Repository: CosmWasm/cosmwasm (rust)

Issue:
Generics support for `QueryResponses` derive macro
Currently the use of generics in query endpoint messages are not supported by the `#[derive(QueryResponses)]` macro. 
By supporting generics in `QueryMsg` definitions developers can more easily modularise their smart-contracts. 

Example: 

```rust
#[cosmwasm_schema::cw_serde]
#[derive(QueryResponses)]
#[query_responses(nested)]
pub enum QueryMsg<BaseMsg, AppMsg = Empty> {
    /// A configuration message to a base implementation.
    Base(BaseMsg),
    /// Custom query
    App(AppMsg),
}
```

Pull request description:
Fix generics + nestedness in QueryMsg
* Fixes and closes #1516
* Doc comments in nested QueryMsg with generics caused schema gen errors (failed integrity check due to different schema structure). I removed the integrity check altogether. JSON Schema can represent the same Rust types in various ways and accounting for every possibility would just be maintenance hell. The representation could also change between versions of `schemars` and is pretty much its implementation detail.

Patch:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 34c3b1682..1d780adf8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,6 +32,15 @@ and this project adheres to
 [#1406]: https://github.com/CosmWasm/cosmwasm/pull/1406
 [#1508]: https://github.com/CosmWasm/cosmwasm/issues/1508
 
+### Fixed
+
+- cosmwasm-schema: Nested QueryMsg with generics is now supported by the
+  QueryResponses macro ([#1516]).
+- cosmwasm-schema: A nested QueryMsg no longer causes runtime errors if it
+  contains doc comments.
+
+[#1516]: https://github.com/CosmWasm/cosmwasm/issues/1516
+
 ## [1.1.8] - 2022-11-22
 
 ### Fixed
diff --git a/Cargo.lock b/Cargo.lock
index 0c1203379..815caa2d2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -288,6 +288,7 @@ version = "1.1.8"
 dependencies = [
  "anyhow",
  "cosmwasm-schema-derive",
+ "cosmwasm-std",
  "schemars",
  "semver",
  "serde",
diff --git a/packages/schema-derive/src/query_responses.rs b/packages/schema-derive/src/query_responses.rs
index 195bb93d7..f3d9b755d 100644
--- a/packages/schema-derive/src/query_responses.rs
+++ b/packages/schema-derive/src/query_responses.rs
@@ -1,6 +1,8 @@
 mod context;
 
-use syn::{parse_quote, Expr, ExprTuple, Generics, ItemEnum, ItemImpl, Type, Variant};
+use syn::{
+    parse_quote, Expr, ExprTuple, Generics, ItemEnum, ItemImpl, Type, TypeParamBound, Variant,
+};
 
 use self::context::Context;
 
@@ -13,7 +15,11 @@ pub fn query_responses_derive_impl(input: ItemEnum) -> ItemImpl {
 
         // Handle generics if the type has any
         let (_, type_generics, where_clause) = input.generics.split_for_impl();
-        let impl_generics = impl_generics(&ctx, &input.generics);
+        let impl_generics = impl_generics(
+            &ctx,
+            &input.generics,
+            &[parse_quote! {::cosmwasm_schema::QueryResponses}],
+        );
 
         let subquery_len = subquery_calls.len();
         parse_quote! {
@@ -24,7 +30,7 @@ pub fn query_responses_derive_impl(input: ItemEnum) -> ItemImpl {
                     let subqueries = [
                         #( #subquery_calls, )*
                     ];
-                    ::cosmwasm_schema::combine_subqueries::<#subquery_len, #ident>(subqueries)
+                    ::cosmwasm_schema::combine_subqueries::<#subquery_len, #ident #type_generics>(subqueries)
                 }
             }
         }
@@ -37,7 +43,7 @@ pub fn query_responses_derive_impl(input: ItemEnum) -> ItemImpl {
 
         // Handle generics if the type has any
         let (_, type_generics, where_clause) = input.generics.split_for_impl();
-        let impl_generics = impl_generics(&ctx, &input.generics);
+        let impl_generics = impl_generics(&ctx, &input.generics, &[]);
 
         parse_quote! {
             #[automatically_derived]
@@ -55,7 +61,7 @@ pub fn query_responses_derive_impl(input: ItemEnum) -> ItemImpl {
 
 /// Takes a list of generics from the type definition and produces a list of generics
 /// for the expanded `impl` block, adding trait bounds like `JsonSchema` as appropriate.
-fn impl_generics(ctx: &Context, generics: &Generics) -> Generics {
+fn impl_generics(ctx: &Context, generics: &Generics, bounds: &[TypeParamBound]) -> Generics {
     let mut impl_generics = generics.to_owned();
     for param in impl_generics.type_params_mut() {
         // remove the default type if present, as those are invalid in
@@ -65,7 +71,8 @@ fn impl_generics(ctx: &Context, generics: &Generics) -> Generics {
         if !ctx.no_bounds_for.contains(&param.ident) {
             param
                 .bounds
-                .push(parse_quote! {::cosmwasm_schema::schemars::JsonSchema})
+                .push(parse_quote! {::cosmwasm_schema::schemars::JsonSchema});
+            param.bounds.extend(bounds.to_owned());
         }
     }
 
diff --git a/packages/schema/Cargo.toml b/packages/schema/Cargo.toml
index 543e9c460..4e06a667f 100644
--- a/packages/schema/Cargo.toml
+++ b/packages/schema/Cargo.toml
@@ -16,5 +16,6 @@ thiserror = "1.0.13"
 
 [dev-dependencies]
 anyhow = "1.0.57"
+cosmwasm-std = { version = "1.1.8", path = "../std" }
 semver = "1"
 tempfile = "3"
diff --git a/packages/schema/src/query_response.rs b/packages/schema/src/query_response.rs
index 20cf84e26..85ecc7f3b 100644
--- a/packages/schema/src/query_response.rs
+++ b/packages/schema/src/query_response.rs
@@ -1,9 +1,6 @@
 use std::collections::{BTreeMap, BTreeSet};
 
-use schemars::{
-    schema::{InstanceType, RootSchema, SingleOrVec, SubschemaValidation},
-    JsonSchema,
-};
+use schemars::{schema::RootSchema, JsonSchema};
 use thiserror::Error;
 
 pub use cosmwasm_schema_derive::QueryResponses;
@@ -69,10 +66,6 @@ pub trait QueryResponses: JsonSchema {
     fn response_schemas() -> Result<BTreeMap<String, RootSchema>, IntegrityError> {
         let response_schemas = Self::response_schemas_impl();
 
-        let queries: BTreeSet<_> = response_schemas.keys().cloned().collect();
-
-        check_api_integrity::<Self>(queries)?;
-
         Ok(response_schemas)
     }
 
@@ -95,121 +88,6 @@ pub fn combine_subqueries<const N: usize, T>(
     map
 }
 
-/// Returns possible enum variants from `one_of` analysis
-fn enum_variants(
-    subschemas: SubschemaValidation,
-) -> Result<impl Iterator<Item = Result<String, IntegrityError>>, IntegrityError> {
-    let iter = subschemas
-        .one_of
-        .ok_or(IntegrityError::InvalidQueryMsgSchema)?
-        .into_iter()
-        .map(|s| {
-            let s = s.into_object();
-
-            if let Some(SingleOrVec::Single(ty)) = s.instance_type {
-                match *ty {
-                    // We'll have an object if the Rust enum variant was C-like or tuple-like
-                    InstanceType::Object => s
-                        .object
-                        .ok_or(IntegrityError::InvalidQueryMsgSchema)?
-                        .required
-                        .into_iter()
-                        .next()
-                        .ok_or(IntegrityError::InvalidQueryMsgSchema),
-                    // We might have a string here if the Rust enum variant was unit-like
-                    InstanceType::String => {
-                        let values = s.enum_values.ok_or(IntegrityError::InvalidQueryMsgSchema)?;
-
-                        if values.len() != 1 {
-                            return Err(IntegrityError::InvalidQueryMsgSchema);
-                        }
-
-                        values[0]
-                            .as_str()
-                            .map(String::from)
-                            .ok_or(IntegrityError::InvalidQueryMsgSchema)
-                    }
-                    _ => Err(IntegrityError::InvalidQueryMsgSchema),
-                }
-            } else {
-                Err(IntegrityError::InvalidQueryMsgSchema)
-            }
-        });
-
-    Ok(iter)
-}
-
-fn verify_queries(
-    query_msg: BTreeSet<String>,
-    responses: BTreeSet<String>,
-) -> Result<(), IntegrityError> {
-    if query_msg != responses {
-        return Err(IntegrityError::InconsistentQueries {
-            query_msg,
-            responses,
-        });
-    }
-
-    Ok(())
-}
-
-/// `generated_queries` is expected to be a sorted slice here!
-fn check_api_integrity<T: QueryResponses + ?Sized>(
-    generated_queries: BTreeSet<String>,
-) -> Result<(), IntegrityError> {
-    let schema = crate::schema_for!(T);
-
-    let subschemas = if let Some(subschemas) = schema.schema.subschemas {
-        subschemas
-    } else {
-        // No subschemas - no resposnes are expected
-        return verify_queries(BTreeSet::new(), generated_queries);
-    };
-
-    let schema_queries = if let Some(any_of) = subschemas.any_of {
-        // If `any_of` exists, we assume schema is generated from untagged enum
-        any_of
-            .into_iter()
-            .map(|schema| dbg!(schema.into_object()))
-            .filter_map(|obj| {
-                if let Some(reference) = obj.reference {
-                    // Subschemas can be hidden behind references - we want to map them to proper
-                    // subschemas in such case
-
-                    // Only references to definitions are supported
-                    let reference = match reference.strip_prefix("#/definitions/") {
-                        Some(reference) => reference,
-                        None => {
-                            return Some(Err(IntegrityError::ExternalReference {
-                                reference: reference.to_owned(),
-                            }))
-                        }
-                    };
-
-                    let schema = match schema.definitions.get(reference) {
-                        Some(schema) => schema.clone(),
-                        None => return Some(Err(IntegrityError::InvalidQueryMsgSchema)),
-                    };
-
-                    Ok(schema.into_object().subschemas).transpose()
-                } else {
-                    Ok(obj.subschemas).transpose()
-                }
-            })
-            .map(|subschema| enum_variants(*subschema?))
-            .collect::<Result<Vec<_>, _>>()?
-            .into_iter()
-            .flatten()
-            .collect::<Result<_, _>>()?
-    } else {
-        // If `any_of` is not present, there was no untagged enum on top, we expect normal enum at
-        // this point
-        enum_variants(*subschemas)?.collect::<Result<_, _>>()?
-    };
-
-    verify_queries(schema_queries, generated_queries)
-}
-
 #[derive(Debug, Error, PartialEq, Eq)]
 pub enum IntegrityError {
     #[error("the structure of the QueryMsg schema was unexpected")]
@@ -299,18 +177,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn bad_msg_fails() {
-        let err = BadMsg::response_schemas().unwrap_err();
-        assert_eq!(
-            err,
-            IntegrityError::InconsistentQueries {
-                query_msg: BTreeSet::from(["balance-for".to_string()]),
-                responses: BTreeSet::from(["balance_for".to_string()])
-            }
-        );
-    }
-
     #[derive(Debug, JsonSchema)]
     #[serde(rename_all = "snake_case")]
     #[allow(dead_code)]


Test patch:
diff --git a/packages/schema/tests/idl.rs b/packages/schema/tests/idl.rs
index 5f1f8b036..b8701d423 100644
--- a/packages/schema/tests/idl.rs
+++ b/packages/schema/tests/idl.rs
@@ -1,36 +1,32 @@
 use std::collections::HashMap;
 
-use cosmwasm_schema::{generate_api, QueryResponses, IDL_VERSION};
-use schemars::JsonSchema;
-use serde::{Deserialize, Serialize};
+use cosmwasm_schema::{cw_serde, generate_api, QueryResponses, IDL_VERSION};
 use serde_json::Value;
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema)]
+#[cw_serde]
 pub struct InstantiateMsg {
     pub admin: String,
     pub cap: u128,
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
 pub enum ExecuteMsg {
     Mint { amount: u128 },
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
+#[derive(QueryResponses)]
 pub enum QueryMsg {
     #[returns(u128)]
     Balance { account: String },
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
 pub enum SudoMsg {
     SetAdmin { new_admin: String },
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema)]
+#[cw_serde]
 pub struct MigrateMsg {
     pub admin: String,
     pub cap: u128,
@@ -107,15 +103,15 @@ fn test_query_responses() {
     api.get("responses").unwrap().get("balance").unwrap();
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
+#[derive(QueryResponses)]
 pub enum QueryMsgWithGenerics<T> {
     #[returns(u128)]
     QueryData { data: T },
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
+#[derive(QueryResponses)]
 pub enum QueryMsgWithGenericsAndTraitBounds<T: std::fmt::Debug>
 where
     T: PartialEq,
@@ -124,8 +120,8 @@ where
     QueryData { data: T },
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
+#[derive(QueryResponses)]
 pub enum QueryMsgWithGenericsAndDefaultType<T = u128> {
     #[returns(u128)]
     QueryData { data: T },
@@ -191,7 +187,8 @@ fn test_query_responses_generics_and_trait_bounds() {
     api.get("responses").unwrap().get("query_data").unwrap();
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
+#[cw_serde]
+#[derive(QueryResponses)]
 #[serde(untagged)]
 #[query_responses(nested)]
 pub enum NestedQueryMsg {
@@ -199,8 +196,8 @@ pub enum NestedQueryMsg {
     Sub(SubQueryMsg1),
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
+#[derive(QueryResponses)]
 pub enum SubQueryMsg1 {
     #[returns(u128)]
     Variant1 { test: String },
@@ -208,80 +205,45 @@ pub enum SubQueryMsg1 {
 
 #[test]
 fn test_nested_query_responses() {
-    let api_str = generate_api! {
+    generate_api! {
         instantiate: InstantiateMsg,
         query: NestedQueryMsg,
     }
     .render()
     .to_string()
     .unwrap();
+}
 
-    let api: Value = serde_json::from_str(&api_str).unwrap();
-    let queries = api
-        .get("query")
-        .unwrap()
-        .get("anyOf")
-        .unwrap()
-        .as_array()
-        .unwrap();
-    let definitions = api.get("query").unwrap().get("definitions").unwrap();
-
-    // Find the subqueries
-    assert_eq!(queries.len(), 2);
-    assert_eq!(
-        queries[0].get("$ref").unwrap().as_str().unwrap(),
-        "#/definitions/QueryMsg"
-    );
-    assert_eq!(
-        queries[1].get("$ref").unwrap().as_str().unwrap(),
-        "#/definitions/SubQueryMsg1"
-    );
-    let query_msg_queries = definitions
-        .get("QueryMsg")
-        .unwrap()
-        .get("oneOf")
-        .unwrap()
-        .as_array()
-        .unwrap();
-    let sub_query_msg_queries = definitions
-        .get("SubQueryMsg1")
-        .unwrap()
-        .get("oneOf")
-        .unwrap()
-        .as_array()
-        .unwrap();
-
-    // Find "balance" and "variant1" queries in the query schema
-    assert_eq!(
-        query_msg_queries[0]
-            .get("required")
-            .unwrap()
-            .get(0)
-            .unwrap(),
-        "balance"
-    );
-    assert_eq!(
-        sub_query_msg_queries[0]
-            .get("required")
-            .unwrap()
-            .get(0)
-            .unwrap(),
-        "variant1"
-    );
+#[cw_serde]
+#[derive(QueryResponses)]
+#[serde(untagged)]
+#[query_responses(nested)]
+pub enum NestedQueryMsgGenerics<T, U> {
+    /// doc comment
+    Query(T),
+    Sub(U),
+}
 
-    // Find "balance" and "variant1" queries in responses
-    api.get("responses").unwrap().get("balance").unwrap();
-    api.get("responses").unwrap().get("variant1").unwrap();
+#[test]
+fn test_nested_query_responses_with_generics() {
+    generate_api! {
+        instantiate: InstantiateMsg,
+        query: NestedQueryMsgGenerics<QueryMsg, SubQueryMsg1>,
+    }
+    .render()
+    .to_string()
+    .unwrap();
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
-#[serde(rename_all = "snake_case")]
+#[cw_serde]
+#[derive(QueryResponses)]
 enum QueryMsg2 {
     #[returns(u128)]
     Balance {},
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema, QueryResponses)]
+#[cw_serde]
+#[derive(QueryResponses)]
 #[query_responses(nested)]
 enum NestedNameCollision {
     Q1(QueryMsg),