updates to address coderabbit comments

Author: tlabaj

packages/react-icons/src/__tests__/createIcon.test.tsx

@@ -78,6 +78,17 @@ test('accepts CreateIconProps with nested icon using deprecated svgPath field',
   expect(screen.getByRole('img', { hidden: true }).querySelector('path')).toHaveAttribute('d', 'nested-legacy-d');
 });
 
+test('throws when nested CreateIconProps omits icon', () => {
+  expect(() =>
+    createIcon({
+      name: 'MissingDefaultIcon',
+      rhUiIcon: null
+    })
+  ).toThrow(
+    '@patternfly/react-icons: createIcon requires an `icon` definition when using nested CreateIconProps (name: MissingDefaultIcon).'
+  );
+});
+
 test('sets correct svgPath if array', () => {
   render(<SVGArrayIcon />);
   const paths = screen.getByRole('img', { hidden: true }).querySelectorAll('path');

packages/react-icons/src/createIcon.tsx

@@ -86,9 +86,15 @@ interface NormalizedCreateIconProps {
 function normalizeCreateIconArg(arg: CreateIconProps | LegacyFlatIconDefinition): NormalizedCreateIconProps {
   if (isNestedCreateIconProps(arg)) {
     const p = arg as CreateIconProps;
+    if (p.icon == null) {
+      const label = p.name != null ? ` (name: ${String(p.name)})` : '';
+      throw new Error(
+        `@patternfly/react-icons: createIcon requires an \`icon\` definition when using nested CreateIconProps${label}.`
+      );
+    }
     return {
       name: p.name,
-      icon: p.icon !== undefined && p.icon !== null ? normalizeIconDefinition(p.icon) : undefined,
+      icon: normalizeIconDefinition(p.icon),
       rhUiIcon: p.rhUiIcon != null ? normalizeIconDefinition(p.rhUiIcon) : null
     };
   }