Fix problem with C++ when returning a result containing a &T

rust-diplomat · Feb 7, 2025 · f733576 · f733576
1 parent f7010b3
commit f733576
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Showing 11 changed files with 78 additions and 6 deletions.
diff --git a/example/cpp/include/diplomat_runtime.hpp b/example/cpp/include/diplomat_runtime.hpp
diff --git a/feature_tests/c/include/ResultOpaque.h b/feature_tests/c/include/ResultOpaque.h
diff --git a/feature_tests/cpp/include/ResultOpaque.d.hpp b/feature_tests/cpp/include/ResultOpaque.d.hpp
diff --git a/feature_tests/cpp/include/ResultOpaque.hpp b/feature_tests/cpp/include/ResultOpaque.hpp
diff --git a/feature_tests/cpp/include/diplomat_runtime.hpp b/feature_tests/cpp/include/diplomat_runtime.hpp
diff --git a/feature_tests/dart/lib/src/ResultOpaque.g.dart b/feature_tests/dart/lib/src/ResultOpaque.g.dart
diff --git a/feature_tests/js/api/ResultOpaque.d.ts b/feature_tests/js/api/ResultOpaque.d.ts
diff --git a/feature_tests/js/api/ResultOpaque.mjs b/feature_tests/js/api/ResultOpaque.mjs
diff --git a/feature_tests/kotlin/somelib/src/main/kotlin/dev/diplomattest/somelib/ResultOpaque.kt b/feature_tests/kotlin/somelib/src/main/kotlin/dev/diplomattest/somelib/ResultOpaque.kt
diff --git a/feature_tests/src/result.rs b/feature_tests/src/result.rs
@@ -62,6 +62,12 @@ pub mod ffi {
             Err(Box::new(ResultOpaque(i)))
         }
 
+        /// When we take &str, the return type becomes a Result
+        /// Test that this interacts gracefully with returning a reference type
+        pub fn takes_str<'a>(&'a mut self, _v: &str) -> &'a mut Self {
+            self
+        }
+
         pub fn assert_integer(&self, i: i32) {
             assert_eq!(i, self.0);
         }

diff --git a/tool/templates/cpp/runtime.hpp.jinja b/tool/templates/cpp/runtime.hpp.jinja
@@ -52,7 +52,7 @@ inline capi::DiplomatWrite WriteFromString(std::string& string) {
 
 template<class T> struct Ok {
   T inner;
-  Ok(T&& i): inner(std::move(i)) {}
+  Ok(T&& i): inner(std::forward<T>(i)) {}
   // We don't want to expose an lvalue-capable constructor in general
   // however there is no problem doing this for trivially copyable types
   template<typename X = T, typename = typename std::enable_if<std::is_trivially_copyable<X>::value>::type>
@@ -66,7 +66,7 @@ template<class T> struct Ok {
 
 template<class T> struct Err {
   T inner;
-  Err(T&& i): inner(std::move(i)) {}
+  Err(T&& i): inner(std::forward<T>(i)) {}
   // We don't want to expose an lvalue-capable constructor in general
   // however there is no problem doing this for trivially copyable types
   template<typename X = T, typename = typename std::enable_if<std::is_trivially_copyable<X>::value>::type>