log expected valid constructors

lostbean · Nov 30, 2024 · c6a71d9 · c6a71d9
1 parent cce8c2f
commit c6a71d9
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Showing 2 changed files with 13 additions and 8 deletions.
diff --git a/gleam.toml b/gleam.toml
@@ -1,5 +1,5 @@
 name = "json_blueprint"
-version = "1.2.0"
+version = "1.2.1"
 
 description = "Simplify JSON encoding/decoding while automatically generating JSON schemas for your data types."
 licences = ["MIT"]

diff --git a/src/json/blueprint.gleam b/src/json/blueprint.gleam
@@ -145,13 +145,18 @@ pub fn union_type_decoder(
         _ -> Error([])
       }
     })
-    |> result.replace_error([
-      dynamic.DecodeError(
-        expected: "valid constructor type",
-        found: type_str,
-        path: [],
-      ),
-    ])
+    |> result.map_error(fn(_) {
+      let valid_types =
+        decoders |> list.map(fn(dec) { dec.0 }) |> string.join(", ")
+
+      [
+        dynamic.DecodeError(
+          expected: "valid constructor type, one of: " <> valid_types,
+          found: type_str,
+          path: [],
+        ),
+      ]
+    })
   }
 
   let enum_decoder = fn(data) {