LibJS: Don't "copy construct" temporary value in ThrowCompletionOr ctor

It was possible for the generic ThrowCompletionOr constructor to "copy-construct" a JS Object when instantiating a ThrowCompletionOr via e.g `return *object;`. This happened because it chose the Object(Object& prototype) constructor which will be removed in a subsequent commit. It was not easy to debug. As a first step towards avoiding this in the future, the generic ThrowCompletionOr constructor now takes the value as a const reference.
Author: https://github.com/awesomekling Commit: https://github.com/SerenityOS/serenity/commit/42b5c896e8 Pull-request: https://github.com/SerenityOS/serenity/pull/16487 Reviewed-by: https://github.com/linusg ✅
2022-12-14 12:10:40 +01:00 · 2022-12-14 12:10:40 +01:00 · 42b5c896e8 · 2024-07-17 03:15:37 +09:00
commit 42b5c896e8
parent 3ea1584f2e
1 changed files with 2 additions and 2 deletions
--- a/Userland/Libraries/LibJS/Runtime/Completion.h
+++ b/Userland/Libraries/LibJS/Runtime/Completion.h
@ -268,9 +268,9 @@ public:
    // Most commonly: Value from Object* or similar, so we can omit the curly braces from "return { TRY(...) };".
    // Disabled for POD types to avoid weird conversion shenanigans.
    template<typename WrappedValueType>
-    ThrowCompletionOr(WrappedValueType value)
+    ThrowCompletionOr(WrappedValueType const& value)
    requires(!IsPOD<ValueType>)
-        : m_value(move(value))
+        : m_value(value)
    {
    }