Added test case for issue 1920. See test comments for description.

issues/1920/Cargo.toml

@@ -0,0 +1,20 @@
+[workspace]
+
+[package]
+name = "sea-orm-issues-1790"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
+anyhow = "1"
+serde = "1"
+tokio = { version = "1", features = ["rt", "rt-multi-thread", "macros"] }
+
+[lib]
+path = "src/test.rs"
+
+[dependencies.sea-orm]
+path = "../../"
+default-features = false
+features = ["default", "macros", "runtime-tokio-native-tls", "sqlx-postgres", "tests-cfg"]

issues/1920/src/test.rs

@@ -0,0 +1,84 @@
+use sea_orm::{prelude::*, FromQueryResult};
+use serde::{Deserialize, Serialize};
+
+
+#[derive(Debug, Clone, PartialEq, Eq, EnumIter, DeriveActiveEnum, Serialize, Deserialize)]
+#[sea_orm(
+    rs_type = "String",
+    db_type = "Enum",
+    enum_name = "someenum"
+)]
+pub enum SomeEnum {
+    #[sea_orm(string_value = "foo")]
+    Foo,
+}
+
+#[derive(Clone, Debug, PartialEq, DeriveEntityModel, Eq, Serialize, Deserialize)]
+#[sea_orm(table_name = "some_table")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub id: i32,
+    pub status: Option<SomeEnum>,
+}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {}
+
+impl ActiveModelBehavior for ActiveModel {}
+
+mod tests {
+    use sea_orm::{tests_cfg::cake, DbBackend, Insert, QuerySelect, QueryTrait, Select, SelectColumns};
+
+    use super::*;
+
+    #[test]
+    fn insert_do_nothing_postgres() {
+        let exp1 = Entity::find()
+                .select_only()
+                .column(Column::Status)
+                .build(DbBackend::Postgres)
+                .sql;
+
+        let exp2 = Entity::find()
+                .select_only()
+                .column_as(Column::Status, "status")
+                .build(DbBackend::Postgres)
+                .sql;
+
+        // This seems like it should match...?
+        // // assert_eq!(exp1, exp2);
+        // But it doesn't...
+        assert_ne!(exp1, exp2);
+        // The result is that select_as can't be used with an enum, because DecodeColumn expects Enums to be Text.
+        // So it throws a mismatched_types error.
+        // https://github.com/launchbadge/sqlx/blob/293c55ce896edefc797b6b819c8b27cd327382bb/sqlx-core/src/error.rs#L156
+        // For example:
+        // Error: DatabaseError(Query(SqlxError(ColumnDecode { index: "\"realestateproject_status\"", source: "mismatched types; Rust type `core::option::Option<alloc::string::String>` (as SQL type `TEXT`) is not compatible with SQL type `realestateprojectstatus`" })))
+
+        // Workaround
+        let exp1 = Entity::find()
+            .select_only()
+            .column(Column::Status)
+            .build(DbBackend::Postgres)
+            .sql;
+
+        let exp2 = Entity::find()
+            .select_only()
+            .column_as(
+                Expr::col(Column::Status)
+                    .cast_as(sea_orm::sea_query::Alias::new("TEXT")),
+                "status",
+            )
+            .build(DbBackend::Postgres)
+            .sql;
+
+        // This matches functionally, but not exactly. It's a workaround.
+        // assert_eq!(exp1, exp2);
+
+        // left: "SELECT CAST(\"some_table\".\"status\" AS text) FROM \"some_table\""
+        // right: "SELECT CAST(\"status\" AS TEXT) AS \"status\" FROM \"some_table\""
+
+        // It isn't clear to me WHY the type is being case to text and then back, rather than just being cast to a Rust enum.
+        // The reasoning isn't documented. It seems like it should be possible to cast directly to the enum.
+    }
+}