Revert "fs: make callback mandatory to all async functions"

This reverts commit 9359de9dd2eae06ed5afcb75dad9bd4c466eb69d.

Original Commit Message:

    The "fs" module has two functions called `maybeCallback` and
    `makeCallback`, as of now.

    The `maybeCallback` creates a default function to report errors, if the
    parameter passed is not a function object. Basically, if the callback
    is omitted in some cases, this function is used to create a default
    callback function.

    The `makeCallback`, OTOH, creates a default function only if the
    parameter passed is `undefined`, and if it is not a function object it
    will throw an `Error`.

    This patch removes the `maybeCallback` function and makes the callback
    function argument mandatory for all the async functions.

    PR-URL: https://github.com/nodejs/node/pull/7168
    Reviewed-By: Trevor Norris <trev.norris@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/7846
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/test/parallel/test-fs-readfile-error.js b/test/parallel/test-fs-readfile-error.js
new file mode 100644
index 0000000000..86a2be4e1b
--- /dev/null
+++ b/test/parallel/test-fs-readfile-error.js
@@ -0,0 +1,34 @@
+'use strict';
+var common = require('../common');
+var assert = require('assert');
+var exec = require('child_process').exec;
+var path = require('path');
+
+// `fs.readFile('/')` does not fail on FreeBSD, because you can open and read
+// the directory there.
+if (process.platform === 'freebsd') {
+  common.skip('platform not supported.');
+  return;
+}
+
+function test(env, cb) {
+  var filename = path.join(common.fixturesDir, 'test-fs-readfile-error.js');
+  var execPath = '"' + process.execPath + '" "' + filename + '"';
+  var options = { env: Object.assign(process.env, env) };
+  exec(execPath, options, function(err, stdout, stderr) {
+    assert(err);
+    assert.equal(stdout, '');
+    assert.notEqual(stderr, '');
+    cb('' + stderr);
+  });
+}
+
+test({ NODE_DEBUG: '' }, common.mustCall(function(data) {
+  assert(/EISDIR/.test(data));
+  assert(!/test-fs-readfile-error/.test(data));
+}));
+
+test({ NODE_DEBUG: 'fs' }, common.mustCall(function(data) {
+  assert(/EISDIR/.test(data));
+  assert(/test-fs-readfile-error/.test(data));
+}));