Avoid spinning waiting for git-gui.exe on Windows

* src/w32proc.c (waitpid): If GetExitCodeProcess returns
STILL_ACTIVE, and we were called with WNOHANG, pretend that the
process exited.  (Bug#28268)

1 files changed, 10 insertions, 5 deletions

diff --git a/src/w32proc.c b/src/w32proc.c
index ffd5f0d0a1a..71bd28d3c24 100644
--- a/src/w32proc.c
+++ b/src/w32proc.c
@@ -1492,12 +1492,17 @@ waitpid (pid_t pid, int *status, int options)
     }
   if (retval == STILL_ACTIVE)
     {
-      /* Should never happen.  */
+      /* Should never happen.  But it does, with invoking git-gui.exe
+         asynchronously.  So we punt, and just report this process as
+         exited with exit code 259, when we are called with WNOHANG
+         from child_status_changed, because in that case we already
+         _know_ the process has died.  */
       DebPrint (("Wait.WaitForMultipleObjects returned an active process\n"));
-      if (pid > 0 && dont_wait)
-        return 0;
-      errno = EINVAL;
-      return -1;
+      if (!(pid > 0 && dont_wait))
+        {
+          errno = EINVAL;
+          return -1;
+        }
     }
 
   /* Massage the exit code from the process to match the format expected