Fix issue 43: Add package name to RustBufferI if it needs it

bindgen/src/gen_go/mod.rs

@@ -475,6 +475,21 @@ pub mod filters {
         Ok(result)
     }
 
+    // Return the Go package name for the given type, if it has one, followed by a '.'
+    // Returns the empty string if the type has no package name associated with it e.g primitive types.
+    //
+    // for multi-package bindings, it may be required to specify which
+    // RustBufferI should be used when creating completeFunc. Failure to
+    // specify the right package here will result in compilation errors.
+    pub fn maybe_namespace(type_: &impl AsType) -> Result<String, askama::Error> {
+        let type_label = oracle().find(type_).type_label();
+        if let Some((package_name, _)) = type_label.split_once(".") {
+            Ok(format!("{}.", package_name))
+        } else {
+            Ok(String::from(""))
+        }
+    }
+
     /// FFI type name to be used to reference cgo types. Such that they exactly match to the cgo bindings and can be used with `//export`.
     pub fn ffi_type_name_cgo_safe<T: Clone + Into<FfiType>>(
         type_: &T,

bindgen/templates/macros.go

@@ -60,7 +60,7 @@
 {% macro return_type_decl_async(func) %}
 	{%- match func.return_type() -%}
 	{%- when Some with (return_type) -%}
-		{{ return_type|ffi_type_name }}
+		{{return_type|maybe_namespace}}{{ return_type|ffi_type_name }}
         {%- when None -%}
 	{%- endmatch %}
 {%- endmacro %}

binding_tests/issue43_test.go

@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package binding_tests
+
+import (
+	"testing"
+
+	"github.com/NordSecurity/uniffi-bindgen-go/binding_tests/generated/issue43"
+	"github.com/stretchr/testify/assert"
+)
+
+// Ensure you can call async functions which return types in a different package.
+// See https://github.com/NordSecurity/uniffi-bindgen-go/issues/43
+
+func TestIssue43(t *testing.T) {
+	record := issue43.GetAsyncExternalType()
+	assert.Equal(t, record.Id, "foo")
+	assert.Equal(t, record.Tag, "bar")
+}

fixtures/Cargo.toml

@@ -41,4 +41,5 @@ uniffi-go-fixture-destroy = { path = "destroy" }
 uniffi-go-fixture-errors = { path = "errors" }
 uniffi-go-fixture-name-case = { path = "name-case" }
 uniffi-go-fixture-objects = { path = "objects" }
+uniffi-go-fixture-issue43 = { path = "regressions/issue43" }
 uniffi-go-fixture-issue45 = { path = "regressions/issue45" }

fixtures/regressions/issue43/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "uniffi-go-fixture-issue43"
+version = "1.0.0"
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["lib", "cdylib"]
+name = "uniffi_go_issue43"
+
+[dependencies]
+uniffi = {path = "../../../3rd-party/uniffi-rs/uniffi"}
+uniffi_macros = {path = "../../../3rd-party/uniffi-rs/uniffi_macros"}
+uniffi-go-fixture-issue45 = {path = "../issue45"}
+
+[build-dependencies]
+uniffi_build = {path = "../../../3rd-party/uniffi-rs/uniffi_build", features=["builtin-bindgen"]}

fixtures/regressions/issue43/build.rs

@@ -0,0 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+fn main() {
+    uniffi_build::generate_scaffolding("./src/issue43.udl").unwrap();
+}

fixtures/regressions/issue43/src/issue43.udl

@@ -0,0 +1 @@
+namespace issue43 {};

fixtures/regressions/issue43/src/lib.rs

@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[uniffi::export]
+async fn get_async_external_type() -> uniffi_go_issue45::Record {
+    uniffi_go_issue45::Record {
+        id: "foo".to_string(),
+        tag: "bar".to_string(),
+    }
+}
+
+include!(concat!(env!("OUT_DIR"), "/issue43.uniffi.rs"));

fixtures/regressions/issue45/src/lib.rs

@@ -3,9 +3,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #[derive(uniffi::Record)]
-struct Record {
-    id: String,
-    tag: String,
+pub struct Record {
+    pub id: String,
+    pub tag: String,
 }
 
 // Ensure multiple futures packages work fine together, the other one being

fixtures/src/lib.rs

@@ -37,6 +37,7 @@ mod uniffi_fixtures {
     // Go specific
     uniffi_go_destroy::uniffi_reexport_scaffolding!();
     uniffi_go_errors::uniffi_reexport_scaffolding!();
+    uniffi_go_issue43::uniffi_reexport_scaffolding!();
     uniffi_go_issue45::uniffi_reexport_scaffolding!();
     uniffi_go_name_case::uniffi_reexport_scaffolding!();
     uniffi_go_objects::uniffi_reexport_scaffolding!();