fix: prevent UnboundLocalError and TaskLock race condition in run_dbt_commands

[sentry]

This PR addresses two related issues in the run_dbt_commands Celery task:

1. UnboundLocalError: local variable 'taskprogress' referenced before assignment

   • Problem: An UnboundLocalError occurred if an exception was raised early in the try block (e.g., during TaskLock.objects.get_or_create) before the taskprogress variable was initialized. The except handler then tried to call taskprogress.add(), leading to the error.
   • Fix: taskprogress is now initialized to None before the try block, and its usage in the except handler is guarded with an if taskprogress is not None: check.

2. Race condition in TaskLock.objects.get_or_create

   • Problem: The TaskLock model has a OneToOneField on orgtask, meaning orgtask_id is unique. However, get_or_create was attempting to look up by (orgtask, locked_by, celery_task_id). If two concurrent tasks for the same orgtask (but different celery_task_ids) ran, the get part would fail (due to celery_task_id mismatch), the create part would then fail with an IntegrityError (due to orgtask_id uniqueness), and the subsequent get retry would also fail, propagating the IntegrityError.
   • Fix: Modified TaskLock.objects.get_or_create to use only orgtask=orgtask for the lookup, moving locked_by and celery_task_id into the defaults dictionary. This ensures the lookup correctly identifies an existing lock by its unique orgtask. If a lock already exists, the celery_task_id and locked_by fields are explicitly updated to reflect the current task taking ownership.

Fixes DALGO-BACKEND-1EQ

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.86%. Comparing base (c6de97f) to head (2a3b674).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1404      +/-   ##
==========================================
+ Coverage   59.58%   59.86%   +0.28%     
==========================================
  Files         138      138              
  Lines       16544    16560      +16     
==========================================
+ Hits         9857     9913      +56     
+ Misses       6687     6647      -40     

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