id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
36318	Bad stack trace during rollback	Gordon Wrigley		"TL;DNR the value of `connection.rollback_exc` is being set in one celery task and then raised in another later celery task.

I'm on 4.2.20 and I got this stack trace from a celery worker

{{{
UniqueViolation: duplicate key value violates unique constraint ""retain_consumer_firm_id_email_hash_3f1266dc_uniq""
DETAIL:  Key (firm_id, email_hash)=(ac90f753-3f10-44f2-af43-b851371c5572, 863397f56c061afbaa0822c9c16ece2b55f2e972) already exists.

  File ""django/db/backends/utils.py"", line 89, in _execute
    return self.cursor.execute(sql, params)

IntegrityError: duplicate key value violates unique constraint ""retain_consumer_firm_id_email_hash_3f1266dc_uniq""
DETAIL:  Key (firm_id, email_hash)=(ac90f753-3f10-44f2-af43-b851371c5572, 863397f56c061afbaa0822c9c16ece2b55f2e972) already exists.

  File ""data_import/import_from_csv.py"", line 1692, in _consumer_from_row
    consumer.save()
  File ""core/models/consumer.py"", line 615, in save
    return super().save(*args, **kwargs)
  File ""core/models/firm_user.py"", line 197, in save
    super().save(update_fields=update_fields, **kwargs)
  File ""common/models.py"", line 900, in save
    super().save(*args, **kwargs)
  File ""django/contrib/auth/base_user.py"", line 76, in save
    super().save(*args, **kwargs)
  File ""django/db/models/base.py"", line 814, in save
    self.save_base(
  File ""django/db/models/base.py"", line 877, in save_base
    updated = self._save_table(
  File ""django/db/models/base.py"", line 1020, in _save_table
    results = self._do_insert(
  File ""django/db/models/base.py"", line 1061, in _do_insert
    return manager._insert(
  File ""django/db/models/manager.py"", line 87, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File ""django/db/models/query.py"", line 1805, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File ""django/db/models/sql/compiler.py"", line 1822, in execute_sql
    cursor.execute(sql, params)
  File ""django/db/backends/utils.py"", line 67, in execute
    return self._execute_with_wrappers(
  File ""django/db/backends/utils.py"", line 80, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File ""django/db/backends/utils.py"", line 84, in _execute
    with self.db.wrap_database_errors:
  File ""django/db/utils.py"", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File ""django/db/backends/utils.py"", line 89, in _execute
    return self.cursor.execute(sql, params)

TransactionManagementError: An error occurred in the current transaction. You can't execute queries until the end of the 'atomic' block.
  File ""celery/app/trace.py"", line 760, in __protected_call__
    return self.run(*args, **kwargs)
  File ""common/tasks.py"", line 19, in wrapper
    return func(*args, **kwargs)
  File ""contextlib.py"", line 81, in inner
    return func(*args, **kwds)
  File ""product_selection/tasks.py"", line 129, in try_product_import
    product_import.save()
  File ""common/models.py"", line 900, in save
    super().save(*args, **kwargs)
  File ""django/db/models/base.py"", line 814, in save
    self.save_base(
  File ""django/db/models/base.py"", line 877, in save_base
    updated = self._save_table(
  File ""django/db/models/base.py"", line 990, in _save_table
    updated = self._do_update(
  File ""django/db/models/base.py"", line 1054, in _do_update
    return filtered._update(values) > 0
  File ""django/db/models/query.py"", line 1231, in _update
    return query.get_compiler(self.db).execute_sql(CURSOR)
  File ""django/db/models/sql/compiler.py"", line 1984, in execute_sql
    cursor = super().execute_sql(result_type)
  File ""django/db/models/sql/compiler.py"", line 1562, in execute_sql
    cursor.execute(sql, params)
  File ""django/db/backends/utils.py"", line 67, in execute
    return self._execute_with_wrappers(
  File ""django/db/backends/utils.py"", line 80, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File ""django/db/backends/utils.py"", line 83, in _execute
    self.db.validate_no_broken_transaction()
  File ""django/db/backends/base/base.py"", line 531, in validate_no_broken_transaction
    raise TransactionManagementError(
}}}

There's two related problems with this. First the lines around `File ""data_import/import_from_csv.py"", line 1692, in _consumer_from_row` look like this
{{{
            try:
                with transaction.atomic():
                    consumer.save()
                if change_log:
                    self.record_log(consumer, change_log)
            except IntegrityError:
}}}
So that has been well handled and the transaction is good again.

Secondly there is no relationship between the `File ""product_selection/tasks.py"", line 129, in try_product_import` code path from the `TransactionManagementError` and the `File ""data_import/import_from_csv.py"", line 1692` in _consumer_from_row` code path from the `IntegrityError` and `UniqueViolation`, these are totally unrelated celery tasks.

It looks for all intents as if the stack for the `IntegrityError`/`UniqueViolation` has been captured in one celery task and then raised in a different later celery task.

Digging through the code and adding prints supports this view.
1. `connection.rollback_exc` is never cleared anywhere
2. `Atomic.__exit__` can set `connection.needs_rollback = True` when it wasn't true already and without setting `connection.rollback_exc` this creates the possibility for the observed behaviour.

I'm not sure how critical it is to reproduction, but the actual error that killed the transaction looks like this
{{{
decimal.InvalidOperation: [<class 'decimal.ConversionSyntax'>]
  File ""django/db/models/fields/__init__.py"", line 1741, in to_python
    decimal_value = decimal.Decimal(value)

django.core.exceptions.ValidationError: ['“3 3 3 2 1” value must be a decimal number.']
  File ""product_selection/tasks.py"", line 123, in try_product_import
    Product.objects.bulk_create(new_products, skip_save_logic=True)
  File ""django/db/models/manager.py"", line 87, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File ""common/models.py"", line 772, in bulk_create
    return super().bulk_create(*args, **kwargs)
  File ""django/db/models/query.py"", line 786, in bulk_create
    returned_columns = self._batched_insert(
  File ""django/db/models/query.py"", line 1831, in _batched_insert
    self._insert(
  File ""django/db/models/query.py"", line 1805, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File ""django/db/models/sql/compiler.py"", line 1821, in execute_sql
    for sql, params in self.as_sql():
  File ""django/db/models/sql/compiler.py"", line 1747, in as_sql
    self.prepare_value(field, self.pre_save_val(field, obj))
  File ""django/db/models/sql/compiler.py"", line 1686, in prepare_value
    return field.get_db_prep_save(value, connection=self.connection)
  File ""django/db/models/fields/__init__.py"", line 1760, in get_db_prep_save
    self.to_python(value), self.max_digits, self.decimal_places
  File ""django/db/models/fields/__init__.py"", line 1743, in to_python
    raise exceptions.ValidationError(
}}}

My understanding is this should have been captured into `rollback_exc` when `needs_rollback` was set to True
That happens in `Atomic.__exit__` when `exc_type` is set and `connection.needs_rollback` is False
I can't test this on 5.2 but `Atomic.__exit__` looks unchanged."	Uncategorized	new	Uncategorized	4.2	Normal				Unreviewed	0	0	0	0	0	0