test: add test to verify that a sorted set is automatically deleted if its last element is removed (#10261)

* test: add test to verify that a sorted set is automatically deleted if its last element is removed

* fix: remote empty zsets when all elements have been removed #yolo

* Revert "fix: remote empty zsets when all elements have been removed #yolo"

This reverts commit 0ac73244bb.

* fix: altered behaviour in module.exists instead of zrem

src/database/postgres/main.js

@@ -17,6 +17,13 @@ module.exports = function (module) {
 			return;
 		}
 
+		// Redis/Mongo consider empty zsets as non-existent, match that behaviour
+		const type = await module.type(key);
+		if (type === 'zset') {
+			const members = await module.getSortedSetRange(key, 0, 0);
+			return members.length > 0;
+		}
+
 		if (Array.isArray(key)) {
 			const res = await module.pool.query({
 				name: 'existsArray',

test/database/sorted.js

@@ -1085,6 +1085,11 @@ describe('Sorted Set methods', () => {
 			});
 		});
 
+		it('should not think the sorted set exists if the last element is removed', async () => {
+			await db.sortedSetRemove('sorted3', 'value1');
+			assert.strictEqual(await db.exists('sorted3'), false);
+		});
+
 		it('should remove multiple values from multiple keys', (done) => {
 			db.sortedSetAdd('multiTest1', [1, 2, 3, 4], ['one', 'two', 'three', 'four'], (err) => {
 				assert.ifError(err);