cfail tests for derive

Author: sfackler

postgres-derive-test/Cargo.toml

@@ -4,6 +4,8 @@ version = "0.1.0"
 authors = ["Steven Fackler <[email protected]>"]
 edition = "2018"
 
-[dependencies]
+[dev-dependencies]
+trybuild = "1.0"
+
 postgres-types = { path = "../postgres-types", features = ["derive"] }
 postgres = { path = "../postgres" }

postgres-derive-test/src/compile-fail/invalid-types.rs

@@ -0,0 +1,25 @@
+use postgres_types::{FromSql, ToSql};
+
+#[derive(ToSql)]
+struct ToSqlUnit;
+
+#[derive(FromSql)]
+struct FromSqlUnit;
+
+#[derive(ToSql)]
+struct ToSqlTuple(i32, i32);
+
+#[derive(FromSql)]
+struct FromSqlTuple(i32, i32);
+
+#[derive(ToSql)]
+enum ToSqlEnum {
+    Foo(i32),
+}
+
+#[derive(FromSql)]
+enum FromSqlEnum {
+    Foo(i32),
+}
+
+fn main() {}

postgres-derive-test/src/compile-fail/invalid-types.stderr

@@ -0,0 +1,35 @@
+error: #[derive(ToSql)] may only be applied to structs, single field tuple structs, and enums
+ --> $DIR/invalid-types.rs:4:1
+  |
+4 | struct ToSqlUnit;
+  | ^^^^^^^^^^^^^^^^^
+
+error: #[derive(FromSql)] may only be applied to structs, single field tuple structs, and enums
+ --> $DIR/invalid-types.rs:7:1
+  |
+7 | struct FromSqlUnit;
+  | ^^^^^^^^^^^^^^^^^^^
+
+error: #[derive(ToSql)] may only be applied to structs, single field tuple structs, and enums
+  --> $DIR/invalid-types.rs:10:1
+   |
+10 | struct ToSqlTuple(i32, i32);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: #[derive(FromSql)] may only be applied to structs, single field tuple structs, and enums
+  --> $DIR/invalid-types.rs:13:1
+   |
+13 | struct FromSqlTuple(i32, i32);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: non-C-like enums are not supported
+  --> $DIR/invalid-types.rs:17:5
+   |
+17 |     Foo(i32),
+   |     ^^^^^^^^
+
+error: non-C-like enums are not supported
+  --> $DIR/invalid-types.rs:22:5
+   |
+22 |     Foo(i32),
+   |     ^^^^^^^^

postgres-derive-test/src/compile-fail/unknown-override.rs

@@ -0,0 +1,15 @@
+use postgres_types::{FromSql, ToSql};
+
+#[derive(FromSql)]
+#[postgres(foo = "bar")]
+struct Foo {
+    a: i32,
+}
+
+#[derive(ToSql)]
+#[postgres(foo = "bar")]
+struct Bar {
+    a: i32,
+}
+
+fn main() {}

postgres-derive-test/src/compile-fail/unknown-override.stderr

@@ -0,0 +1,11 @@
+error: unknown override
+ --> $DIR/unknown-override.rs:4:12
+  |
+4 | #[postgres(foo = "bar")]
+  |            ^^^
+
+error: unknown override
+  --> $DIR/unknown-override.rs:10:12
+   |
+10 | #[postgres(foo = "bar")]
+   |            ^^^

postgres-derive-test/src/lib.rs

@@ -25,3 +25,8 @@ where
         assert_eq!(val, &result);
     }
 }
+
+#[test]
+fn compile_fail() {
+    trybuild::TestCases::new().compile_fail("src/compile-fail/*.rs");
+}

postgres-derive/src/fromsql.rs

@@ -51,7 +51,7 @@ pub fn expand_derive_fromsql(input: DeriveInput) -> Result<TokenStream, Error> {
         _ => {
             return Err(Error::new_spanned(
                 input,
-                "#[derive(ToSql)] may only be applied to structs, single field tuple structs, and enums",
+                "#[derive(FromSql)] may only be applied to structs, single field tuple structs, and enums",
             ))
         }
     };

postgres-derive/src/lib.rs

@@ -18,11 +18,15 @@ mod tosql;
 #[proc_macro_derive(ToSql, attributes(postgres))]
 pub fn derive_tosql(input: TokenStream) -> TokenStream {
     let input = syn::parse(input).unwrap();
-    tosql::expand_derive_tosql(input).unwrap().into()
+    tosql::expand_derive_tosql(input)
+        .unwrap_or_else(|e| e.to_compile_error())
+        .into()
 }
 
 #[proc_macro_derive(FromSql, attributes(postgres))]
 pub fn derive_fromsql(input: TokenStream) -> TokenStream {
     let input = syn::parse(input).unwrap();
-    fromsql::expand_derive_fromsql(input).unwrap().into()
+    fromsql::expand_derive_fromsql(input)
+        .unwrap_or_else(|e| e.to_compile_error())
+        .into()
 }