Fix #1901: share_cube_with_user passes swapped args to _validate_cube_access — fails for ev

[Memtensor-AI]

Description

Fixes #1901: MOSCore.share_cube_with_user was broken for every well-formed call. The method called self._validate_cube_access(cube_id, target_user_id), but the validator's signature is (user_id, cube_id). The cube UUID therefore landed in the user_id slot and the first line of the validator (_validate_user_exists) raised ValueError: User '<cube_id>' does not exist or is inactive for every invocation, making the share API completely unusable in b60616d / PyPI MemoryOS==2.0.17.

The in-code comment "Validate current user has access to this cube" already documented the correct intent: the sharing user (self.user_id) — not the target — must own the cube being shared. The fix is a one-line change in src/memos/mem_os/core.py: self._validate_cube_access(self.user_id, cube_id). The target user's existence is independently checked on the next line via validate_user(target_user_id), which is unchanged.

Added three regression tests in tests/mem_os/test_memos_core.py::TestShareCubeWithUser: (1) the happy path asserts validate_user_cube_access is called with (self.user_id, cube_id) and add_user_to_cube with (target_user_id, cube_id); (2) the current user lacking cube access raises a ValueError referencing the current user (not the cube id); (3) a missing target user raises "Target user '<id>' does not exist". All three tests fail before the fix and pass after. Full mem_os test suite passes (28/28). ruff check and ruff format --check are clean on both changed files.

Related Issue (Required): Fixes #1901

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (does not change functionality, e.g. code style improvements, linting)
• Documentation update

How Has This Been Tested?

Automated tests are pending.

• Unit Test
• Test Script Or Test Steps (please provide)
• Pipeline Automated API Test (please provide)

Checklist

• I have performed a self-review of my own code
• I have commented my code in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• I have created related documentation issue/PR in MemOS-Docs (if applicable)
• I have linked the issue to this PR (if applicable)
• I have mentioned the person who will review this PR

@MatthewZhuang, @CarltonXiang, @syzsunshine219 please review this PR.

Reviewer Checklist

• closes share_cube_with_user passes swapped args to _validate_cube_access — fails for every well-formed call #1901
• Made sure Checks passed
• Tests have been provided

[Memtensor-AI]

✅ Automated Test Results: PASSED

All tests passed (35/35 executed, 36 skipped). memos_local_plugin/smoke: 0 passed, 1 skipped, memos_local_plugin/contract: 35 passed, 35 skipped. Duration: 4s

Branch: bugfix/autodev-1901