make sure to reuse snippet completions when being told to do so

re microsoft#173244

Author: jrieken

src/vs/editor/contrib/suggest/browser/suggest.ts

@@ -266,6 +266,12 @@ export async function provideSuggestionItems(
 		if (!_snippetSuggestSupport || options.kindFilter.has(languages.CompletionItemKind.Snippet)) {
 			return;
 		}
+		// we have items from a previous session that we can reuse
+		const reuseItems = options.providerItemsToReuse.get(_snippetSuggestSupport);
+		if (reuseItems) {
+			reuseItems.forEach(item => result.push(item));
+			return;
+		}
 		if (options.providerFilter.size > 0 && !options.providerFilter.has(_snippetSuggestSupport)) {
 			return;
 		}

src/vs/editor/contrib/suggest/test/browser/suggestModel.test.ts

@@ -4,7 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 import * as assert from 'assert';
 import { Event } from 'vs/base/common/event';
-import { Disposable, DisposableStore } from 'vs/base/common/lifecycle';
+import { Disposable, DisposableStore, toDisposable } from 'vs/base/common/lifecycle';
 import { URI } from 'vs/base/common/uri';
 import { mock } from 'vs/base/test/common/mock';
 import { CoreEditingCommands } from 'vs/editor/browser/coreCommands';
@@ -38,6 +38,7 @@ import { IWorkspaceContextService } from 'vs/platform/workspace/common/workspace
 import { LanguageFeaturesService } from 'vs/editor/common/services/languageFeaturesService';
 import { ILanguageFeaturesService } from 'vs/editor/common/services/languageFeatures';
 import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
+import { setSnippetSuggestSupport } from 'vs/editor/contrib/suggest/browser/suggest';
 
 
 function createMockEditor(model: TextModel, languageFeaturesService: ILanguageFeaturesService): ITestCodeEditor {
@@ -1124,4 +1125,66 @@ suite('SuggestModel - TriggerAndCancelOracle', function () {
 			});
 		});
 	});
+
+	test('Snippets gone from IntelliSense #173244', function () {
+
+		const old = setSnippetSuggestSupport({
+			provideCompletionItems(doc, pos, ctx) {
+				return {
+					suggestions: [{
+						label: 'log',
+						kind: CompletionItemKind.Snippet,
+						insertText: 'log',
+						range: getDefaultSuggestRange(doc, pos)
+					}]
+				};
+			}
+		});
+		disposables.add(toDisposable(() => old && setSnippetSuggestSupport(old)));
+
+		disposables.add(registry.register({ scheme: 'test' }, {
+			triggerCharacters: ['.'],
+			provideCompletionItems(doc, pos, ctx) {
+				return {
+					suggestions: [{
+						label: 'locals',
+						kind: CompletionItemKind.Property,
+						insertText: 'locals',
+						range: getDefaultSuggestRange(doc, pos)
+					}],
+					incomplete: true
+				};
+			},
+		}));
+
+		return withOracle(async function (model, editor) {
+
+			await assertEvent(model.onDidSuggest, () => {
+				editor.setValue('');
+				editor.setSelection(new Selection(1, 1, 1, 1));
+				editor.trigger('keyboard', Handler.Type, { text: 'l' });
+
+
+			}, event => {
+				assert.strictEqual(event.triggerOptions.auto, true);
+				assert.strictEqual(event.triggerOptions.triggerCharacter, undefined);
+				assert.strictEqual(event.triggerOptions.triggerKind, undefined);
+				assert.strictEqual(event.completionModel.items.length, 2);
+				assert.strictEqual(event.completionModel.items[0].textLabel, 'locals');
+				assert.strictEqual(event.completionModel.items[1].textLabel, 'log');
+			});
+
+			await assertEvent(model.onDidSuggest, () => {
+				editor.trigger('keyboard', Handler.Type, { text: 'o' });
+
+			}, event => {
+				assert.strictEqual(event.triggerOptions.triggerKind, CompletionTriggerKind.TriggerForIncompleteCompletions);
+				assert.strictEqual(event.triggerOptions.auto, true);
+				assert.strictEqual(event.completionModel.items.length, 2);
+				assert.strictEqual(event.completionModel.items[0].textLabel, 'locals');
+				assert.strictEqual(event.completionModel.items[1].textLabel, 'log');
+			});
+
+		});
+	});
 });