src: don't abort when package.json is a directory

PR-URL: https://github.com/nodejs/node/pull/18270
Fixes: https://github.com/nodejs/node/issues/8307
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Bradley Farias <bradley.meck@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

src/node_file.cc

@@ -673,6 +673,12 @@ static void InternalModuleReadJSON(const FunctionCallbackInfo<Value>& args) {
     return;
   }
 
+  std::shared_ptr<void> defer_close(nullptr, [fd, loop] (...) {
+    uv_fs_t close_req;
+    CHECK_EQ(0, uv_fs_close(loop, &close_req, fd, nullptr));
+    uv_fs_req_cleanup(&close_req);
+  });
+
   const size_t kBlockSize = 32 << 10;
   std::vector<char> chars;
   int64_t offset = 0;
@@ -689,14 +695,12 @@ static void InternalModuleReadJSON(const FunctionCallbackInfo<Value>& args) {
     numchars = uv_fs_read(loop, &read_req, fd, &buf, 1, offset, nullptr);
     uv_fs_req_cleanup(&read_req);
 
-    CHECK_GE(numchars, 0);
+    if (numchars < 0)
+      return;
+
     offset += numchars;
   } while (static_cast<size_t>(numchars) == kBlockSize);
 
-  uv_fs_t close_req;
-  CHECK_EQ(0, uv_fs_close(loop, &close_req, fd, nullptr));
-  uv_fs_req_cleanup(&close_req);
-
   size_t start = 0;
   if (offset >= 3 && 0 == memcmp(&chars[0], "\xEF\xBB\xBF", 3)) {
     start = 3;  // Skip UTF-8 BOM.

test/parallel/test-module-loading-error.js

@@ -78,3 +78,10 @@ common.expectsError(
     code: 'ERR_INVALID_ARG_VALUE',
     message: 'The argument \'id\' must be a non-empty string. Received \'\''
   });
+
+common.expectsError(
+  () => { require('../fixtures/packages/is-dir'); },
+  {
+    code: 'MODULE_NOT_FOUND',
+    message: 'Cannot find module \'../fixtures/packages/is-dir\''
+  });