Account for case when builder is external, entity exists, but docs do not.

Co-authored-by: Jeremy Guarini <jguarini@paloaltonetworks.com>
Signed-off-by: Eric Peterson <ericpeterson@spotify.com>

plugins/techdocs/src/reader/components/TechDocsReaderPageHeader/TechDocsReaderPageHeader.test.tsx

@@ -148,6 +148,28 @@ describe('<TechDocsReaderPageHeader />', () => {
     });
   });
 
+  it('should not render a techdocs page header if techdocs metadata is missing', async () => {
+    getTechDocsMetadata.mockResolvedValue(undefined);
+
+    await act(async () => {
+      const rendered = await renderInTestApp(
+        <Wrapper>
+          <TechDocsReaderPageHeader />
+        </Wrapper>,
+        {
+          mountedRoutes: {
+            '/catalog/:namespace/:kind/:name/*': entityRouteRef,
+            '/docs': rootRouteRef,
+          },
+        },
+      );
+
+      await waitFor(() => {
+        expect(rendered.container.innerHTML).not.toContain('header');
+      });
+    });
+  });
+
   it('should render a link back to the component page', async () => {
     getTechDocsMetadata.mockResolvedValue(mockTechDocsMetadata);
 

plugins/techdocs/src/reader/components/TechDocsReaderPageHeader/TechDocsReaderPageHeader.tsx

@@ -71,7 +71,7 @@ export const TechDocsReaderPageHeader = (
     subtitle,
     setSubtitle,
     entityRef,
-    metadata: { value: metadata },
+    metadata: { value: metadata, loading: metadataLoading },
     entityMetadata: { value: entityMetadata, loading: entityMetadataLoading },
   } = useTechDocsReaderPage();
 
@@ -146,9 +146,11 @@ export const TechDocsReaderPageHeader = (
     </>
   );
 
-  // If there is no entity metadata, there's no reason to show the header.
-  if (entityMetadataLoading === false && entityMetadata === undefined)
-    return null;
+  // If there is no entity or techdocs metadata, there's no reason to show the
+  // header (hides the header on 404 error pages).
+  const noEntMetadata = !entityMetadataLoading && entityMetadata === undefined;
+  const noTdMetadata = !metadataLoading && metadata === undefined;
+  if (noEntMetadata || noTdMetadata) return null;
 
   return (
     <Header