Fix SelfRef relations, add reverse SelfRef (#99)

## PR Info
- Closes #94

## New Features

- [X] Relations derive produces the reverse of a SelfRef relation

## Bug Fixes

- [X] Relations derive could not handle properly SelfRef relations

derive/src/relation.rs

@@ -13,11 +13,11 @@ pub struct SeaOrm {
 }
 
 pub fn compact_relation_fn(item: &syn::DataEnum) -> Result<TokenStream, crate::error::Error> {
-    let (loaders, functions): (Vec<_>, Vec<_>) = item
+    let relations_parameters: Vec<(String, Option<String>, Option<String>, bool)>  = item
         .variants
         .iter()
         .map(
-            |variant| -> Result<(TokenStream, TokenStream), crate::error::Error> {
+            |variant| -> Result<(String, Option<String>, Option<String>, bool), crate::error::Error> {
                 let attrs = SeaOrm::from_attributes(&variant.attrs)?;
 
                 let belongs_to = match attrs.belongs_to {
@@ -30,22 +30,12 @@ pub fn compact_relation_fn(item: &syn::DataEnum) -> Result<TokenStream, crate::e
                     _ => None,
                 };
 
-                relation_fn(variant.ident.to_string(), belongs_to, has_many)
+                Ok((variant.ident.to_string(), belongs_to, has_many, false))
             },
         )
-        .collect::<Result<Vec<_>, crate::error::Error>>()?
-        .into_iter()
-        .map(|(loader, func)| (loader, func))
-        .unzip();
+        .collect::<Result<Vec<_>, crate::error::Error>>()?;
 
-    Ok(quote! {
-        #(#loaders)*
-
-        #[async_graphql::ComplexObject]
-        impl Model {
-            #(#functions)*
-        }
-    })
+    produce_relations(relations_parameters)
 }
 
 #[derive(Debug)]
@@ -122,23 +112,50 @@ pub fn expanded_relation_fn(item: &syn::ItemImpl) -> Result<TokenStream, crate::
         })
         .collect::<Result<Vec<ExpandedParams>, crate::error::Error>>()?;
 
-    let (loaders, functions): (Vec<_>, Vec<_>) = expanded_params
+    let relations_parameters: Vec<(String, Option<String>, Option<String>, bool)> = expanded_params
         .iter()
-        .map(
-            |params| -> Result<(TokenStream, TokenStream), crate::error::Error> {
-                let belongs_to = if params.relation_type.to_string().eq("belongs_to") {
-                    Some(params.related_type.to_token_stream().to_string())
-                } else {
-                    None
-                };
+        .map(|params| -> Result<(String, Option<String>, Option<String>, bool), crate::error::Error> {
+            let belongs_to = if params.relation_type.to_string().eq("belongs_to") {
+                Some(params.related_type.to_token_stream().to_string())
+            } else {
+                None
+            };
+
+            let has_many = if params.relation_type.to_string().ne("belongs_to") {
+                Some(params.related_type.to_token_stream().to_string())
+            } else {
+                None
+            };
+
+            let relation_name = params.variant.to_string();
+
+            Ok((relation_name, belongs_to, has_many, false))
+        })
+        .collect::<Result<Vec<_>, crate::error::Error>>()?;
 
-                let has_many = if params.relation_type.to_string().ne("belongs_to") {
-                    Some(params.related_type.to_token_stream().to_string())
-                } else {
-                    None
-                };
+    produce_relations(relations_parameters)
+}
 
-                relation_fn(params.variant.to_string(), belongs_to, has_many)
+pub fn produce_relations(
+    relations_parameters: Vec<(String, Option<String>, Option<String>, bool)>,
+) -> Result<TokenStream, crate::error::Error> {
+    let relations_copy = relations_parameters.clone();
+
+    let reverse_self_references_parameters = relations_copy
+        .into_iter()
+        .filter(|(_, belongs_to, has_one, _)| {
+            belongs_to.eq(&Some("Entity".into())) || has_one.eq(&Some("Entity".into()))
+        })
+        .map(|(relation_name, belongs_to, has_many, _)| {
+            (relation_name, has_many, belongs_to, true)
+        });
+
+    let (loaders, functions): (Vec<_>, Vec<_>) = relations_parameters
+        .into_iter()
+        .chain(reverse_self_references_parameters)
+        .map(
+            |(relation_name, belongs_to, has_many, reverse)| -> Result<(TokenStream, TokenStream), crate::error::Error> {
+                relation_fn(relation_name, belongs_to, has_many, reverse)
             },
         )
         .collect::<Result<Vec<_>, crate::error::Error>>()?
@@ -147,8 +164,6 @@ pub fn expanded_relation_fn(item: &syn::ItemImpl) -> Result<TokenStream, crate::
         .unzip();
 
     Ok(quote! {
-        #item
-
         #(#loaders)*
 
         #[async_graphql::ComplexObject]
@@ -162,9 +177,22 @@ pub fn relation_fn(
     relation_name: String,
     belongs_to: Option<String>,
     has_many: Option<String>,
+    reverse: bool,
 ) -> Result<(TokenStream, TokenStream), crate::error::Error> {
     let relation_ident = format_ident!("{}", relation_name.to_upper_camel_case());
 
+    let relation_name = if reverse {
+        format_ident!("{}Reverse", relation_name.to_upper_camel_case())
+    } else {
+        format_ident!("{}", relation_name.to_upper_camel_case())
+    };
+
+    let (reverse, column_type) = if reverse {
+        (quote! { true }, quote! { to_col })
+    } else {
+        (quote! { false }, quote! { from_col })
+    };
+
     let target_path = if let Some(target_path) = &has_many {
         target_path
     } else if let Some(target_path) = &belongs_to {
@@ -180,9 +208,7 @@ pub fn relation_fn(
             .parse()
             .unwrap()
     } else {
-        return Err(crate::error::Error::Internal(
-            "Cannot parse entity path".into(),
-        ));
+        quote! { self }
     };
 
     let (return_type, extra_imports, map_method) = if has_many.is_some() {
@@ -200,7 +226,7 @@ pub fn relation_fn(
     };
 
     let relation_enum = quote! {Relation::#relation_ident};
-    let foreign_key_name = format_ident!("{}FK", relation_ident).to_token_stream();
+    let foreign_key_name = format_ident!("{}FK", relation_name).to_token_stream();
 
     Ok((
         quote! {
@@ -230,6 +256,7 @@ pub fn relation_fn(
                         ::fetch_relation_data::<#path::Entity, #path::Filter, #path::OrderBy>(
                             keys,
                             #relation_enum.def(),
+                            #reverse,
                             &self.db,
                         ).await?
                         .into_iter()
@@ -242,7 +269,7 @@ pub fn relation_fn(
             }
         },
         quote! {
-            pub async fn #relation_ident<'a>(
+            pub async fn #relation_name<'a>(
                 &self,
                 ctx: &async_graphql::Context<'a>,
             ) -> Option<#return_type> {
@@ -253,16 +280,17 @@ pub fn relation_fn(
                     .data::<async_graphql::dataloader::DataLoader<crate::OrmDataloader>>()
                     .unwrap();
 
-                let from_column: Column = Column::from_str(
+                // TODO support multiple value keys
+                let target_column: Column = Column::from_str(
                     #relation_enum
                         .def()
-                        .from_col
+                        .#column_type
                         .to_string()
                         .to_snake_case()
                         .as_str()
                 ).unwrap();
 
-                let key = #foreign_key_name(seaography::RelationKeyStruct(self.get(from_column), None, None));
+                let key = #foreign_key_name(seaography::RelationKeyStruct(self.get(target_column), None, None));
 
                 let data: Option<_> = data_loader.load_one(key).await.unwrap();
 

examples/mysql/Cargo.toml

@@ -4,11 +4,11 @@ name = 'seaography-mysql-example'
 version = '0.2.0'
 
 [dependencies]
-async-graphql = { version = "4.0.10", features = ["decimal", "chrono", "dataloader"] }
-async-graphql-poem = { version = "4.0.10" }
+poem = { version = "1.3.29" }
+async-graphql = { version = "4.0.14", features = ["decimal", "chrono", "dataloader"] }
+async-graphql-poem = { version = "4.0.14" }
 async-trait = { version = "0.1.53" }
 dotenv = "0.15.0"
-poem = { version = "1.3.29" }
 sea-orm = { version = "^0.10", features = ["sqlx-mysql", "runtime-async-std-native-tls"] }
 tokio = { version = "1.17.0", features = ["macros", "rt-multi-thread"] }
 tracing = { version = "0.1.34" }

examples/mysql/sakila-schema.sql

@@ -186,9 +186,9 @@ CREATE TABLE film_category (
 
 --
 -- Table structure for table `film_text`
--- 
+--
 -- InnoDB added FULLTEXT support in 5.6.10. If you use an
--- earlier version, then consider upgrading (recommended) or 
+-- earlier version, then consider upgrading (recommended) or
 -- changing InnoDB to MyISAM as the film_text engine
 --
 
@@ -315,6 +315,7 @@ CREATE TABLE staff (
   first_name VARCHAR(45) NOT NULL,
   last_name VARCHAR(45) NOT NULL,
   address_id INT NOT NULL,
+  reports_to_id INT,
   picture BLOB DEFAULT NULL,
   email VARCHAR(50) DEFAULT NULL,
   store_id INT NOT NULL,
@@ -326,6 +327,7 @@ CREATE TABLE staff (
   KEY idx_fk_store_id (store_id),
   KEY idx_fk_address_id (address_id),
   CONSTRAINT fk_staff_store FOREIGN KEY (store_id) REFERENCES store (store_id) ON DELETE RESTRICT ON UPDATE CASCADE,
+  CONSTRAINT fk_staff_staff FOREIGN KEY (reports_to_id) REFERENCES staff (staff_id) ON DELETE RESTRICT ON UPDATE CASCADE,
   CONSTRAINT fk_staff_address FOREIGN KEY (address_id) REFERENCES address (address_id) ON DELETE RESTRICT ON UPDATE CASCADE
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 

examples/mysql/src/entities/customer.rs

@@ -21,7 +21,7 @@ pub struct Model {
     pub address_id: i32,
     pub active: i8,
     pub create_date: DateTime,
-    pub last_update: Option<DateTimeUtc>,
+    pub last_update: DateTimeUtc,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation, seaography::macros::RelationsCompact)]

examples/mysql/src/entities/film_text.rs

@@ -19,13 +19,7 @@ pub struct Model {
     pub description: Option<String>,
 }
 
-#[derive(Copy, Clone, Debug, EnumIter, seaography::macros::RelationsCompact)]
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation, seaography::macros::RelationsCompact)]
 pub enum Relation {}
 
-impl RelationTrait for Relation {
-    fn def(&self) -> RelationDef {
-        panic!("No RelationDef")
-    }
-}
-
 impl ActiveModelBehavior for ActiveModel {}

examples/mysql/src/entities/language.rs

@@ -18,13 +18,7 @@ pub struct Model {
     pub last_update: DateTimeUtc,
 }
 
-#[derive(Copy, Clone, Debug, EnumIter, seaography::macros::RelationsCompact)]
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation, seaography::macros::RelationsCompact)]
 pub enum Relation {}
 
-impl RelationTrait for Relation {
-    fn def(&self) -> RelationDef {
-        panic!("No RelationDef")
-    }
-}
-
 impl ActiveModelBehavior for ActiveModel {}

examples/mysql/src/entities/payment.rs

@@ -20,7 +20,7 @@ pub struct Model {
     #[sea_orm(column_type = "Decimal(Some((5, 2)))")]
     pub amount: Decimal,
     pub payment_date: DateTime,
-    pub last_update: Option<DateTimeUtc>,
+    pub last_update: DateTimeUtc,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation, seaography::macros::RelationsCompact)]

examples/mysql/src/entities/staff.rs

@@ -17,6 +17,7 @@ pub struct Model {
     pub first_name: String,
     pub last_name: String,
     pub address_id: i32,
+    pub reports_to_id: Option<i32>,
     pub picture: Option<Vec<u8>>,
     pub email: Option<String>,
     pub store_id: i32,
@@ -44,6 +45,14 @@ pub enum Relation {
         on_delete = "Restrict"
     )]
     Store,
+    #[sea_orm(
+        belongs_to = "Entity",
+        from = "Column::ReportsToId",
+        to = "Column::StaffId",
+        on_update = "Restrict",
+        on_delete = "Restrict"
+    )]
+    SelfRef,
     #[sea_orm(has_many = "super::payment::Entity")]
     Payment,
     #[sea_orm(has_many = "super::rental::Entity")]

examples/mysql/src/main.rs

@@ -37,7 +37,6 @@ async fn main() {
         .with_max_level(tracing::Level::INFO)
         .with_test_writer()
         .init();
-
     let database = Database::connect(&*DATABASE_URL)
         .await
         .expect("Fail to initialize database connection");
@@ -61,7 +60,6 @@ async fn main() {
         &*ENDPOINT,
         get(graphql_playground).post(GraphQL::new(schema)),
     );
-
     println!("Visit GraphQL Playground at http://{}", *URL);
     Server::new(TcpListener::bind(&*URL))
         .run(app)

examples/mysql/tests/query_tests.rs

@@ -442,4 +442,62 @@ async fn test_cursor_pagination_no_next() {
         }
         "#,
     )
-}
+}
+
+#[tokio::test]
+async fn test_self_ref() {
+    let schema = get_schema().await;
+
+    assert_eq(
+        schema
+            .execute(
+                r#"
+                {
+                  staff {
+                    nodes {
+                      firstName
+                      reportsToId
+                      selfRefReverse {
+                        staffId
+                        firstName
+                      }
+                      selfRef {
+                        staffId
+                        firstName
+                      }
+                    }
+                  }
+                }
+        "#,
+            )
+            .await,
+        r#"
+        {
+          "staff": {
+            "nodes": [
+              {
+                "firstName": "Mike",
+                "reportsToId": null,
+                "selfRefReverse": [
+                  {
+                    "staffId": 2,
+                    "firstName": "Jon"
+                  }
+                ],
+                "selfRef": null
+              },
+              {
+                "firstName": "Jon",
+                "reportsToId": 1,
+                "selfRefReverse": null,
+                "selfRef": {
+                  "staffId": 1,
+                  "firstName": "Mike"
+                }
+              }
+            ]
+          }
+        }
+        "#,
+    )
+}