Fixed npe in log #1596

pkg/yqlib/operator_variables.go

@@ -82,10 +82,11 @@ func variableLoopSingleChild(d *dataTreeNavigator, context Context, originalExp
 		newContext.SetVariable(variableName, variableValue)
 
 		rhs, err := d.GetMatchingNodes(newContext, originalExp.RHS)
-		log.Debug("PROCESSING VARIABLE DONE, got back: ", rhs.MatchingNodes.Len())
+
 		if err != nil {
 			return Context{}, err
 		}
+		log.Debug("PROCESSING VARIABLE DONE, got back: ", rhs.MatchingNodes.Len())
 		results.PushBackList(rhs.MatchingNodes)
 	}
 

pkg/yqlib/operator_variables_test.go

@@ -13,6 +13,12 @@ var variableOperatorScenarios = []expressionScenario{
 			"D0, P[], (doc)::{}\n",
 		},
 	},
+	{
+		skipDoc:       true,
+		document:      `{}`,
+		expression:    `.a.b as $foo`,
+		expectedError: "must use variable with a pipe, e.g. `exp as $x | ...`",
+	},
 	{
 		document:      "a: [cat]",
 		skipDoc:       true,