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

Resolving a path against root with `path.relative()` should not include a trailing slash. Fixes: #28549 PR-URL: #28556 Reviewed-By: Rich Trott <[email protected]> Reviewed-By: Weijia Wang <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Jiawen Geng <[email protected]> Reviewed-By: Yongsheng Zhang <[email protected]>
nodejs · Jul 20, 2019 · 18c56df · 18c56df
1 parent 17df75f
commit 18c56df
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Showing 2 changed files with 12 additions and 6 deletions.
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', '/', '../../..']
     ]
   ]
 ];