fix: avoid duplicate anonymous error types

examples/async_more/src/org_example_more.rs

@@ -134,22 +134,25 @@ pub trait VarlinkCallError: varlink::CallTrait {
     }
 }
 impl VarlinkCallError for varlink::Call<'_> {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct r#State {
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub r#start: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub r#progress: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub r#end: Option<bool>,
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct TestMoreError_Args {
     pub r#reason: String,
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Reply {
     pub r#pong: String,
 }
 impl varlink::VarlinkReply for Ping_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Args {
     pub r#ping: String,
 }
@@ -159,23 +162,23 @@ pub trait Call_Ping: VarlinkCallError + Send {
         self.reply_struct(Ping_Reply { r#pong }.into())
     }
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct StopServing_Reply {}
 impl varlink::VarlinkReply for StopServing_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct StopServing_Args {}
 #[allow(dead_code)]
 pub trait Call_StopServing: VarlinkCallError + Send {
     fn reply(&mut self) -> varlink::Result<()> {
         self.reply_struct(varlink::Reply::parameters(None))
     }
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct TestMore_Reply {
     pub r#state: State,
 }
 impl varlink::VarlinkReply for TestMore_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct TestMore_Args {
     pub r#n: i64,
 }

examples/async_ping/src/org_example_ping.rs

@@ -132,16 +132,16 @@ pub trait VarlinkCallError: varlink::CallTrait {
     }
 }
 impl VarlinkCallError for varlink::Call<'_> {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct PingError_Args {
     pub r#parameter: i64,
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Reply {
     pub r#pong: String,
 }
 impl varlink::VarlinkReply for Ping_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Args {
     pub r#ping: String,
 }

examples/more/src/org_example_more.rs

@@ -133,22 +133,25 @@ pub trait VarlinkCallError: varlink::CallTrait {
     }
 }
 impl VarlinkCallError for varlink::Call<'_> {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct r#State {
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub r#start: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub r#progress: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub r#end: Option<bool>,
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct TestMoreError_Args {
     pub r#reason: String,
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Reply {
     pub r#pong: String,
 }
 impl varlink::VarlinkReply for Ping_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Args {
     pub r#ping: String,
 }
@@ -159,10 +162,10 @@ pub trait Call_Ping: VarlinkCallError {
     }
 }
 impl Call_Ping for varlink::Call<'_> {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct StopServing_Reply {}
 impl varlink::VarlinkReply for StopServing_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct StopServing_Args {}
 #[allow(dead_code)]
 pub trait Call_StopServing: VarlinkCallError {
@@ -171,12 +174,12 @@ pub trait Call_StopServing: VarlinkCallError {
     }
 }
 impl Call_StopServing for varlink::Call<'_> {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct TestMore_Reply {
     pub r#state: State,
 }
 impl varlink::VarlinkReply for TestMore_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct TestMore_Args {
     pub r#n: i64,
 }

examples/ping/src/org_example_ping.rs

@@ -131,16 +131,16 @@ pub trait VarlinkCallError: varlink::CallTrait {
     }
 }
 impl VarlinkCallError for varlink::Call<'_> {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct PingError_Args {
     pub r#parameter: i64,
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Reply {
     pub r#pong: String,
 }
 impl varlink::VarlinkReply for Ping_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Ping_Args {
     pub r#ping: String,
 }
@@ -151,10 +151,10 @@ pub trait Call_Ping: VarlinkCallError {
     }
 }
 impl Call_Ping for varlink::Call<'_> {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Upgrade_Reply {}
 impl varlink::VarlinkReply for Upgrade_Reply {}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
 pub struct Upgrade_Args {}
 #[allow(dead_code)]
 pub trait Call_Upgrade: VarlinkCallError {

varlink_generator/src/lib.rs

@@ -917,7 +917,12 @@ fn generate_error_code(
 ) {
     // Errors traits
     {
-        let mut error_structs_and_enums = TokenStream::new();
+        // Scratch sink for the anonymous helper types produced as a side effect
+        // of `to_rust_string` below. We only need the type *names* here (for the
+        // reply_* signatures); the definitions themselves are emitted by
+        // `VError::to_tokenstream` alongside each error's `_Args` struct. Emitting
+        // them here too would duplicate every anonymous error helper type.
+        let mut discard = TokenStream::new();
         let mut funcs = TokenStream::new();
         {
             let mut errors = Vec::new();
@@ -1093,7 +1098,7 @@ fn generate_error_code(
                             e.vtype
                                 .to_rust_string(
                                     format!("{}_Args_{}", t.name, e.name).as_ref(),
-                                    &mut error_structs_and_enums,
+                                    &mut discard,
                                     options,
                                 )
                                 .as_ref(),
@@ -1122,7 +1127,6 @@ fn generate_error_code(
             ));
         }
         ts.extend(quote!(
-            #error_structs_and_enums
             #[allow(dead_code)]
             pub trait VarlinkCallError: varlink::CallTrait {
                 #funcs

varlink_generator/tests/generator.rs

@@ -77,3 +77,22 @@ fn test_generate() {
     let _ = std::fs::remove_file(path);
     let _ = std::fs::remove_file(path2);
 }
+
+// Regression: an `error` whose parameters contain anonymous nested types must
+// emit each generated helper type exactly once. The error definitions are
+// visited by two passes (the error-code/reply_* generation and the per-error
+// `_Args` struct generation); a bug had both passes emit the anonymous helper
+// types, producing duplicate `struct`/`enum` definitions that fail to compile.
+#[test]
+fn error_anonymous_types_emitted_once() {
+    let src = "interface org.example.test\n\
+               error Foo (bar: (a: int, b: string), baz: (x: bool))\n";
+    let code = varlink_generator::compile(src.to_string())
+        .unwrap()
+        .to_string();
+
+    for def in ["struct r#Foo_Args_bar", "struct r#Foo_Args_baz"] {
+        let count = code.matches(def).count();
+        assert_eq!(count, 1, "`{def}` was emitted {count} times, expected once");
+    }
+}

varlink_generator/tests/org.example.complex.rs_out

@@ -129,23 +129,6 @@ impl From<&varlink::Reply> for ErrorKind {
         }
     }
 }
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
-pub struct r#ErrorFoo_Args_enum {
-    pub r#b: bool,
-    pub r#c: i64,
-    pub r#interface: Interface,
-}
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Default)]
-pub enum r#ErrorFoo_Args_bar {
-    #[default]
-    r#type,
-    r#enum,
-    r#int,
-    r#bool,
-    r#string,
-    r#if,
-    r#let,
-}
 #[allow(dead_code)]
 pub trait VarlinkCallError: varlink::CallTrait {
     fn reply_error_bar(&mut self) -> varlink::Result<()> {