[Pg-kit] Fix malformed array literal error on indexes

[Kratious]

Fix #2715, fix #2744

The issue is the expression text to array conversion happening in (('{' || pg_get_expr(i.indexprs, i.indrelid)|| '}')::text[])[k.i]. Commas in an expression become delimiters and split the expression up prematurely. Some special characters like double quotes can cause the malformed array literal errors.

The postgres function pg_get_indexdef does what the snippet above is trying to do, but safely.

I tried adding a test to introspect/pg.test.ts, but some of the indexes get added to list of "alteredIndexes" as the indexes get transformed a little bit and don't pass the json diff snapshots check (e.g. lower(first_name) becomes lower(\"first_name\") and gets flagged as altered).

Which is why the test below has a expect(statements.length).toBe(10);. I decided to leave the test out of my PR for now. This test fails in the main branch but passes with this fix at the very least.

test('basic index test', async () => {
	const client = new PGlite();

	const schema = {
		users: pgTable('users', {
			firstName: text('first_name'),
			lastName: text('last_name'),
			data: jsonb('data'),
		}, (table) => ({
			singleColumn: index('single_column').on(table.firstName),
			multiColumn: index('multi_column').on(table.firstName, table.lastName),
			singleExpression: index('single_expression').on(sql`lower(${table.firstName})`),
			multiExpression: index('multi_expression').on(sql`lower(${table.firstName})`, sql`lower(${table.lastName})`),
			expressionWithComma: index('expression_with_comma').on(sql`(lower(${table.firstName}) || ', '::text || lower(${table.lastName}))`),
			expressionWithDoubleQuote: index('expression_with_double_quote').on(sql`('"'::text || ${table.firstName})`),
			expressionWithJsonbOperator: index('expression_with_jsonb_operator').on(sql`(${table.data} #>> '{a,b,1}'::text[])`),
		})),
	};

	const { statements, sqlStatements } = await introspectPgToFile(
		client,
		schema,
		'basic-index-introspect',
	);

	expect(statements.length).toBe(10);
	expect(sqlStatements.length).toBe(10);
});

[juspky]

@AndriiSherman could you please review this when you have spare time?