Fix tag hides task (#586)

* Fix limited tags fetch

* fixup! Fix limited tags fetch

Author: chrisvel

backend/routes/tasks/queries/query-builders.js

@@ -1,5 +1,5 @@
 const { Task, Tag, Project, sequelize } = require('../../../models');
-const { Op } = require('sequelize');
+const { Op, QueryTypes } = require('sequelize');
 const permissionsService = require('../../../services/permissionsService');
 const {
     getSafeTimezone,
@@ -222,10 +222,7 @@ async function filterTasksByParams(
             }
     }
 
-    if (params.tag) {
-        includeClause[0].where = { name: params.tag };
-        includeClause[0].required = true;
-    }
+    let tagFilteredTaskIds = null;
 
     if (params.priority) {
         whereClause.priority = Task.getPriorityValue(params.priority);
@@ -268,6 +265,33 @@ async function filterTasksByParams(
         }
     }
 
+    if (params.tag) {
+        const taggedTaskIds = await sequelize.query(
+            `SELECT DISTINCT tasks_tags.task_id
+             FROM tasks_tags
+             INNER JOIN tags ON tags.id = tasks_tags.tag_id
+             WHERE tags.name = :tagName`,
+            {
+                replacements: { tagName: params.tag },
+                type: QueryTypes.SELECT,
+            }
+        );
+
+        tagFilteredTaskIds = taggedTaskIds.map((row) => row.task_id);
+
+        // No tasks found with this tag - return early to avoid unnecessary query
+        if (tagFilteredTaskIds.length === 0) {
+            return [];
+        }
+    }
+
+    if (tagFilteredTaskIds) {
+        whereClause.id = {
+            ...(whereClause.id || {}),
+            [Op.in]: tagFilteredTaskIds,
+        };
+    }
+
     const finalWhereClause = {
         [Op.and]: [ownedOrShared, whereClause],
     };

backend/tests/integration/tasks.test.js

@@ -284,6 +284,27 @@ describe('Tasks Routes', () => {
             expect(response.body.Tags.map((t) => t.name)).toContain('work');
             expect(response.body.Tags.map((t) => t.name)).toContain('urgent');
         });
+
+        it('should return all tags when filtering by a specific tag', async () => {
+            const taskData = {
+                name: 'Task with multiple tags',
+                tags: [{ name: 'alpha' }, { name: 'beta' }],
+            };
+
+            const createResponse = await agent.post('/api/task').send(taskData);
+            expect(createResponse.status).toBe(201);
+
+            const response = await agent.get('/api/tasks?tag=alpha');
+
+            expect(response.status).toBe(200);
+            expect(response.body.tasks.length).toBe(1);
+
+            const [task] = response.body.tasks;
+            const tagNames = (task.tags || []).map((t) => t.name);
+
+            expect(tagNames).toEqual(expect.arrayContaining(['alpha', 'beta']));
+            expect(tagNames.length).toBe(2);
+        });
     });
 
     describe('Subtasks filtering', () => {