Don't clone pidlLast in SHBindToParent.

dlls/shell32/pidl.c

@@ -1278,55 +1278,41 @@ BOOL WINAPI SHGetPathFromIDListW(LPCITEMIDLIST pidl, LPWSTR pszPath)
  */
 HRESULT WINAPI SHBindToParent(LPCITEMIDLIST pidl, REFIID riid, LPVOID *ppv, LPCITEMIDLIST *ppidlLast)
 {
-    IShellFolder    * psf;
-    LPITEMIDLIST    pidlChild, pidlParent;
+    IShellFolder    * psfDesktop;
     HRESULT         hr=E_FAIL;
 
     TRACE_(shell)("pidl=%p\n", pidl);
     pdump(pidl);
-
+    
+    if (!pidl || !ppv)
+        return E_INVALIDARG;
+    
     *ppv = NULL;
     if (ppidlLast)
         *ppidlLast = NULL;
 
+    hr = SHGetDesktopFolder(&psfDesktop);
+    if (FAILED(hr))
+        return hr;
+
     if (_ILIsPidlSimple(pidl))
     {
-        IShellFolder* desktop;
-
         /* we are on desktop level */
-        hr = SHGetDesktopFolder(&desktop);
-
-        if (SUCCEEDED(hr))
-        {
-            hr = IShellFolder_QueryInterface(desktop, riid, ppv);
-
-            if (SUCCEEDED(hr) && ppidlLast)
-                *ppidlLast = ILClone(pidl);
-
-            IShellFolder_Release(desktop);
-        }
+        hr = IShellFolder_QueryInterface(psfDesktop, riid, ppv);
     }
     else
     {
-        pidlChild =  ILClone(ILFindLastID(pidl));
-        pidlParent = ILClone(pidl);
+        LPITEMIDLIST pidlParent = ILClone(pidl);
         ILRemoveLastID(pidlParent);
-
-        hr = SHGetDesktopFolder(&psf);
-
-        if (SUCCEEDED(hr))
-            hr = IShellFolder_BindToObject(psf, pidlParent, NULL, riid, ppv);
-
-        if (SUCCEEDED(hr) && ppidlLast)
-            *ppidlLast = pidlChild;
-        else
-            ILFree (pidlChild);
-
+        hr = IShellFolder_BindToObject(psfDesktop, pidlParent, NULL, riid, ppv);
         SHFree (pidlParent);
-        if (psf)
-            IShellFolder_Release(psf);
     }
 
+    IShellFolder_Release(psfDesktop);
+
+    if (SUCCEEDED(hr) && ppidlLast)
+        *ppidlLast = ILFindLastID(pidl);
+
     TRACE_(shell)("-- psf=%p pidl=%p ret=0x%08lx\n", *ppv, (ppidlLast)?*ppidlLast:NULL, hr);
     return hr;
 }

dlls/shell32/tests/shlfolder.c

@@ -304,7 +304,8 @@ static void test_GetDisplayName(void)
     STRRET strret;
     LPSHELLFOLDER psfDesktop, psfPersonal;
     IUnknown *psfFile;
-    LPITEMIDLIST pidlTestFile;
+    SHITEMID emptyitem = { 0, { 0 } };
+    LPITEMIDLIST pidlTestFile, pidlEmpty = (LPITEMIDLIST)&emptyitem;
     LPCITEMIDLIST pidlLast;
     static const WCHAR wszFileName[] = { 'w','i','n','e','t','e','s','t','.','f','o','o',0 };
     static const WCHAR wszDirName[] = { 'w','i','n','e','t','e','s','t',0 };
@@ -372,6 +373,17 @@ static void test_GetDisplayName(void)
 
     if(!pSHBindToParent) return;
 
+    /* SHBindToParent fails, if called with a NULL PIDL. */
+    hr = pSHBindToParent(NULL, &IID_IShellFolder, (VOID**)&psfPersonal, &pidlLast);
+    ok (FAILED(hr), "SHBindToParent(NULL) should fail!\n");
+
+    /* But it succeeds with an empty PIDL. */
+    hr = pSHBindToParent(pidlEmpty, &IID_IShellFolder, (VOID**)&psfPersonal, &pidlLast);
+    ok (SUCCEEDED(hr), "SHBindToParent(empty PIDL) should succeed! hr = %08lx\n", hr);
+    ok (pidlLast == pidlEmpty, "The last element of an empty PIDL should be the PIDL itself!\n");
+    if (SUCCEEDED(hr)) 
+        IShellFolder_Release(psfPersonal);
+    
     /* Binding to the folder and querying the display name of the file also works. */
     hr = pSHBindToParent(pidlTestFile, &IID_IShellFolder, (VOID**)&psfPersonal, &pidlLast); 
     ok (SUCCEEDED(hr), "SHBindToParent failed! hr = %08lx\n", hr);
@@ -382,8 +394,8 @@ static void test_GetDisplayName(void)
 
     /* This test shows that Windows doesn't allocate a new pidlLast, but returns a pointer into 
      * pidlTestFile (In accordance with MSDN). */
-    todo_wine{ok (pILFindLastID(pidlTestFile) == pidlLast, 
-                                "SHBindToParent doesn't return the last id of the pidl param!\n");}
+    ok (pILFindLastID(pidlTestFile) == pidlLast, 
+                                "SHBindToParent doesn't return the last id of the pidl param!\n");
     
     hr = IShellFolder_GetDisplayNameOf(psfPersonal, pidlLast, SHGDN_FORPARSING, &strret);
     ok (SUCCEEDED(hr), "Personal->GetDisplayNameOf failed! hr = %08lx\n", hr);