path: using .relative() should not return a trailing slash

BridgeAR · targos · commit 18c56df9281a · 2019-07-20T11:10:25.000+02:00
Resolving a path against root with `path.relative()` should not include a trailing slash. Fixes: #28549 PR-URL: #28556 Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Weijia Wang <starkwang@126.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Jiawen Geng <technicalcute@gmail.com> Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
diff --git a/lib/path.js b/lib/path.js
@@ -1090,11 +1090,16 @@ const posix = {
           // For example: from='/'; to='/foo'
           return to.slice(toStart + i);
         }
-      } else if (fromLen > length &&
-                 from.charCodeAt(fromStart + i) === CHAR_FORWARD_SLASH) {
-        // 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 (fromLen > length) {
+        if (from.charCodeAt(fromStart + i) === CHAR_FORWARD_SLASH) {
+          // 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/bar'; to='/'
+          lastCommonSep = 0;
+        }
       }
     }
 
diff --git a/test/parallel/test-path-relative.js b/test/parallel/test-path-relative.js
@@ -47,7 +47,8 @@ const relativeTests = [
      ['/foo/bar/baz-quux', '/foo/bar/baz', '../baz'],
      ['/foo/bar/baz', '/foo/bar/baz-quux', '../baz-quux'],
      ['/baz-quux', '/baz', '../baz'],
-     ['/baz', '/baz-quux', '../baz-quux']
+     ['/baz', '/baz-quux', '../baz-quux'],
+     ['/page1/page2/foo', '/', '../../..']
     ]
   ]
 ];

Original file line number	Diff line number	Diff line change
`@@ -47,7 +47,8 @@ const relativeTests = [`
`47`	`47`	`['/foo/bar/baz-quux', '/foo/bar/baz', '../baz'],`
`48`	`48`	`['/foo/bar/baz', '/foo/bar/baz-quux', '../baz-quux'],`
`49`	`49`	`['/baz-quux', '/baz', '../baz'],`
`50`		`- ['/baz', '/baz-quux', '../baz-quux']`
	`50`	`+ ['/baz', '/baz-quux', '../baz-quux'],`
	`51`	`+ ['/page1/page2/foo', '/', '../../..']`
`51`	`52`	`]`
`52`	`53`	`]`
`53`	`54`	`];`