc

@@ -558,7 +558,11 @@ v8::MaybeLocal<v8::Module> ResolveCallback(v8::Local<v8::Context> context,
 
  if (d->resolve_module_.IsEmpty()) {
  // Resolution Error.
- isolate->ThrowException(v8_str("module resolution error"));
+ std::stringstream err_ss;
+ err_ss << "NotFound: Cannot resolve module \"" << specifier_c
+ << "\" from \"" << referrer_filename << "\"";
+ auto resolve_error = v8_str(err_ss.str().c_str());
+ isolate->ThrowException(resolve_error);
  return v8::MaybeLocal<v8::Module>();
  } else {
  auto module = d->resolve_module_.Get(isolate);
@@ -612,6 +616,8 @@ bool ExecuteMod(v8::Local<v8::Context> context, const char* js_filename,
  auto module = maybe_module.ToLocalChecked();
  auto maybe_ok = module->InstantiateModule(context, ResolveCallback);
  if (maybe_ok.IsNothing()) {
+ DCHECK(try_catch.HasCaught());
+ HandleException(context, try_catch.Exception());
  return false;
  }
 

src/isolate.rs

@@ -403,8 +403,15 @@ extern "C" fn resolve_cb(
  debug!("module_resolve callback {} {}", specifier, referrer);
  let isolate = unsafe { Isolate::from_raw_ptr(user_data) };
 
- let out =
- code_fetch_and_maybe_compile(&isolate.state, specifier, referrer).unwrap();
+ let maybe_out =
+ code_fetch_and_maybe_compile(&isolate.state, specifier, referrer);
+
+ if maybe_out.is_err() {
+ // Resolution failure
+ return;
+ }
+
+ let out = maybe_out.unwrap();
 
  let filename = CString::new(out.filename.clone()).unwrap();
  let filename_ptr = filename.as_ptr() as *const i8;

tests/error_009_missing_js_module.js

@@ -0,0 +1 @@
+import "./bad-module.js";

tests/error_009_missing_js_module.js.out

@@ -0,0 +1 @@
+NotFound: Cannot resolve module "./bad-module.js" from "[WILDCARD]/tests/error_009_missing_js_module.js"

tests/error_009_missing_js_module.test

@@ -0,0 +1,4 @@
+args: tests/error_009_missing_js_module.js
+check_stderr: true
+exit_code: 1
+output: tests/error_009_missing_js_module.js.out