Refactor kube-derive using darling

kube-derive/Cargo.toml

@@ -32,3 +32,4 @@ serde_yaml = "0.8.14"
 k8s-openapi = { version = "0.11.0", default-features = false, features = ["v1_20"] }
 schemars = { version = "0.8.0", features = ["chrono"] }
 chrono = "0.4.19"
+trybuild = "1.0"

kube-derive/src/custom_resource.rs

@@ -46,7 +46,7 @@ pub(crate) fn derive(input: proc_macro2::TokenStream) -> proc_macro2::TokenStrea
         _ => {
             return syn::Error::new_spanned(
                 &derive_input.ident,
-                r#"Enums or Unions can not #[derive(CustomResource)"#,
+                r#"Enums or Unions can not #[derive(CustomResource)]"#,
             )
             .to_compile_error()
         }

kube-derive/tests/test_ui.rs

@@ -0,0 +1,10 @@
+// Test that `kube-derive` outputs helpful error messages.
+// If you make a change, remove `tests/ui/*.stderr` and run `cargo test`.
+// Then copy the files that appear under `wip/` if it's what you expected.
+// Alternatively, run `TRYBUILD=overwrite cargo test`.
+// See https://github.com/dtolnay/trybuild
+#[test]
+fn test_failures() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/ui/*.rs");
+}

kube-derive/tests/ui/enum_fails.rs

@@ -0,0 +1,10 @@
+use kube_derive::CustomResource;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+#[derive(CustomResource, Serialize, Deserialize, Debug, Clone, JsonSchema)]
+enum FooSpec {
+    Foo,
+}
+
+fn main() {}

kube-derive/tests/ui/enum_fails.stderr

@@ -0,0 +1,5 @@
+error: Enums or Unions can not #[derive(CustomResource)]
+ --> $DIR/enum_fails.rs:6:6
+  |
+6 | enum FooSpec {
+  |      ^^^^^^^

kube-derive/tests/ui/fail_with_suggestion.rs

@@ -0,0 +1,11 @@
+use kube_derive::CustomResource;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+#[derive(CustomResource, Serialize, Deserialize, Debug, Clone, JsonSchema)]
+#[kube(group = "clux.dev", version = "v1", kind = "Foo", shortnames = "foo")]
+struct FooSpec {
+    foo: String,
+}
+
+fn main() {}

kube-derive/tests/ui/fail_with_suggestion.stderr

@@ -0,0 +1,5 @@
+error: Unknown field: `shortnames`. Did you mean `shortname`?
+ --> $DIR/fail_with_suggestion.rs:6:58
+  |
+6 | #[kube(group = "clux.dev", version = "v1", kind = "Foo", shortnames = "foo")]
+  |                                                          ^^^^^^^^^^

kube-derive/tests/ui/missing_required.rs

@@ -0,0 +1,10 @@
+use kube_derive::CustomResource;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+#[derive(CustomResource, Serialize, Deserialize, Debug, Clone, JsonSchema)]
+struct FooSpec {
+    foo: String,
+}
+
+fn main() {}

kube-derive/tests/ui/missing_required.stderr

@@ -0,0 +1,23 @@
+error: Missing field `group`
+ --> $DIR/missing_required.rs:5:10
+  |
+5 | #[derive(CustomResource, Serialize, Deserialize, Debug, Clone, JsonSchema)]
+  |          ^^^^^^^^^^^^^^
+  |
+  = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Missing field `version`
+ --> $DIR/missing_required.rs:5:10
+  |
+5 | #[derive(CustomResource, Serialize, Deserialize, Debug, Clone, JsonSchema)]
+  |          ^^^^^^^^^^^^^^
+  |
+  = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Missing field `kind`
+ --> $DIR/missing_required.rs:5:10
+  |
+5 | #[derive(CustomResource, Serialize, Deserialize, Debug, Clone, JsonSchema)]
+  |          ^^^^^^^^^^^^^^
+  |
+  = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)