path: fix path.relative() for prefixes at device root

Fixes #5485
nodejs · Feb 29, 2016 · d1e13c2 · d1e13c2
1 parent 3c79bbd
commit d1e13c2
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Showing 2 changed files with 30 additions and 14 deletions.
diff --git a/lib/path.js b/lib/path.js
@@ -618,7 +618,7 @@ const win32 = {
  // We get here if `from` is the exact base path for `to`.
  // For example: from='C:\\foo\\bar'; to='C:\\foo\\bar\\baz'
  return toOrig.slice(toStart + i + 1);
- } else if (lastCommonSep === 2) {
+ } else if (i === 2) {
  // We get here if `from` is the device root.
  // For example: from='C:\\'; to='C:\\foo'
  return toOrig.slice(toStart + i);
@@ -629,7 +629,7 @@ const win32 = {
  // We get here if `to` is the exact base path for `from`.
  // For example: from='C:\\foo\\bar'; to='C:\\foo'
  lastCommonSep = i;
- } else if (lastCommonSep === 2) {
+ } else if (i === 2) {
  // We get here if `to` is the device root.
  // For example: from='C:\\foo\\bar'; to='C:\\'
  lastCommonSep = 3;
@@ -1300,16 +1300,26 @@ const posix = {
  var i = 0;
  for (; i <= length; ++i) {
  if (i === length) {
- if (lastCommonSep === -1) {
- lastCommonSep = i;
- } else if (toLen > length && to.charCodeAt(i + 1) === 47/*/*/) {
- // We get here if `from` is the exact base path for `to`.
- // For example: from='/foo/bar'; to='/foo/bar/baz'
- return to.slice(i + 2);
- } else if (fromLen > length && from.charCodeAt(i + 1) === 47/*/*/) {
- // We get here if `to` is the exact base path for `from`.
- // For example: from='/foo/bar/baz'; to='/foo/bar'
- lastCommonSep = i;
+ if (toLen > length) {
+ if (to.charCodeAt(toStart + i) === 47/*/*/) {
+ // We get here if `from` is the exact base path for `to`.
+ // For example: from='/foo/bar'; to='/foo/bar/baz'
+ return to.slice(toStart + i + 1);
+ } else if (i === 0) {
+ // We get here if `from` is the root
+ // For example: from='/'; to='/foo'
+ return to.slice(toStart + i);
+ }
+ } else if (fromLen > length) {
+ if (from.charCodeAt(fromStart + i) === 47/*/*/) {
+ // We get here if `to` is the exact base path for `from`.
+ // For example: from='/foo/bar/baz'; to='/foo/bar'
+ lastCommonSep = i;
+ } else if (i === 0) {
+ // We get here if `to` is the root.
+ // For example: from='/foo'; to='/'
+ lastCommonSep = 0;
+ }
  }
  break;
  }

diff --git a/test/parallel/test-path.js b/test/parallel/test-path.js
@@ -476,7 +476,11 @@ const relativeTests = [
  ['\\\\foo\\bar', '\\\\foo\\bar\\baz', 'baz'],
  ['\\\\foo\\bar\\baz', '\\\\foo\\bar', '..'],
  ['\\\\foo\\bar\\baz-quux', '\\\\foo\\bar\\baz', '..\\baz'],
- ['\\\\foo\\bar\\baz', '\\\\foo\\bar\\baz-quux', '..\\baz-quux']
+ ['\\\\foo\\bar\\baz', '\\\\foo\\bar\\baz-quux', '..\\baz-quux'],
+ ['C:\\baz-quux', 'C:\\baz', '..\\baz'],
+ ['C:\\baz', 'C:\\baz-quux', '..\\baz-quux'],
+ ['\\\\foo\\baz-quux', '\\\\foo\\baz', '..\\baz'],
+ ['\\\\foo\\baz', '\\\\foo\\baz-quux', '..\\baz-quux']
  ]
  ],
  [ path.posix.relative,
@@ -490,7 +494,9 @@ const relativeTests = [
  ['/foo/test', '/foo/test/bar/package.json', 'bar/package.json'],
  ['/Users/a/web/b/test/mails', '/Users/a/web/b', '../..'],
  ['/foo/bar/baz-quux', '/foo/bar/baz', '../baz'],
- ['/foo/bar/baz', '/foo/bar/baz-quux', '../baz-quux']
+ ['/foo/bar/baz', '/foo/bar/baz-quux', '../baz-quux'],
+ ['/baz-quux', '/baz', '../baz'],
+ ['/baz', '/baz-quux', '../baz-quux']
  ]
  ]
 ];