Usage of assert outside of tests

[rdimaio]

Description

Right now, we are using assert in production code, outside tests (see the linter log below).

Some usage examples:

rucio/bin/rucio-auditor

Line 58 in bc8fae0

assert len(rses) > 0

rucio/bin/rucio-dumper

Line 128 in 3397448

assert args.sum in set(record_type.get_fieldnames())

rucio/lib/rucio/common/dumper/consistency.py

Lines 44 to 47 in 3397448

	assert prev_date_fname is not None
	assert next_date_fname is not None
	else:
	assert subcommand == 'consistency-manual'

rucio/lib/rucio/core/lock.py

Line 83 in 3397448

assert isinstance(scope, InternalScope)

This is not necessarily bad, but assertions are removed when Python is run with optimization requested (compiling to optimised byte code, python -O ... producing *.opt-1.pyc files). This is likely never going to be an issue for Rucio, but I still wanted to open an issue to discuss this.

Additionally, when assert fails, it raises AssertionError. In the context of our usage of assert, I think we could raise more specific exceptions with clearer messages, which might also help from the point of view of debugging.

To do

I would like us to decide on one of these options:

• We decide that the current production usage of assert is fine. In this case, we only need to set the linter to ignore S101 (usage of assert) and no other changes will be needed.
• We decide that we want to replace our usage of assert with regular condition checking and custom exceptions. In this case, we'd need to make these changes.

See also

• Ruff's docs: https://docs.astral.sh/ruff/rules/assert/
• Bandit's docs: https://bandit.readthedocs.io/en/latest/plugins/b101_assert_used.html

Linter log

❯ ruff check --select S101                                                                                                                                                                                                                                                                                               ─╯
bin/rucio-admin:1198:5: S101 Use of `assert` detected
bin/rucio-auditor:51:5: S101 Use of `assert` detected
bin/rucio-auditor:58:5: S101 Use of `assert` detected
bin/rucio-auditor:72:5: S101 Use of `assert` detected
bin/rucio-dumper:99:9: S101 Use of `assert` detected
bin/rucio-dumper:117:9: S101 Use of `assert` detected
bin/rucio-dumper:128:13: S101 Use of `assert` detected
lib/rucio/client/lockclient.py:61:9: S101 Use of `assert` detected
lib/rucio/common/dumper/__init__.py:73:9: S101 Use of `assert` detected
lib/rucio/common/dumper/consistency.py:44:13: S101 Use of `assert` detected
lib/rucio/common/dumper/consistency.py:45:13: S101 Use of `assert` detected
lib/rucio/common/dumper/consistency.py:47:13: S101 Use of `assert` detected
lib/rucio/common/dumper/consistency.py:169:5: S101 Use of `assert` detected
lib/rucio/common/dumper/consistency.py:304:5: S101 Use of `assert` detected
lib/rucio/common/dumper/consistency.py:392:5: S101 Use of `assert` detected
lib/rucio/common/dumper/data_models.py:160:13: S101 Use of `assert` detected
lib/rucio/common/dumper/data_models.py:240:9: S101 Use of `assert` detected
lib/rucio/common/dumper/data_models.py:267:9: S101 Use of `assert` detected
lib/rucio/common/dumper/data_models.py:295:13: S101 Use of `assert` detected
lib/rucio/common/utils.py:1910:9: S101 Use of `assert` detected
lib/rucio/common/utils.py:1948:9: S101 Use of `assert` detected
lib/rucio/core/lock.py:83:9: S101 Use of `assert` detected
lib/rucio/core/lock.py:92:9: S101 Use of `assert` detected
lib/rucio/core/oidc.py:100:9: S101 Use of `assert` detected
lib/rucio/daemons/auditor/srmdumps.py:67:9: S101 Use of `assert` detected
lib/rucio/db/sqla/session.py:225:5: S101 Use of `assert` detected
lib/rucio/db/sqla/session.py:261:5: S101 Use of `assert` detected
lib/rucio/db/sqla/session.py:280:5: S101 Use of `assert` detected
lib/rucio/db/sqla/util.py:125:13: S101 Use of `assert` detected
lib/rucio/db/sqla/util.py:309:9: S101 Use of `assert` detected
lib/rucio/transfertool/fts3_plugins.py:125:13: S101 Use of `assert` detected
lib/rucio/web/rest/flaskapi/v1/dids.py:457:13: S101 Use of `assert` detected
Found 32 errors.