keep recently used item selected as long as it's in the top suggestions group, #78571

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

@@ -22,10 +22,10 @@ export abstract class Memory {
 		if (items.length === 0) {
 			return 0;
 		}
-		let topScore = items[0].score;
+		let topScore = items[0].score[0];
 		for (let i = 1; i < items.length; i++) {
 			const { score, completion: suggestion } = items[i];
-			if (score !== topScore) {
+			if (score[0] !== topScore) {
 				// stop when leaving the group of top matches
 				break;
 			}
@@ -81,33 +81,42 @@ export class LRUMemory extends Memory {
 	}
 
 	select(model: ITextModel, pos: IPosition, items: CompletionItem[]): number {
-		// in order of completions, select the first
-		// that has been used in the past
-		let { word } = model.getWordUntilPosition(pos);
-		if (word.length !== 0) {
-			return super.select(model, pos, items);
+
+		if (items.length === 0) {
+			return 0;
 		}
 
-		let lineSuffix = model.getLineContent(pos.lineNumber).substr(pos.column - 10, pos.column - 1);
+		const lineSuffix = model.getLineContent(pos.lineNumber).substr(pos.column - 10, pos.column - 1);
 		if (/\s$/.test(lineSuffix)) {
 			return super.select(model, pos, items);
 		}
 
-		let res = -1;
+		let topScore = items[0].score[0];
+		let indexPreselect = -1;
+		let indexRecency = -1;
 		let seq = -1;
 		for (let i = 0; i < items.length; i++) {
-			const { completion: suggestion } = items[i];
-			const key = `${model.getLanguageIdentifier().language}/${suggestion.label}`;
-			const item = this._cache.get(key);
-			if (item && item.touch > seq && item.type === suggestion.kind && item.insertText === suggestion.insertText) {
+			if (items[i].score[0] !== topScore) {
+				// consider only top items
+				break;
+			}
+			const key = `${model.getLanguageIdentifier().language}/${items[i].completion.label}`;
+			const item = this._cache.peek(key);
+			if (item && item.touch > seq && item.type === items[i].completion.kind && item.insertText === items[i].completion.insertText) {
 				seq = item.touch;
-				res = i;
+				indexRecency = i;
+			}
+			if (items[i].completion.preselect && indexPreselect === -1) {
+				// stop when seeing an auto-select-item
+				return indexPreselect = i;
 			}
 		}
-		if (res === -1) {
-			return super.select(model, pos, items);
+		if (indexRecency !== -1) {
+			return indexRecency;
+		} else if (indexPreselect !== -1) {
+			return indexPreselect;
 		} else {
-			return res;
+			return 0;
 		}
 	}
 

src/vs/editor/contrib/suggest/test/suggestMemory.test.ts

@@ -101,6 +101,29 @@ suite('SuggestMemories', function () {
 		]), 0);
 	});
 
+	test('`"editor.suggestSelection": "recentlyUsed"` should be a little more sticky #78571', function () {
+
+		let item1 = createSuggestItem('gamma', 0);
+		let item2 = createSuggestItem('game', 0);
+		items = [item1, item2];
+
+		let mem = new LRUMemory();
+		buffer.setValue('    foo.');
+		mem.memorize(buffer, { lineNumber: 1, column: 1 }, item2);
+
+		assert.equal(mem.select(buffer, { lineNumber: 1, column: 2 }, items), 0); // leading whitespace -> ignore recent items
+
+		mem.memorize(buffer, { lineNumber: 1, column: 9 }, item2);
+		assert.equal(mem.select(buffer, { lineNumber: 1, column: 9 }, items), 1); // foo.
+
+		buffer.setValue('    foo.g');
+		assert.equal(mem.select(buffer, { lineNumber: 1, column: 10 }, items), 1); // foo.g, 'gamma' and 'game' have the same score
+
+		item1.score = [10, 0, 0];
+		assert.equal(mem.select(buffer, { lineNumber: 1, column: 10 }, items), 0); // foo.g, 'gamma' has higher score
+
+	});
+
 	test('intellisense is not showing top options first #43429', function () {
 		// ensure we don't memorize for whitespace prefixes