Odoo request transaction logic example

cursor_rollbacks.py

# PSQL DB cursor mock
class Cursor:
    def __init__(self):
        print('cursor: BEGIN')
    def commit(self):
        print('cursor: COMMIT')
    def rollback(self):
        print('cursor: ROLLBACK')
    def close(self):
        print('cursor: CLOSE')

cr = Cursor()

def failingCode():
    # Let's open a black hole (•̀ᴗ•́ )و ̑̑
    return 2 / 0


def yourCode():
    try:
        # ... some code that changes data ...
        failingCode()
        # ... some more code ...
    except Exception:
        # Because the error is not re-raised,
        # This stops Odoo from rollback'ing any bad changes
        print('I caught it!')


# This is roughly what happens in Odoo core
try:
    # Your code should not catch errors without re-raising ...
    yourCode()
    cr.commit()
except Exception:
    # ... because "rollback" would not get executed.
    cr.rollback()
finally:
    cr.close()
    
    
# When executed, this code prints:
"""
cursor: BEGIN
I caught it!
cursor: COMMIT
cursor: CLOSE
"""
# Notice how there is no "cursor: ROLLBACK" message.