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)]",
+        "#[sqlx(transparent)] is 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/derives.rs

@@ -1,5 +1,5 @@
 use sqlx_mysql::MySql;
-use sqlx_test::new;
+use sqlx_test::{new, test_type};
 
 #[sqlx::test]
 async fn test_derive_strong_enum() -> anyhow::Result<()> {
@@ -300,3 +300,23 @@ async fn test_derive_weak_enum() -> anyhow::Result<()> {
 
     Ok(())
 }
+
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct TransparentTuple(i64);
+
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct TransparentNamed {
+    field: i64,
+}
+
+test_type!(transparent_tuple<TransparentTuple>(Mysql,
+    "0" == TransparentTuple(0),
+    "23523" == TransparentTuple(23523)
+));
+
+test_type!(transparent_named<TransparentNamed>(Mysql,
+    "0" == TransparentNamed { field: 0 },
+    "23523" == TransparentNamed { field: 23523 },
+));

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
@@ -143,11 +150,16 @@ struct FloatRange(PgRange<f64>);
 #[sqlx(type_name = "int4rangeL0pC")]
 struct RangeInclusive(PgRange<i32>);
 
-test_type!(transparent<Transparent>(Postgres,
+test_type!(transparent_tuple<Transparent>(Postgres,
     "0" == Transparent(0),
     "23523" == Transparent(23523)
 ));
 
+test_type!(transparent_named<TransparentNamed>(Postgres,
+    "0" == TransparentNamed { field: 0 },
+    "23523" == TransparentNamed { field: 23523 },
+));
+
 test_type!(transparent_array<TransparentArray>(Postgres,
     "'{}'::int8[]" == TransparentArray(vec![]),
     "'{ 23523, 123456, 789 }'::int8[]" == TransparentArray(vec![23523, 123456, 789])

tests/sqlite/derives.rs

@@ -12,3 +12,23 @@ test_type!(origin_enum<Origin>(Sqlite,
     "1" == Origin::Foo,
     "2" == Origin::Bar,
 ));
+
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct TransparentTuple(i64);
+
+#[derive(PartialEq, Eq, Debug, sqlx::Type)]
+#[sqlx(transparent)]
+struct TransparentNamed {
+    field: i64,
+}
+
+test_type!(transparent_tuple<TransparentTuple>(Sqlite,
+    "0" == TransparentTuple(0),
+    "23523" == TransparentTuple(23523)
+));
+
+test_type!(transparent_named<TransparentNamed>(Sqlite,
+    "0" == TransparentNamed { field: 0 },
+    "23523" == TransparentNamed { field: 23523 },
+));