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linter: warn about foreign key constraints in create table defs #945

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Merged
kodiakhq merged 2 commits into from
Feb 21, 2026
Merged

linter: warn about foreign key constraints in create table defs #945

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c84d70d
linter: warn about foreign key constraints in create table defs
sbdchd Feb 21, 2026
5038885
lint
sbdchd Feb 21, 2026
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2 changes: 1 addition & 1 deletion crates/squawk_ide/src/binder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -281,7 +281,7 @@ fn bind_stmt(b: &mut Binder, stmt: ast::Stmt) {
ast::Stmt::Listen(listen) => bind_listen(b, listen),
ast::Stmt::Set(set) => bind_set(b, set),
ast::Stmt::CreatePolicy(create_policy) => bind_create_policy(b, create_policy),
_ => {}
_ => (),
}
}

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2 changes: 1 addition & 1 deletion crates/squawk_ide/src/document_symbols.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -201,7 +201,7 @@ pub fn document_symbols(file: &ast::SourceFile) -> Vec<DocumentSymbol> {
}
}

_ => {}
_ => (),
}
}

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7 changes: 4 additions & 3 deletions crates/squawk_linter/src/analyze.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,14 @@ fn has_foreign_key_constraint(create_table: &ast::CreateTable) -> bool {
return true;
}
ast::TableArg::Column(column) => {
if let Some(ast::ColumnConstraint::ReferencesConstraint(_)) =
column.constraint()
if column
.constraints()
.any(|c| matches!(c, ast::ColumnConstraint::ReferencesConstraint(_)))
{
return true;
}
}
_ => {}
_ => (),
}
}
}
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166 changes: 109 additions & 57 deletions crates/squawk_linter/src/rules/adding_foreign_key_constraint.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,63 +15,103 @@ pub(crate) fn adding_foreign_key_constraint(ctx: &mut Linter, parse: &Parse<Sour
let tables_created = tables_created_in_transaction(ctx.settings.assume_in_transaction, &file);
// TODO: use match_ast! like in #api_walkthrough
for stmt in file.stmts() {
if let ast::Stmt::AlterTable(alter_table) = stmt {
if let Some(table_name) = alter_table
.relation_name()
.and_then(|x| x.path())
.and_then(|x| x.segment())
.and_then(|x| x.name_ref())
{
for action in alter_table.actions() {
match action {
ast::AlterTableAction::AddConstraint(add_constraint) => {
if add_constraint.not_valid().is_some()
|| tables_created.contains(&Identifier::new(&table_name.text()))
{
// Adding foreign key is okay when:
// - NOT VALID is specified.
// - The table is created in the same transaction
continue;
match stmt {
ast::Stmt::AlterTable(alter_table) => {
if let Some(table_name) = alter_table
.relation_name()
.and_then(|x| x.path())
.and_then(|x| x.segment())
.and_then(|x| x.name_ref())
{
for action in alter_table.actions() {
match action {
ast::AlterTableAction::AddConstraint(add_constraint) => {
if add_constraint.not_valid().is_some()
|| tables_created.contains(&Identifier::new(&table_name.text()))
{
// Adding foreign key is okay when:
// - NOT VALID is specified.
// - The table is created in the same transaction
continue;
}
if let Some(constraint) = add_constraint.constraint() {
if matches!(
constraint,
ast::Constraint::ForeignKeyConstraint(_)
| ast::Constraint::ReferencesConstraint(_)
) {
ctx.report(
Violation::for_node(
Rule::AddingForeignKeyConstraint,
message.into(),
constraint.syntax(),
)
.help(help),
)
}
}
}
if let Some(constraint) = add_constraint.constraint() {
if matches!(
constraint,
ast::Constraint::ForeignKeyConstraint(_)
| ast::Constraint::ReferencesConstraint(_)
) {
ctx.report(
Violation::for_node(
Rule::AddingForeignKeyConstraint,
message.into(),
constraint.syntax(),
ast::AlterTableAction::AddColumn(add_column) => {
for constraint in add_column.constraints() {
if matches!(
constraint,
ast::Constraint::ForeignKeyConstraint(_)
| ast::Constraint::ReferencesConstraint(_)
) {
ctx.report(
Violation::for_node(
Rule::AddingForeignKeyConstraint,
message.into(),
constraint.syntax(),
)
.help(help),
)
.help(help),
)
}
}
}
_ => continue,
}
ast::AlterTableAction::AddColumn(add_column) => {
for constraint in add_column.constraints() {
if matches!(
constraint,
ast::Constraint::ForeignKeyConstraint(_)
| ast::Constraint::ReferencesConstraint(_)
) {
ctx.report(
Violation::for_node(
Rule::AddingForeignKeyConstraint,
message.into(),
constraint.syntax(),
)
.help(help),
}
}
}
ast::Stmt::CreateTable(create_table) => {
if let Some(table_arg_list) = create_table.table_arg_list() {
for arg in table_arg_list.args() {
match arg {
ast::TableArg::TableConstraint(
ast::TableConstraint::ForeignKeyConstraint(fk),
) => {
ctx.report(
Violation::for_node(
Rule::AddingForeignKeyConstraint,
message.into(),
fk.syntax(),
)
.help(help),
);
}
ast::TableArg::Column(column) => {
for constraint in column.constraints() {
if let ast::ColumnConstraint::ReferencesConstraint(refs) =
constraint
{
ctx.report(
Violation::for_node(
Rule::AddingForeignKeyConstraint,
message.into(),
refs.syntax(),
)
.help(help),
);
}
}
}
_ => (),
}
_ => continue,
}
}
}
_ => (),
}
}
}
Expand All @@ -90,20 +130,32 @@ mod test {
#[test]
fn create_table_with_foreign_key_constraint() {
let sql = r#"
BEGIN;
CREATE TABLE email (
id BIGINT GENERATED ALWAYS AS IDENTITY,
user_id BIGINT,
email TEXT,
PRIMARY KEY(id),
CONSTRAINT fk_user
FOREIGN KEY ("user_id")
REFERENCES "user" ("id")
);
COMMIT;
BEGIN;
CREATE TABLE email (
id BIGINT GENERATED ALWAYS AS IDENTITY,
user_id BIGINT,
email TEXT,
PRIMARY KEY(id),
CONSTRAINT fk_user
FOREIGN KEY ("user_id")
REFERENCES "user" ("id")
);
COMMIT;
"#;

lint_ok(sql, Rule::AddingForeignKeyConstraint);
assert_snapshot!(lint_errors(sql, Rule::AddingForeignKeyConstraint));
}

#[test]
fn create_table_with_column_references() {
let sql = r#"
CREATE TABLE table_name (
id BIGSERIAL NOT NULL,
my_fk_id INTEGER NOT NULL REFERENCES other_table (id) ON DELETE CASCADE
);
"#;

assert_snapshot!(lint_errors(sql, Rule::AddingForeignKeyConstraint));
}

#[test]
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2 changes: 1 addition & 1 deletion crates/squawk_linter/src/rules/adding_not_null_field.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -124,7 +124,7 @@ pub(crate) fn adding_not_null_field(ctx: &mut Linter, parse: &Parse<SourceFile>)
.help("Make the field nullable and use a `CHECK` constraint instead."),
);
}
_ => {}
_ => (),
}
}
}
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10 changes: 10 additions & 0 deletions ...ter__rules__adding_foreign_key_constraint__test__create_table_with_column_references.snap
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Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
---
source: crates/squawk_linter/src/rules/adding_foreign_key_constraint.rs
expression: "lint_errors(sql, Rule::AddingForeignKeyConstraint)"
---
warning[adding-foreign-key-constraint]: Adding a foreign key constraint requires a table scan and a `SHARE ROW EXCLUSIVE` lock on both tables, which blocks writes to each table.
╭▸
4 │ my_fk_id INTEGER NOT NULL REFERENCES other_table (id) ON DELETE CASCADE
│ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
│
╰ help: Add `NOT VALID` to the constraint in one transaction and then VALIDATE the constraint in a separate transaction.
12 changes: 12 additions & 0 deletions ...rules__adding_foreign_key_constraint__test__create_table_with_foreign_key_constraint.snap
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Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
---
source: crates/squawk_linter/src/rules/adding_foreign_key_constraint.rs
expression: "lint_errors(sql, Rule::AddingForeignKeyConstraint)"
---
warning[adding-foreign-key-constraint]: Adding a foreign key constraint requires a table scan and a `SHARE ROW EXCLUSIVE` lock on both tables, which blocks writes to each table.
╭▸
8 │ ┏ CONSTRAINT fk_user
9 │ ┃ FOREIGN KEY ("user_id")
10 │ ┃ REFERENCES "user" ("id")
│ ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
│
╰ help: Add `NOT VALID` to the constraint in one transaction and then VALIDATE the constraint in a separate transaction.
4 changes: 2 additions & 2 deletions crates/squawk_syntax/src/ast/generated/nodes.rs
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4 changes: 2 additions & 2 deletions crates/squawk_syntax/src/postgresql.ungram
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Original file line number Diff line number Diff line change
Expand Up @@ -604,11 +604,11 @@ CompressionMethod =
Column =
'period'?
(
Name WithOptions? constraint:ColumnConstraint?
Name WithOptions? constraints:ColumnConstraint*
DeferrableConstraintOption? NotDeferrableConstraintOption?
InitiallyDeferredConstraintOption? InitiallyImmediateConstraintOption?
NotEnforced? Enforced?
| Name Type Storage? CompressionMethod? Collate? constraint:ColumnConstraint?
| Name Type Storage? CompressionMethod? Collate? constraints:ColumnConstraint*
DeferrableConstraintOption? NotDeferrableConstraintOption?
InitiallyDeferredConstraintOption? InitiallyImmediateConstraintOption?
NotEnforced? Enforced?
Expand Down
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