fix

assets/javascripts/discourse/components/param-input/category-id-input.gjs

@@ -0,0 +1,22 @@
+import Component from "@glimmer/component";
+import CategoryChooser from "select-kit/components/category-chooser";
+
+export default class GroupListInput extends Component {
+  // CategoryChooser will try to modify the value of value,
+  // triggering a setting-on-hash error. So we have to do the dirty work.
+  get data() {
+    return {
+      value: this.args.field.value,
+    };
+  }
+
+  <template>
+    <@field.Custom id={{@field.id}} @_tmp={{this.valueChange}}>
+      <CategoryChooser
+        @value={{this.data.value}}
+        @onChange={{@field.set}}
+        name={{@info.identifier}}
+      />
+    </@field.Custom>
+  </template>
+}

lib/discourse_data_explorer/parameter.rb

@@ -4,7 +4,7 @@ module ::DiscourseDataExplorer
   class Parameter
     attr_accessor :identifier, :type, :default, :nullable
 
-    def initialize(identifier, type, default, nullable)
+    def initialize(identifier, type, default, nullable, check: true)
       unless identifier
         raise ValidationError.new("Parameter declaration error - identifier is missing")
       end
@@ -25,7 +25,7 @@ def initialize(identifier, type, default, nullable)
       @default = default
       @nullable = nullable
       begin
-        cast_to_ruby default if default.present?
+        cast_to_ruby default if default.present? && check
       rescue ValidationError
         raise ValidationError.new(
                 "Parameter declaration error - the default value is not a valid #{type}",
@@ -89,7 +89,7 @@ def self.create_from_sql(sql, opts = {})
             type = type.strip
 
             begin
-              ret_params << Parameter.new(ident, type, default, nullable)
+              ret_params << Parameter.new(ident, type, default, nullable, check: false)
             rescue StandardError
               raise if opts[:strict]
             end