Improve validation error for unused variable

Related GraphQL-js commit: graphql/graphql-js@1b639e3

Author: syrusakbary

graphql/core/validation/rules/no_unused_variables.py

@@ -15,20 +15,23 @@ def enter_OperationDefinition(self, node, key, parent, path, ancestors):
     def leave_OperationDefinition(self, operation, key, parent, path, ancestors):
         variable_name_used = set()
         usages = self.context.get_recursive_variable_usages(operation)
+        op_name = operation.name and operation.name.value or None
 
         for variable_usage in usages:
             variable_name_used.add(variable_usage.node.name.value)
 
         for variable_definition in self.variable_definitions:
             if variable_definition.variable.name.value not in variable_name_used:
                 self.context.report_error(GraphQLError(
-                    self.unused_variable_message(variable_definition.variable.name.value),
+                    self.unused_variable_message(variable_definition.variable.name.value, op_name),
                     [variable_definition]
                 ))
 
     def enter_VariableDefinition(self, node, key, parent, path, ancestors):
         self.variable_definitions.append(node)
 
     @staticmethod
-    def unused_variable_message(variable_name):
+    def unused_variable_message(variable_name, op_name):
+        if op_name:
+            return 'Variable "${}" is never used in operation "{}".'.format(variable_name, op_name)
         return 'Variable "${}" is never used.'.format(variable_name)

tests/core_validation/test_no_unused_variables.py

@@ -3,16 +3,16 @@
 from .utils import expect_fails_rule, expect_passes_rule
 
 
-def unused_variable(variable_name, line, column):
+def unused_variable(variable_name, op_name, line, column):
     return {
-        'message': NoUnusedVariables.unused_variable_message(variable_name),
+        'message': NoUnusedVariables.unused_variable_message(variable_name, op_name),
         'locations': [SourceLocation(line, column)]
     }
 
 
 def test_uses_all_variables():
     expect_passes_rule(NoUnusedVariables, '''
-      query Foo($a: String, $b: String, $c: String) {
+      query ($a: String, $b: String, $c: String) {
         field(a: $a, b: $b, c: $c)
       }
     ''')
@@ -99,11 +99,11 @@ def test_variable_used_by_recursive_fragment():
 
 def test_variable_not_used():
     expect_fails_rule(NoUnusedVariables, '''
-      query Foo($a: String, $b: String, $c: String) {
+      query ($a: String, $b: String, $c: String) {
         field(a: $a, b: $b)
       }
     ''', [
-        unused_variable('c', 2, 41)
+        unused_variable('c', None, 2, 38)
     ])
 
 
@@ -113,8 +113,8 @@ def test_multiple_variables_not_used():
         field(b: $b)
       }
     ''', [
-        unused_variable('a', 2, 17),
-        unused_variable('c', 2, 41)
+        unused_variable('a', 'Foo', 2, 17),
+        unused_variable('c', 'Foo', 2, 41)
     ])
 
 
@@ -137,7 +137,7 @@ def test_variable_not_used_in_fragments():
         field
       }
     ''', [
-        unused_variable('c', 2, 41)
+        unused_variable('c', 'Foo', 2, 41)
     ])
 
 
@@ -160,8 +160,8 @@ def test_multiple_variables_not_used_in_fragments():
         field
       }
     ''', [
-        unused_variable('a', 2, 17),
-        unused_variable('c', 2, 41)
+        unused_variable('a', 'Foo', 2, 17),
+        unused_variable('c', 'Foo', 2, 41)
     ])
 
 
@@ -177,7 +177,7 @@ def test_variable_not_used_by_unreferenced_fragment():
         field(b: $b)
       }
     ''', [
-        unused_variable('b', 2, 17),
+        unused_variable('b', 'Foo', 2, 17),
     ])
 
 
@@ -196,6 +196,6 @@ def test_variable_not_used_by_fragment_used_by_other_operation():
         field(b: $b)
       }
     ''', [
-        unused_variable('b', 2, 17),
-        unused_variable('a', 5, 17),
+        unused_variable('b', 'Foo', 2, 17),
+        unused_variable('a', 'Bar', 5, 17),
     ])