Fix busy issues with the history window (#4889)

For #4853

Also address some linting errors from previous submissions.

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- [x] Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR)
- [x] Title summarizes what is changing
- [x] Has a [news entry](https://github.com/Microsoft/vscode-python/tree/master/news) file (remember to thank yourself!)
- [ ] Has sufficient logging.
- [ ] Has telemetry for enhancements.
- [x] Unit tests & system/integration tests are added/updated
- [ ] [Test plan](https://github.com/Microsoft/vscode-python/blob/master/.github/test_plan.md) is updated as appropriate
- [ ] [`package-lock.json`](https://github.com/Microsoft/vscode-python/blob/master/package-lock.json) has been regenerated by running `npm install` (if dependencies have changed)
- [ ] The wiki is updated with any design decisions/details.

news/2 Fixes/4853.md

@@ -0,0 +1 @@
+Fix status bar when using Live Share or just starting the Python Interactive window.

package.nls.json

@@ -158,6 +158,7 @@
     "DataScience.liveShareSyncFailure": "Synchronization failure during live share startup.",
     "DataScience.liveShareServiceFailure": "Failure starting '{0}' service during live share connection.",
     "DataScience.documentMismatch": "Cannot run cells, duplicate documents for {0} found.",
+    "DataScience.pythonInteractiveCreateFailed": "Failure to create a 'Python Interactive' window. Try reinstalling the Python extension.",
     "diagnostics.warnSourceMaps": "Source map support is enabled in the Python Extension, this will adversely impact performance of the extension.",
     "diagnostics.disableSourceMaps": "Disable Source Map Support",
     "diagnostics.warnBeforeEnablingSourceMaps": "Enabling source map support in the Python Extension will adversely impact performance of the extension.",

src/client/common/utils/localize.ts

@@ -143,6 +143,8 @@ export namespace DataScience {
     export const liveShareServiceFailure = localize('DataScience.liveShareServiceFailure', 'Failure starting \'{0}\' service during live share connection.');
     export const documentMismatch = localize('DataScience.documentMismatch', 'Cannot run cells, duplicate documents for {0} found.');
     export const jupyterGetVariablesBadResults = localize('DataScience.jupyterGetVariablesBadResults', 'Failed to fetch variable info from the Jupyter server.');
+    export const pythonInteractiveCreateFailed = localize('DataScience.pythonInteractiveCreateFailed', 'Failure to create a \'Python Interactive\' window. Try reinstalling the Python extension.');
+
 }
 
 export namespace DebugConfigurationPrompts {

src/client/datascience/history/historyProvider.ts

@@ -9,6 +9,7 @@ import * as vsls from 'vsls/vscode';
 import { ILiveShareApi, IWorkspaceService } from '../../common/application/types';
 import { IAsyncDisposable, IAsyncDisposableRegistry, IConfigurationService, IDisposableRegistry } from '../../common/types';
 import { createDeferred, Deferred } from '../../common/utils/async';
+import * as localize from '../../common/utils/localize';
 import { IServiceContainer } from '../../ioc/types';
 import { Identifiers, LiveShare, LiveShareCommands, Settings } from '../constants';
 import { PostOffice } from '../liveshare/postOffice';
@@ -64,14 +65,18 @@ export class HistoryProvider implements IHistoryProvider, IAsyncDisposable {
 
     public async getOrCreateActive() : Promise<IHistory> {
         if (!this.activeHistory) {
-            this.activeHistory = await this.create();
+            await this.create();
         }
 
         // Make sure all other providers have an active history.
         await this.synchronizeCreate();
 
         // Now that all of our peers have sync'd, return the history to use.
-        return this.activeHistory;
+        if (this.activeHistory) {
+            return this.activeHistory;
+        }
+
+        throw new Error(localize.DataScience.pythonInteractiveCreateFailed());
     }
 
     public async getNotebookOptions() : Promise<INotebookServerOptions> {
@@ -107,15 +112,16 @@ export class HistoryProvider implements IHistoryProvider, IAsyncDisposable {
         return this.postOffice.dispose();
     }
 
-    private async create() : Promise<IHistory> {
-        const result = this.serviceContainer.get<IHistory>(IHistory);
-        const handler = result.closed(this.onHistoryClosed);
-        this.disposables.push(result);
+    private async create() : Promise<void> {
+        // Set it as soon as we create it. The .ctor for the history window
+        // may cause a subclass to talk to the IHistoryProvider to get the active history.
+        this.activeHistory = this.serviceContainer.get<IHistory>(IHistory);
+        const handler = this.activeHistory.closed(this.onHistoryClosed);
+        this.disposables.push(this.activeHistory);
         this.disposables.push(handler);
-        this.activeHistoryExecuteHandler = result.onExecutedCode(this.onHistoryExecute);
+        this.activeHistoryExecuteHandler = this.activeHistory.onExecutedCode(this.onHistoryExecute);
         this.disposables.push(this.activeHistoryExecuteHandler);
-        await result.ready;
-        return result;
+        await this.activeHistory.ready;
     }
 
     private onPeerCountChanged(newCount: number) {
@@ -133,7 +139,7 @@ export class HistoryProvider implements IHistoryProvider, IAsyncDisposable {
             // The other side is creating a history window. Create on this side. We don't need to show
             // it as the running of new code should do that.
             if (!this.activeHistory) {
-                this.activeHistory = await this.create();
+                await this.create();
             }
 
             // Tell the requestor that we got its message (it should be waiting for all peers to sync)

src/client/telemetry/importTracker.ts

@@ -54,8 +54,9 @@ export class ImportTracker implements IImportTracker {
         this.documentManager.textDocuments.forEach(d => this.onOpenedOrSavedDocument(d));
     }
 
-    private getDocumentLines(document: TextDocument) : string [] {
-        return Array.apply(null, {length: Math.min(document.lineCount, MAX_DOCUMENT_LINES)}).map((a, i) => {
+    private getDocumentLines(document: TextDocument) : (string | undefined)[] {
+        const array = new Array(null, Math.min(document.lineCount, MAX_DOCUMENT_LINES));
+        return array.map((_a: any, i: number) => {
             const line = document.lineAt(i);
             if (line && !line.isEmptyOrWhitespace) {
                 return line.text;
@@ -74,8 +75,9 @@ export class ImportTracker implements IImportTracker {
 
     private scheduleDocument(document: TextDocument) {
         // If already scheduled, cancel.
-        if (this.pendingDocs.has(document.fileName)) {
-            clearTimeout(this.pendingDocs.get(document.fileName));
+        const currentTimeout = this.pendingDocs.get(document.fileName);
+        if (currentTimeout) {
+            clearTimeout(currentTimeout);
             this.pendingDocs.delete(document.fileName);
         }
 
@@ -100,12 +102,12 @@ export class ImportTracker implements IImportTracker {
         this.lookForImports(lines, EventName.KNOWN_IMPORT_FROM_EXECUTION);
     }
 
-    private lookForImports(lines: string[], eventName: string) {
+    private lookForImports(lines: (string | undefined)[], eventName: string) {
         try {
             // Use a regex to parse each line, looking for imports
             const matches: Set<string> = new Set<string>();
             for (const s of lines) {
-                const match = ImportRegEx.exec(s);
+                const match = s ? ImportRegEx.exec(s) : null;
                 if (match && match.length > 2) {
                     // Could be a from or a straight import. from is the first entry.
                     const actual = match[1] ? match[1] : match[2];

src/test/datascience/liveshare.functional.test.tsx

@@ -145,15 +145,14 @@ suite('LiveShare tests', () => {
         // The history provider create needs to be rewritten to make the history window think the mounted web panel is
         // ready.
         const origFunc = (historyProvider as any).create.bind(historyProvider);
-        (historyProvider as any).create = async (): Promise<IHistory> => {
-            const createResult = await origFunc();
+        (historyProvider as any).create = async (): Promise<void> => {
+            await origFunc();
+            const history = historyProvider.getActive();
 
             // During testing the MainPanel sends the init message before our history is created.
             // Pretend like it's happening now
-            const listener = ((createResult as any).messageListener) as HistoryMessageListener;
+            const listener = ((history as any).messageListener) as HistoryMessageListener;
             listener.onMessage(HistoryMessages.Started, {});
-
-            return createResult;
         };
 
         return result;