use pg_query::protobuf::AlterTableType;
use pg_query::NodeEnum;
use super::Rule;
use crate::{RuleHit, Severity};
pub struct SetNotNull;
impl Rule for SetNotNull {
fn id(&self) -> &'static str {
"set-not-null"
}
fn severity(&self) -> Severity {
Severity::Error
}
fn check(&self, node: &NodeEnum, out: &mut Vec<RuleHit>) {
for cmd in super::alter_table_cmds(node) {
if matches!(
AlterTableType::try_from(cmd.subtype),
Ok(AlterTableType::AtSetNotNull)
) {
out.push(RuleHit {
message: "ALTER COLUMN ... SET NOT NULL scans the entire table under an ACCESS \
EXCLUSIVE lock."
.into(),
guidance: "On PG12+, first add `CHECK (col IS NOT NULL) NOT VALID`, run VALIDATE \
CONSTRAINT, then SET NOT NULL (it reuses the validated check and skips \
the scan). Drop the helper CHECK afterward if you like."
.into(),
fix: None,
});
}
}
}
}
#[cfg(test)]
mod tests {
use crate::{lint_sql, LintOptions};
#[test]
fn flags_set_not_null() {
let findings = lint_sql(
"ALTER TABLE t ALTER COLUMN a SET NOT NULL",
&LintOptions::default(),
)
.unwrap();
assert!(findings.iter().any(|f| f.rule_id == "set-not-null"));
}
#[test]
fn ignores_drop_not_null() {
let findings = lint_sql(
"ALTER TABLE t ALTER COLUMN a DROP NOT NULL",
&LintOptions::default(),
)
.unwrap();
assert!(findings.iter().all(|f| f.rule_id != "set-not-null"));
}
}