[MOHAMMED WASIM KHAN (wasim-builds)]

Summary

Closes #14683

SqlServerCollection._lambda_parser rendered None comparisons as [field] = ? or [field] <> ? binding the string literal 'None'. Because SQL Server evaluates equality with NULL under ANSI_NULLS ON as UNKNOWN, search filters targeting None could never match NULL rows. In addition:

• ast.Is and ast.IsNot raised NotImplementedError: Unsupported operator: <class 'ast.Is'> on x.tenant is None and x.tenant is not None.
• Booleans were bound as string 'True' / 'False' instead of '1' / '0' (which is expected by SQL Server BIT columns and is already used by _cast_value).
• Omitted search arguments in default_dynamic_filter_function generating lambda x: x.tenant == None bound 'None' as a query parameter.

Changes

1. SqlServerCollection._lambda_parser:
   • Inspect comparison operators (ast.Eq, ast.NotEq, ast.Is, ast.IsNot).
   • Normalize operands so if left_node is ast.Constant with value is None, it swaps left_node and right_node.
   • When comparing against None:
     • If both sides are scalar constants, evaluate to T-SQL (1 = 1) or (1 = 0).
     • Otherwise, render [column] IS NULL (for ast.Eq, ast.Is) or [column] IS NOT NULL (for ast.NotEq, ast.IsNot) without appending any parameter to command.parameters.
     • Raise NotImplementedError if ast.Is or ast.IsNot is used with a non-None operand.
   • In case ast.Constant():, bind booleans as '1' if True else '0' to match _cast_value and SQL Server BIT semantics.
   • Avoid double-parsing right_node across comparison operator branches.
2. Unit Tests:
   • Added parameterized test_null_filter_parser in tests/unit/connectors/memory/test_sql_server.py covering 28 cases mirroring Postgres null filter parser tests (== None, != None, is None, is not None, reversed comparisons, constant truth evaluation, compound boolean expressions, boolean bindings '1'/'0', and string 'None').
   • Added test_null_filter_query_parameter_order verifying SELECT query parameter alignment when combining null filters with vector and range filters.
   • Added test_dynamic_null_filter verifying default_dynamic_filter_function(tenant=None) generates [tenant] IS NULL without parameters.
   • Added test_unsupported_is_operator verifying unsupported is comparisons raise NotImplementedError.

Verification

• uv run pytest tests/unit/connectors/memory/test_sql_server.py (73 passed in 0.16s).
• uv run ruff check tests/unit/connectors/memory/test_sql_server.py semantic_kernel/connectors/sql_server.py (all checks passed).
• uv run ruff format --check tests/unit/connectors/memory/test_sql_server.py semantic_kernel/connectors/sql_server.py (all formatted).

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota.