be more strict about identifier printing

When stringifying a query, we would print the identifier bare most
of the time. This caused issues when stringifying an identifier
that contained elements of syntax. For example, querying for the
value "in-bytes" would fail because the mapper would serialize it to
in-bytes and would parse it as an expression. Same problem occured
when using keywords as identifier names, such as select or in.

Fixes #3547

influxql/ast.go

@@ -1992,26 +1992,6 @@ func (f *Field) Name() string {
 func (f *Field) String() string {
 	str := f.Expr.String()
 
-	switch f.Expr.(type) {
-	case *VarRef:
-		quoted := false
-		// Escape any double-quotes in the field
-		if strings.Contains(str, `"`) {
-			str = strings.Replace(str, `"`, `\"`, -1)
-			quoted = true
-		}
-
-		// Escape any single-quotes in the field
-		if strings.Contains(str, `'`) {
-			quoted = true
-		}
-
-		// Double-quote field names with spaces or that were previously escaped
-		if strings.Contains(str, " ") || quoted {
-			str = fmt.Sprintf("\"%s\"", str)
-		}
-	}
-
 	if f.Alias == "" {
 		return str
 	}
@@ -2132,7 +2112,9 @@ type VarRef struct {
 }
 
 // String returns a string representation of the variable reference.
-func (r *VarRef) String() string { return r.Val }
+func (r *VarRef) String() string {
+	return QuoteIdent(r.Val)
+}
 
 // Call represents a function call.
 type Call struct {

influxql/ast_test.go

@@ -44,35 +44,35 @@ func TestSelectStatement_Substatement(t *testing.T) {
 		{
 			stmt: `SELECT sum(aa.value) + sum(bb.value) FROM aa, bb`,
 			expr: &influxql.VarRef{Val: "aa.value"},
-			sub:  `SELECT aa.value FROM aa`,
+			sub:  `SELECT "aa.value" FROM aa`,
 		},
 
 		// 2. Simple merge
 		{
 			stmt: `SELECT sum(aa.value) + sum(bb.value) FROM aa, bb`,
 			expr: &influxql.VarRef{Val: "bb.value"},
-			sub:  `SELECT bb.value FROM bb`,
+			sub:  `SELECT "bb.value" FROM bb`,
 		},
 
 		// 3. Join with condition
 		{
 			stmt: `SELECT sum(aa.value) + sum(bb.value) FROM aa, bb WHERE aa.host = 'servera' AND bb.host = 'serverb'`,
 			expr: &influxql.VarRef{Val: "bb.value"},
-			sub:  `SELECT bb.value FROM bb WHERE bb.host = 'serverb'`,
+			sub:  `SELECT "bb.value" FROM bb WHERE "bb.host" = 'serverb'`,
 		},
 
 		// 4. Join with complex condition
 		{
 			stmt: `SELECT sum(aa.value) + sum(bb.value) FROM aa, bb WHERE aa.host = 'servera' AND (bb.host = 'serverb' OR bb.host = 'serverc') AND 1 = 2`,
 			expr: &influxql.VarRef{Val: "bb.value"},
-			sub:  `SELECT bb.value FROM bb WHERE (bb.host = 'serverb' OR bb.host = 'serverc') AND 1.000 = 2.000`,
+			sub:  `SELECT "bb.value" FROM bb WHERE ("bb.host" = 'serverb' OR "bb.host" = 'serverc') AND 1.000 = 2.000`,
 		},
 
 		// 5. 4 with different condition order
 		{
 			stmt: `SELECT sum(aa.value) + sum(bb.value) FROM aa, bb WHERE ((bb.host = 'serverb' OR bb.host = 'serverc') AND aa.host = 'servera') AND 1 = 2`,
 			expr: &influxql.VarRef{Val: "bb.value"},
-			sub:  `SELECT bb.value FROM bb WHERE ((bb.host = 'serverb' OR bb.host = 'serverc')) AND 1.000 = 2.000`,
+			sub:  `SELECT "bb.value" FROM bb WHERE (("bb.host" = 'serverb' OR "bb.host" = 'serverc')) AND 1.000 = 2.000`,
 		},
 	}
 

influxql/parser.go

@@ -2217,6 +2217,11 @@ func QuoteIdent(segments ...string) string {
 
 // IdentNeedsQuotes returns true if the ident string given would require quotes.
 func IdentNeedsQuotes(ident string) bool {
+	// check if this identifier is a keyword
+	tok := Lookup(ident)
+	if tok != IDENT {
+		return true
+	}
 	for i, r := range ident {
 		if i == 0 && !isIdentFirstChar(r) {
 			return true

influxql/parser_test.go

@@ -1664,6 +1664,8 @@ func TestQuoteIdent(t *testing.T) {
 		s     string
 	}{
 		{[]string{``}, ``},
+		{[]string{`select`}, `"select"`},
+		{[]string{`in-bytes`}, `"in-bytes"`},
 		{[]string{`foo`, `bar`}, `"foo".bar`},
 		{[]string{`foo`, ``, `bar`}, `"foo"..bar`},
 		{[]string{`foo bar`, `baz`}, `"foo bar".baz`},