module: mark DEP0019 as EOL and remove compat code

This removes the compatibilty code that was in place to allow an unintended
interaction between `require('.')` and `NODE_PATH`. The compatibility code and
the accompanying deprecation warning has been in place since 2015-04-17.

PR-URL: #3384
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

doc/api/deprecations.md

@@ -201,7 +201,7 @@ code.
 <a id="DEP0019"></a>
 ### DEP0019: require('.') resolved outside directory
 
-Type: Runtime
+Type: End-of-Life
 
 In certain cases, `require('.')` may resolve outside the package directory.
 This behavior is deprecated and will be removed in a future major Node.js

lib/module.js

@@ -159,7 +159,6 @@ function tryExtensions(p, exts, isMain) {
   return false;
 }
 
-var warned = false;
 Module._findPath = function(request, paths, isMain) {
   if (path.isAbsolute(request)) {
     paths = [''];
@@ -221,18 +220,6 @@ Module._findPath = function(request, paths, isMain) {
     }
 
     if (filename) {
-      // Warn once if '.' resolved outside the module dir
-      if (request === '.' && i > 0) {
-        if (!warned) {
-          warned = true;
-          process.emitWarning(
-            'warning: require(\'.\') resolved outside the package ' +
-            'directory. This functionality is deprecated and will be removed ' +
-            'soon.',
-            'DeprecationWarning', 'DEP0019');
-        }
-      }
-
       Module._pathCache[cacheKey] = filename;
       return filename;
     }
@@ -335,8 +322,7 @@ Module._resolveLookupPaths = function(request, parent, newReturn) {
   }
 
   // Check for relative path
-  if (request.length < 2 ||
-      request.charCodeAt(0) !== 46/*.*/ ||
+  if (request.charCodeAt(0) !== 46/*.*/ &&
       (request.charCodeAt(1) !== 46/*.*/ &&
        request.charCodeAt(1) !== 47/*/*/)) {
     var paths = modulePaths;
@@ -347,16 +333,6 @@ Module._resolveLookupPaths = function(request, parent, newReturn) {
         paths = parent.paths.concat(paths);
     }
 
-    // Maintain backwards compat with certain broken uses of require('.')
-    // by putting the module's directory in front of the lookup paths.
-    if (request === '.') {
-      if (parent && parent.filename) {
-        paths.unshift(path.dirname(parent.filename));
-      } else {
-        paths.unshift(path.resolve(request));
-      }
-    }
-
     debug('looking for %j in %j', request, paths);
     return (newReturn ? (paths.length > 0 ? paths : null) : [request, paths]);
   }

test/parallel/test-require-dot.js

@@ -10,9 +10,7 @@ const b = require(fixtures.path('module-require', 'relative', 'dot-slash.js'));
 assert.strictEqual(a.value, 42);
 assert.strictEqual(a, b, 'require(".") should resolve like require("./")');
 
+// require('.') should not lookup in NODE_PATH
 process.env.NODE_PATH = fixtures.path('module-require', 'relative');
 m._initPaths();
-
-const c = require('.');
-
-assert.strictEqual(c.value, 42, 'require(".") should honor NODE_PATH');
+assert.throws(() => { require('.'); }, Error, "Cannot find module '.'");