[RaphaelFakhri]

What this changes

Weaviate serializes the completedAt timestamp of a backup or export that has not finished yet as Go's zero time, 0001-01-01T00:00:00.000Z. The client parsed that value as-is, so for a running backup or export:

• client.backup.list_backups(...) returned completed_at=datetime(1, 1, 1, tzinfo=UTC).
• client.export.get_status(...) returned completed_at=datetime(1, 1, 1, tzinfo=UTC).

Both fields are typed Optional[datetime] with a None default, so code that checks completed_at is None to detect an unfinished operation, or that computes a duration from it, gets a wrong answer.

This change adds a field validator to BackupListReturn.completed_at and ExportStatusReturn.completed_at that maps the zero time to None. Real timestamps pass through unchanged.

Fixes #2216

Reproduction

Against Weaviate 1.40.0 with backup-filesystem and EXPORT_ENABLED=true:

c.backup.create(backup_id="bk2", backend=BackupStorage.FILESYSTEM)
print(c.backup.list_backups(backend=BackupStorage.FILESYSTEM)[0].completed_at)
# before: 0001-01-01 00:00:00+00:00
# after:  None

The raw response from GET /v1/backups/filesystem while the backup runs:

[{"classes":["Article"],"completedAt":"0001-01-01T00:00:00.000Z","id":"bk1","startedAt":"2026-10-21T06:49:36.565Z","status":"STARTED"}]

Tests

• test/test_backup.py: an unset completedAt maps to None; a set one is kept.
• test/test_export.py (new): the same two cases for ExportStatusReturn.

pytest test/test_backup.py test/test_export.py: 2 of the new tests fail without the fix and all 7 pass with it. pytest test passes (546 passed, 1 skipped). ruff format, ruff check, and flake8 are clean on the changed files.

[orca-security-eu]

Orca Security Scan Summary

Status	Check	Issues by priority
Passed	Infrastructure as Code	0   0   0   0	View in Orca
Passed	SAST	0   0   0   0	View in Orca
Passed	Secrets	0   0   0   0	View in Orca
Passed	Vulnerabilities	0   0   0   0	View in Orca

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