test: add untagged enum test

.vscode/settings.json

@@ -6,6 +6,7 @@
     "dataless",
     "deserializations",
     "docsrs",
+    "formatdoc",
     "impls",
     "indoc",
     "ipnetwork",

confik-macros/Cargo.toml

@@ -22,7 +22,9 @@ syn = { version = "2", features = ["extra-traits"] }
 [dev-dependencies]
 assert_matches = "1.5"
 confik = "0.11"
+indoc = "2"
 rustversion = "1"
 serde = { version = "1", features = ["derive"] }
+serde-bool = "0.1"
 toml = "0.8"
 trybuild = { version = "1", features = ["diff"] }

confik-macros/tests/trybuild.rs

@@ -28,6 +28,7 @@ fn compile_macros() {
     t.pass("tests/trybuild/22-dataless-types.rs");
     t.pass("tests/trybuild/23-where-clause.rs");
     t.pass("tests/trybuild/24-field-try-from.rs");
+    t.pass("tests/trybuild/pass-enum-untagged.rs");
 
     t.compile_fail("tests/trybuild/fail-default-parse.rs");
     t.compile_fail("tests/trybuild/fail-default-invalid-expr.rs");

confik-macros/tests/trybuild/21-field-from.rs

@@ -1,4 +1,5 @@
 //! Check that the `from` attribute works
+
 use confik::{Configuration, TomlSource};
 
 #[derive(Debug, Configuration, PartialEq, Eq)]

confik-macros/tests/trybuild/pass-enum-untagged.rs

@@ -0,0 +1,66 @@
+//! Checks "untagged enum" behavior / fall-through when deserializing.
+
+use confik::{Configuration, TomlSource};
+
+#[derive(Debug, serde::Deserialize)]
+#[serde(untagged)]
+enum S3Auth {
+    K8sServiceAccount {
+        use_k8s_service_account: serde_bool::True,
+    },
+
+    ApiKey {
+        access_key: String,
+        access_secret: String,
+    },
+}
+
+impl Configuration for S3Auth {
+    type Builder = Option<Self>;
+}
+
+#[derive(Debug, Configuration)]
+struct Config {
+    s3_auth: S3Auth,
+}
+
+fn main() {
+    let config = indoc::formatdoc! {"
+        [s3_auth]
+        use_k8s_service_account = false
+    "};
+    Config::builder()
+        .override_with(TomlSource::new(config))
+        .try_build()
+        .expect_err("Successfully built with incorrect boolean inner value");
+
+    let config = indoc::formatdoc! {"
+        [s3_auth]
+        use_k8s_service_account = true
+    "};
+    let config = Config::builder()
+        .override_with(TomlSource::new(config))
+        .try_build()
+        .expect("Failed to build");
+    assert_matches::assert_matches!(config.s3_auth, S3Auth::K8sServiceAccount { .. });
+
+    let config = indoc::formatdoc! {"
+        [s3_auth]
+        access_key = \"foo\"
+        access_secret = \"bar\"
+    "};
+    let config = Config::builder()
+        .override_with(TomlSource::new(config))
+        .try_build()
+        .expect("Failed to build");
+    assert_matches::assert_matches!(config.s3_auth, S3Auth::ApiKey { .. });
+}
+
+// /// Only successfully deserializes from a `true` value boolean.
+// struct True;
+
+// impl serde::Deserialize for True {}
+
+// impl config::Configuration for True {
+//     type Builder = Option<Self>;
+// }