A RIGHT or FULL JOIN doesn't make the joins to its left nullable #4690

Version

1.31.1

What happened?

A RIGHT JOIN or FULL JOIN makes everything joined before it nullable, and a parenthesised join on the nullable side of a LEFT JOIN is nullable as a whole. sqlc decides each join from its own type alone, so the tables of the earlier join are generated as never null.

For the query below I get Name string. I expected pgtype.Text: a book whose author_id matches no author comes back with a NULL name.

type ListTitlesRow struct {
	Name  string
	Title string
}

The same happens with FROM authors a LEFT JOIN (books b JOIN books c ON c.id = b.id) ON b.author_id = a.id: the columns of b and c are never null.

It is the same on main (3ad8b20). I found no existing issue; #604 is a different case.

isTableRequired passes a fixed value down for each join type and ignores the side it was reached through. A five-line fix with test cases is here: Bockit@fd812e9

The analysis was done with AI help and checked by me.

Relevant log output

No response

Database schema

CREATE TABLE authors (id BIGSERIAL PRIMARY KEY, name text NOT NULL);
CREATE TABLE books (id BIGSERIAL PRIMARY KEY, author_id bigint NOT NULL, title text NOT NULL);

SQL queries

-- name: ListTitles :many
SELECT a.name, c.title
FROM authors a
LEFT JOIN books b ON b.author_id = a.id
RIGHT JOIN books c ON c.author_id = a.id;

Configuration

version: "2"
sql:
  - engine: postgresql
    schema: schema.sql
    queries: query.sql
    gen:
      go:
        package: db
        out: db
        sql_package: pgx/v5

Playground URL

No response

What operating system are you using?

macOS

What database engines are you using?

PostgreSQL

What type of code are you generating?

Go