Aaron Hill : cmd: Set errorlevel to 0 when 'call' is invoked with an empty string.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 8e54cad6a15b3901a748fa228d1a7e456911b9ca
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=8e54cad6a15b3901a748fa228d1a7e456911b9ca

Author: Aaron Hill <aa1ronham at gmail.com>
Date:   Mon Oct 12 17:36:05 2020 -0400

cmd: Set errorlevel to 0 when 'call' is invoked with an empty string.

Previously, invoking 'call' with an empty string would leave errorlevel
unchanged. Reset errorlevel to 0 to match the behavior of
the Windows 'cmd.exe'.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=49982
Signed-off-by: Aaron Hill <aa1ronham at gmail.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 programs/cmd/tests/test_builtins.cmd | 3 +++
 programs/cmd/wcmdmain.c              | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/programs/cmd/tests/test_builtins.cmd b/programs/cmd/tests/test_builtins.cmd
index 73b0917c275..c7418b759e4 100644
--- a/programs/cmd/tests/test_builtins.cmd
+++ b/programs/cmd/tests/test_builtins.cmd
@@ -3149,6 +3149,9 @@ echo %ErrorLevel% should be 7
 if errorlevel 7 echo setting var worked too well, bad
 call :setError 3
 echo %ErrorLevel% should still be 7
+rem Verify that (call ) sets errorlevel to 0
+(call )
+if errorlevel 1 echo errorlevel should have been 0
 
 echo ------------ Testing GOTO ------------
 if a==a goto dest1
diff --git a/programs/cmd/wcmdmain.c b/programs/cmd/wcmdmain.c
index 47e43fcd675..2b55a39dca3 100644
--- a/programs/cmd/wcmdmain.c
+++ b/programs/cmd/wcmdmain.c
@@ -1053,6 +1053,11 @@ void WCMD_run_program (WCHAR *command, BOOL called)
   firstParam = WCMD_parameter(command, 0, NULL, FALSE, TRUE);
   if (!firstParam) return;
 
+  if (!firstParam[0]) {
+      errorlevel = 0;
+      return;
+  }
+
   /* Calculate the search path and stem to search for */
   if (wcspbrk (firstParam, delims) == NULL) {  /* No explicit path given, search path */
     static const WCHAR curDir[] = {'.',';','\0'};