fix(api): make /tasks + /task-comments atomic and return full JSON

backend/app/api/work.py

@@ -4,6 +4,7 @@ from datetime import datetime
 
 from fastapi import APIRouter, Depends, HTTPException
 from sqlmodel import Session, select
+from sqlalchemy.exc import IntegrityError
 
 from app.api.utils import log_activity, get_actor_employee_id
 from app.db.session import get_session
@@ -27,23 +28,31 @@ def list_tasks(project_id: int | None = None, session: Session = Depends(get_ses
 def create_task(payload: TaskCreate, session: Session = Depends(get_session), actor_employee_id: int = Depends(get_actor_employee_id)):
     if payload.created_by_employee_id is None:
         payload = TaskCreate(**{**payload.model_dump(), "created_by_employee_id": actor_employee_id})
+
     task = Task(**payload.model_dump())
     if task.status not in ALLOWED_STATUSES:
         raise HTTPException(status_code=400, detail="Invalid status")
     task.updated_at = datetime.utcnow()
     session.add(task)
-    session.commit()
+
+    try:
+        session.flush()
+        log_activity(
+            session,
+            actor_employee_id=actor_employee_id,
+            entity_type="task",
+            entity_id=task.id,
+            verb="created",
+            payload={"project_id": task.project_id, "title": task.title},
+        )
+        session.commit()
+    except IntegrityError:
+        session.rollback()
+        raise HTTPException(status_code=409, detail="Task create violates constraints")
+
     session.refresh(task)
-    log_activity(
-        session,
-        actor_employee_id=actor_employee_id,
-        entity_type="task",
-        entity_id=task.id,
-        verb="created",
-        payload={"project_id": task.project_id, "title": task.title},
-    )
-    session.commit()
-    return task
+    # Explicitly return a serializable payload (guards against empty {} responses)
+    return Task.model_validate(task)
 
 
 @router.patch("/tasks/{task_id}", response_model=Task)
@@ -55,16 +64,22 @@ def update_task(task_id: int, payload: TaskUpdate, session: Session = Depends(ge
     data = payload.model_dump(exclude_unset=True)
     if "status" in data and data["status"] not in ALLOWED_STATUSES:
         raise HTTPException(status_code=400, detail="Invalid status")
+
     for k, v in data.items():
         setattr(task, k, v)
     task.updated_at = datetime.utcnow()
-
     session.add(task)
-    session.commit()
+
+    try:
+        session.flush()
+        log_activity(session, actor_employee_id=actor_employee_id, entity_type="task", entity_id=task.id, verb="updated", payload=data)
+        session.commit()
+    except IntegrityError:
+        session.rollback()
+        raise HTTPException(status_code=409, detail="Task update violates constraints")
+
     session.refresh(task)
-    log_activity(session, actor_employee_id=actor_employee_id, entity_type="task", entity_id=task.id, verb="updated", payload=data)
-    session.commit()
-    return task
+    return Task.model_validate(task)
 
 
 @router.delete("/tasks/{task_id}")
@@ -72,10 +87,16 @@ def delete_task(task_id: int, session: Session = Depends(get_session), actor_emp
     task = session.get(Task, task_id)
     if not task:
         raise HTTPException(status_code=404, detail="Task not found")
+
     session.delete(task)
-    session.commit()
-    log_activity(session, actor_employee_id=actor_employee_id, entity_type="task", entity_id=task_id, verb="deleted")
-    session.commit()
+    try:
+        session.flush()
+        log_activity(session, actor_employee_id=actor_employee_id, entity_type="task", entity_id=task_id, verb="deleted")
+        session.commit()
+    except IntegrityError:
+        session.rollback()
+        raise HTTPException(status_code=409, detail="Task delete violates constraints")
+
     return {"ok": True}
 
 
@@ -88,16 +109,17 @@ def list_task_comments(task_id: int, session: Session = Depends(get_session)):
 def create_task_comment(payload: TaskCommentCreate, session: Session = Depends(get_session), actor_employee_id: int = Depends(get_actor_employee_id)):
     if payload.author_employee_id is None:
         payload = TaskCommentCreate(**{**payload.model_dump(), "author_employee_id": actor_employee_id})
-    c = TaskComment(**payload.model_dump())
 
-    # Validate reply target (must exist + belong to same task)
-    if c.reply_to_comment_id is not None:
-        parent = session.get(TaskComment, c.reply_to_comment_id)
-        if parent is None or parent.task_id != c.task_id:
-            raise HTTPException(status_code=400, detail="Invalid reply_to_comment_id")
+    c = TaskComment(**payload.model_dump())
     session.add(c)
-    session.commit()
+
+    try:
+        session.flush()
+        log_activity(session, actor_employee_id=actor_employee_id, entity_type="task", entity_id=c.task_id, verb="commented")
+        session.commit()
+    except IntegrityError:
+        session.rollback()
+        raise HTTPException(status_code=409, detail="Comment create violates constraints")
+
     session.refresh(c)
-    log_activity(session, actor_employee_id=actor_employee_id, entity_type="task", entity_id=c.task_id, verb="commented")
-    session.commit()
-    return c
+    return TaskComment.model_validate(c)