Set parser recursion limit for fuzz tests. (#8673)

Very large inputs that generate large ASTs can cause some of the
sanitizers to timeout. Setting a smaller complexity limit should help
filter out those cases.

Co-authored-by: jonathanmetzman <31354670+jonathanmetzman@users.noreply.github.com>

projects/cel-go/fuzz_compile.go

@@ -1,7 +1,7 @@
 package cel
 
 func FuzzCompile(data []byte) int {
-	env, err := NewEnv()
+	env, err := getCELFuzzEnv()
 	if err != nil {
 		panic("impossible to create env")
 	}

projects/cel-go/fuzz_env.go

@@ -0,0 +1,8 @@
+package cel
+
+// Create environment for running under Address sanitizer without timing out.
+func getCELFuzzEnv() (*Env, error) {
+	// Very dense expressions (balanced trees) can cause address sanitizer to
+	// timeout even though they typically fail in under a second uninstrumented.
+	return NewEnv(ParserRecursionLimit(60))
+}

projects/cel-go/fuzz_eval.go

@@ -18,7 +18,12 @@ func FuzzEval(data []byte) int {
 	for k, _ := range gen.Inputs {
 		declares = append(declares, decls.NewVar(k, decls.String))
 	}
-	env, err := NewEnv(Declarations(declares...))
+	env, err := getCELFuzzEnv()
+	if err != nil {
+		panic("impossible to create env")
+	}
+
+	env, err = env.Extend(Declarations(declares...))
 	if err != nil {
 		panic("impossible to create env")
 	}