Prevent Draftail from crashing on links to the root page

client/src/components/Draftail/sources/ModalWorkflowSource.js

@@ -50,7 +50,11 @@ export const getChooserConfig = (entityType, entity, selectedText) => {
       const data = entity.getData();
 
       if (data.id) {
-        url = `${global.chooserUrls.pageChooser}${data.parentId}/`;
+        if (data.parentId !== null) {
+          url = `${global.chooserUrls.pageChooser}${data.parentId}/`;
+        } else {
+          url = global.chooserUrls.pageChooser;
+        }
       } else if (data.url.startsWith('mailto:')) {
         url = global.chooserUrls.emailLinkChooser;
         urlParams.link_url = data.url.replace('mailto:', '');

client/src/components/Draftail/sources/ModalWorkflowSource.test.js

@@ -61,7 +61,13 @@ describe('ModalWorkflowSource', () => {
 
       it('page', () => {
         expect(getChooserConfig({ type: 'LINK' }, {
-          getData: () => ({ id: 1, parentId: 0 })
+          getData: () => ({ id: 2, parentId: 1 })
+        }, '')).toMatchSnapshot();
+      });
+
+      it('root page', () => {
+        expect(getChooserConfig({ type: 'LINK' }, {
+          getData: () => ({ id: 1, parentId: null })
         }, '')).toMatchSnapshot();
       });
 

client/src/components/Draftail/sources/__snapshots__/ModalWorkflowSource.test.js.snap

@@ -103,7 +103,22 @@ Object {
   "onload": Object {
     "type": "page",
   },
-  "url": "/admin/choose-page/0/",
+  "url": "/admin/choose-page/1/",
+  "urlParams": Object {
+    "allow_email_link": true,
+    "allow_external_link": true,
+    "link_text": "",
+    "page_type": "wagtailcore.page",
+  },
+}
+`;
+
+exports[`ModalWorkflowSource #getChooserConfig LINK root page 1`] = `
+Object {
+  "onload": Object {
+    "type": "page",
+  },
+  "url": "/admin/choose-page/",
   "urlParams": Object {
     "allow_email_link": true,
     "allow_external_link": true,

wagtail/admin/rich_text/converters/html_to_contentstate.py

@@ -208,10 +208,12 @@ class PageLinkElementHandler(LinkElementHandler):
         except Page.DoesNotExist:
             return {}
 
+        parent_page = page.get_parent()
+
         return {
             'id': page.id,
             'url': page.url,
-            'parentId': page.get_parent().id,
+            'parentId': parent_page.id if parent_page else None,
         }
 
 

wagtail/admin/tests/test_contentstate.py

@@ -337,6 +337,28 @@ class TestHtmlToContentState(TestCase):
             ]
         })
 
+    def test_link_to_root_page(self):
+        converter = ContentstateConverter(features=['link'])
+        result = json.loads(converter.from_database_format(
+            '''
+            <p>an <a linktype="page" id="1">internal</a> link</p>
+            '''
+        ))
+        self.assertContentStateEqual(result, {
+            'entityMap': {
+                '0': {
+                    'mutability': 'MUTABLE', 'type': 'LINK',
+                    'data': {'id': 1, 'url': None, 'parentId': None}
+                }
+            },
+            'blocks': [
+                {
+                    'inlineStyleRanges': [], 'text': 'an internal link', 'depth': 0, 'type': 'unstyled', 'key': '00000',
+                    'entityRanges': [{'offset': 3, 'length': 8, 'key': 0}]
+                },
+            ]
+        })
+
     def test_document_link(self):
         converter = ContentstateConverter(features=['document-link'])
         result = json.loads(converter.from_database_format(