fix: generated column on public schema

[tianzhou]

Fix #194

[Copilot]

Pull request overview

This PR fixes issue #194 related to generated columns that reference functions from different schemas. The fix ensures that cross-schema function references in generated column expressions are properly qualified with their schema names.

Key Changes:

• Modified the GetColumnsForSchema SQL query to use a LATERAL join with set_config to control the search_path when evaluating generated column expressions
• Added test data demonstrating a generated column that calls a function from a different schema (util.extract_domain)
• Improved parameter naming from dollar_1 to tableSchema in the Go code

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
ir/queries/queries.sql	Refactored GetColumnsForSchema query with CTE and LATERAL join to properly qualify cross-schema function references in generated columns
ir/queries/queries.sql.go	Generated Go code reflecting the SQL query changes and improved parameter naming
testdata/dump/tenant/util.sql	Added extract_domain function to test cross-schema function usage
testdata/dump/tenant/tenant.sql	Added website column and domain generated column to users table for testing
testdata/dump/tenant/pgschema.sql	Expected output showing properly qualified function reference in generated column

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[Copilot]

The dummy column in the LATERAL subquery is used solely to ensure set_config is evaluated before pg_get_expr. While this works, it's a workaround that relies on left-to-right evaluation order in the SELECT clause. Consider adding a comment explaining this pattern or using a more explicit approach, such as a custom function that wraps pg_get_expr with search_path control.

Suggested change

	SELECT
	SELECT
	-- The dummy column ensures set_config is evaluated (for its side effect)
	-- before pg_get_expr, relying on PostgreSQL's left-to-right SELECT evaluation.

[Copilot]

The search_path is constructed using string concatenation: cb.table_schema || ', pg_catalog'. While schema names from information_schema.columns are generally safe, PostgreSQL allows schema names with special characters, quotes, or commas. If a schema name contains a comma or other special characters, this could lead to unexpected behavior or potentially a security issue. Consider using proper quoting for the schema name, such as using quote_ident() or validating that the schema name doesn't contain problematic characters.

Suggested change

	set_config('search_path', cb.table_schema || ', pg_catalog', true) as dummy,
	set_config('search_path', format('%I, pg_catalog', cb.table_schema), true) as dummy,

[Copilot]

The search_path is constructed using string concatenation: cb.table_schema || ', pg_catalog'. While schema names from information_schema.columns are generally safe, PostgreSQL allows schema names with special characters, quotes, or commas. If a schema name contains a comma or other special characters, this could lead to unexpected behavior or potentially a security issue. Consider using proper quoting for the schema name, such as using quote_ident() or validating that the schema name doesn't contain problematic characters.

Suggested change

	set_config('search_path', cb.table_schema || ', pg_catalog', true) as dummy,
	set_config('search_path', quote_ident(cb.table_schema) || ', pg_catalog', true) as dummy,

[Copilot]

The parameter name tableSchema is more descriptive than dollar_1, but this creates inconsistency with other similar functions in this file (e.g., GetAggregatesForSchema, GetConstraintsForSchema, etc.) which still use dollar_1. Consider updating all similar functions to use descriptive parameter names for consistency.

Suggested change

	func (q *Queries) GetColumnsForSchema(ctx context.Context, tableSchema sql.NullString) ([]GetColumnsForSchemaRow, error) {
	rows, err := q.db.QueryContext(ctx, getColumnsForSchema, tableSchema)
	func (q *Queries) GetColumnsForSchema(ctx context.Context, dollar_1 sql.NullString) ([]GetColumnsForSchemaRow, error) {
	rows, err := q.db.QueryContext(ctx, getColumnsForSchema, dollar_1)