[sharadgaur]

Summary

Add parsing, formatting and AST traversal support for row-policy statements:

• CREATE, ALTER and DROP [ROW] POLICY
• SHOW CREATE [ROW] POLICY and SHOW [ROW] POLICIES

Handles policy/table bindings, conditions, policy modes, user/role sets, access storage and cluster clauses. Preserves the difference between omitted ALTER clauses and explicit changes such as USING NONE or TO NONE.

Example

CREATE ROW POLICY example_policy ON db.example_table
USING value > 0 TO example_role;

ALTER ROW POLICY example_policy ON db.example_table USING value > 10;
SHOW CREATE ROW POLICY example_policy ON db.example_table;
DROP ROW POLICY IF EXISTS example_policy ON db.example_table;

Compatibility

Adds policy visit methods to ASTVisitor; DefaultASTVisitor provides their default implementations.

Supports SELECT policy syntax. Parsing does not execute policies or provide access-control enforcement. Also fixes numeric tuple-access token separation found during roundtrip testing.

Tests

Includes AST and formatting fixtures, roundtrip tests, traversal checks, malformed-input coverage and fuzz regressions. Validated with the unit, race and compatibility suites, native ClickHouse formatter comparisons and bounded fuzzing.