Fix some issues

app/services/log_service.py

@@ -46,6 +46,14 @@ def log_action(user_id, action, entity_type=None, entity_id=None, details=None):
     entity_type : str | None  – 'ticket', 'comment', 'user', etc.
     entity_id   : int | None  – primary key of the affected entity
     details     : str | None  – free-form JSON or human-readable details
+
+    Transaction note
+    ----------------
+    This function deliberately does NOT call db.session.commit(). The entry
+    is added to the current session and committed by the caller alongside its
+    own business objects. This ensures the log entry is only persisted when
+    the parent operation succeeds — an independent commit here would leave
+    orphaned log entries for operations that were subsequently rolled back.
     """
     ip = _get_real_ip()
 
@@ -59,7 +67,8 @@ def log_action(user_id, action, entity_type=None, entity_id=None, details=None):
             ip_address  = ip,
         )
         db.session.add(entry)
-        db.session.commit()
+        # flush to surface constraint violations early without committing
+        db.session.flush()
         logger.info(
             f'[ACTIVITY] action={action} entity={entity_type}:{entity_id} '
             f'user_id={user_id} ip={ip}'
@@ -70,7 +79,13 @@ def log_action(user_id, action, entity_type=None, entity_id=None, details=None):
 
 
 def log_ticket_history(ticket, field_name, old_value, new_value, changed_by_id):
-    """Record a granular field-level change on a ticket."""
+    """Record a granular field-level change on a ticket.
+
+    Transaction note
+    ----------------
+    Like log_action, this function does NOT commit — the caller is responsible
+    for committing the session after all field changes have been recorded.
+    """
     from app.models import TicketHistory
     try:
         entry = TicketHistory(
@@ -81,7 +96,7 @@ def log_ticket_history(ticket, field_name, old_value, new_value, changed_by_id):
             new_value  = str(new_value) if new_value is not None else None,
         )
         db.session.add(entry)
-        db.session.commit()
+        db.session.flush()
         logger.info(
             f'[TICKET HISTORY] ticket_id={ticket.id} field={field_name} '
             f'"{old_value}" -> "{new_value}" by user_id={changed_by_id}'