From 6a26b8cc1773aa8765b9b8ff0275bd809666c7f7 Mon Sep 17 00:00:00 2001
From: Chris Tsang <tyt2y7@gmail.com>
Date: Thu, 3 Jun 2021 13:07:35 +0800
Subject: [PATCH] ActiveModelBehavior

---
 sea-orm-macros/src/derives/active_model.rs | 14 +++++++++++++-
 src/entity/active_model.rs                 | 12 +++++++++++-
 src/entity/prelude.rs                      |  8 ++++----
 src/tests_cfg/cake.rs                      |  4 ++++
 src/tests_cfg/cake_filling.rs              |  4 ++++
 src/tests_cfg/filling.rs                   |  4 ++++
 src/tests_cfg/fruit.rs                     |  4 ++++
 7 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/sea-orm-macros/src/derives/active_model.rs b/sea-orm-macros/src/derives/active_model.rs
index 30ca937f..4a394623 100644
--- a/sea-orm-macros/src/derives/active_model.rs
+++ b/sea-orm-macros/src/derives/active_model.rs
@@ -31,11 +31,17 @@ pub fn expand_derive_active_model(ident: Ident, data: Data) -> syn::Result<Token
     let ty: Vec<Type> = fields.into_iter().map(|Field { ty, .. }| ty).collect();
 
     Ok(quote!(
-        #[derive(Clone, Debug, Default)]
+        #[derive(Clone, Debug)]
         pub struct ActiveModel {
             #(pub #field: sea_orm::ActiveValue<#ty>),*
         }
 
+        impl Default for ActiveModel {
+            fn default() -> Self {
+                <Self as sea_orm::ActiveModelBehavior>::new()
+            }
+        }
+
         impl From<#ident> for ActiveModel {
             fn from(m: #ident) -> Self {
                 Self {
@@ -70,6 +76,12 @@ pub fn expand_derive_active_model(ident: Ident, data: Data) -> syn::Result<Token
                     #(<Self::Entity as EntityTrait>::Column::#name => self.#field = sea_orm::ActiveValue::unset()),*
                 }
             }
+
+            fn default() -> Self {
+                Self {
+                    #(#field: sea_orm::ActiveValue::unset()),*
+                }
+            }
         }
     ))
 }
diff --git a/src/entity/active_model.rs b/src/entity/active_model.rs
index 953f0384..2f7ae3d9 100644
--- a/src/entity/active_model.rs
+++ b/src/entity/active_model.rs
@@ -44,7 +44,7 @@ where
     ActiveValue::unchanged(value)
 }
 
-pub trait ActiveModelTrait: Clone + Debug + Default {
+pub trait ActiveModelTrait: Clone + Debug {
     type Entity: EntityTrait;
 
     fn take(&mut self, c: <Self::Entity as EntityTrait>::Column) -> ActiveValue<Value>;
@@ -54,6 +54,16 @@ pub trait ActiveModelTrait: Clone + Debug + Default {
     fn set(&mut self, c: <Self::Entity as EntityTrait>::Column, v: Value);
 
     fn unset(&mut self, c: <Self::Entity as EntityTrait>::Column);
+
+    fn default() -> Self;
+}
+
+pub trait ActiveModelBehavior: ActiveModelTrait {
+    type Entity: EntityTrait;
+
+    fn new() -> Self {
+        <Self as ActiveModelTrait>::default()
+    }
 }
 
 impl<V> ActiveValue<V>
diff --git a/src/entity/prelude.rs b/src/entity/prelude.rs
index 1edc6508..62d82027 100644
--- a/src/entity/prelude.rs
+++ b/src/entity/prelude.rs
@@ -1,6 +1,6 @@
 pub use crate::{
-    ActiveModelTrait, ColumnTrait, ColumnType, DeriveActiveModel, DeriveColumn, DeriveEntity,
-    DeriveModel, DerivePrimaryKey, EntityName, EntityTrait, EnumIter, Iden, IdenStatic, ModelTrait,
-    PrimaryKeyToColumn, PrimaryKeyTrait, QueryFilter, QueryResult, Related, RelationDef,
-    RelationTrait, Select, TypeErr, Value,
+    ActiveModelBehavior, ActiveModelTrait, ColumnTrait, ColumnType, DeriveActiveModel,
+    DeriveColumn, DeriveEntity, DeriveModel, DerivePrimaryKey, EntityName, EntityTrait, EnumIter,
+    Iden, IdenStatic, ModelTrait, PrimaryKeyToColumn, PrimaryKeyTrait, QueryFilter, QueryResult,
+    Related, RelationDef, RelationTrait, Select, TypeErr, Value,
 };
diff --git a/src/tests_cfg/cake.rs b/src/tests_cfg/cake.rs
index 7c5b2b1d..6b17e1b3 100644
--- a/src/tests_cfg/cake.rs
+++ b/src/tests_cfg/cake.rs
@@ -74,3 +74,7 @@ impl Model {
         Entity::find_related().belongs_to::<Entity>(self)
     }
 }
+
+impl ActiveModelBehavior for ActiveModel {
+    type Entity = Entity;
+}
diff --git a/src/tests_cfg/cake_filling.rs b/src/tests_cfg/cake_filling.rs
index 93db9cd9..1837d6c8 100644
--- a/src/tests_cfg/cake_filling.rs
+++ b/src/tests_cfg/cake_filling.rs
@@ -54,3 +54,7 @@ impl RelationTrait for Relation {
         }
     }
 }
+
+impl ActiveModelBehavior for ActiveModel {
+    type Entity = Entity;
+}
diff --git a/src/tests_cfg/filling.rs b/src/tests_cfg/filling.rs
index 673e62ee..856598d5 100644
--- a/src/tests_cfg/filling.rs
+++ b/src/tests_cfg/filling.rs
@@ -57,3 +57,7 @@ impl Model {
         Entity::find_related().belongs_to::<Entity>(self)
     }
 }
+
+impl ActiveModelBehavior for ActiveModel {
+    type Entity = Entity;
+}
diff --git a/src/tests_cfg/fruit.rs b/src/tests_cfg/fruit.rs
index b852d2f6..c99433c2 100644
--- a/src/tests_cfg/fruit.rs
+++ b/src/tests_cfg/fruit.rs
@@ -44,3 +44,7 @@ impl RelationTrait for Relation {
         panic!()
     }
 }
+
+impl ActiveModelBehavior for ActiveModel {
+    type Entity = Entity;
+}