[DevTest Labs] az lab vm create: Fix --expiration-date always failing with a datetime comparison error

[om singhal (Om-singhaI)]

Related command

az lab vm create --expiration-date

Description

--expiration-date is unusable on az lab vm create. Every date fails, which is what #31611 reports.

By the time _validate_expiration_date runs, AAZDateTimeArg has already normalized the argument into a UTC timestamp, since AAZCommand._handler calls format_args() before pre_operations. So the validator always parses an offset aware datetime. It compared that against datetime.datetime.utcnow(), which is naive, and Python won't compare the two.

The validator does no I/O, so this reproduces on dev with no Azure credentials. The snippet sets the argument up through the same AAZCommandCtx.format_args() call the command goes through:

from azure.cli.core.aaz import AAZArgumentsSchema, AAZDateTimeArg
from azure.cli.core.aaz._command_ctx import AAZCommandCtx
from azure.cli.core.mock import DummyCli
from azure.cli.command_modules.lab.validators import _validate_expiration_date

schema = AAZArgumentsSchema()
schema.expiration_date = AAZDateTimeArg(options=['--expiration-date'])
ctx = AAZCommandCtx(cli_ctx=DummyCli(), schema=schema,
                    command_args={'expiration_date': '2030-06-17T22:00:00.000Z'})
ctx.format_args()
_validate_expiration_date(ctx.args)

TypeError: can't compare offset-naive and offset-aware datetimes

Swap in 2030-06-17 22:00:00, 2030-06-17 22:00:00+00:00 or 2030-06-17 22:00:00.000+00:00 and the traceback is identical. Those are the four date strings from the issue, with the year bumped so the date is still in the future.

I switched the comparison to datetime.datetime.now(datetime.timezone.utc). That drops a utcnow() call too, which has been deprecated since Python 3.12.

Testing Guide

ExpirationDateValidatorTest in test_lab_validators.py sets the argument up the same way, then checks that a future date passes, a past date still raises ArgumentUsageError, and an omitted date is left alone. Revert validators.py and both date tests fail with the TypeError above.

The recorded scenario tests never passed --expiration-date, which is why none of them caught this. They still pass:

python -m pytest src/azure-cli/azure/cli/command_modules/lab/tests/latest/ -q
8 passed, 1 skipped

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Thank you for your contribution om singhal (@Om-singhaI)! We will review the pull request and get back to you soon.

[Copilot]

🟢 Approval recommended

The fix and regression tests address the reported failure with no unresolved blocking issues.

Pull request overview

Fixes az lab vm create --expiration-date datetime comparison failures.

Changes:

• Uses timezone-aware UTC validation.
• Adds future, past, and omitted expiration-date tests.

File summaries

File	Description
src/azure-cli/azure/cli/command_modules/lab/validators.py	Corrects expiration-date comparison.
src/azure-cli/azure/cli/command_modules/lab/tests/latest/test_lab_validators.py	Adds expiration-date validator coverage.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Lite

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[Yong Zhang (yonzhan)]

DevTest Labs