Forbid wildcards in binary expressions

When rewriting fields, wildcards within binary expressions were skipped.
This now throws an error whenever it finds a wildcard within a binary
expression in order to prevent the panic that occurs.

CHANGELOG.md

@@ -11,6 +11,10 @@
 - [#7821](https://github.com/influxdata/influxdb/issues/7821): Expose some configuration settings via SHOW DIAGNOSTICS
 - [#8025](https://github.com/influxdata/influxdb/issues/8025): Support single and multiline comments in InfluxQL.
 
+### Bugfixes
+
+- [#8064](https://github.com/influxdata/influxdb/issues/8064): Forbid wildcards in binary expressions.
+
 ## v1.2.2 [2017-03-14]
 
 ### Release Notes

influxql/ast.go

@@ -1273,6 +1273,26 @@ func (s *SelectStatement) RewriteFields(m FieldMapper) (*SelectStatement, error)
 						Alias: fmt.Sprintf("%s_%s", f.Name(), ref.Val),
 					})
 				}
+			case *BinaryExpr:
+				// Search for regexes or wildcards within the binary
+				// expression. If we find any, throw an error indicating that
+				// it's illegal.
+				var regex, wildcard bool
+				WalkFunc(expr, func(n Node) {
+					switch n.(type) {
+					case *RegexLiteral:
+						regex = true
+					case *Wildcard:
+						wildcard = true
+					}
+				})
+
+				if wildcard {
+					return nil, fmt.Errorf("unsupported expression with wildcard: %s", f.Expr)
+				} else if regex {
+					return nil, fmt.Errorf("unsupported expression with regex field: %s", f.Expr)
+				}
+				rwFields = append(rwFields, f)
 			default:
 				rwFields = append(rwFields, f)
 			}

influxql/ast_test.go

@@ -326,6 +326,7 @@ func TestSelectStatement_RewriteFields(t *testing.T) {
 	var tests = []struct {
 		stmt    string
 		rewrite string
+		err     string
 	}{
 		// No wildcards
 		{
@@ -462,6 +463,35 @@ func TestSelectStatement_RewriteFields(t *testing.T) {
 			stmt:    `SELECT * FROM (SELECT mean(value1) FROM cpu GROUP BY host) GROUP BY *`,
 			rewrite: `SELECT mean::float FROM (SELECT mean(value1::float) FROM cpu GROUP BY host) GROUP BY host`,
 		},
+
+		// Invalid queries that can't be rewritten should return an error (to
+		// avoid a panic in the query engine)
+		{
+			stmt: `SELECT count(*) / 2 FROM cpu`,
+			err:  `unsupported expression with wildcard: count(*) / 2`,
+		},
+
+		{
+			stmt: `SELECT * / 2 FROM (SELECT count(*) FROM cpu)`,
+			err:  `unsupported expression with wildcard: * / 2`,
+		},
+
+		{
+			stmt: `SELECT count(/value/) / 2 FROM cpu`,
+			err:  `unsupported expression with regex field: count(/value/) / 2`,
+		},
+
+		// This one should be possible though since there's no wildcard in the
+		// binary expression.
+		{
+			stmt:    `SELECT value1 + value2, * FROM cpu`,
+			rewrite: `SELECT value1::float + value2::integer, host::tag, region::tag, value1::float, value2::integer FROM cpu`,
+		},
+
+		{
+			stmt:    `SELECT value1 + value2, /value/ FROM cpu`,
+			rewrite: `SELECT value1::float + value2::integer, value1::float, value2::integer FROM cpu`,
+		},
 	}
 
 	for i, tt := range tests {
@@ -496,12 +526,20 @@ func TestSelectStatement_RewriteFields(t *testing.T) {
 
 		// Rewrite statement.
 		rw, err := stmt.(*influxql.SelectStatement).RewriteFields(&ic)
-		if err != nil {
-			t.Errorf("%d. %q: error: %s", i, tt.stmt, err)
-		} else if rw == nil {
-			t.Errorf("%d. %q: unexpected nil statement", i, tt.stmt)
-		} else if rw := rw.String(); tt.rewrite != rw {
-			t.Errorf("%d. %q: unexpected rewrite:\n\nexp=%s\n\ngot=%s\n\n", i, tt.stmt, tt.rewrite, rw)
+		if tt.err != "" {
+			if err != nil && err.Error() != tt.err {
+				t.Errorf("%d. %q: unexpected error: %s != %s", i, tt.stmt, err.Error(), tt.err)
+			} else if err == nil {
+				t.Errorf("%d. %q: expected error", i, tt.stmt)
+			}
+		} else {
+			if err != nil {
+				t.Errorf("%d. %q: error: %s", i, tt.stmt, err)
+			} else if rw == nil && tt.err == "" {
+				t.Errorf("%d. %q: unexpected nil statement", i, tt.stmt)
+			} else if rw := rw.String(); tt.rewrite != rw {
+				t.Errorf("%d. %q: unexpected rewrite:\n\nexp=%s\n\ngot=%s\n\n", i, tt.stmt, tt.rewrite, rw)
+			}
 		}
 	}
 }