server: differentiate between missing and undefined doc in default de…

…cision (#5420)

Since "document missing or undefined" caused confusion, we can be
more helpful and report whether the default decision document is
missing, or whether it's there but undefined. I would probably have
preferred for undefined to just result in an empty/undefined result,
but that'd be quite a breaking change at this point in time, so
hopefully this can at least make things a little less convoluted.

Fixes #5344

Signed-off-by: Anders Eknert <anders@eknert.com>

server/server.go

@@ -1014,7 +1014,13 @@ func (s *Server) v0QueryPath(w http.ResponseWriter, r *http.Request, urlPath str
 	}
 
 	if len(rs) == 0 {
-		err := types.NewErrorV1(types.CodeUndefinedDocument, fmt.Sprintf("%v: %v", types.MsgUndefinedError, stringPathToDataRef(urlPath)))
+		ref := stringPathToDataRef(urlPath)
+
+		var messageType = types.MsgMissingError
+		if len(s.getCompiler().GetRulesForVirtualDocument(ref)) > 0 {
+			messageType = types.MsgFoundUndefinedError
+		}
+		err := types.NewErrorV1(types.CodeUndefinedDocument, fmt.Sprintf("%v: %v", messageType, ref))
 		if logErr := logger.Log(ctx, txn, decisionID, r.RemoteAddr, urlPath, "", goInput, input, nil, ndbCache, err, m); logErr != nil {
 			writer.ErrorAuto(w, logErr)
 			return

server/server_test.go

@@ -3198,7 +3198,7 @@ func TestDecisionLogging(t *testing.T) {
 			code:   404,
 			response: `{
 				"code": "undefined_document",
-				"message": "document missing or undefined: data.test"
+				"message": "document missing: data.test"
 			  }`,
 		},
 	}
@@ -3406,6 +3406,15 @@ func TestUnversionedPost(t *testing.T) {
 		t.Fatalf("Expected not found before policy added but got %v", f.recorder)
 	}
 
+	expectedBody := `{
+  "code": "undefined_document",
+  "message": "document missing: data.system.main"
+}
+`
+	if f.recorder.Body.String() != expectedBody {
+		t.Errorf("Expected %s got %s", expectedBody, f.recorder.Body.String())
+	}
+
 	module := `
 	package system.main
 
@@ -3425,6 +3434,36 @@ func TestUnversionedPost(t *testing.T) {
 	if f.recorder.Code != 200 || f.recorder.Body.String() != expected {
 		t.Fatalf(`Expected HTTP 200 / %v but got: %v`, expected, f.recorder)
 	}
+
+	module = `
+	package system
+
+	main {
+		input.foo == "bar"
+	}
+	`
+
+	if err := f.v1("PUT", "/policies/test", module, 200, ""); err != nil {
+		t.Fatal(err)
+	}
+
+	f.reset()
+	f.server.Handler.ServeHTTP(f.recorder, func() *http.Request {
+		return newReqUnversioned(http.MethodPost, "/", `{"input": {"foo": "bar"}}`)
+	}())
+
+	if f.recorder.Code != 404 {
+		t.Fatalf("Expected not found before policy added but got %v", f.recorder)
+	}
+
+	expectedBody = `{
+  "code": "undefined_document",
+  "message": "document undefined: data.system.main"
+}
+`
+	if f.recorder.Body.String() != expectedBody {
+		t.Errorf("Expected %s got %s", expectedBody, f.recorder.Body.String())
+	}
 }
 
 func TestQueryV1Explain(t *testing.T) {

server/types/types.go

@@ -80,6 +80,8 @@ const (
 	MsgUnauthorizedUndefinedError = "authorization policy missing or undefined"
 	MsgUnauthorizedError          = "request rejected by administrative policy"
 	MsgUndefinedError             = "document missing or undefined"
+	MsgMissingError               = "document missing"
+	MsgFoundUndefinedError        = "document undefined"
 	MsgPluginConfigError          = "error(s) occurred while configuring plugin(s)"
 )