Fix database.table.column references throwing to close #2186

[joshuablac]

Closes #2186

Problem

A three-part database.table.column reference throws Cannot read properties of undefined (reading '<table>') wherever it is used, not only in ON:

SELECT * FROM db.t1 JOIN db.t2 ON db.t1.id = db.t2.id   -- throws
SELECT db.t1.id FROM db.t1                               -- throws
SELECT * FROM db.t1 WHERE db.t1.id = 1                   -- throws
SELECT * FROM db.t1 ORDER BY db.t1.id                    -- throws

Cause

As the issue describes, db.t1.id is parsed as (db.t1) -> id: a two-part column (tableid: 'db', columnid: 't1') followed by a property access. The compiled code reads p['db']['t1'], which is undefined.

Why this doesn't use the grammar change from the issue

I tried the change the issue proposes (%nonassoc LOW_PREC plus Literal DOT Literal %prec LOW_PREC). It fixes db.table.column, and the existing suite still passes. But it breaks alias.column.property, which works on develop and has no test:

alasql('SELECT t.obj.x AS v FROM ? t', [[{obj: {x: 10}}]]);
// develop:            [{v: 10}]
// with grammar change: TypeError: Cannot read properties of undefined (reading 'x')

The parser can't tell db.table.col from alias.col.prop, because the difference depends on what the names refer to. So I resolve it at compile time instead.

Fix

In Op.toJS for ->, a left side a.b is compiled as the column a.b.<right> only when all of these hold:

• a is not a source alias of the query
• a is an existing database
• b is a source of the query

Every other -> compiles exactly as before. The only expressions whose behavior changes are ones that throw today. No grammar change.

Note: an unaliased SELECT db.t1.id FROM db.t1 gets the key db.t1->id, the same automatic naming any -> expression gets. Use AS for a clean name.

Tests

• Added test/test2186.js (named after the A_2186 / B_2186 tables from the issue):
  • database.table.column in ON, in the SELECT list, WHERE and ORDER BY, and with USE <db>
  • a regression check that alias.column.property (t.obj.x, t.obj.y.z, and the t.obj->x key name) behaves as before
• The 3 database-qualified cases fail on develop and pass with this change.
• Full suite (bun test, same command as yarn test-only): 2253 pass, 213 skip. The only failures are the 2 CLI tests in test2149.js, which fail the same way on unmodified develop in my local setup (a space in my checkout path, and the version-injection step of build.sh not running).

This fix was written with AI assistance (Claude Code) and verified locally as described above.

🤖 Generated with Claude Code

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