feat(api): field-level set_fields 422 body (#28); enum-type SearchHitView.visibility (#38)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/api/src/admin_objects.rs

@@ -510,6 +510,15 @@ pub(crate) async fn create_field_definition(
     }
 }
 
+/// Field-level rejection detail for `set_fields`, so the UI can highlight the field.
+#[derive(Serialize, ToSchema)]
+pub(crate) struct FieldErrorView {
+    /// The flexible-field key that was rejected.
+    pub field: String,
+    /// Machine code: "unknown" | "type_mismatch" | "unresolved".
+    pub code: String,
+}
+
 /// Replace an object's flexible-field values (validated against the registry).
 ///
 /// **Replace semantics:** the body is the *complete* desired field set. Omitting a key
@@ -525,7 +534,7 @@ pub(crate) async fn create_field_definition(
         (status = 401),
         (status = 403),
         (status = 404, description = "Object not found"),
-        (status = 422, description = "Unknown field, type mismatch, or unresolved reference")
+        (status = 422, body = FieldErrorView, description = "A field was rejected")
     )
 )]
 pub(crate) async fn set_fields(
@@ -533,34 +542,57 @@ pub(crate) async fn set_fields(
     State(state): State<AppState>,
     Path(id): Path<String>,
     Json(values): Json<serde_json::Map<String, serde_json::Value>>,
-) -> Result<StatusCode, StatusCode> {
-    let object_id = id.parse::<ObjectId>().map_err(|_| StatusCode::NOT_FOUND)?;
+) -> axum::response::Response {
+    use axum::response::IntoResponse;
 
-    let mut tx = state
-        .db
-        .pool()
-        .begin()
-        .await
-        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+    let Ok(object_id) = id.parse::<ObjectId>() else {
+        return StatusCode::NOT_FOUND.into_response();
+    };
+
+    let mut tx = match state.db.pool().begin().await {
+        Ok(tx) => tx,
+        Err(_) => return StatusCode::INTERNAL_SERVER_ERROR.into_response(),
+    };
 
     let result =
         db::catalog::set_object_fields(&mut tx, actor(&auth.user), object_id, &values).await;
 
     match result {
         Ok(()) => {
-            tx.commit()
-                .await
-                .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+            if tx.commit().await.is_err() {
+                return StatusCode::INTERNAL_SERVER_ERROR.into_response();
+            }
 
             reindex(&state, object_id).await;
 
-            Ok(StatusCode::NO_CONTENT)
+            StatusCode::NO_CONTENT.into_response()
         }
-        Err(db::catalog::FieldError::ObjectNotFound) => Err(StatusCode::NOT_FOUND),
-        Err(db::catalog::FieldError::Db(_)) => Err(StatusCode::INTERNAL_SERVER_ERROR),
-        Err(db::catalog::FieldError::UnknownField(_)) => Err(StatusCode::UNPROCESSABLE_ENTITY),
-        Err(db::catalog::FieldError::TypeMismatch { .. }) => Err(StatusCode::UNPROCESSABLE_ENTITY),
-        Err(db::catalog::FieldError::Unresolved { .. }) => Err(StatusCode::UNPROCESSABLE_ENTITY),
+        Err(db::catalog::FieldError::ObjectNotFound) => StatusCode::NOT_FOUND.into_response(),
+        Err(db::catalog::FieldError::Db(_)) => StatusCode::INTERNAL_SERVER_ERROR.into_response(),
+        Err(db::catalog::FieldError::UnknownField(field)) => (
+            StatusCode::UNPROCESSABLE_ENTITY,
+            Json(FieldErrorView {
+                field,
+                code: "unknown".to_owned(),
+            }),
+        )
+            .into_response(),
+        Err(db::catalog::FieldError::TypeMismatch { field, .. }) => (
+            StatusCode::UNPROCESSABLE_ENTITY,
+            Json(FieldErrorView {
+                field,
+                code: "type_mismatch".to_owned(),
+            }),
+        )
+            .into_response(),
+        Err(db::catalog::FieldError::Unresolved { field, .. }) => (
+            StatusCode::UNPROCESSABLE_ENTITY,
+            Json(FieldErrorView {
+                field,
+                code: "unresolved".to_owned(),
+            }),
+        )
+            .into_response(),
     }
 }