Argument and variables nullability

.gitignore

@@ -24,7 +24,7 @@ coverage_result.txt
 .DS_Store
 .vscode
 luacov.*.out*
-/node_modules
+**/node_modules
 /package-lock.json
 *.mo
 .history

.luacheckrc

@@ -8,6 +8,7 @@ include_files = {
 }
 exclude_files = {
     '.rocks',
+    'test/integration/fuzzing_nullability_test.lua',
 }
 new_read_globals = {
     box = { fields = {

Makefile

@@ -3,7 +3,7 @@ SHELL := /bin/bash
 .PHONY: .rocks
 .rocks: graphql-scm-1.rockspec Makefile
 		tarantoolctl rocks make
-		tarantoolctl rocks install luatest 0.5.5
+		tarantoolctl rocks install luatest 0.5.7
 		tarantoolctl rocks install luacov 0.13.0
 		tarantoolctl rocks install luacheck 0.26.0
 

graphql/execute.lua

@@ -176,7 +176,7 @@ local function completeValue(fieldType, result, subSelections, context, opts)
     local innerType = fieldType.ofType
     local completedResult = completeValue(innerType, result, subSelections, context, opts)
 
-    if completedResult == nil then
+    if type(completedResult) == 'nil' then
       local err = string.format(
         'No value provided for non-null %s %q',
         (innerType.name or innerType.__type),
@@ -193,7 +193,7 @@ local function completeValue(fieldType, result, subSelections, context, opts)
   end
 
   if result == nil then
-    return nil
+    return result
   end
 
   if fieldTypeName == 'List' then

graphql/rules.lua

@@ -198,13 +198,15 @@ function rules.uniqueArgumentNames(node, _)
   end
 end
 
+local coerce_opts = { strict_non_null = true, skip_variables = true }
+
 function rules.argumentsOfCorrectType(node, context)
   if node.arguments then
     local parentField = getParentField(context, node.name.value)
     for _, argument in pairs(node.arguments) do
       local name = argument.name.value
       local argumentType = parentField.arguments[name]
-      util.coerceValue(argument.value, argumentType.kind or argumentType)
+      util.coerceValue(argument.value, argumentType.kind or argumentType, nil, coerce_opts)
     end
   end
 end
@@ -406,11 +408,9 @@ end
 function rules.variableDefaultValuesHaveCorrectType(node, context)
   if node.variableDefinitions then
     for _, definition in ipairs(node.variableDefinitions) do
-      if definition.type.kind == 'nonNullType' and definition.defaultValue then
-        error('Non-null variables can not have default values')
-      elseif definition.defaultValue then
+      if definition.defaultValue then
         local variableType = query_util.typeFromAST(definition.type, context.schema)
-        util.coerceValue(definition.defaultValue, variableType)
+        util.coerceValue(definition.defaultValue, variableType, nil, coerce_opts)
       end
     end
   end
@@ -507,12 +507,14 @@ local function isVariableTypesValid(argument, argumentType, context,
       error('Unknown variable "' .. variableName .. '"')
     end
 
-    local hasDefault = variableDefinition.defaultValue ~= nil
+    local hasNonNullDefault = (variableDefinition.defaultValue ~= nil) and
+                              (variableDefinition.defaultValue.kind ~= 'null')
 
     local variableType = query_util.typeFromAST(variableDefinition.type,
       context.schema)
 
-    if hasDefault and variableType.__type ~= 'NonNull' then
+    local realVariableTypeName = util.getTypeName(variableType)
+    if hasNonNullDefault and variableType.__type ~= 'NonNull' then
       variableType = types.nonNull(variableType)
     end
 
@@ -526,7 +528,7 @@ local function isVariableTypesValid(argument, argumentType, context,
     if not isTypeSubTypeOf(variableType, argumentType, context) then
       return false, ('Variable "%s" type mismatch: the variable type "%s" ' ..
         'is not compatible with the argument type "%s"'):format(variableName,
-        util.getTypeName(variableType), util.getTypeName(argumentType))
+        realVariableTypeName, util.getTypeName(argumentType))
     end
   elseif argument.value.kind == 'list' then
     -- find variables deeper

graphql/util.lua

@@ -83,8 +83,13 @@ local function coerceValue(node, schemaType, variables, opts)
   variables = variables or {}
   opts = opts or {}
   local strict_non_null = opts.strict_non_null or false
+  local skip_variables = opts.skip_variables or false
   local defaultValues = opts.defaultValues or {}
 
+  if node and node.kind == 'variable' and skip_variables then
+    return nil
+  end
+
   if schemaType.__type == 'NonNull' then
     local res = coerceValue(node, schemaType.ofType, variables, opts)
     if strict_non_null and res == nil then

graphql/validate_variables.lua

@@ -7,15 +7,17 @@ local function error(...)
 end
 
 -- Traverse type more or less likewise util.coerceValue do.
-local function checkVariableValue(variableName, value, variableType)
+local function checkVariableValue(variableName, value, variableType, isNonNullDefaultDefined)
   check(variableName, 'variableName', 'string')
   check(variableType, 'variableType', 'table')
 
   local isNonNull = variableType.__type == 'NonNull'
+  isNonNullDefaultDefined = isNonNullDefaultDefined or false
 
   if isNonNull then
     variableType = types.nullable(variableType)
-    if value == nil then
+    if (type(value) == 'cdata' and value == nil) or
+       (type(value) == 'nil' and not isNonNullDefaultDefined) then
       error(('Variable %q expected to be non-null'):format(variableName))
     end
   end
@@ -116,8 +118,19 @@ local function validate_variables(context)
 
   -- check that variable values have correct type
   for variableName, variableType in pairs(context.variableTypes) do
+    -- Check if default value presents.
+    local isNonNullDefaultDefined = false
+    for _, variableDefinition in ipairs(context.operation.variableDefinitions) do
+      if variableDefinition.variable.name.value == variableName and
+         variableDefinition.defaultValue ~= nil then
+        if (variableDefinition.defaultValue.value ~= nil) or (variableDefinition.defaultValue.values ~= nil) then
+          isNonNullDefaultDefined = true
+        end
+      end
+    end
+
     local value = (context.variables or {})[variableName]
-    checkVariableValue(variableName, value, variableType)
+    checkVariableValue(variableName, value, variableType, isNonNullDefaultDefined)
   end
 end
 

test/helpers.lua

@@ -0,0 +1,36 @@
+local types = require('graphql.types')
+local schema = require('graphql.schema')
+local parse = require('graphql.parse')
+local validate = require('graphql.validate')
+local execute = require('graphql.execute')
+
+local helpers = {}
+
+helpers.test_schema_name = 'default'
+
+function helpers.check_request(query, query_schema, mutation_schema, directives, opts)
+    opts = opts or {}
+    local root = {
+        query = types.object({
+            name = 'Query',
+            fields = query_schema or {},
+        }),
+        mutation = types.object({
+            name = 'Mutation',
+            fields = mutation_schema or {},
+        }),
+        directives = directives,
+    }
+
+    local compiled_schema = schema.create(root, helpers.test_schema_name, opts)
+
+    local parsed = parse.parse(query)
+
+    validate.validate(compiled_schema, parsed)
+
+    local rootValue = {}
+    local variables = opts.variables or {}
+    return execute.execute(compiled_schema, parsed, rootValue, variables)
+end
+
+return helpers

test/integration/codegen/fuzzing_nullability/README.md

@@ -0,0 +1,10 @@
+To install dependencies, run
+```bash
+npm install
+```
+
+To generate test file, run
+```bash
+node generate.js > ../../fuzzing_nullability_test.lua
+```
+in this directory.