From 4e721f780e72bc7a0c780a477b76b7f09126c145 Mon Sep 17 00:00:00 2001
From: Doug Lyons <douglyons@douglyons.com>
Date: Sun, 23 Feb 2020 10:47:48 -0600
Subject: [PATCH] [SHELL32] Fix unneeded error Popup with Git for Windows.
 (#1854)

* Fix unnecessary error popup when installing Git for Windows.
* Add reasons for return value of 42.
---
 dll/win32/shell32/shlexec.cpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/dll/win32/shell32/shlexec.cpp b/dll/win32/shell32/shlexec.cpp
index 099a964c93e..3feab9c2ff6 100644
--- a/dll/win32/shell32/shlexec.cpp
+++ b/dll/win32/shell32/shlexec.cpp
@@ -1080,6 +1080,22 @@ static unsigned dde_connect(const WCHAR* key, const WCHAR* start, WCHAR* ddeexec
             TRACE("Couldn't launch\n");
             goto error;
         }
+        /* if ddeexec is NULL, then we just need to exit here */
+        if (ddeexec == NULL)
+        {
+            TRACE("Exiting because ddeexec is NULL. ret=42.\n");
+            /* See https://docs.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-shellexecutew */
+            /* for reason why we use 42 here and also "Shell32_apitest ShellExecuteW" regression test */
+            return 42;
+        }
+        /* if ddeexec is 'empty string', then we just need to exit here */
+        if (wcscmp(ddeexec, L"") == 0)
+        {
+            TRACE("Exiting because ddeexec is 'empty string'. ret=42.\n");
+            /* See https://docs.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-shellexecutew */
+            /* for reason why we use 42 here and also "Shell32_apitest ShellExecuteW" regression test */
+            return 42;
+        }
         hConv = DdeConnect(ddeInst, hszApp, hszTopic, NULL);
         if (!hConv)
         {