use pg_query::NodeEnum;
use super::Rule;
use crate::RuleHit;
pub struct AddTrigger;
impl Rule for AddTrigger {
fn id(&self) -> &'static str {
"add-trigger"
}
fn check(&self, node: &NodeEnum, out: &mut Vec<RuleHit>) {
if matches!(node, NodeEnum::CreateTrigStmt(_)) {
out.push(RuleHit {
message: "CREATE TRIGGER takes a SHARE ROW EXCLUSIVE lock (blocking writes and other \
DDL, though not reads) and changes behavior for every subsequent write to \
the table."
.into(),
guidance: "Create the trigger during a low-traffic window; its lock conflicts with \
concurrent writes on the table."
.into(),
fix: None,
});
}
}
}
#[cfg(test)]
mod tests {
use crate::{lint_sql, LintOptions, Severity};
fn findings(sql: &str) -> Vec<crate::Finding> {
lint_sql(sql, &LintOptions::default()).unwrap()
}
fn trigger_sql(table: &str) -> String {
format!("CREATE TRIGGER trg AFTER INSERT ON {table} FOR EACH ROW EXECUTE FUNCTION f()")
}
#[test]
fn flags_create_trigger() {
assert!(findings(&trigger_sql("t"))
.iter()
.any(|f| f.rule_id == "add-trigger"));
}
#[test]
fn add_trigger_is_a_warning() {
let f = findings(&trigger_sql("t"))
.into_iter()
.find(|f| f.rule_id == "add-trigger")
.expect("rule must fire");
assert_eq!(f.severity, Severity::Warning);
}
#[test]
fn silent_on_non_trigger_statements() {
assert!(findings("SELECT 1")
.iter()
.all(|f| f.rule_id != "add-trigger"));
}
#[test]
fn silent_on_trigger_for_same_migration_new_table() {
let sql = format!("CREATE TABLE foo (id int); {}", trigger_sql("foo"));
assert!(findings(&sql).iter().all(|f| f.rule_id != "add-trigger"));
}
}