e2e: prevent identifiers from being keywords

e2e/generator/names.go

@@ -1,6 +1,10 @@
 package generator
 
-import "github.com/brianvoe/gofakeit/v6"
+import (
+	"github.com/brianvoe/gofakeit/v6"
+
+	"github.com/authzed/spicedb/pkg/schemadsl/lexer"
+)
 
 type UniqueGenerator struct {
 	seen  map[string]struct{}
@@ -17,6 +21,10 @@ func NewUniqueGenerator(regex string) *UniqueGenerator {
 func (g *UniqueGenerator) Next() string {
 	for {
 		val := gofakeit.Regex(g.regex)
+		if lexer.IsKeyword(val) {
+			continue
+		}
+
 		if _, ok := g.seen[val]; !ok {
 			g.seen[val] = struct{}{}
 			return val

pkg/schemadsl/lexer/lex_def.go

@@ -53,11 +53,17 @@ const (
 )
 
 // keywords contains the full set of keywords supported.
-var keywords = map[string]bool{
-	"definition": true,
-	"relation":   true,
-	"permission": true,
-	"nil":        true,
+var keywords = map[string]struct{}{
+	"definition": {},
+	"relation":   {},
+	"permission": {},
+	"nil":        {},
+}
+
+// IsKeyword returns whether the specified input string is a reserved keyword.
+func IsKeyword(candidate string) bool {
+	_, ok := keywords[candidate]
+	return ok
 }
 
 // syntheticPredecessors contains the full set of token types after which, if a newline is found,