shell32: ShellExec with empty operation should behave same as with NULL operation.

dlls/shell32/classes.c

@@ -129,7 +129,7 @@ BOOL HCR_GetDefaultVerbW( HKEY hkeyClass, LPCWSTR szVerb, LPWSTR szDest, DWORD l
 
 	TRACE("%p %s %p\n", hkeyClass, debugstr_w(szVerb), szDest);
 
-        if (szVerb)
+        if (szVerb && *szVerb)
         {
             lstrcpynW(szDest, szVerb, len);
             return TRUE;

dlls/shell32/shlexec.c

@@ -1517,7 +1517,7 @@ static UINT_PTR SHELL_execute_url( LPCWSTR lpFile, LPCWSTR wFile, LPCWSTR wcmd,
     TRACE("Got URL: %s\n", debugstr_w(lpFile));
     /* Looking for ...protocol\shell\lpOperation\command */
     len = iSize + lstrlenW(wShell) + lstrlenW(wCommand) + 1;
-    if (psei->lpVerb)
+    if (psei->lpVerb && *psei->lpVerb)
         len += lstrlenW(psei->lpVerb);
     else
         len += lstrlenW(wszOpen);
@@ -1525,7 +1525,7 @@ static UINT_PTR SHELL_execute_url( LPCWSTR lpFile, LPCWSTR wFile, LPCWSTR wcmd,
     memcpy(lpstrProtocol, lpFile, iSize*sizeof(WCHAR));
     lpstrProtocol[iSize] = '\0';
     strcatW(lpstrProtocol, wShell);
-    strcatW(lpstrProtocol, psei->lpVerb? psei->lpVerb: wszOpen);
+    strcatW(lpstrProtocol, psei->lpVerb && *psei->lpVerb ? psei->lpVerb: wszOpen);
     strcatW(lpstrProtocol, wCommand);
 
     /* Remove File Protocol from lpFile */

dlls/shell32/tests/shlexec.c

@@ -92,7 +92,10 @@ static void strcat_param(char* str, const char* param)
 static char shell_call[2048]="";
 static int shell_execute(LPCSTR operation, LPCSTR file, LPCSTR parameters, LPCSTR directory)
 {
-    INT_PTR rc;
+    INT_PTR rc, rcEmpty = 0;
+
+    if(!operation)
+        rcEmpty = shell_execute("", file, parameters, directory);
 
     strcpy(shell_call, "ShellExecute(");
     strcat_param(shell_call, operation);
@@ -139,6 +142,10 @@ static int shell_execute(LPCSTR operation, LPCSTR file, LPCSTR parameters, LPCST
     if (rc > 32)
         dump_child();
 
+    if(!operation)
+        ok(rc == rcEmpty || broken(rc > 32 && rcEmpty == SE_ERR_NOASSOC) /* NT4 */,
+                "Got different return value with empty string: %lu %lu\n", rc, rcEmpty);
+
     return rc;
 }