Generate an enum for @oneOf input (#450)

* Add `is_one_of` to input

* Extract struct building from input codegen

* Generate enums for `oneOf` input

* Clippy fixes

* Empty commit for CI

---------

Co-authored-by: Surma <surma@surma.dev>

graphql_client/tests/input_object_variables.rs

@@ -39,7 +39,7 @@ fn input_object_variables_default() {
         msg: default_input_object_variables_query::Variables::default_msg(),
     };
 
-    let out = serde_json::to_value(&variables).unwrap();
+    let out = serde_json::to_value(variables).unwrap();
 
     let expected_default = serde_json::json!({
         "msg":{"content":null,"to":{"category":null,"email":"rosa.luxemburg@example.com","name":null}}
@@ -130,7 +130,7 @@ pub struct RustNameQuery;
 #[test]
 fn rust_name_correctly_mapped() {
     use rust_name_query::*;
-    let value = serde_json::to_value(&Variables {
+    let value = serde_json::to_value(Variables {
         extern_: Some("hello".to_owned()),
         msg: <_>::default(),
     })

graphql_client/tests/one_of_input.rs

@@ -0,0 +1,30 @@
+use graphql_client::*;
+use serde_json::*;
+
+#[derive(GraphQLQuery)]
+#[graphql(
+    schema_path = "tests/one_of_input/schema.graphql",
+    query_path = "tests/one_of_input/query.graphql",
+    variables_derives = "Clone"
+)]
+pub struct OneOfMutation;
+
+#[test]
+fn one_of_input() {
+    use one_of_mutation::*;
+
+    let author = Param::Author(Author { id: 1 });
+    let _ = Param::Name("Mark Twain".to_string());
+    let _ = Param::RecursiveDirect(Box::new(author.clone()));
+    let _ = Param::RecursiveIndirect(Box::new(Recursive {
+        param: Box::new(author.clone()),
+    }));
+    let _ = Param::RequiredInts(vec![1]);
+    let _ = Param::OptionalInts(vec![Some(1)]);
+
+    let query = OneOfMutation::build_query(Variables { param: author });
+    assert_eq!(
+        json!({ "param": { "author":{ "id": 1 } } }),
+        serde_json::to_value(&query.variables).expect("json"),
+    );
+}

graphql_client/tests/one_of_input/query.graphql

@@ -0,0 +1,3 @@
+mutation OneOfMutation($param: Param!) {
+  oneOfMutation(query: $param)
+}

graphql_client/tests/one_of_input/schema.graphql

@@ -0,0 +1,24 @@
+schema {
+  mutation: Mutation
+}
+
+type Mutation {
+  oneOfMutation(mutation: Param!): Int
+}
+
+input Param @oneOf {
+  author: Author
+  name: String
+  recursiveDirect: Param
+  recursiveIndirect: Recursive
+  requiredInts: [Int!]
+  optionalInts: [Int]
+}
+
+input Author {
+  id: Int!
+}
+
+input Recursive {
+  param: Param!
+}

graphql_client_cli/src/main.rs

@@ -153,7 +153,7 @@ fn set_env_logger() {
         .init();
 }
 
-fn colored_level<'a>(style: &'a mut Style, level: Level) -> StyledValue<'a, &'static str> {
+fn colored_level(style: &mut Style, level: Level) -> StyledValue<'_, &'static str> {
     match level {
         Level::Trace => style.set_color(Color::Magenta).value("TRACE"),
         Level::Debug => style.set_color(Color::Blue).value("DEBUG"),

graphql_client_codegen/src/codegen/inputs.rs

@@ -2,9 +2,10 @@ use super::shared::{field_rename_annotation, keyword_replace};
 use crate::{
     codegen_options::GraphQLClientCodegenOptions,
     query::{BoundQuery, UsedTypes},
-    schema::input_is_recursive_without_indirection,
+    schema::{input_is_recursive_without_indirection, StoredInputType},
+    type_qualifiers::GraphqlTypeQualifier,
 };
-use heck::ToSnakeCase;
+use heck::{ToSnakeCase, ToUpperCamelCase};
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::quote;
 
@@ -17,48 +18,112 @@ pub(super) fn generate_input_object_definitions(
     all_used_types
         .inputs(query.schema)
         .map(|(_input_id, input)| {
-            let normalized_name = options.normalization().input_name(input.name.as_str());
-            let safe_name = keyword_replace(normalized_name);
-            let struct_name = Ident::new(safe_name.as_ref(), Span::call_site());
-
-            let fields = input.fields.iter().map(|(field_name, field_type)| {
-                let safe_field_name = keyword_replace(field_name.to_snake_case());
-                let annotation = field_rename_annotation(field_name, safe_field_name.as_ref());
-                let name_ident = Ident::new(safe_field_name.as_ref(), Span::call_site());
-                let normalized_field_type_name = options
-                    .normalization()
-                    .field_type(field_type.id.name(query.schema));
-                let optional_skip_serializing_none =
-                    if *options.skip_serializing_none() && field_type.is_optional() {
-                        Some(quote!(#[serde(skip_serializing_if = "Option::is_none")]))
-                    } else {
-                        None
-                    };
-                let type_name = Ident::new(normalized_field_type_name.as_ref(), Span::call_site());
-                let field_type_tokens = super::decorate_type(&type_name, &field_type.qualifiers);
-                let field_type = if field_type
-                    .id
-                    .as_input_id()
-                    .map(|input_id| input_is_recursive_without_indirection(input_id, query.schema))
-                    .unwrap_or(false)
-                {
-                    quote!(Box<#field_type_tokens>)
-                } else {
-                    field_type_tokens
-                };
-
-                quote!(
-                    #optional_skip_serializing_none
-                    #annotation pub #name_ident: #field_type
-                )
-            });
-
-            quote! {
-                #variable_derives
-                pub struct #struct_name{
-                    #(#fields,)*
-                }
+            if input.is_one_of {
+                generate_enum(input, options, variable_derives, query)
+            } else {
+                generate_struct(input, options, variable_derives, query)
             }
         })
         .collect()
 }
+
+fn generate_struct(
+    input: &StoredInputType,
+    options: &GraphQLClientCodegenOptions,
+    variable_derives: &impl quote::ToTokens,
+    query: &BoundQuery<'_>,
+) -> TokenStream {
+    let normalized_name = options.normalization().input_name(input.name.as_str());
+    let safe_name = keyword_replace(normalized_name);
+    let struct_name = Ident::new(safe_name.as_ref(), Span::call_site());
+
+    let fields = input.fields.iter().map(|(field_name, field_type)| {
+        let safe_field_name = keyword_replace(field_name.to_snake_case());
+        let annotation = field_rename_annotation(field_name, safe_field_name.as_ref());
+        let name_ident = Ident::new(safe_field_name.as_ref(), Span::call_site());
+        let normalized_field_type_name = options
+            .normalization()
+            .field_type(field_type.id.name(query.schema));
+        let optional_skip_serializing_none =
+            if *options.skip_serializing_none() && field_type.is_optional() {
+                Some(quote!(#[serde(skip_serializing_if = "Option::is_none")]))
+            } else {
+                None
+            };
+        let type_name = Ident::new(normalized_field_type_name.as_ref(), Span::call_site());
+        let field_type_tokens = super::decorate_type(&type_name, &field_type.qualifiers);
+        let field_type = if field_type
+            .id
+            .as_input_id()
+            .map(|input_id| input_is_recursive_without_indirection(input_id, query.schema))
+            .unwrap_or(false)
+        {
+            quote!(Box<#field_type_tokens>)
+        } else {
+            field_type_tokens
+        };
+
+        quote!(
+            #optional_skip_serializing_none
+            #annotation pub #name_ident: #field_type
+        )
+    });
+
+    quote! {
+        #variable_derives
+        pub struct #struct_name{
+            #(#fields,)*
+        }
+    }
+}
+
+fn generate_enum(
+    input: &StoredInputType,
+    options: &GraphQLClientCodegenOptions,
+    variable_derives: &impl quote::ToTokens,
+    query: &BoundQuery<'_>,
+) -> TokenStream {
+    let normalized_name = options.normalization().input_name(input.name.as_str());
+    let safe_name = keyword_replace(normalized_name);
+    let enum_name = Ident::new(safe_name.as_ref(), Span::call_site());
+
+    let variants = input.fields.iter().map(|(field_name, field_type)| {
+        let variant_name = field_name.to_upper_camel_case();
+        let safe_variant_name = keyword_replace(&variant_name);
+
+        let annotation = field_rename_annotation(field_name.as_ref(), &variant_name);
+        let name_ident = Ident::new(safe_variant_name.as_ref(), Span::call_site());
+
+        let normalized_field_type_name = options
+            .normalization()
+            .field_type(field_type.id.name(query.schema));
+        let type_name = Ident::new(normalized_field_type_name.as_ref(), Span::call_site());
+
+        // Add the required qualifier so that the variant's field isn't wrapped in Option
+        let mut qualifiers = vec![GraphqlTypeQualifier::Required];
+        qualifiers.extend(field_type.qualifiers.iter().cloned());
+
+        let field_type_tokens = super::decorate_type(&type_name, &qualifiers);
+        let field_type = if field_type
+            .id
+            .as_input_id()
+            .map(|input_id| input_is_recursive_without_indirection(input_id, query.schema))
+            .unwrap_or(false)
+        {
+            quote!(Box<#field_type_tokens>)
+        } else {
+            field_type_tokens
+        };
+
+        quote!(
+            #annotation #name_ident(#field_type)
+        )
+    });
+
+    quote! {
+        #variable_derives
+        pub enum #enum_name{
+            #(#variants,)*
+        }
+    }
+}

graphql_client_codegen/src/deprecation.rs

@@ -8,22 +8,17 @@ pub enum DeprecationStatus {
 }
 
 /// The available deprecation strategies.
-#[derive(Debug, PartialEq, Eq, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone, Default)]
 pub enum DeprecationStrategy {
     /// Allow use of deprecated items in queries, and say nothing.
     Allow,
     /// Fail compilation if a deprecated item is used.
     Deny,
     /// Allow use of deprecated items in queries, but warn about them (default).
+    #[default]
     Warn,
 }
 
-impl Default for DeprecationStrategy {
-    fn default() -> Self {
-        DeprecationStrategy::Warn
-    }
-}
-
 impl std::str::FromStr for DeprecationStrategy {
     type Err = ();
 

graphql_client_codegen/src/schema.rs

@@ -210,6 +210,7 @@ impl StoredInputFieldType {
 pub(crate) struct StoredInputType {
     pub(crate) name: String,
     pub(crate) fields: Vec<(String, StoredInputFieldType)>,
+    pub(crate) is_one_of: bool,
 }
 
 /// Intermediate representation for a parsed GraphQL schema used during code generation.

graphql_client_codegen/src/schema/graphql_parser_conversion.rs

@@ -289,6 +289,11 @@ fn ingest_input<'doc, T>(schema: &mut Schema, input: &mut parser::InputObjectTyp
 where
     T: graphql_parser::query::Text<'doc>,
 {
+    let is_one_of = input
+        .directives
+        .iter()
+        .any(|directive| directive.name.as_ref() == "oneOf");
+
     let input = super::StoredInputType {
         name: input.name.as_ref().into(),
         fields: input
@@ -305,6 +310,7 @@ where
                 )
             })
             .collect(),
+        is_one_of,
     };
 
     schema.stored_inputs.push(input);

graphql_client_codegen/src/schema/json_conversion.rs

@@ -296,6 +296,9 @@ fn ingest_input(schema: &mut Schema, input: &mut FullType) {
     let input = super::StoredInputType {
         fields,
         name: input.name.take().expect("Input without a name"),
+        // The one-of input spec is not stable yet, thus the introspection query does not have
+        // `isOneOf`, so this is always false.
+        is_one_of: false,
     };
 
     schema.stored_inputs.push(input);