Fix error when float variable value is greater 10^15-1

Author: no1seman

graphql/types.lua

@@ -318,7 +318,19 @@ types.long = types.scalar({
 })
 
 local function isFloat(value)
-  return type(value) == 'number'
+  if type(value) == 'number' then
+    return true
+  end
+
+  if type(value) == 'cdata' then
+    if ffi.istype('int64_t', value) then
+      return value >= -2^53 and value < 2^53
+    elseif ffi.istype('uint64_t', value) then
+      return value < 2^53
+    end
+  end
+
+  return false
 end
 
 local function coerceFloat(value)

test/integration/graphql_test.lua

@@ -2051,3 +2051,65 @@ g.test_propagate_defaults_to_callback = function()
     t.assert_equals(errors, nil)
     t.assert_items_equals(json.decode(data.prefix.test_mutation), result)
 end
+
+function g.test_float_variables()
+    local query = [[
+        query ($arg: Float) { test(arg: $arg) }
+    ]]
+
+    local floats_positive = {
+        '9007199254740991',
+        '-9007199254740992',
+        '0',
+        '9007199254740991.1',
+        '-9007199254740992.1',
+        '99999999999999',
+        '100000000000000',
+        '-99999999999999',
+        '-100000000000000',
+        '1e1',
+        '-1e1',
+        'inf',
+        '-inf',
+    }
+
+    local floats_negative = {
+        {'9007199254740992', 'Wrong variable \"arg\" for the Scalar \"Float\"'},
+        {'-9007199254740993', 'Wrong variable \"arg\" for the Scalar \"Float\"'},
+    }
+
+    local function callback(_, args)
+        return args[1].value
+    end
+
+    local query_schema = {
+        ['test'] = {
+            kind = types.float.nonNull,
+            arguments = {
+                arg = types.float,
+            },
+            resolve = callback,
+        }
+    }
+
+    -- Positive tests
+    for  _, value in ipairs(floats_positive) do
+        t.assert_items_equals(
+            check_request(query, query_schema, nil, nil, {variables = json.decode('{"arg": '.. value .. '}')}),
+            {test = tonumber(value)}
+        )
+    end
+    t.assert_nan(
+        check_request(query, query_schema, nil, nil, {variables = json.decode('{"arg": nan}')}).test
+    )
+
+    -- Negative tests
+    for _, case in ipairs(floats_negative) do
+        t.assert_error_msg_equals(
+                case[2],
+                function()
+                    check_request(query, query_schema, nil, nil, {variables = json.decode('{"arg": '.. case[1] .. '}')})
+                end
+        )
+    end
+end