Allow disabling case convertion

integration_tests/juniper_tests/src/codegen/derive_enum.rs

@@ -16,6 +16,13 @@ enum SomeEnum {
     Full,
 }
 
+#[derive(juniper::GraphQLEnum, Debug, PartialEq)]
+#[graphql(rename = "none")]
+enum NoRenameEnum {
+    OneVariant,
+    AnotherVariant,
+}
+
 /// Enum doc.
 #[derive(juniper::GraphQLEnum)]
 enum DocEnum {
@@ -64,6 +71,12 @@ fn test_derived_enum() {
     assert_eq!(meta.name(), Some("Some"));
     assert_eq!(meta.description(), Some(&"enum descr".to_string()));
 
+    // Test no rename variant.
+    assert_eq!(
+        <_ as ToInputValue>::to_input_value(&NoRenameEnum::AnotherVariant),
+        InputValue::scalar("AnotherVariant")
+    );
+
     // Test Regular variant.
     assert_eq!(
         <_ as ToInputValue>::to_input_value(&SomeEnum::Regular),

integration_tests/juniper_tests/src/codegen/derive_input_object.rs

@@ -20,6 +20,12 @@ struct Input {
     other: Option<bool>,
 }
 
+#[derive(GraphQLInputObject, Debug, PartialEq)]
+#[graphql(rename = "none")]
+struct NoRenameInput {
+    regular_field: String,
+}
+
 /// Object comment.
 #[derive(GraphQLInputObject, Debug, PartialEq)]
 struct DocComment {
@@ -147,6 +153,21 @@ fn test_derived_input_object() {
             other: Some(true),
         }
     );
+
+    // Test disable renaming
+
+    let input: InputValue = ::serde_json::from_value(serde_json::json!({
+        "regular_field": "hello",
+    }))
+    .unwrap();
+
+    let output: NoRenameInput = FromInputValue::from_input_value(&input).unwrap();
+    assert_eq!(
+        output,
+        NoRenameInput {
+            regular_field: "hello".into(),
+        }
+    );
 }
 
 #[test]

integration_tests/juniper_tests/src/codegen/derive_object.rs

@@ -32,6 +32,7 @@ struct Nested {
 }
 
 struct Query;
+struct NoRenameQuery;
 
 /// Object comment.
 #[derive(GraphQLObject, Debug, PartialEq)]
@@ -72,6 +73,12 @@ struct SkippedFieldObj {
     skipped: i32,
 }
 
+#[derive(GraphQLObject, Debug, PartialEq)]
+#[graphql(rename = "none")]
+struct NoRenameObj {
+    one_field: bool,
+    another_field: i32,
+}
 struct Context;
 impl juniper::Context for Context {}
 
@@ -123,6 +130,30 @@ impl Query {
             skipped: 42,
         }
     }
+
+    fn no_rename_obj() -> NoRenameObj {
+        NoRenameObj {
+            one_field: true,
+            another_field: 146,
+        }
+    }
+}
+
+#[juniper::graphql_object(rename = "none")]
+impl NoRenameQuery {
+    fn obj() -> Obj {
+        Obj {
+            regular_field: false,
+            c: 22,
+        }
+    }
+
+    fn no_rename_obj() -> NoRenameObj {
+        NoRenameObj {
+            one_field: true,
+            another_field: 146,
+        }
+    }
 }
 
 #[tokio::test]
@@ -173,6 +204,98 @@ async fn test_doc_comment_override() {
     .await;
 }
 
+#[tokio::test]
+async fn test_no_rename_root() {
+    let doc = r#"
+        {
+            no_rename_obj {
+                one_field
+                another_field
+            }
+
+            obj {
+                regularField
+            }
+        }"#;
+
+    let schema = RootNode::new(
+        NoRenameQuery,
+        EmptyMutation::<()>::new(),
+        EmptySubscription::<()>::new(),
+    );
+
+    assert_eq!(
+        execute(doc, None, &schema, &Variables::new(), &()).await,
+        Ok((
+            Value::object(
+                vec![
+                    (
+                        "no_rename_obj",
+                        Value::object(
+                            vec![
+                                ("one_field", Value::scalar(true)),
+                                ("another_field", Value::scalar(146)),
+                            ]
+                            .into_iter()
+                            .collect(),
+                        ),
+                    ),
+                    (
+                        "obj",
+                        Value::object(
+                            vec![("regularField", Value::scalar(false)),]
+                                .into_iter()
+                                .collect(),
+                        ),
+                    )
+                ]
+                .into_iter()
+                .collect()
+            ),
+            vec![]
+        ))
+    );
+}
+
+#[tokio::test]
+async fn test_no_rename_obj() {
+    let doc = r#"
+        {
+            noRenameObj {
+                one_field
+                another_field
+            }
+        }"#;
+
+    let schema = RootNode::new(
+        Query,
+        EmptyMutation::<()>::new(),
+        EmptySubscription::<()>::new(),
+    );
+
+    assert_eq!(
+        execute(doc, None, &schema, &Variables::new(), &()).await,
+        Ok((
+            Value::object(
+                vec![(
+                    "noRenameObj",
+                    Value::object(
+                        vec![
+                            ("one_field", Value::scalar(true)),
+                            ("another_field", Value::scalar(146)),
+                        ]
+                        .into_iter()
+                        .collect(),
+                    ),
+                )]
+                .into_iter()
+                .collect()
+            ),
+            vec![]
+        ))
+    );
+}
+
 #[tokio::test]
 async fn test_derived_object() {
     assert_eq!(

juniper_codegen/src/derive_enum.rs

@@ -4,7 +4,7 @@ use syn::{ext::IdentExt, spanned::Spanned, Data, Fields};
 
 use crate::{
     result::{GraphQLScope, UnsupportedAttribute},
-    util::{self, span_container::SpanContainer},
+    util::{self, span_container::SpanContainer, RenameRule},
 };
 
 pub fn impl_enum(ast: syn::DeriveInput, error: GraphQLScope) -> syn::Result<TokenStream> {
@@ -48,7 +48,12 @@ pub fn impl_enum(ast: syn::DeriveInput, error: GraphQLScope) -> syn::Result<Toke
                 .name
                 .clone()
                 .map(SpanContainer::into_inner)
-                .unwrap_or_else(|| util::to_upper_snake_case(&field_name.unraw().to_string()));
+                .unwrap_or_else(|| {
+                    attrs
+                        .rename
+                        .unwrap_or(RenameRule::ScreamingSnakeCase)
+                        .apply(&field_name.unraw().to_string())
+                });
 
             let resolver_code = quote!( #ident::#field_name );
 

juniper_codegen/src/derive_input_object.rs

@@ -1,7 +1,7 @@
 #![allow(clippy::match_wild_err_arm)]
 use crate::{
     result::{GraphQLScope, UnsupportedAttribute},
-    util::{self, span_container::SpanContainer},
+    util::{self, span_container::SpanContainer, RenameRule},
 };
 use proc_macro2::TokenStream;
 use quote::{quote, ToTokens};
@@ -50,7 +50,10 @@ pub fn impl_input_object(ast: syn::DeriveInput, error: GraphQLScope) -> syn::Res
             let field_ident = field.ident.as_ref().unwrap();
             let name = match field_attrs.name {
                 Some(ref name) => name.to_string(),
-                None => crate::util::to_camel_case(&field_ident.unraw().to_string()),
+                None => attrs
+                    .rename
+                    .unwrap_or(RenameRule::CamelCase)
+                    .apply(&field_ident.unraw().to_string()),
             };
 
             if let Some(span) = field_attrs.skip {

juniper_codegen/src/derive_object.rs

@@ -1,6 +1,6 @@
 use crate::{
     result::{GraphQLScope, UnsupportedAttribute},
-    util::{self, span_container::SpanContainer},
+    util::{self, span_container::SpanContainer, RenameRule},
 };
 use proc_macro2::TokenStream;
 use quote::quote;
@@ -50,7 +50,12 @@ pub fn build_derive_object(ast: syn::DeriveInput, error: GraphQLScope) -> syn::R
                 .name
                 .clone()
                 .map(SpanContainer::into_inner)
-                .unwrap_or_else(|| util::to_camel_case(&field_name.unraw().to_string()));
+                .unwrap_or_else(|| {
+                    attrs
+                        .rename
+                        .unwrap_or(RenameRule::CamelCase)
+                        .apply(&field_name.unraw().to_string())
+                });
 
             if name.starts_with("__") {
                 error.no_double_underscore(if let Some(name) = field_attrs.name {

juniper_codegen/src/impl_object.rs

@@ -2,7 +2,7 @@
 
 use crate::{
     result::{GraphQLScope, UnsupportedAttribute},
-    util::{self, span_container::SpanContainer},
+    util::{self, span_container::SpanContainer, RenameRule},
 };
 use proc_macro2::TokenStream;
 use quote::quote;
@@ -44,6 +44,8 @@ fn create(
         .map(SpanContainer::into_inner)
         .unwrap_or_else(|| _impl.type_ident.unraw().to_string());
 
+    let top_attrs = &_impl.attrs;
+
     let fields = _impl
         .methods
         .iter()
@@ -78,7 +80,12 @@ fn create(
                     let final_name = attrs
                         .argument(&arg_name)
                         .and_then(|attrs| attrs.rename.clone().map(|ident| ident.value()))
-                        .unwrap_or_else(|| util::to_camel_case(&arg_name));
+                        .unwrap_or_else(|| {
+                            top_attrs
+                                .rename
+                                .unwrap_or(RenameRule::CamelCase)
+                                .apply(&arg_name)
+                        });
 
                     let expect_text = format!(
                         "Internal error: missing argument {} - validation must have failed",
@@ -137,7 +144,12 @@ fn create(
                 .name
                 .clone()
                 .map(SpanContainer::into_inner)
-                .unwrap_or_else(|| util::to_camel_case(&ident.unraw().to_string()));
+                .unwrap_or_else(|| {
+                    top_attrs
+                        .rename
+                        .unwrap_or(RenameRule::CamelCase)
+                        .apply(&ident.unraw().to_string())
+                });
 
             if name.starts_with("__") {
                 error.no_double_underscore(if let Some(name) = attrs.name {

juniper_codegen/src/util/mod.rs

@@ -5,6 +5,7 @@ pub mod parse_impl;
 pub mod span_container;
 
 use std::collections::HashMap;
+use std::str::FromStr;
 
 use proc_macro2::{Span, TokenStream};
 use proc_macro_error::abort;
@@ -295,6 +296,40 @@ pub fn is_valid_name(field_name: &str) -> bool {
     chars.all(|c| c.is_ascii_alphanumeric() || c == '_')
 }
 
+/// The different possible ways to change case of fields in a struct, or variants in an enum.
+#[derive(Copy, Clone, PartialEq, Debug)]
+pub enum RenameRule {
+    /// Don't apply a default rename rule.
+    None,
+    /// Rename to "camelCase" style.
+    CamelCase,
+    /// Rename to "SCREAMING_SNAKE_CASE" style
+    ScreamingSnakeCase,
+}
+
+impl RenameRule {
+    pub fn apply(&self, field: &str) -> String {
+        match self {
+            Self::None => field.to_owned(),
+            Self::CamelCase => to_camel_case(field),
+            Self::ScreamingSnakeCase => to_upper_snake_case(field),
+        }
+    }
+}
+
+impl FromStr for RenameRule {
+    type Err = ();
+
+    fn from_str(rule: &str) -> Result<Self, Self::Err> {
+        match rule {
+            "none" => Ok(Self::None),
+            "camelCase" => Ok(Self::CamelCase),
+            "SCREAMING_SNAKE_CASE" => Ok(Self::ScreamingSnakeCase),
+            _ => Err(()),
+        }
+    }
+}
+
 #[derive(Default, Debug)]
 pub struct ObjectAttributes {
     pub name: Option<SpanContainer<String>>,
@@ -304,6 +339,7 @@ pub struct ObjectAttributes {
     pub interfaces: Vec<SpanContainer<syn::Type>>,
     pub no_async: Option<SpanContainer<()>>,
     pub is_internal: bool,
+    pub rename: Option<RenameRule>,
 }
 
 impl Parse for ObjectAttributes {
@@ -365,6 +401,15 @@ impl Parse for ObjectAttributes {
                 "internal" => {
                     output.is_internal = true;
                 }
+                "rename" => {
+                    input.parse::<syn::Token![=]>()?;
+                    let val = input.parse::<syn::LitStr>()?;
+                    if let Ok(rename) = RenameRule::from_str(&val.value()) {
+                        output.rename = Some(rename);
+                    } else {
+                        return Err(syn::Error::new(val.span(), "unknown rename rule"));
+                    }
+                }
                 _ => {
                     return Err(syn::Error::new(ident.span(), "unknown attribute"));
                 }