Identify duplicated foreign key constraints by prefix (#245)

When duplicating a column for backfilling, ensure that any FK
constraints on the column are duplicated with a special prefix to
identify them as duplicated constraints. Naming the duplicated FK
constraints in this way allows the rename process to ensure that it only
attempts to rename duplicated FK constraints.

pkg/migrations/duplicate.go

@@ -61,7 +61,7 @@ func (d *Duplicator) Duplicate(ctx context.Context) error {
 	for _, fk := range d.table.ForeignKeys {
 		if slices.Contains(fk.Columns, d.column.Name) {
 			sql += fmt.Sprintf(", "+cAddForeignKeySQL,
-				pq.QuoteIdentifier(TemporaryName(fk.Name)),
+				pq.QuoteIdentifier(DuplicationName(fk.Name)),
 				strings.Join(quoteColumnNames(copyAndReplace(fk.Columns, d.column.Name, d.asName)), ", "),
 				pq.QuoteIdentifier(fk.ReferencedTable),
 				strings.Join(quoteColumnNames(fk.ReferencedColumns), ", "))
@@ -73,6 +73,18 @@ func (d *Duplicator) Duplicate(ctx context.Context) error {
 	return err
 }
 
+func DuplicationName(name string) string {
+	return "_pgroll_dup_" + name
+}
+
+func IsDuplicatedName(name string) bool {
+	return strings.HasPrefix(name, "_pgroll_dup_")
+}
+
+func StripDuplicationPrefix(name string) string {
+	return strings.TrimPrefix(name, "_pgroll_dup_")
+}
+
 func copyAndReplace(xs []string, oldValue, newValue string) []string {
 	ys := slices.Clone(xs)
 

pkg/migrations/op_change_type_test.go

@@ -213,7 +213,7 @@ func TestChangeColumnType(t *testing.T) {
 			},
 			afterStart: func(t *testing.T, db *sql.DB) {
 				// A temporary FK constraint has been created on the temporary column
-				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.TemporaryName("fk_employee_department"))
+				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.DuplicationName("fk_employee_department"))
 			},
 			afterRollback: func(t *testing.T, db *sql.DB) {
 			},

pkg/migrations/op_set_check_test.go

@@ -285,7 +285,7 @@ func TestSetCheckConstraint(t *testing.T) {
 			},
 			afterStart: func(t *testing.T, db *sql.DB) {
 				// A temporary FK constraint has been created on the temporary column
-				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.TemporaryName("fk_employee_department"))
+				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.DuplicationName("fk_employee_department"))
 			},
 			afterRollback: func(t *testing.T, db *sql.DB) {
 			},

pkg/migrations/op_set_fk.go

@@ -85,7 +85,7 @@ func (o *OpSetForeignKey) Complete(ctx context.Context, conn *sql.DB, s *schema.
 	// Validate the foreign key constraint
 	_, err := conn.ExecContext(ctx, fmt.Sprintf("ALTER TABLE IF EXISTS %s VALIDATE CONSTRAINT %s",
 		pq.QuoteIdentifier(o.Table),
-		pq.QuoteIdentifier(TemporaryName(o.References.Name))))
+		pq.QuoteIdentifier(o.References.Name)))
 	if err != nil {
 		return err
 	}
@@ -173,7 +173,7 @@ func (o *OpSetForeignKey) addForeignKeyConstraint(ctx context.Context, conn *sql
 
 	_, err := conn.ExecContext(ctx, fmt.Sprintf("ALTER TABLE %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s (%s) NOT VALID",
 		pq.QuoteIdentifier(o.Table),
-		pq.QuoteIdentifier(TemporaryName(o.References.Name)),
+		pq.QuoteIdentifier(o.References.Name),
 		pq.QuoteIdentifier(tempColumnName),
 		pq.QuoteIdentifier(o.References.Table),
 		pq.QuoteIdentifier(o.References.Column),

pkg/migrations/op_set_fk_test.go

@@ -77,7 +77,7 @@ func TestSetForeignKey(t *testing.T) {
 				ColumnMustExist(t, db, "public", "posts", migrations.TemporaryName("user_id"))
 
 				// A temporary FK constraint has been created on the temporary column
-				NotValidatedForeignKeyMustExist(t, db, "public", "posts", migrations.TemporaryName("fk_users_id"))
+				NotValidatedForeignKeyMustExist(t, db, "public", "posts", "fk_users_id")
 
 				// Inserting some data into the `users` table works.
 				MustInsert(t, db, "public", "02_add_fk_constraint", "users", map[string]string{
@@ -348,7 +348,7 @@ func TestSetForeignKey(t *testing.T) {
 			},
 			afterStart: func(t *testing.T, db *sql.DB) {
 				// A temporary FK constraint has been created on the temporary column
-				ValidatedForeignKeyMustExist(t, db, "public", "posts", migrations.TemporaryName("fk_users_id_1"))
+				ValidatedForeignKeyMustExist(t, db, "public", "posts", migrations.DuplicationName("fk_users_id_1"))
 			},
 			afterRollback: func(t *testing.T, db *sql.DB) {
 			},

pkg/migrations/op_set_notnull_test.go

@@ -291,7 +291,7 @@ func TestSetNotNull(t *testing.T) {
 			},
 			afterStart: func(t *testing.T, db *sql.DB) {
 				// A temporary FK constraint has been created on the temporary column
-				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.TemporaryName("fk_employee_department"))
+				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.DuplicationName("fk_employee_department"))
 			},
 			afterRollback: func(t *testing.T, db *sql.DB) {
 			},

pkg/migrations/op_set_unique_test.go

@@ -330,7 +330,7 @@ func TestSetColumnUnique(t *testing.T) {
 			},
 			afterStart: func(t *testing.T, db *sql.DB) {
 				// A temporary FK constraint has been created on the temporary column
-				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.TemporaryName("fk_employee_department"))
+				ValidatedForeignKeyMustExist(t, db, "public", "employees", migrations.DuplicationName("fk_employee_department"))
 			},
 			afterRollback: func(t *testing.T, db *sql.DB) {
 			},

pkg/migrations/rename.go

@@ -35,11 +35,15 @@ func RenameDuplicatedColumn(ctx context.Context, conn *sql.DB, table *schema.Tab
 	// to their original name
 	var renameConstraintSQL string
 	for _, fk := range table.ForeignKeys {
+		if !IsDuplicatedName(fk.Name) {
+			continue
+		}
+
 		if slices.Contains(fk.Columns, TemporaryName(column.Name)) {
 			renameConstraintSQL = fmt.Sprintf(cRenameConstraintSQL,
 				pq.QuoteIdentifier(table.Name),
 				pq.QuoteIdentifier(fk.Name),
-				pq.QuoteIdentifier(StripTemporaryPrefix(fk.Name)),
+				pq.QuoteIdentifier(StripDuplicationPrefix(fk.Name)),
 			)
 
 			_, err = conn.ExecContext(ctx, renameConstraintSQL)