Fix encoding and decoding of MySQL enums in sqlx::Type (#3371)

Cargo.toml

@@ -287,6 +287,11 @@ name = "mysql-describe"
 path = "tests/mysql/describe.rs"
 required-features = ["mysql"]
 
+[[test]]
+name = "mysql-derives"
+path = "tests/mysql/derives.rs"
+required-features = ["mysql", "derive"]
+
 [[test]]
 name = "mysql-macros"
 path = "tests/mysql/macros.rs"

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

@@ -183,10 +183,6 @@ fn expand_derive_has_sql_type_strong_enum(
                 fn type_info() -> ::sqlx::mysql::MySqlTypeInfo {
                     ::sqlx::mysql::MySqlTypeInfo::__enum()
                 }
-
-                fn compatible(ty: &::sqlx::mysql::MySqlTypeInfo) -> ::std::primitive::bool {
-                    *ty == ::sqlx::mysql::MySqlTypeInfo::__enum()
-                }
             }
         ));
     }

sqlx-mysql/src/type_info.rs

@@ -27,9 +27,17 @@ impl MySqlTypeInfo {
 
     #[doc(hidden)]
     pub const fn __enum() -> Self {
+        // Newer versions of MySQL seem to expect that a parameter binding of `MYSQL_TYPE_ENUM`
+        // means that the value is encoded as an integer.
+        //
+        // For "strong" enums inputted as strings, we need to specify this type instead
+        // for wider compatibility. This works on all covered versions of MySQL and MariaDB.
+        //
+        // Annoyingly, MySQL's developer documentation doesn't really explain this anywhere;
+        // this had to be determined experimentally.
         Self {
-            r#type: ColumnType::Enum,
-            flags: ColumnFlags::BINARY,
+            r#type: ColumnType::String,
+            flags: ColumnFlags::ENUM,
             max_size: None,
         }
     }

sqlx-test/Cargo.toml

@@ -9,5 +9,3 @@ sqlx = { default-features = false, path = ".." }
 env_logger = "0.11"
 dotenvy = "0.15.0"
 anyhow = "1.0.26"
-async-std = { version = "1.8.0", features = [ "attributes" ] }
-tokio = { version = "1.0.1", features = [ "full" ] }

tests/mysql/derives.rs

@@ -0,0 +1,302 @@
+use sqlx_mysql::MySql;
+use sqlx_test::new;
+
+#[sqlx::test]
+async fn test_derive_strong_enum() -> anyhow::Result<()> {
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    #[sqlx(rename_all = "PascalCase")]
+    enum PascalCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    #[sqlx(rename_all = "camelCase")]
+    enum CamelCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    #[sqlx(rename_all = "snake_case")]
+    enum SnakeCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    #[sqlx(rename_all = "SCREAMING_SNAKE_CASE")]
+    enum ScreamingSnakeCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    #[sqlx(rename_all = "kebab-case")]
+    enum KebabCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    #[sqlx(rename_all = "lowercase")]
+    enum LowerCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    #[sqlx(rename_all = "UPPERCASE")]
+    enum UpperCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::Type, PartialEq, Eq, Debug)]
+    enum DefaultCaseEnum {
+        FooFoo,
+        BarBar,
+        BazBaz,
+    }
+
+    #[derive(sqlx::FromRow, PartialEq, Eq, Debug)]
+    struct StrongEnumRow {
+        pascal_case: PascalCaseEnum,
+        camel_case: CamelCaseEnum,
+        snake_case: SnakeCaseEnum,
+        screaming_snake_case: ScreamingSnakeCaseEnum,
+        kebab_case: KebabCaseEnum,
+        lowercase: LowerCaseEnum,
+        uppercase: UpperCaseEnum,
+        default_case: DefaultCaseEnum,
+    }
+
+    let mut conn = new::<MySql>().await?;
+
+    sqlx::raw_sql(
+        r#"
+            CREATE TEMPORARY TABLE strong_enum (
+                pascal_case ENUM('FooFoo', 'BarBar', 'BazBaz'),
+                camel_case ENUM('fooFoo', 'barBar', 'bazBaz'),
+                snake_case ENUM('foo_foo', 'bar_bar', 'baz_baz'),
+                screaming_snake_case ENUM('FOO_FOO', 'BAR_BAR', 'BAZ_BAZ'),
+                kebab_case ENUM('foo-foo', 'bar-bar', 'baz-baz'),
+                lowercase ENUM('foofoo', 'barbar', 'bazbaz'),
+                uppercase ENUM('FOOFOO', 'BARBAR', 'BAZBAZ'),
+                default_case ENUM('FooFoo', 'BarBar', 'BazBaz')
+            );
+        "#,
+    )
+    .execute(&mut conn)
+    .await?;
+
+    let input = StrongEnumRow {
+        pascal_case: PascalCaseEnum::FooFoo,
+        camel_case: CamelCaseEnum::BarBar,
+        snake_case: SnakeCaseEnum::BazBaz,
+        screaming_snake_case: ScreamingSnakeCaseEnum::FooFoo,
+        kebab_case: KebabCaseEnum::BarBar,
+        lowercase: LowerCaseEnum::BazBaz,
+        uppercase: UpperCaseEnum::FooFoo,
+        default_case: DefaultCaseEnum::BarBar,
+    };
+
+    sqlx::query(
+        r#"
+            INSERT INTO strong_enum(
+                pascal_case,
+                camel_case,
+                snake_case,
+                screaming_snake_case,
+                kebab_case,
+                lowercase,
+                uppercase,
+                default_case
+            )
+            VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+        "#,
+    )
+    .bind(&input.pascal_case)
+    .bind(&input.camel_case)
+    .bind(&input.snake_case)
+    .bind(&input.screaming_snake_case)
+    .bind(&input.kebab_case)
+    .bind(&input.lowercase)
+    .bind(&input.uppercase)
+    .bind(&input.default_case)
+    .execute(&mut conn)
+    .await?;
+
+    let output: StrongEnumRow = sqlx::query_as("SELECT * FROM strong_enum")
+        .fetch_one(&mut conn)
+        .await?;
+
+    assert_eq!(input, output);
+
+    Ok(())
+}
+
+#[sqlx::test]
+async fn test_derive_weak_enum() -> anyhow::Result<()> {
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(i8)]
+    enum WeakEnumI8 {
+        Foo = i8::MIN,
+        Bar = 0,
+        Baz = i8::MAX,
+    }
+
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(i16)]
+    enum WeakEnumI16 {
+        Foo = i16::MIN,
+        Bar = 0,
+        Baz = i16::MAX,
+    }
+
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(i32)]
+    enum WeakEnumI32 {
+        Foo = i32::MIN,
+        Bar = 0,
+        Baz = i32::MAX,
+    }
+
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(i64)]
+    enum WeakEnumI64 {
+        Foo = i64::MIN,
+        Bar = 0,
+        Baz = i64::MAX,
+    }
+
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(u8)]
+    enum WeakEnumU8 {
+        Foo = 0,
+        Bar = 1,
+        Baz = u8::MAX,
+    }
+
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(u16)]
+    enum WeakEnumU16 {
+        Foo = 0,
+        Bar = 1,
+        Baz = u16::MAX,
+    }
+
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(u32)]
+    enum WeakEnumU32 {
+        Foo = 0,
+        Bar = 1,
+        Baz = u32::MAX,
+    }
+
+    #[derive(sqlx::Type, Debug, PartialEq, Eq)]
+    #[repr(u64)]
+    enum WeakEnumU64 {
+        Foo = 0,
+        Bar = 1,
+        Baz = u64::MAX,
+    }
+
+    #[derive(sqlx::FromRow, Debug, PartialEq, Eq)]
+    struct WeakEnumRow {
+        i8: WeakEnumI8,
+        i16: WeakEnumI16,
+        i32: WeakEnumI32,
+        i64: WeakEnumI64,
+        u8: WeakEnumU8,
+        u16: WeakEnumU16,
+        u32: WeakEnumU32,
+        u64: WeakEnumU64,
+    }
+
+    let mut conn = new::<MySql>().await?;
+
+    sqlx::raw_sql(
+        r#"
+            CREATE TEMPORARY TABLE weak_enum (
+                i8 TINYINT,
+                i16 SMALLINT,
+                i32 INT,
+                i64 BIGINT,
+                u8 TINYINT UNSIGNED,
+                u16 SMALLINT UNSIGNED,
+                u32 INT UNSIGNED,
+                u64 BIGINT UNSIGNED
+            )
+        "#,
+    )
+    .execute(&mut conn)
+    .await?;
+
+    let rows_in = vec![
+        WeakEnumRow {
+            i8: WeakEnumI8::Foo,
+            i16: WeakEnumI16::Foo,
+            i32: WeakEnumI32::Foo,
+            i64: WeakEnumI64::Foo,
+            u8: WeakEnumU8::Foo,
+            u16: WeakEnumU16::Foo,
+            u32: WeakEnumU32::Foo,
+            u64: WeakEnumU64::Foo,
+        },
+        WeakEnumRow {
+            i8: WeakEnumI8::Bar,
+            i16: WeakEnumI16::Bar,
+            i32: WeakEnumI32::Bar,
+            i64: WeakEnumI64::Bar,
+            u8: WeakEnumU8::Bar,
+            u16: WeakEnumU16::Bar,
+            u32: WeakEnumU32::Bar,
+            u64: WeakEnumU64::Bar,
+        },
+        WeakEnumRow {
+            i8: WeakEnumI8::Baz,
+            i16: WeakEnumI16::Baz,
+            i32: WeakEnumI32::Baz,
+            i64: WeakEnumI64::Baz,
+            u8: WeakEnumU8::Baz,
+            u16: WeakEnumU16::Baz,
+            u32: WeakEnumU32::Baz,
+            u64: WeakEnumU64::Baz,
+        },
+    ];
+
+    for row in &rows_in {
+        sqlx::query(
+            r#"
+                INSERT INTO weak_enum(i8, i16, i32, i64, u8, u16, u32, u64)
+                VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+            "#,
+        )
+        .bind(&row.i8)
+        .bind(&row.i16)
+        .bind(&row.i32)
+        .bind(&row.i64)
+        .bind(&row.u8)
+        .bind(&row.u16)
+        .bind(&row.u32)
+        .bind(&row.u64)
+        .execute(&mut conn)
+        .await?;
+    }
+
+    let rows_out: Vec<WeakEnumRow> = sqlx::query_as("SELECT * FROM weak_enum")
+        .fetch_all(&mut conn)
+        .await?;
+
+    assert_eq!(rows_in, rows_out);
+
+    Ok(())
+}