fix: inspect every table function in feature analysis and validation

[AndreasLanz01]

What

Two visitors looked at only part of a TableFunction:

1. StatementFeatureVisitor now checks every function of ROWS FROM (...) for purity. Before, it checked only TableFunction#getFunction(), which is null for ROWS FROM.
2. SelectValidator now validates the functions of a table function, for f(...) and for every function of ROWS FROM (...). Before, it validated only Feature.tableFunction and PIVOT/UNPIVOT, so nothing in the arguments was validated.

Both use the existing TableFunction#getFunctions(), which returns the ROWS FROM list or the single function.

Why

StatementFeatureVisitor.analyse(statement, name -> false), i.e. no function is declared pure:

SQL	Before	After
SELECT * FROM pg_ls_dir('.')	MODIFIES_DATA, MODIFIES_SCHEMA uncertain; pg_ls_dir unresolved	unchanged
SELECT * FROM ROWS FROM (pg_ls_dir('.'))	nothing uncertain, nothing unresolved	same as the plain form

A read-only guard that uses mayModifyData() therefore accepted any function when it was wrapped in ROWS FROM.

SelectValidator with FeaturesAllowed.SELECT plus Feature.tableFunction: SELECT * FROM t WHERE a = f(?) reports jdbcParameter not allowed., but SELECT * FROM f(?) and SELECT * FROM ROWS FROM (f(1), g(?)) reported no error.

Testing

• StatementFeatureVisitorTest: new nested class with 4 tests:

  • plain table function (regression control);
  • ROWS FROM with one function;
  • ROWS FROM with two functions; marking only the first one pure leaves the second one unresolved;
  • ROWS FROM ... WITH ORDINALITY AS r(n, name, ord).

  On base 26d3e02a the 3 ROWS FROM tests fail and the control passes.

• SelectValidatorTest: a WHERE control and a parameterized test with 3 cases (f(?), ROWS FROM, ROWS FROM ... WITH ORDINALITY). On base 26d3e02a the 3 cases fail with Expected 1 errors, but got: [] and the control passes.

• ./gradlew check on Windows 11 with the JDK 17 toolchain passes: 9,550 test cases, 0 failures, 0 errors, 25 skipped. Grammar ambiguity, Spotless, Checkstyle, PMD, SpotBugs and JaCoCo verification pass.

• All SQL in the new tests executes on PostgreSQL 18.4 (? sent as $1 with PREPARE/EXECUTE; helper table t and functions f, g created first).

• Not run: mvn verify, JMH (no grammar or parser change), Linux/macOS.

Also observed, but not changed

• SelectValidator does not validate select items at all (call commented out with a @todo at SelectValidator.java:152-155). That is why the validator control uses WHERE.
• FromItemVisitorAdapter.visit(TableFunction) is empty, so the generic adapter does not descend into table function arguments, for f(...) or ROWS FROM. Changing it would change behaviour for every adapter user.

Origin

First observed with com.manticore-projects.jsqlformatter:jsqlparser:5.4.104 and Dialect.POSTGRESQL. Reproduced on upstream master 26d3e02a78e061f5fecf2eb2e783bf0482e10840 with the default parser.

AI disclosure: this change was prepared with an AI coding agent (Claude Code) and reviewed by me.