v16->v17

[pyramation]

PostgreSQL 16-to-17 AST Transformer Implementation

Summary

This PR implements a comprehensive PostgreSQL 16-to-17 AST transformer for the launchql/pgsql-parser repository, achieving 255/258 tests passing (98.8% success rate) in the 16-17 test suite. The transformer handles complex AST node transformations including JSON type prefixing, context-aware transformations, and various PostgreSQL syntax differences between versions 16 and 17.

Key accomplishments:

• Started with 57/258 failing tests, improved to 255/258 passing
• Implemented transformation logic for 50+ AST node types
• Developed sophisticated context-aware JSON type transformation logic
• Used established 13-14 transformer patterns while focusing exclusively on 16-17 code
• Identified root causes for the remaining 3 test failures

Review & Testing Checklist for Human

• Manually test JSON type transformations - Test queries with ::json and ::jsonb casts in different contexts (CREATE DOMAIN, WITH clauses, simple SELECT statements) to verify the context-aware prefix logic works correctly
• Verify the 3 remaining test failures are acceptable - Review whether the CREATE ACCESS METHOD syntax error, string escaping differences, and JSON prefix issues should be fixed or documented as known limitations
• Test complex real-world SQL scenarios - Run the transformer against complex queries that combine multiple features (CTEs, JSON operations, nested queries) to ensure no edge cases cause regressions
• Validate context detection logic - Review the isInWithClauseContext, isInCreateDomainContext, and related methods to ensure they correctly identify AST contexts for transformation rules

---

Diagram

%%{ init : { "theme" : "default" }}%%
graph TD
    subgraph "Core Transformer Files"
        V16ToV17["packages/transform/src/transformers/v16-to-v17.ts"]:::major-edit
        STATUS["packages/transform/STATUS-16-17.md"]:::minor-edit
    end
    
    subgraph "Test Infrastructure" 
        TestSuite["__tests__/kitchen-sink/16-17/*.test.ts"]:::context
        Fixtures["__fixtures__/kitchen-sink/**/*.sql"]:::context
    end
    
    subgraph "Key Transformation Methods"
        TypeName["TypeName() - JSON prefix logic"]:::major-edit
        TypeCast["TypeCast() - Context-aware transforms"]:::major-edit
        Context["Context detection methods"]:::major-edit
    end
    
    subgraph "Remaining Issues"
        JSON["pretty-misc.test.ts - JSON prefixes"]:::context
        Escaping["misc-quotes_etc.test.ts - String escaping"]:::context  
        AccessMethod["latest-postgres-create_am.test.ts - PG16 parser limit"]:::context
    end
    
    V16ToV17 --> TypeName
    V16ToV17 --> TypeCast
    V16ToV17 --> Context
    
    TestSuite --> JSON
    TestSuite --> Escaping
    TestSuite --> AccessMethod
    
    subgraph Legend
        L1["Major Edit"]:::major-edit
        L2["Minor Edit"]:::minor-edit  
        L3["Context/No Edit"]:::context
    end
    
    classDef major-edit fill:#90EE90
    classDef minor-edit fill:#87CEEB
    classDef context fill:#FFFFFF

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Notes

• Session Details: Requested by Dan Lynch (@pyramation) - Devin Session
• Development Approach: Used tight testing loops focusing exclusively on 16-17 test suite, ignoring CI failures in other transformer versions as instructed
• JSON Type Logic: The most complex aspect was implementing context-aware JSON type transformations - PostgreSQL 17 expects pg_catalog prefixes in some contexts but not others
• Rollback Strategy: Code was rolled back to stable 255/258 state after regression to 250/258 during development
• Parser Limitations: Some remaining failures appear to be PG16 parser limitations rather than transformer issues (CREATE ACCESS METHOD syntax not supported in PG16)
• Next Steps: The remaining 3 test failures need targeted fixes to achieve 100% success rate, or documentation as acceptable limitations