feat: add kernel metadata fallback

cspell.json

@@ -61,7 +61,12 @@
     "stylelintcache",
     "testutils",
     "venv",
-    "ydoc"
+    "ydoc",
+    "kernelspec",
+    "ipykernel",
+    "ipython",
+    "nbconvert",
+    "pygments"
   ],
   "useGitignore": true
 }

src/kernel-metadata-fallback.ts

@@ -0,0 +1,20 @@
+// Fallback kernel metadata to use until the .deepnote file format includes kernel information
+export const kernelMetadataFallback = {
+  kernelspec: {
+    display_name: 'Python 3 (ipykernel)',
+    language: 'python',
+    name: 'python3'
+  },
+  language_info: {
+    codemirror_mode: {
+      name: 'ipython',
+      version: 3
+    },
+    file_extension: '.py',
+    mimetype: 'text/x-python',
+    name: 'python',
+    nbconvert_exporter: 'python',
+    pygments_lexer: 'ipython3',
+    version: '3.12.11'
+  }
+};

src/transform-deepnote-yaml-to-notebook-content.ts

@@ -2,6 +2,7 @@ import { IDeepnoteNotebookContent, IDeepnoteNotebookMetadata } from './types';
 import { blankCodeCell, blankDeepnoteNotebookContent } from './fallback-data';
 import { deserializeDeepnoteFile } from '@deepnote/blocks';
 import { convertDeepnoteBlockToJupyterCell } from './convert-deepnote-block-to-jupyter-cell';
+import { kernelMetadataFallback } from './kernel-metadata-fallback';
 
 export async function transformDeepnoteYamlToNotebookContent(
   yamlString: string
@@ -42,6 +43,7 @@ export async function transformDeepnoteYamlToNotebookContent(
     return {
       cells,
       metadata: {
+        ...kernelMetadataFallback,
         deepnote: {
           notebooks
         }