Sort wildcard expresion field names for consistent output

influxql/ast.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"regexp"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -654,6 +655,8 @@ func (s *SelectStatement) RewriteWildcards(fields Fields, dimensions Dimensions)
 	for _, f := range s.Fields {
 		switch f.Expr.(type) {
 		case *Wildcard:
+			// Sort wildcard fields for consistent output
+			sort.Sort(fields)
 			rwFields = append(rwFields, fields...)
 		default:
 			rwFields = append(rwFields, f)
@@ -1573,6 +1576,11 @@ func (f *Field) String() string {
 	return fmt.Sprintf("%s AS %s", f.Expr.String(), f.Alias)
 }
 
+// Sort Interface for Field
+func (f Fields) Len() int           { return len(f) }
+func (f Fields) Less(i, j int) bool { return f[i].Name() < f[j].Name() }
+func (f Fields) Swap(i, j int)      { f[i], f[j] = f[j], f[i] }
+
 // Dimensions represents a list of dimensions.
 type Dimensions []*Dimension
 

server_test.go

@@ -1741,7 +1741,8 @@ func TestServer_ExecuteWildcardQuery(t *testing.T) {
 	results := s.ExecuteQuery(MustParseQuery(`SELECT * FROM cpu`), "foo", nil)
 	if res := results.Results[0]; res.Err != nil {
 		t.Fatalf("unexpected error during SELECT *: %s", res.Err)
-	} else if s := mustMarshalJSON(res); s != `{"series":[{"name":"cpu","columns":["time","value","val-x"],"values":[["2000-01-01T00:00:00Z",10,null],["2000-01-01T00:00:10Z",null,20],["2000-01-01T00:00:20Z",30,40]]}]}` {
+	} else if s, e := mustMarshalJSON(res), `{"series":[{"name":"cpu","columns":["time","val-x","value"],"values":[["2000-01-01T00:00:00Z",null,10],["2000-01-01T00:00:10Z",20,null],["2000-01-01T00:00:20Z",40,30]]}]}`; s != e {
+		t.Logf("expected                            %s\n", e)
 		t.Fatalf("unexpected results during SELECT *: %s", s)
 	}
 }