dns: report out of memory properly

lib/internal/errors.js

@@ -28,7 +28,6 @@ const READABLE_OPERATOR = {
 
 const {
   errmap,
-  UV_EAI_MEMORY,
   UV_EAI_NODATA,
   UV_EAI_NONAME
 } = process.binding('uv');
@@ -639,9 +638,7 @@ function dnsException(code, syscall, hostname) {
   if (typeof code === 'number') {
     // FIXME(bnoordhuis) Remove this backwards compatibility nonsense and pass
     // the true error to the user. ENOTFOUND is not even a proper POSIX error!
-    if (code === UV_EAI_MEMORY ||
-        code === UV_EAI_NODATA ||
-        code === UV_EAI_NONAME) {
+    if (code === UV_EAI_NODATA || code === UV_EAI_NONAME) {
       code = 'ENOTFOUND'; // Fabricated error name.
     } else {
       code = lazyInternalUtil().getSystemErrorName(code);

test/parallel/test-dns-memory-error.js

@@ -0,0 +1,15 @@
+// Flags: --expose-internals
+'use strict';
+
+// Check that if libuv reports a memory error on a DNS query, that the memory
+// error is passed through and not replaced with ENOTFOUND.
+
+require('../common');
+
+const assert = require('assert');
+const errors = require('internal/errors');
+
+const { UV_EAI_MEMORY } = process.binding('uv');
+const memoryError = errors.dnsException(UV_EAI_MEMORY, 'fhqwhgads');
+
+assert.strictEqual(memoryError.code, 'EAI_MEMORY');

test/parallel/test-http-dns-error.js

@@ -29,7 +29,7 @@ const assert = require('assert');
 const http = require('http');
 const https = require('https');
 
-const host = '*'.repeat(256);
+const host = '*'.repeat(64);
 const MAX_TRIES = 5;
 
 let errCode = 'ENOTFOUND';

test/parallel/test-net-dns-error.js

@@ -25,7 +25,7 @@ const common = require('../common');
 const assert = require('assert');
 const net = require('net');
 
-const host = '*'.repeat(256);
+const host = '*'.repeat(64);
 const errCode = common.isOpenBSD ? 'EAI_FAIL' : 'ENOTFOUND';
 
 const socket = net.connect(42, host, common.mustNotCall());