graphql_query_derive: support deriving for input variables as well

This just hijacks the `reponse_derives` attribute right now since it
controls derives for generated data structures and `Variables` shares
much of that.

Fixes #103.

Author: mathstuf

CHANGELOG.md

@@ -42,6 +42,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Aliases in queries are now supported.
 
+- The traits in `response_derives` are now used for input types as well.
+
 ### Fixed
 
 - Handle all Rust keywords as field names in codegen by appending `_` to the generated names, so a field called `type` in a GraphQL query will become a `type_` field in the generated struct. Thanks to @scrogson!

graphql_query_derive/Cargo.toml

@@ -11,6 +11,7 @@ proc-macro = true
 
 [dependencies]
 failure = "0.1"
+itertools = "0.7"
 lazy_static = "1.0"
 quote = "^0.6"
 syn = "0.14"

graphql_query_derive/src/inputs.rs

@@ -30,9 +30,10 @@ impl GqlInput {
 
             quote!(#rename pub #name: #ty)
         });
+        let variables_derives = context.variables_derives();
 
         Ok(quote! {
-            #[derive(Debug, Serialize)]
+            #variables_derives
             pub struct #name {
                 #(#fields,)*
             }
@@ -134,7 +135,7 @@ mod tests {
         };
 
         let expected: String = vec![
-            "# [ derive ( Debug , Serialize ) ] ",
+            "# [ derive ( Serialize , Clone ) ] ",
             "pub struct Cat { ",
             "pub offsprings : Vec < Cat > , ",
             "# [ serde ( rename = \"pawsCount\" ) ] ",
@@ -146,6 +147,7 @@ mod tests {
 
         let mut context = QueryContext::new_empty();
         context.schema.inputs.insert(cat.name.clone(), cat);
+        context.ingest_additional_derives("Clone").unwrap();
 
         assert_eq!(
             format!(

graphql_query_derive/src/lib.rs

@@ -4,6 +4,7 @@
 extern crate failure;
 extern crate graphql_parser;
 extern crate heck;
+extern crate itertools;
 #[macro_use]
 extern crate lazy_static;
 extern crate proc_macro;

graphql_query_derive/src/operations.rs

@@ -42,8 +42,10 @@ impl Operation {
     pub(crate) fn expand_variables(&self, context: &QueryContext) -> TokenStream {
         let variables = &self.variables;
 
+        let variables_derives = context.variables_derives();
+
         if variables.is_empty() {
-            return quote!(#[derive(Serialize)]
+            return quote!(#variables_derives
             pub struct Variables;);
         }
 
@@ -62,7 +64,7 @@ impl Operation {
             .map(|variable| variable.generate_default_value_constructor(context));
 
         quote! {
-            #[derive(Serialize)]
+            #variables_derives
             pub struct Variables {
                 #(#fields,)*
             }

graphql_query_derive/src/query.rs

@@ -1,6 +1,7 @@
 use deprecation::DeprecationStrategy;
 use failure;
 use fragments::GqlFragment;
+use itertools::Itertools;
 use operations::Operation;
 use proc_macro2::Span;
 use proc_macro2::TokenStream;
@@ -15,6 +16,7 @@ pub(crate) struct QueryContext {
     pub schema: Schema,
     pub selected_operation: Option<Operation>,
     pub deprecation_strategy: DeprecationStrategy,
+    variables_derives: Vec<Ident>,
     response_derives: Vec<Ident>,
 }
 
@@ -26,6 +28,7 @@ impl QueryContext {
             schema,
             selected_operation: None,
             deprecation_strategy,
+            variables_derives: vec![Ident::new("Serialize", Span::call_site())],
             response_derives: vec![Ident::new("Deserialize", Span::call_site())],
         }
     }
@@ -38,6 +41,7 @@ impl QueryContext {
             schema: Schema::new(),
             selected_operation: None,
             deprecation_strategy: DeprecationStrategy::Allow,
+            variables_derives: vec![Ident::new("Serialize", Span::call_site())],
             response_derives: vec![Ident::new("Deserialize", Span::call_site())],
         }
     }
@@ -71,6 +75,12 @@ impl QueryContext {
             ));
         }
 
+        self.variables_derives.extend(
+            attribute_value
+                .split(',')
+                .map(|s| s.trim())
+                .map(|s| Ident::new(s, Span::call_site())),
+        );
         self.response_derives.extend(
             attribute_value
                 .split(',')
@@ -80,8 +90,16 @@ impl QueryContext {
         Ok(())
     }
 
+    pub(crate) fn variables_derives(&self) -> TokenStream {
+        let derives = self.variables_derives.iter().unique();
+
+        quote! {
+            #[derive( #(#derives),* )]
+        }
+    }
+
     pub(crate) fn response_derives(&self) -> TokenStream {
-        let derives = &self.response_derives;
+        let derives = self.response_derives.iter().unique();
 
         quote! {
             #[derive( #(#derives),* )]