path: remove dead code in favor of unit tests

Remove dead code paths that are created by assertions that will never
trigger. They may only trigger if either the `splitDeviceRe` or
`splitPathRe` regular expressions are modified. If at some point they
are modified, current unit tests will catch most of the resulting
errors and this commit adds extra tests to catch the remaining errors.

PR-URL: nodejs#2282
Reviewed-By: Roman Reiss <me@silverwind.io>

lib/path.js

@@ -76,7 +76,7 @@ function win32SplitPath(filename) {
   // Separate device+slash from tail
   var result = splitDeviceRe.exec(filename),
       device = (result[1] || '') + (result[2] || ''),
-      tail = result[3] || '';
+      tail = result[3];
   // Split the tail into dir, basename and extension
   var result2 = splitTailRe.exec(tail),
       dir = result2[1],
@@ -386,9 +386,6 @@ win32.parse = function(pathString) {
   assertPath(pathString);
 
   var allParts = win32SplitPath(pathString);
-  if (!allParts || allParts.length !== 4) {
-    throw new TypeError("Invalid path '" + pathString + "'");
-  }
   return {
     root: allParts[0],
     dir: allParts[0] + allParts[1].slice(0, -1),
@@ -590,13 +587,6 @@ posix.parse = function(pathString) {
   assertPath(pathString);
 
   var allParts = posixSplitPath(pathString);
-  if (!allParts || allParts.length !== 4) {
-    throw new TypeError("Invalid path '" + pathString + "'");
-  }
-  allParts[1] = allParts[1] || '';
-  allParts[2] = allParts[2] || '';
-  allParts[3] = allParts[3] || '';
-
   return {
     root: allParts[0],
     dir: allParts[0] + allParts[1].slice(0, -1),

test/parallel/test-path-parse-format.js

@@ -9,6 +9,7 @@ var winPaths = [
   '\\foo\\C:',
   'file',
   '.\\file',
+  '',
 
   // unc
   '\\\\server\\share\\file_path',
@@ -32,7 +33,8 @@ var unixPaths = [
   'file',
   '.\\file',
   './file',
-  'C:\\foo'
+  'C:\\foo',
+  ''
 ];
 
 var unixSpecialCaseFormatTests = [
@@ -52,8 +54,6 @@ var errors = [
    message: /Path must be a string. Received 1/},
   {method: 'parse', input: [],
    message: /Path must be a string. Received undefined/},
-  // {method: 'parse', input: [''],
-  //  message: /Invalid path/}, // omitted because it's hard to trigger!
   {method: 'format', input: [null],
    message: /Parameter 'pathObject' must be an object, not/},
   {method: 'format', input: [''],
@@ -93,8 +93,13 @@ function checkErrors(path) {
 }
 
 function checkParseFormat(path, paths) {
-  paths.forEach(function(element, index, array) {
+  paths.forEach(function(element) {
     var output = path.parse(element);
+    assert.strictEqual(typeof output.root, 'string');
+    assert.strictEqual(typeof output.dir, 'string');
+    assert.strictEqual(typeof output.base, 'string');
+    assert.strictEqual(typeof output.ext, 'string');
+    assert.strictEqual(typeof output.name, 'string');
     assert.strictEqual(path.format(output), element);
     assert.strictEqual(output.dir, output.dir ? path.dirname(element) : '');
     assert.strictEqual(output.base, path.basename(element));