fix(derives): lift requirement of Copy + Clone on weak enums

Author: mehcode

sqlx-macros/src/derives/encode.rs

@@ -98,21 +98,27 @@ fn expand_derive_encode_weak_enum(
 ) -> syn::Result<proc_macro2::TokenStream> {
     let attr = check_weak_enum_attributes(input, &variants)?;
     let repr = attr.repr.unwrap();
-
     let ident = &input.ident;
 
+    let mut values = Vec::new();
+
+    for v in variants {
+        let id = &v.ident;
+        values.push(quote!(#ident :: #id => (#ident :: #id as #repr),));
+    }
+
     Ok(quote!(
         impl<'q, DB: sqlx::Database> sqlx::encode::Encode<'q, DB> for #ident where #repr: sqlx::encode::Encode<'q, DB> {
             fn encode_by_ref(&self, buf: &mut <DB as sqlx::database::HasArguments<'q>>::ArgumentBuffer) -> sqlx::encode::IsNull {
-                <#repr as sqlx::encode::Encode<DB>>::encode_by_ref(&(*self as #repr), buf)
-            }
+                let value = match self {
+                    #(#values)*
+                };
 
-            fn produces(&self) -> Option<DB::TypeInfo> {
-                <#repr as sqlx::encode::Encode<DB>>::produces(&(*self as #repr))
+                <#repr as sqlx::encode::Encode<DB>>::encode_by_ref(&value, buf)
             }
 
             fn size_hint(&self) -> usize {
-                <#repr as sqlx::encode::Encode<DB>>::size_hint(&(*self as #repr))
+                <#repr as sqlx::encode::Encode<DB>>::size_hint(&Default::default())
             }
         }
     ))
@@ -127,6 +133,7 @@ fn expand_derive_encode_strong_enum(
     let ident = &input.ident;
 
     let mut value_arms = Vec::new();
+
     for v in variants {
         let id = &v.ident;
         let attributes = parse_child_attributes(&v.attrs)?;

tests/mysql/macros.rs

@@ -132,6 +132,14 @@ enum MyEnum {
     Blue,
 }
 
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[repr(i32)]
+enum MyCEnum {
+    Red = 0,
+    Green,
+    Blue,
+}
+
 #[sqlx_macros::test]
 async fn test_column_override_wildcard() -> anyhow::Result<()> {
     struct Record {
@@ -172,7 +180,13 @@ async fn test_column_override_exact_enum() -> anyhow::Result<()> {
 
     assert_eq!(record.color, MyEnum::Red);
 
+    let record = sqlx::query!("select * from (select 2 as `color: MyCEnum`) records")
+        .fetch_one(&mut conn)
+        .await?;
+
+    assert_eq!(record.color, MyCEnum::Blue);
+
     Ok(())
 }
 
-// we don't emit bind parameter typechecks for MySQL so testing the overrides is redundant
+// we don't emit bind parameter type-checks for MySQL so testing the overrides is redundant