Throw an error when an invalid expression is used with aux iterators

influxql/select.go

@@ -110,20 +110,27 @@ func buildAuxIterators(fields Fields, ic IteratorCreator, opt IteratorOptions) (
 
  // Generate iterators for each field.
  itrs := make([]Iterator, len(fields))
- for i, f := range fields {
- expr := Reduce(f.Expr, nil)
- switch expr := expr.(type) {
- case *VarRef:
- itrs[i] = aitr.Iterator(expr.Val)
- case *BinaryExpr:
- itr, err := buildExprIterator(expr, aitr, opt)
- if err != nil {
- return nil, fmt.Errorf("error constructing iterator for field '%s': %s", f.String(), err)
+ if err := func() error {
+ for i, f := range fields {
+ expr := Reduce(f.Expr, nil)
+ switch expr := expr.(type) {
+ case *VarRef:
+ itrs[i] = aitr.Iterator(expr.Val)
+ case *BinaryExpr:
+ itr, err := buildExprIterator(expr, aitr, opt)
+ if err != nil {
+ return fmt.Errorf("error constructing iterator for field '%s': %s", f.String(), err)
+ }
+ itrs[i] = itr
+ default:
+ return fmt.Errorf("invalid expression type: %T", expr)
  }
- itrs[i] = itr
- default:
- panic("unreachable")
  }
+ return nil
+ }(); err != nil {
+ Iterators(Iterators(itrs).filterNonNil()).Close()
+ aitr.Close()
+ return nil, err
  }
 
  // Background the primary iterator since there is no reader for it.

influxql/select_test.go

@@ -2021,6 +2021,10 @@ func TestSelect_InvalidQueries(t *testing.T) {
  q: `SELECT 'value' FROM cpu`,
  err: `invalid expression type: *influxql.StringLiteral`,
  },
+ {
+ q: `SELECT 'value', value FROM cpu`,
+ err: `invalid expression type: *influxql.StringLiteral`,
+ },
  }
 
  for i, tt := range tests {