fix(go): fix the build error of generated code for empty resource type (

#930)

* add test cases for issue929

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

* feat(go): generate exported interfaces when exported_resources are not empty

this commit changes the `wit_bindgen_go::interface::Finish()` function to generate the interface functions when either export_funcs are not empty or exported_resources are not empty.

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

* test(go): add one more test

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

* skip issue929 tests for rust

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

* skip issue929 tests for teavm-java

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

* skip issue929 tests for csharp

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

---------

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

crates/csharp/tests/codegen.rs

@@ -61,6 +61,10 @@ macro_rules! codegen_test {
                         "wasi-filesystem",
                         "wasi-http",
                         "wasi-io",
+                        "issue929",
+                        "issue929-no-import",
+                        "issue929-no-export",
+                        "issue929-only-methods",
                     ]
                     .contains(&$name)
                     {

crates/go/src/interface.rs

@@ -937,7 +937,7 @@ impl InterfaceGenerator<'_> {
     }
 
     pub(crate) fn finish(&mut self) {
-        if !self.export_funcs.is_empty() {
+        if !self.export_funcs.is_empty() || !self.exported_resources.is_empty() {
             let interface_var_name = &self.get_interface_var_name();
             let interface_name = &self.namespace();
 

crates/rust/tests/codegen.rs

@@ -5,6 +5,10 @@ mod codegen_tests {
     macro_rules! codegen_test {
         (wasi_cli $name:tt $test:tt) => {};
         (wasi_http $name:tt $test:tt) => {};
+        (issue929 $name:tt $test:tt) => {};
+        (issue929_no_import $name:tt $test:tt) => {};
+        (issue929_no_export $name:tt $test:tt) => {};
+        (issue929_only_methods $name:tt $test:tt) => {};
         ($id:ident $name:tt $test:tt) => {
             mod $id {
                 wit_bindgen::generate!({

crates/rust/tests/codegen_no_std.rs

@@ -16,6 +16,10 @@ mod codegen_tests {
     macro_rules! codegen_test {
         (wasi_cli $name:tt $test:tt) => {};
         (wasi_http $name:tt $test:tt) => {};
+        (issue929 $name:tt $test:tt) => {};
+        (issue929_no_import $name:tt $test:tt) => {};
+        (issue929_no_export $name:tt $test:tt) => {};
+        (issue929_only_methods $name:tt $test:tt) => {};
         ($id:ident $name:tt $test:tt) => {
             mod $id {
                 wit_bindgen::generate!({

crates/teavm-java/tests/codegen.rs

@@ -25,6 +25,10 @@ macro_rules! codegen_test {
     (wasi_filesystem $name:tt $test:tt) => {};
     (wasi_http $name:tt $test:tt) => {};
     (wasi_io $name:tt $test:tt) => {};
+    (issue929 $name:tt $test:tt) => {};
+    (issue929_no_import $name:tt $test:tt) => {};
+    (issue929_no_export $name:tt $test:tt) => {};
+    (issue929_only_methods $name:tt $test:tt) => {};
 
     ($id:ident $name:tt $test:tt) => {
         #[test]

tests/codegen/issue929-no-export.wit

@@ -0,0 +1,14 @@
+package foo:bar;
+
+interface f {
+    resource fd;
+}
+
+interface utils {
+    use f.{fd};
+    my-func: func() -> own<fd>;
+}
+
+world test {
+    export utils;
+}

tests/codegen/issue929-no-import.wit

@@ -0,0 +1,15 @@
+package foo:bar;
+
+interface f {
+    resource fd;
+}
+
+interface utils {
+    use f.{fd};
+    my-func: func() -> own<fd>;
+}
+
+world test {
+    export f;
+    export utils;
+}

tests/codegen/issue929-only-methods.wit

@@ -0,0 +1,19 @@
+package foo:bar;
+
+interface f {
+    resource fd {
+        get-a: func() -> s32;
+        set-a: func(a: s32);
+    }
+}
+
+interface utils {
+    use f.{fd};
+    my-func: func() -> own<fd>;
+}
+
+world test {
+    import f;
+    export f;
+    export utils;
+}

tests/codegen/issue929.wit

@@ -0,0 +1,16 @@
+package foo:bar;
+
+interface f {
+    resource fd;
+}
+
+interface utils {
+    use f.{fd};
+    my-func: func() -> own<fd>;
+}
+
+world test {
+    import f;
+    export f;
+    export utils;
+}