lib: don't error in repl when cwd doesn't exist

The current working directory may not exist when the REPL starts up.
Don't treat that as an error because it's still possible to do many
useful things.  This is like the previous commit but for the REPL.

Fixes: #1184
PR-URL: #1194
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Rod Vagg <rod@vagg.org>

lib/repl.js

@@ -40,8 +40,16 @@ function hasOwnProperty(obj, prop) {
 }
 
 
-// hack for require.resolve("./relative") to work properly.
-module.filename = path.resolve('repl');
+try {
+  // hack for require.resolve("./relative") to work properly.
+  module.filename = path.resolve('repl');
+} catch (e) {
+  // path.resolve('repl') fails when the current working directory has been
+  // deleted.  Fall back to the directory name of the (absolute) executable
+  // path.  It's not really correct but what are the alternatives?
+  const dirname = path.dirname(process.execPath);
+  module.filename = path.resolve(dirname, 'repl');
+}
 
 // hack for repl require to work properly with node_modules folders
 module.paths = require('module')._nodeModulePaths(module.filename);

test/parallel/test-cwd-enoent-repl.js

@@ -0,0 +1,26 @@
+var common = require('../common');
+var assert = require('assert');
+var fs = require('fs');
+var spawn = require('child_process').spawn;
+
+// Fails with EINVAL on SmartOS, EBUSY on Windows.
+if (process.platform === 'sunos' || process.platform === 'win32') {
+  console.log('1..0 # Skipped: cannot rmdir current working directory');
+  return;
+}
+
+var dirname = common.tmpDir + '/cwd-does-not-exist-' + process.pid;
+fs.mkdirSync(dirname);
+process.chdir(dirname);
+fs.rmdirSync(dirname);
+
+var proc = spawn(process.execPath, ['--interactive']);
+proc.stdout.pipe(process.stdout);
+proc.stderr.pipe(process.stderr);
+proc.stdin.write('require("path");\n');
+proc.stdin.write('process.exit(42);\n');
+
+proc.once('exit', common.mustCall(function(exitCode, signalCode) {
+  assert.equal(exitCode, 42);
+  assert.equal(signalCode, null);
+}));