Eric Allam
02cf9c81ad
## Summary A Query page (TRQL) query that pulls fields out of a run's `output` with JSON functions (`JSONExtractString`, `JSONExtractInt`, `JSONHas`, and the rest of the family) failed with "The first argument of function ... should be a string containing JSON, illegal type: JSON". Those queries now work. ## Root cause and fix `output` is a native ClickHouse `JSON` column, but `JSONExtract*`, `JSONHas`, `JSONLength`, and `JSONType` all expect a String containing JSON text. The compiler already swaps in the column's String companion (`output_text`) when a JSON column is selected or compared, but not inside function-call arguments, so it emitted `JSONExtractInt(output, 'x')` against the native column. The fix prints the companion column for the first argument of these functions when it resolves to a bare JSON field, keeping the table alias when qualified (so it works in JOINs): JSONExtractInt(output, 'x') -> JSONExtractInt(output_text, 'x') JSONExtractArrayRaw(assumeNotNull(output), 'y') -> JSONExtractArrayRaw(assumeNotNull(output_text), 'y') It also reaches through value-preserving passthrough wrappers like `assumeNotNull(...)`, while leaving value-changing wrappers like `toJSONString(output)` on the native column (that argument is already a String). The swap is also semantically correct, not just a type fix: `output_text` is the unwrapped data JSON that the TRQL `output` model already represents, so field paths line up. Covered by printer unit tests and a ClickHouse integration test that runs the whole family (plus the wrapped and `toJSONString` cases) against a real native-JSON column. Both new cases fail with the exact "illegal type: JSON" error without the fix.
TSQL (TriggerSQL)
TriggerSQL is a DSL that is safely converted into ClickHouse SQL queries with protection against SQL injection and it's tenant-safe (users can only query their own data).
Attribution
This package is derived from PostHog's HogQL (MIT License). See NOTICE.md for the full copyright notice.
ANTLR Grammar
The ANTLR grammar is heavily inspired by PostHog's HogQL.
These are found in ./src/grammar and are the .g4 files.
Generating the source code
pnpm run grammar:build