fix: remove dependency on derivative (#294)

* add derive-where

* gen Default for non unit enum

* remove derive_where and derivative

* use absolute path of std::default::Default

Author: flaneur2020

Cargo.lock

@@ -50,7 +50,6 @@ faststr = "0.2"
 [dev-dependencies]
 
 tokio = { version = "1", features = ["io-util"] }
-derivative = "2"
 tempfile = "3"
 diffy = "0.4"
 criterion = { version = "0.5", features = ["html_reports"] }

examples/Cargo.toml

@@ -50,7 +50,6 @@ faststr = "0.2"
 [dev-dependencies]
 pilota = { path = "../pilota" }
 tokio = { version = "1", features = ["io-util"] }
-derivative = "2"
 tempfile = "3"
 diffy = "0.4"
 criterion = { version = "0.5", features = ["html_reports"] }

pilota-build/Cargo.toml

@@ -391,18 +391,42 @@ impl Plugin for ImplDefaultPlugin {
                 cx.with_adjust_mut(def_id, |adj| adj.add_attrs(&["#[derive(Default)]".into()]))
             }
             Item::Enum(e) => {
-                if !e.variants.is_empty() {
-                    cx.with_adjust_mut(def_id, |adj| {
-                        adj.add_attrs(&[
-                            "#[derive(::pilota::derivative::Derivative)]".into(),
-                            "#[derivative(Default)]".into(),
-                        ]);
-                    });
-
-                    if let Some(v) = e.variants.first() {
-                        cx.with_adjust_mut(v.did, |adj| {
-                            adj.add_attrs(&["#[derivative(Default)]".into()]);
-                        })
+                if let Some(first_variant) = e.variants.first() {
+                    let is_unit_variant = first_variant.fields.is_empty();
+                    if is_unit_variant {
+                        cx.with_adjust_mut(def_id, |adj| {
+                            adj.add_attrs(&["#[derive(Default)]".into()]);
+                        });
+
+                        if let Some(v) = e.variants.first() {
+                            cx.with_adjust_mut(v.did, |adj| {
+                                adj.add_attrs(&["#[default]".into()]);
+                            })
+                        }
+                    } else {
+                        // for non unit variant, we need to impl Default for the enum
+                        let enum_name = cx.rust_name(def_id);
+                        let variant_name = cx.rust_name(first_variant.did);
+                        let fields = first_variant
+                            .fields
+                            .iter()
+                            .map(|_| "::std::default::Default::default()".to_string())
+                            .join(",\n");
+
+                        cx.with_adjust_mut(def_id, |adj| {
+                            adj.add_nested_item(
+                                format!(
+                                    r#"
+                                    impl ::std::default::Default for {enum_name} {{
+                                        fn default() -> Self {{
+                                            {enum_name}::{variant_name} ({fields})
+                                        }}
+                                    }}
+                                "#
+                                )
+                                .into(),
+                            )
+                        });
                     }
                 }
             }

pilota-build/src/plugin/mod.rs

@@ -195,9 +195,16 @@ pub mod serde {
                     + __protocol.struct_end_len()
             }
         }
-        #[derive(PartialOrd, Hash, Eq, Ord, Debug, ::pilota::derivative::Derivative)]
-        #[derivative(Default)]
-        #[derive(::pilota::serde::Serialize, ::pilota::serde::Deserialize)]
+        #[derive(
+            PartialOrd,
+            Hash,
+            Eq,
+            Ord,
+            Debug,
+            Default,
+            ::pilota::serde::Serialize,
+            ::pilota::serde::Deserialize,
+        )]
         #[serde(untagged)]
         #[serde(transparent)]
         #[derive(Clone, PartialEq, Copy)]

pilota-build/test_data/plugin/serde.rs

@@ -84,9 +84,7 @@ pub mod nested_message {
     }
 
     pub mod tt1 {
-        #[derive(PartialOrd, Hash, Eq, Ord, Debug, ::pilota::derivative::Derivative)]
-        #[derivative(Default)]
-        #[derive(Clone, PartialEq, Copy)]
+        #[derive(PartialOrd, Hash, Eq, Ord, Debug, Default, Clone, PartialEq, Copy)]
         #[repr(transparent)]
         pub struct Label(i32);
 

pilota-build/test_data/protobuf/nested_message.rs

@@ -97,11 +97,14 @@ pub mod oneof {
     }
 
     pub mod test {
-        #[derive(PartialOrd, Hash, Eq, Ord, Debug, ::pilota::derivative::Derivative)]
-        #[derivative(Default)]
-        #[derive(Clone, PartialEq)]
+
+        impl ::std::default::Default for Test {
+            fn default() -> Self {
+                Test::A(::std::default::Default::default())
+            }
+        }
+        #[derive(PartialOrd, Hash, Eq, Ord, Debug, Clone, PartialEq)]
         pub enum Test {
-            #[derivative(Default)]
             A(::pilota::FastStr),
 
             B(i32),
@@ -168,11 +171,13 @@ pub mod oneof {
                 ::core::result::Result::Ok(())
             }
         }
-        #[derive(PartialOrd, Hash, Eq, Ord, Debug, ::pilota::derivative::Derivative)]
-        #[derivative(Default)]
-        #[derive(Clone, PartialEq)]
+        impl ::std::default::Default for Type {
+            fn default() -> Self {
+                Type::S(::std::default::Default::default())
+            }
+        }
+        #[derive(PartialOrd, Hash, Eq, Ord, Debug, Clone, PartialEq)]
         pub enum Type {
-            #[derivative(Default)]
             S(::pilota::FastStr),
 
             I(i32),