Keep order of generic args (fixes #400)

specta-serde/src/validate.rs

@@ -1,4 +1,4 @@
-use std::collections::{BTreeMap, HashSet};
+use std::collections::HashSet;
 
 use specta::{
     datatype::{DataType, Enum, EnumRepr, Fields, Generic, Literal, Primitive},
@@ -13,28 +13,18 @@ use crate::Error;
 /// Validate the type and apply the Serde transformations.
 pub fn validate(types: &TypeCollection) -> Result<(), Error> {
     for ndt in types.into_unsorted_iter() {
-        inner(
-            ndt.ty(),
-            &types,
-            &Default::default(),
-            &mut Default::default(),
-        )?;
+        inner(ndt.ty(), &types, &[], &mut Default::default())?;
     }
 
     Ok(())
 }
 
 // TODO: Remove this once we redo the Typescript exporter.
 pub fn validate_dt(ty: &DataType, types: &TypeCollection) -> Result<(), Error> {
-    inner(ty, &types, &Default::default(), &mut Default::default())?;
+    inner(ty, &types, &[], &mut Default::default())?;
 
     for ndt in types.into_unsorted_iter() {
-        inner(
-            ndt.ty(),
-            &types,
-            &Default::default(),
-            &mut Default::default(),
-        )?;
+        inner(ndt.ty(), &types, &[], &mut Default::default())?;
     }
 
     Ok(())
@@ -43,7 +33,7 @@ pub fn validate_dt(ty: &DataType, types: &TypeCollection) -> Result<(), Error> {
 fn inner(
     dt: &DataType,
     types: &TypeCollection,
-    generics: &BTreeMap<Generic, DataType>,
+    generics: &[(Generic, DataType)],
     checked_references: &mut HashSet<SpectaID>,
 ) -> Result<(), Error> {
     match dt {
@@ -91,7 +81,7 @@ fn inner(
         }
         DataType::Reference(r) => {
             for (_, dt) in r.generics() {
-                inner(dt, types, &Default::default(), checked_references)?;
+                inner(dt, types, &[], checked_references)?;
             }
 
             #[allow(clippy::panic)]
@@ -113,7 +103,7 @@ fn inner(
 fn is_valid_map_key(
     key_ty: &DataType,
     types: &TypeCollection,
-    generics: &BTreeMap<Generic, DataType>,
+    generics: &[(Generic, DataType)],
 ) -> Result<(), Error> {
     match key_ty {
         DataType::Primitive(ty) => match ty {
@@ -177,13 +167,16 @@ fn is_valid_map_key(
         }
         DataType::Reference(r) => {
             let ty = types.get(r.sid()).expect("Type was never populated"); // TODO: Error properly
-
             is_valid_map_key(ty.ty(), types, r.generics())
         }
         DataType::Generic(g) => {
-            let ty = generics.get(g).expect("bruh");
+            let ty = generics
+                .iter()
+                .find(|(gen, _)| gen == g)
+                .map(|(_, dt)| dt)
+                .expect("bruh");
 
-            is_valid_map_key(&ty, types, &Default::default())
+            is_valid_map_key(ty, types, &[])
         }
         _ => Err(Error::InvalidMapKey),
     }

specta-typescript/src/inline.rs

@@ -1,25 +1,23 @@
 //! Helpers for generating [Type::reference] implementations.
 
-use std::collections::HashMap;
-
 use specta::TypeCollection;
 
 use specta::datatype::{DataType, Field, Fields, Generic, NamedDataType};
 
 #[doc(hidden)] // TODO: Make this private
 pub fn inline_and_flatten_ndt(ndt: &mut NamedDataType, types: &TypeCollection) {
-    inner(ndt.ty_mut(), types, false, false, &Default::default(), 0);
+    inner(ndt.ty_mut(), types, false, false, &[], 0);
 }
 
 pub(crate) fn inline(dt: &mut DataType, types: &TypeCollection) {
-    inner(dt, types, false, true, &Default::default(), 0)
+    inner(dt, types, false, true, &[], 0)
 }
 
 fn field(
     f: &mut Field,
     types: &TypeCollection,
     truely_force_inline: bool,
-    generics: &HashMap<Generic, DataType>,
+    generics: &[(Generic, DataType)],
     depth: usize,
 ) {
     // TODO: truely_force_inline
@@ -38,7 +36,7 @@ fn fields(
     f: &mut Fields,
     types: &TypeCollection,
     truely_force_inline: bool,
-    generics: &HashMap<Generic, DataType>,
+    generics: &[(Generic, DataType)],
     depth: usize,
 ) {
     match f {
@@ -61,7 +59,7 @@ fn inner(
     types: &TypeCollection,
     force_inline: bool,
     truely_force_inline: bool,
-    generics: &HashMap<Generic, DataType>,
+    generics: &[(Generic, DataType)],
     depth: usize,
 ) {
     // TODO: Can we be smart enough to determine loops, instead of just trying X times and bailing out????
@@ -125,15 +123,20 @@ fn inner(
             }
         }
         DataType::Generic(g) => {
-            let mut ty = generics.get(g).unwrap().clone(); // TODO: Properly handle this error
+            let mut ty = generics
+                .iter()
+                .find(|(gen, _)| gen == g)
+                .map(|(_, dt)| dt)
+                .unwrap()
+                .clone(); // TODO: Properly handle this error
 
             if truely_force_inline {
                 inner(
                     &mut ty,
                     types,
                     false,
                     truely_force_inline,
-                    &Default::default(), // TODO: What should this be?
+                    &[], // TODO: What should this be?
                     depth + 1,
                 );
                 *dt = ty;
@@ -150,13 +153,13 @@ fn inner(
                         false,
                         truely_force_inline,
                         &r.generics()
-                            .clone()
-                            .into_iter()
+                            .iter()
+                            .cloned()
                             .map(|(g, mut dt)| {
                                 resolve_generics(&mut dt, generics);
                                 (g, dt)
                             })
-                            .collect(),
+                            .collect::<Vec<_>>(),
                         depth + 1,
                     );
                     *dt = ty;
@@ -168,7 +171,7 @@ fn inner(
 }
 
 /// Following all `DataType::Reference`'s filling in any `DataType::Generic`'s with the correct value.
-fn resolve_generics(dt: &mut DataType, generics: &HashMap<Generic, DataType>) {
+fn resolve_generics(dt: &mut DataType, generics: &[(Generic, DataType)]) {
     // TODO: This could so only re-alloc if the type has a generics that needs replacing.
     match dt {
         DataType::List(l) => {
@@ -201,8 +204,9 @@ fn resolve_generics(dt: &mut DataType, generics: &HashMap<Generic, DataType>) {
             // This method is run when not inlining so for `export` we do expect `DataType::Generic`.
             // TODO: Functions main documentation should explain this.
             *dt = generics
-                .get(g)
-                .cloned()
+                .iter()
+                .find(|(gen, _)| gen == g)
+                .map(|(_, dt)| dt.clone())
                 .unwrap_or(DataType::Generic(g.clone()));
         }
         _ => {}

specta/src/datatype/reference.rs

@@ -1,7 +1,5 @@
 //! Helpers for generating [Type::reference] implementations.
 
-use std::collections::BTreeMap;
-
 use crate::SpectaID;
 
 use super::{DataType, Generic};
@@ -11,15 +9,15 @@ use super::{DataType, Generic};
 #[non_exhaustive]
 pub struct Reference {
     pub(crate) sid: SpectaID,
-    pub(crate) generics: BTreeMap<Generic, DataType>,
+    pub(crate) generics: Vec<(Generic, DataType)>,
     pub(crate) inline: bool,
 }
 
 impl Reference {
     /// TODO: Explain invariant.
     pub fn construct(
         sid: SpectaID,
-        generics: impl Into<BTreeMap<Generic, DataType>>,
+        generics: impl Into<Vec<(Generic, DataType)>>,
         inline: bool,
     ) -> Self {
         Self {
@@ -35,12 +33,12 @@ impl Reference {
     }
 
     /// Get the generic parameters set on this reference which will be filled in by the [NamedDataType].
-    pub fn generics(&self) -> &BTreeMap<Generic, DataType> {
+    pub fn generics(&self) -> &[(Generic, DataType)] {
         &self.generics
     }
 
     /// Get the generic parameters set on this reference which will be filled in by the [NamedDataType].
-    pub fn generics_mut(&mut self) -> &mut BTreeMap<Generic, DataType> {
+    pub fn generics_mut(&mut self) -> &mut Vec<(Generic, DataType)> {
         &mut self.generics
     }
 

tests/tests/ts_rs/generics.rs

@@ -219,3 +219,25 @@ fn inline() {
 
 //     assert_ts_export!(D::<&str, 41>, "export type D<T> = { t: Array<T>, }")
 // }
+
+// https://github.com/specta-rs/specta/issues/400
+#[test]
+fn generic_parameter_order_preserved() {
+    #[derive(Type)]
+    #[specta(export = false)]
+    struct Pair<Z, A> {
+        first: Z,
+        second: A,
+    }
+
+    #[derive(Type)]
+    #[specta(export = false)]
+    struct Container {
+        pair: Pair<i32, String>,
+    }
+
+    assert_ts_export!(
+        Container,
+        "export type Container = { pair: Pair<number, string> };"
+    );
+}