Coverage for /home/admin/Documents/AI/applications/lexigram-dev/lexigram/experimental/ai/lexigram-ai-llm/src/lexigram/ai/llm/pinning.py: 50%

1"""Model revision pinning and policy enforcement (LXF-003).""" 

2 

3from __future__ import annotations 

4 

5from enum import StrEnum 

6 

7from lexigram.ai.llm.exceptions import ModelRevisionMismatchError 

8 

9__all__ = [ 

10 "ModelPinPolicy", 

11 "enforce_pin_policy", 

12] 

13 

14 

15class ModelPinPolicy(StrEnum): 

16 """Policy for pinning LLM model revisions. 

17 

18 Controls how strictly the configured ``model_revision`` is enforced 

19 against the revision returned by the provider. 

20 """ 

21 

22 EXACT = "exact" 

23 """Reject any response where the provider's revision does not exactly 

24 match the configured revision.""" 

25 

26 LATEST_MINOR = "latest_minor" 

27 """Accept any revision within the same major prefix (everything before 

28 the last ``-``). Use when minor patch updates are safe.""" 

29 

30 LATEST = "latest" 

31 """Accept any revision. The provider always returns the latest available 

32 revision (default — reproduces current behavior).""" 

33 

34 

35def enforce_pin_policy( 

36 expected_revision: str | None, 

37 actual_revision: str, 

38 policy: ModelPinPolicy, 

39) -> None: 

40 """Enforce a model pin policy. 

41 

42 Args: 

43 expected_revision: The configured pinned revision, or ``None``. 

44 actual_revision: The revision returned by the provider. 

45 policy: The pin policy to enforce. 

46 

47 Raises: 

48 ModelRevisionMismatchError: When the policy is violated. 

49 """ 

50 if policy == ModelPinPolicy.LATEST: 

51 return 

52 

53 if expected_revision is None: 

54 return 

55 

56 if policy == ModelPinPolicy.EXACT: 

57 if expected_revision != actual_revision: 

58 raise ModelRevisionMismatchError( 

59 f"Model revision mismatch (EXACT): expected {expected_revision!r}, " 

60 f"got {actual_revision!r}" 

61 ) 

62 

63 if policy == ModelPinPolicy.LATEST_MINOR: 

64 major_expected = ( 

65 expected_revision.rsplit("-", 1)[0] 

66 if "-" in expected_revision 

67 else expected_revision 

68 ) 

69 major_actual = ( 

70 actual_revision.rsplit("-", 1)[0] 

71 if "-" in actual_revision 

72 else actual_revision 

73 ) 

74 if major_expected != major_actual: 

75 raise ModelRevisionMismatchError( 

76 f"Model revision mismatch (LATEST_MINOR): expected major {major_expected!r}, " 

77 f"got {major_actual!r}" 

78 )