Standardise module load order for native and registered file extensions.

This patch standardises the load order for modules. Highest priority is trying to load exactly the file the user specified, followed by native extensions, followed by registered extra extensions, etc.

In full, if we require('foo') having registered '.coffee' as an alternative extension, we try and load the following files in order:

    foo
    foo.js
    foo.node
    foo.coffee
    foo/index.js
    foo/index.node
    foo/index.coffee

lib/module.js

@@ -59,8 +59,6 @@ function requireNative (id) {
   return loadNative(id).exports;
 }
 
-
-
 // Event
 
 var eventsFn = process.compile("(function (exports) {" + natives.events + "\n})",
@@ -93,6 +91,8 @@ if (process.env["NODE_PATH"]) {
   modulePaths = process.env["NODE_PATH"].split(":").concat(modulePaths);
 }
 
+var moduleNativeExtensions = ['js', 'node'];
+
 /* Sync unless callback given */
 function findModulePath (id, dirs, callback) {
   process.assert(dirs.constructor == Array);
@@ -106,10 +106,6 @@ function findModulePath (id, dirs, callback) {
     return;
   }
 
-  if (/\.(js|node)$/.exec(id)) {
-    throw new Error("No longer accepting filename extension in module names");
-  }
-
   if (dirs.length == 0) {
     if (callback) {
       callback();
@@ -126,22 +122,17 @@ function findModulePath (id, dirs, callback) {
     rest = [];
   }
 
-  var locations = [
-    path.join(dir, id + ".js"),
-    path.join(dir, id + ".node"),
-    path.join(dir, id, "index.js"),
-    path.join(dir, id, "index.node"),
-    path.join(dir, id)
-  ];
+  var ext, locDirect = [], locIndex = [];
+  var extensions = moduleNativeExtensions.concat(Object.keys(extensionCache));
 
-  var ext;
-  var extensions = Object.keys(extensionCache);
   for (var i = 0, l = extensions.length; i < l; i++) {
-    var ext = extensions[i];
-    locations.push(path.join(dir, id + ext));
-    locations.push(path.join(dir, id, 'index' + ext));
+    ext = extensions[i];
+    locDirect.push(path.join(dir, id + '.' + ext));
+    locIndex.push(path.join(dir, id, 'index.' + ext));
   }
 
+  var locations = [path.join(dir, id)].concat(locDirect).concat(locIndex);
+
   var fs = requireNative('fs');
 
   function searchLocations () {
@@ -192,12 +183,7 @@ function resolveModulePath(request, parent) {
   if (request.charAt(0) == "." && (request.charAt(1) == "/" || request.charAt(1) == ".")) {
     // Relative request
 
-    var exts = ['js', 'node'], ext;
-    var extensions = Object.keys(extensionCache);
-    for (var i = 0, l = extensions.length; i < l; i++) {
-      var ext = extensions[i];
-      exts.push(ext.slice(1));
-    }
+    var exts = moduleNativeExtensions.concat(Object.keys(extensionCache));
 
     var parentIdPath = path.dirname(parent.id +
       (path.basename(parent.filename).match(new RegExp('^index\\.(' + exts.join('|') + ')$')) ? "/." : ""));
@@ -293,7 +279,7 @@ function registerExtension(ext, compiler) {
     throw new Error('require.registerExtension: Second argument not a valid compiler function.');
   }
 
-  extensionCache[ext] = compiler;
+  extensionCache[ext.slice(1)] = compiler;
 }
 
 
@@ -364,7 +350,7 @@ Module.prototype._compile = function (content, filename) {
   content = content.replace(/^\#\!.*/, '');
 
   // Compile content if needed
-  var ext = path.extname(filename);
+  var ext = path.extname(filename).slice(1);
   if (extensionCache[ext]) {
     content = extensionCache[ext](content);
   }

test/fixtures/module-load-order/file1

@@ -0,0 +1 @@
+exports.file1 = 'file1';

test/fixtures/module-load-order/file1.js

@@ -0,0 +1 @@
+exports.file1 = 'file1.js';

test/fixtures/module-load-order/file1.node

@@ -0,0 +1 @@
+exports.file1 = 'file1.node';

test/fixtures/module-load-order/file1.reg

@@ -0,0 +1 @@
+exports.file1 = 'file1.reg';

test/fixtures/module-load-order/file1.reg2

@@ -0,0 +1 @@
+exports.file1 = 'file1.reg2';

test/fixtures/module-load-order/file2.js

@@ -0,0 +1 @@
+exports.file2 = 'file2.js';

test/fixtures/module-load-order/file2.node

@@ -0,0 +1 @@
+exports.file2 = 'file2.node';

test/fixtures/module-load-order/file2.reg

@@ -0,0 +1 @@
+exports.file2 = 'file2.reg';

test/fixtures/module-load-order/file2.reg2

@@ -0,0 +1 @@
+exports.file2 = 'file2.reg2';

test/fixtures/module-load-order/file2/index.js

@@ -0,0 +1 @@
+exports.file2 = 'file2/index.js';

test/fixtures/module-load-order/file2/index.node

@@ -0,0 +1 @@
+exports.file2 = 'file2/index.node';

test/fixtures/module-load-order/file2/index.reg

@@ -0,0 +1 @@
+exports.file2 = 'file2/index.reg';

test/fixtures/module-load-order/file2/index.reg2

@@ -0,0 +1 @@
+exports.file2 = 'file2/index.reg2';

test/fixtures/module-load-order/file3.node

@@ -0,0 +1 @@
+exports.file3 = 'file3.node';

test/fixtures/module-load-order/file3.reg

@@ -0,0 +1 @@
+exports.file3 = 'file3.reg';

test/fixtures/module-load-order/file3.reg2

@@ -0,0 +1 @@
+exports.file3 = 'file3.reg2';

test/fixtures/module-load-order/file3/index.js

@@ -0,0 +1 @@
+exports.file3 = 'file3/index.js';

test/fixtures/module-load-order/file3/index.node

@@ -0,0 +1 @@
+exports.file3 = 'file3/index.node';

test/fixtures/module-load-order/file3/index.reg

@@ -0,0 +1 @@
+exports.file3 = 'file3/index.reg';

test/fixtures/module-load-order/file3/index.reg2

@@ -0,0 +1 @@
+exports.file3 = 'file3/index.reg2';

test/fixtures/module-load-order/file4.reg

@@ -0,0 +1 @@
+exports.file4 = 'file4.reg';

test/fixtures/module-load-order/file4.reg2

@@ -0,0 +1 @@
+exports.file4 = 'file4.reg2';

test/fixtures/module-load-order/file4/index.js

@@ -0,0 +1 @@
+exports.file4 = 'file4/index.js';

test/fixtures/module-load-order/file4/index.node

@@ -0,0 +1 @@
+exports.file4 = 'file4/index.node';

test/fixtures/module-load-order/file4/index.reg

@@ -0,0 +1 @@
+exports.file4 = 'file4/index.reg';

test/fixtures/module-load-order/file4/index.reg2

@@ -0,0 +1 @@
+exports.file4 = 'file4/index.reg2';

test/fixtures/module-load-order/file5.reg2

@@ -0,0 +1 @@
+exports.file5 = 'file5.reg2';

test/fixtures/module-load-order/file5/index.js

@@ -0,0 +1 @@
+exports.file5 = 'file5/index.js';

test/fixtures/module-load-order/file5/index.node

@@ -0,0 +1 @@
+exports.file5 = 'file5/index.node';

test/fixtures/module-load-order/file5/index.reg

@@ -0,0 +1 @@
+exports.file5 = 'file5/index.reg';

test/fixtures/module-load-order/file5/index.reg2

@@ -0,0 +1 @@
+exports.file5 = 'file5/index.reg2';

test/fixtures/module-load-order/file6/index.js

@@ -0,0 +1 @@
+exports.file6 = 'file6/index.js';

test/fixtures/module-load-order/file6/index.node

@@ -0,0 +1 @@
+exports.file6 = 'file6/index.node';

test/fixtures/module-load-order/file6/index.reg

@@ -0,0 +1 @@
+exports.file6 = 'file6/index.reg';

test/fixtures/module-load-order/file6/index.reg2

@@ -0,0 +1 @@
+exports.file6 = 'file6/index.reg2';

test/fixtures/module-load-order/file7/index.node

@@ -0,0 +1 @@
+exports.file7 = 'file7/index.node';

test/fixtures/module-load-order/file7/index.reg

@@ -0,0 +1 @@
+exports.file7 = 'file7/index.reg';

test/fixtures/module-load-order/file7/index.reg2

@@ -0,0 +1 @@
+exports.file7 = 'file7/index.reg2';

test/fixtures/module-load-order/file8/index.reg

@@ -0,0 +1 @@
+exports.file8 = 'file8/index.reg';

test/fixtures/module-load-order/file8/index.reg2

@@ -0,0 +1 @@
+exports.file8 = 'file8/index.reg2';

test/fixtures/module-load-order/file9/index.reg2

@@ -0,0 +1 @@
+exports.file9 = 'file9/index.reg2';

test/simple/test-module-loading.js

@@ -123,6 +123,36 @@ require.async("../fixtures/empty", function (err, a) {
   }
 });
 
+// Check load order is as expected
+common.debug('load order');
+
+var loadOrder = '../fixtures/module-load-order/',
+    msg       = "Load order incorrect.";
+
+require.registerExtension('.reg',  function(content) { return content; });
+require.registerExtension('.reg2', function(content) { return content; });
+
+assert.equal(require(loadOrder + 'file1').file1, 'file1',            msg);
+assert.equal(require(loadOrder + 'file2').file2, 'file2.js',         msg);
+try {
+  require(loadOrder + 'file3');
+} catch (e) {
+  // Not a real .node module, but we know we require'd the right thing.
+  assert.ok(e.message.match(/^dlopen/));
+  assert.ok(e.message.match(/file3\.node/));
+}
+assert.equal(require(loadOrder + 'file4').file4, 'file4.reg',        msg);
+assert.equal(require(loadOrder + 'file5').file5, 'file5.reg2',       msg);
+assert.equal(require(loadOrder + 'file6').file6, 'file6/index.js',   msg);
+try {
+  require(loadOrder + 'file7');
+} catch (e) {
+  assert.ok(e.message.match(/^dlopen/));
+  assert.ok(e.message.match(/file7\/index\.node/));
+}
+assert.equal(require(loadOrder + 'file8').file8, 'file8/index.reg',  msg);
+assert.equal(require(loadOrder + 'file9').file9, 'file9/index.reg2', msg);
+
 process.addListener("exit", function () {
   assert.equal(true, a.A instanceof Function);
   assert.equal("A done", a.A());