Fix #3937 Create new notebook (Mac) and receive TypeError (#3965)

- Handles empty file scenario, with fixes along the way for missing metadata (bonus win)
- In non-empty file still shows error and kernel stuck in loading state. #3964 opened to track this issue and fix later

src/sql/parts/notebook/models/notebookModel.ts

@@ -523,7 +523,7 @@ export class NotebookModel extends Disposable implements INotebookModel {
 	// Get default language if saved in notebook file
 	// Otherwise, default to python
 	private getDefaultLanguageInfo(notebook: nb.INotebookContents): nb.ILanguageInfo {
-		return notebook!.metadata!.language_info || {
+		return (notebook && notebook.metadata && notebook.metadata.language_info) ? notebook.metadata.language_info : {
 			name: this._providerId === SQL_NOTEBOOK_PROVIDER ? 'sql' : 'python',
 			version: '',
 			mimetype: this._providerId === SQL_NOTEBOOK_PROVIDER ? 'x-sql' : 'x-python'
@@ -532,7 +532,7 @@ export class NotebookModel extends Disposable implements INotebookModel {
 
 	// Get default kernel info if saved in notebook file
 	private getSavedKernelInfo(notebook: nb.INotebookContents): nb.IKernelInfo {
-		return notebook!.metadata!.kernelspec;
+		return (notebook && notebook.metadata && notebook.metadata.kernelspec) ? notebook.metadata.kernelspec : undefined;
 	}
 
 	private getKernelSpecFromDisplayName(displayName: string): nb.IKernelSpec {
@@ -645,28 +645,39 @@ export class NotebookModel extends Disposable implements INotebookModel {
 	 * @param kernelSpec KernelSpec for new kernel
 	 */
 	private setProviderIdForKernel(kernelSpec: nb.IKernelSpec): void {
-		let sessionManagerFound: boolean = false;
-		for (let i = 0; i < this.notebookManagers.length; i++) {
-			if (this.notebookManagers[i].sessionManager && this.notebookManagers[i].sessionManager.specs && this.notebookManagers[i].sessionManager.specs.kernels) {
-				let index = this.notebookManagers[i].sessionManager.specs.kernels.findIndex(kernel => kernel.name === kernelSpec.name);
-				if (index >= 0) {
-					this._activeClientSession = this._clientSessions[i];
-					if (this.notebookManagers[i].providerId !== this._providerId) {
-						this._providerId = this.notebookManagers[i].providerId;
-						this._onProviderIdChanged.fire(this._providerId);
+		if (!kernelSpec) {
+			// Just use the 1st non-default provider, we don't have a better heuristic
+			let notebookManagers = this.notebookOptions.notebookManagers.filter(manager => manager.providerId !== DEFAULT_NOTEBOOK_PROVIDER);
+			if (!notebookManagers.length) {
+				notebookManagers = this.notebookOptions.notebookManagers;
+			}
+			if (notebookManagers.length > 0) {
+				this._providerId = notebookManagers[0].providerId;
+			}
+		} else {
+			let sessionManagerFound: boolean = false;
+			for (let i = 0; i < this.notebookManagers.length; i++) {
+				if (this.notebookManagers[i].sessionManager && this.notebookManagers[i].sessionManager.specs && this.notebookManagers[i].sessionManager.specs.kernels) {
+					let index = this.notebookManagers[i].sessionManager.specs.kernels.findIndex(kernel => kernel.name === kernelSpec.name);
+					if (index >= 0) {
+						this._activeClientSession = this._clientSessions[i];
+						if (this.notebookManagers[i].providerId !== this._providerId) {
+							this._providerId = this.notebookManagers[i].providerId;
+							this._onProviderIdChanged.fire(this._providerId);
+						}
+						sessionManagerFound = true;
+						break;
 					}
-					sessionManagerFound = true;
-					break;
 				}
 			}
-		}
 
-		// If no SessionManager exists, utilize passed in StandardKernels to see if we can intelligently set _providerId
-		if (!sessionManagerFound) {
-			let provider = this._kernelDisplayNameToNotebookProviderIds.get(kernelSpec.display_name);
-			if (provider) {
-				this._providerId = provider;
-				this._onProviderIdChanged.fire(this._providerId);
+			// If no SessionManager exists, utilize passed in StandardKernels to see if we can intelligently set _providerId
+			if (!sessionManagerFound) {
+				let provider = this._kernelDisplayNameToNotebookProviderIds.get(kernelSpec.display_name);
+				if (provider) {
+					this._providerId = provider;
+					this._onProviderIdChanged.fire(this._providerId);
+				}
 			}
 		}
 	}

src/sql/parts/notebook/notebook.component.ts

@@ -101,7 +101,7 @@ export class NotebookComponent extends AngularDisposable implements OnInit, OnDe
 	}
 
 	private updateProfile(): void {
-		this.profile = this.notebookParams!.profile;
+		this.profile = this.notebookParams ? this.notebookParams.profile : undefined;
 		if (!this.profile) {
 			// use global connection if possible
 			let profile = TaskUtilities.getCurrentGlobalConnection(this.objectExplorerService, this.connectionManagementService, this.editorService);

src/sql/workbench/services/notebook/node/localContentManager.ts

@@ -17,6 +17,7 @@ import { localize } from 'vs/nls';
 import { JSONObject } from 'sql/parts/notebook/models/jsonext';
 import { OutputTypes } from 'sql/parts/notebook/models/contracts';
 import { nbversion } from 'sql/parts/notebook/notebookConstants';
+import { nbformat } from 'sql/parts/notebook/models/nbformat';
 
 type MimeBundle = { [key: string]: string | string[] | undefined };
 
@@ -29,7 +30,8 @@ export class LocalContentManager implements nb.ContentManager {
 		let path = notebookUri.fsPath;
 		// Note: intentionally letting caller handle exceptions
 		let notebookFileBuffer = await pfs.readFile(path);
-		let contents: JSONObject = json.parse(notebookFileBuffer.toString());
+		let stringContents = notebookFileBuffer.toString();
+		let contents: JSONObject = json.parse(stringContents);
 
 		if (contents) {
 			if (contents.nbformat === 4) {
@@ -40,9 +42,13 @@ export class LocalContentManager implements nb.ContentManager {
 			if (contents.nbformat) {
 				throw new TypeError(localize('nbformatNotRecognized', 'nbformat v{0}.{1} not recognized', contents.nbformat, contents.nbformat_minor));
 			}
+		} else if (stringContents === '' || stringContents === undefined) {
+			// Empty?
+			return v4.createEmptyNotebook();
 		}
+
 		// else, fallthrough condition
-		throw new TypeError(localize('nbNotSupported', 'This notebook format is not supported'));
+		throw new TypeError(localize('nbNotSupported', 'This file does not have a valid notebook format'));
 
 	}
 
@@ -72,6 +78,15 @@ namespace v4 {
 		return notebook;
 	}
 
+	export function createEmptyNotebook(): nb.INotebookContents {
+		return {
+			cells: [],
+			metadata: undefined,
+			nbformat: nbformat.MAJOR_VERSION,
+			nbformat_minor: nbformat.MINOR_VERSION
+		};
+	}
+
 	function readCell(cell: nb.ICellContents): nb.ICellContents {
 		switch (cell.cell_type) {
 			case 'markdown':