prevent aliases upstack/avoid indirect loops; fix caching bug and add…

… test for it using 2 level deep rand()

eval/eval.go

@@ -577,6 +577,8 @@ func (s *State) applyFunction(name string, fn object.Object, args []object.Objec
 	}
 	if after != before {
 		log.Debugf("Cache miss for %s %v, %d get misses", function.CacheKey, args, after-before)
+		// A miss here is a miss upstack
+		s.env.TriggerNoCache()
 		return res
 	}
 	// Don't cache errors, as it could be due to binding for instance.

eval/eval_test.go

@@ -1009,3 +1009,16 @@ func TestSelfRef(t *testing.T) {
 		t.Errorf("wrong result, got %q", res.Inspect())
 	}
 }
+
+func TestAliasTwice(t *testing.T) {
+	inp := `a=1; b=2;()=>{a=b}();b=5;()=>{a=b}()` // should not crash
+	s := eval.NewState()
+	res, err := eval.EvalString(s, inp, false)
+	if err != nil {
+		t.Errorf("should not have errored: %v", err)
+	}
+	expected := "5"
+	if res.Inspect() != expected {
+		t.Errorf("wrong result, got %q", res.Inspect())
+	}
+}

examples/random.gr

@@ -0,0 +1,14 @@
+// Really this checks we don't cache functions that call non cacheable functions.
+
+func deepRand() {
+	() => {
+		rand()
+	}()
+}
+
+a1 = deepRand(); log("a1", a1)
+a2 = deepRand(); log("a2", a2)
+
+if a1 == a2 {
+	error("a1 and a2 should be different")
+}

main_test.txtar

@@ -301,6 +301,10 @@ stdout '^42$'
 grol -quiet -c 'a=-3; b=5; ()=>{b=a;a=b;b++;a++}();[a,b]'
 stdout '^\[-2,-2\]$'
 
+# 2nd aliasing crashes
+grol -quiet -c 'a=1; b=2;()=>{a=b}();()=>{a=b;println(type(a),type(b))}()'
+stdout '&a.\(INTEGER\) &b.\(INTEGER\)'
+
 -- json_output --
 {
   "63": 63,

object/state.go

@@ -302,7 +302,7 @@ func (e *Environment) SetNoChecks(name string, val Object, create bool) Object {
 	// New name... let's see if it's really new or making it a ref.
 	if ref, ok := e.makeRef(name); ok {
 		log.Debugf("SetNoChecks(%s) created ref %s in %d", name, ref.Name, ref.RefEnv.depth)
-		ref.RefEnv.store[ref.Name] = val
+		ref.RefEnv.store[ref.Name] = Value(val) // kinda neat to make aliases but it can create loops, so not for now.
 		return val
 	}
 	log.Debugf("SetNoChecks(%s) brand new to %d and above", name, e.depth)