Add tests, fix error messages

Author: Xiretza

sqlx-macros-core/src/derives/attributes.rs

@@ -281,7 +281,7 @@ pub fn check_struct_attributes(
 
     assert_attribute!(
         !attributes.transparent,
-        "unexpected #[sqlx(transparent)]",
+        "unexpected #[sqlx(transparent)] - only valid for structs with exactly one field",
         input
     );
 

sqlx-macros-core/src/derives/decode.rs

@@ -34,7 +34,7 @@ pub fn expand_derive_decode(input: &DeriveInput) -> syn::Result<TokenStream> {
             ..
         }) => Err(syn::Error::new_spanned(
             input,
-            "structs with zero or more than one unnamed field are not supported",
+            "tuple structs may only have a single field",
         )),
         Data::Struct(DataStruct {
             fields: Fields::Unit,

sqlx-macros-core/src/derives/encode.rs

@@ -35,7 +35,7 @@ pub fn expand_derive_encode(input: &DeriveInput) -> syn::Result<TokenStream> {
             ..
         }) => Err(syn::Error::new_spanned(
             input,
-            "structs with zero or more than one unnamed field are not supported",
+            "tuple structs may only have a single field",
         )),
         Data::Struct(DataStruct {
             fields: Fields::Unit,

sqlx-macros-core/src/derives/type.rs

@@ -15,6 +15,7 @@ pub fn expand_derive_type(input: &DeriveInput) -> syn::Result<TokenStream> {
     match &input.data {
         // Newtype structs:
         // struct Foo(i32);
+        // struct Foo { field: i32 };
         Data::Struct(DataStruct { fields, .. })
             if fields.len() == 1 && (matches!(fields, Fields::Unnamed(_)) || attrs.transparent) =>
         {
@@ -31,7 +32,7 @@ pub fn expand_derive_type(input: &DeriveInput) -> syn::Result<TokenStream> {
             ..
         }) => Err(syn::Error::new_spanned(
             input,
-            "structs with zero or more than one unnamed field are not supported",
+            "tuple structs may only have a single field",
         )),
         Data::Struct(DataStruct {
             fields: Fields::Unit,

tests/mysql/macros.rs

@@ -585,4 +585,28 @@ async fn test_uuid_is_compatible_mariadb() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct MyIntNamed {
+    inner: i64,
+}
+
+struct NamedTransparentRecord {
+    id: MyIntNamed,
+}
+
+#[sqlx_macros::test]
+async fn test_named_transparent_struct() -> anyhow::Result<()> {
+    let mut conn = new::<MySql>().await?;
+    let (mut conn, id) = with_test_row(&mut conn).await?;
+
+    let record = sqlx::query!("select id as `id: MyIntNamed` from tweet")
+        .fetch_one(&mut *conn)
+        .await?;
+
+    assert_eq!(record.id, MyIntNamed { inner: 1 });
+
+    Ok(())
+}
+
 // we don't emit bind parameter type-checks for MySQL so testing the overrides is redundant

tests/postgres/derives.rs

@@ -12,6 +12,13 @@ use std::ops::Bound;
 #[sqlx(transparent)]
 struct Transparent(i32);
 
+// Also possible for single-field named structs
+#[derive(PartialEq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct TransparentNamed {
+    field: i32,
+}
+
 #[derive(PartialEq, Debug, sqlx::Type)]
 // https://github.com/launchbadge/sqlx/issues/2611
 // Previously, the derive would generate a `PgHasArrayType` impl that errored on an

tests/postgres/macros.rs

@@ -660,3 +660,27 @@ async fn pghstore_tests() -> anyhow::Result<()> {
 
     Ok(())
 }
+
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct MyIntNamed {
+    inner: i64,
+}
+
+struct NamedTransparentRecord {
+    id: MyIntNamed,
+}
+
+#[sqlx_macros::test]
+async fn test_named_transparent_struct() -> anyhow::Result<()> {
+    let mut conn = new::<Postgres>().await?;
+    let mut conn = with_test_row(&mut conn).await?;
+
+    let record = sqlx::query_as!(NamedTransparentRecord, r#"select id as "id: _" from tweet"#)
+        .fetch_one(&mut *conn)
+        .await?;
+
+    assert_eq!(record.id, MyIntNamed { inner: 1 });
+
+    Ok(())
+}

tests/sqlite/macros.rs

@@ -333,4 +333,27 @@ async fn test_column_override_exact_nullable() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct MyIntNamed {
+    inner: i64,
+}
+
+struct NamedTransparentRecord {
+    id: MyIntNamed,
+}
+
+#[sqlx_macros::test]
+async fn test_named_transparent_struct() -> anyhow::Result<()> {
+    let mut conn = new::<Sqlite>().await?;
+
+    let record = sqlx::query_as!(Record, r#"select id as "id: _" from tweet"#)
+        .fetch_one(&mut conn)
+        .await?;
+
+    assert_eq!(record.id, MyIntNamed { inner: 1 });
+
+    Ok(())
+}
+
 // we don't emit bind parameter typechecks for SQLite so testing the overrides is redundant