FIX: Robust resource cleanup of Connection/Cursor for graceful exit & add tests

[bewithgaurav]

ADO Work Item Reference

AB#37889
Github Issue - #131

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Summary

This pull request introduces enhancements to cursor and connection management in the mssql_python library, aiming to improve resource cleanup and debugging capabilities. Key changes include adding destructors for automatic cleanup, enhancing logging for better traceability, and introducing new tests to validate cursor behavior during garbage collection and connection closure.

Resource Cleanup Enhancements:

• Added a __del__ method in mssql_python/connection.py to automatically close connections during object destruction, with error logging for cleanup issues.
• Added a __del__ method in mssql_python/cursor.py to ensure cursors are closed when no longer needed, with error handling during destruction.

Debugging Improvements:

• Enhanced logging in mssql_python/connection.py and mssql_python/cursor.py with detailed print statements for tracking cursor states and operations (e.g., during connection closure, statement execution, and data fetching). [1] [2] [3] [4]

Testing Additions:

• Introduced test_cursor_cleanup_without_close to verify that cursors are properly cleaned up when the connection is not explicitly closed.
• Added test_no_segfault_on_gc to ensure no segmentation faults occur during garbage collection of connections and cursors. This test runs in a subprocess to isolate potential crashes.

[gargsaumya]

LGTM