Fix issue 3561 - Spec.language may be null (#3583)

* Fix issue 3561

Author: rchiodo

news/2 Fixes/3561.md

@@ -0,0 +1 @@
+Fix crash when kernelspec is missing path or language

package-lock.json

@@ -550,7 +550,7 @@ export class JupyterExecution implements IJupyterExecution, Disposable {
 
             // See if any of their paths match
             return specs.findIndex(s => {
-                if (info && s) {
+                if (info && s && s.path) {
                     return this.fileSystem.arePathsSame(s.path, info.path);
                 }
                 return false;
@@ -574,7 +574,7 @@ export class JupyterExecution implements IJupyterExecution, Disposable {
 
         // For each get its details as we will likely need them
         const specDetails = await Promise.all(specs.map(async s => {
-            if (s && s.path.length > 0 && await fs.pathExists(s.path)) {
+            if (s && s.path && s.path.length > 0 && await fs.pathExists(s.path)) {
                 return this.interpreterService.getInterpreterDetails(s.path);
             }
         }));
@@ -583,11 +583,11 @@ export class JupyterExecution implements IJupyterExecution, Disposable {
             const spec = specs[i];
             let score = 0;
 
-            if (spec && spec.path.length > 0 && info && spec.path === info.path) {
+            if (spec && spec.path && spec.path.length > 0 && info && spec.path === info.path) {
                 // Path match
                 score += 10;
             }
-            if (spec && spec.language.toLocaleLowerCase() === 'python') {
+            if (spec && spec.language && spec.language.toLocaleLowerCase() === 'python') {
                 // Language match
                 score += 1;
 
@@ -610,7 +610,7 @@ export class JupyterExecution implements IJupyterExecution, Disposable {
                             }
                         }
                     }
-                } else if (info && info.version_info && spec && spec.path.toLocaleLowerCase() === 'python') {
+                } else if (info && info.version_info && spec && spec.path && spec.path.toLocaleLowerCase() === 'python' && spec.name) {
                     // This should be our current python.
 
                     // Search for a digit on the end of the name. It should match our major version

src/client/datascience/jupyterExecution.ts

@@ -52,9 +52,9 @@ export interface IJupyterExecution {
 }
 
 export interface IJupyterKernelSpec extends Disposable {
-    name: string;
-    language: string;
-    path: string;
+    name: string | undefined;
+    language: string | undefined;
+    path: string | undefined;
 }
 
 export const INotebookImporter = Symbol('INotebookImporter');