From 27c05443c31bf4ae67ceb0056b17ba304804217a Mon Sep 17 00:00:00 2001
From: Kevin Amado <kamadorueda@gmail.com>
Date: Tue, 2 Apr 2024 15:50:22 -0600
Subject: [PATCH] dedup dependencies

---
 macros/src/deps.rs                            | 58 ++++++++++++++-----
 .../tests/enum_with_repeated_dependencies.rs  | 28 +++++++++
 2 files changed, 71 insertions(+), 15 deletions(-)
 create mode 100644 ts-rs/tests/enum_with_repeated_dependencies.rs

diff --git a/macros/src/deps.rs b/macros/src/deps.rs
index 67305394..34c8de96 100644
--- a/macros/src/deps.rs
+++ b/macros/src/deps.rs
@@ -1,54 +1,82 @@
+use std::collections::HashSet;
+
 use proc_macro2::TokenStream;
 use quote::{quote, ToTokens};
 use syn::{Path, Type};
 
 pub struct Dependencies {
-    dependencies: Vec<TokenStream>,
     crate_rename: Path,
+    dependencies: HashSet<Dependency>,
     pub types: Vec<Type>,
 }
 
+#[derive(Hash, Eq, PartialEq)]
+enum Dependency {
+    DependencyTypes { crate_rename: Path, ty: Type },
+    Generics { crate_rename: Path, ty: Type },
+    Type(Type),
+}
+
 impl Dependencies {
     pub fn new(crate_rename: Path) -> Self {
         Self {
-            dependencies: Vec::default(),
+            dependencies: HashSet::default(),
             crate_rename,
             types: Vec::default(),
         }
     }
+
     /// Adds all dependencies from the given type
     pub fn append_from(&mut self, ty: &Type) {
-        let crate_rename = &self.crate_rename;
-        self.dependencies
-            .push(quote![.extend(<#ty as #crate_rename::TS>::dependency_types())]);
+        self.dependencies.insert(Dependency::DependencyTypes {
+            crate_rename: self.crate_rename.clone(),
+            ty: ty.clone(),
+        });
+
         self.types.push(ty.clone());
     }
 
     /// Adds the given type.
     pub fn push(&mut self, ty: &Type) {
-        let crate_rename = &self.crate_rename;
-        self.dependencies.push(quote![.push::<#ty>()]);
-        self.dependencies.push(quote![
-            .extend(<#ty as #crate_rename::TS>::generics())
-        ]);
+        self.dependencies.insert(Dependency::Type(ty.clone()));
+        self.dependencies.insert(Dependency::Generics {
+            crate_rename: self.crate_rename.clone(),
+            ty: ty.clone(),
+        });
         self.types.push(ty.clone());
     }
 
     pub fn append(&mut self, mut other: Dependencies) {
-        if !other.dependencies.is_empty() {
-            self.dependencies.push(quote![.extend(#other)]);
+        self.dependencies.extend(other.dependencies);
+
+        if !other.types.is_empty() {
+            self.types.append(&mut other.types);
         }
-        self.types.append(&mut other.types);
     }
 }
 
 impl ToTokens for Dependencies {
     fn to_tokens(&self, tokens: &mut TokenStream) {
         let crate_rename = &self.crate_rename;
-        let lines = &self.dependencies;
+        let lines = self.dependencies.iter();
+
         tokens.extend(quote![{
             use #crate_rename::typelist::TypeList;
             ()#(#lines)*
-        }])
+        }]);
+    }
+}
+
+impl ToTokens for Dependency {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        tokens.extend(match self {
+            Dependency::DependencyTypes { crate_rename, ty } => {
+                quote![.extend(<#ty as #crate_rename::TS>::dependency_types())]
+            }
+            Dependency::Generics { crate_rename, ty } => {
+                quote![.extend(<#ty as #crate_rename::TS>::generics())]
+            }
+            Dependency::Type(ty) => quote![.push::<#ty>()],
+        });
     }
 }
diff --git a/ts-rs/tests/enum_with_repeated_dependencies.rs b/ts-rs/tests/enum_with_repeated_dependencies.rs
new file mode 100644
index 00000000..08d4b0cb
--- /dev/null
+++ b/ts-rs/tests/enum_with_repeated_dependencies.rs
@@ -0,0 +1,28 @@
+use ts_rs::{
+    typelist::{TypeList, TypeVisitor},
+    TS,
+};
+
+#[derive(Debug, ts_rs::TS)]
+#[ts(export)]
+pub enum EnumWith1Dependency {
+    V001(String),
+    V002(String),
+}
+
+struct DependencyCounter(usize);
+
+impl TypeVisitor for DependencyCounter {
+    fn visit<T: TS + 'static + ?Sized>(&mut self) {
+        self.0 += 1;
+    }
+}
+
+#[test]
+fn dedup_deps() {
+    let mut dependency_counter = DependencyCounter(0);
+
+    EnumWith1Dependency::dependency_types().for_each(&mut dependency_counter);
+
+    assert_eq!(dependency_counter.0, 1);
+}