win: Append process dir to $PATH

This allows executables to be found by :!, system(), and executable() if
they live next to ("sibling" to) nvim.exe. This is what gvim on Windows
does, and also matches the behavior of Win32 SearchPath().

https://github.com/vim/vim/blob/c4a249a736d40ec54794827ef95804c225d0e38f/src/os_win32.c#L354-L370

1 files changed, 22 insertions, 6 deletions

diff --git a/src/nvim/main.c b/src/nvim/main.c
index c7a60d07c1..6194e5f948 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -238,9 +238,7 @@ int main(int argc, char **argv)
   // Check if we have an interactive window.
   check_and_set_isatty(&params);
 
-  // Get the name with which Nvim was invoked, with and without path.
-  set_vim_var_string(VV_PROGPATH, argv[0], -1);
-  set_vim_var_string(VV_PROGNAME, (char *) path_tail((char_u *) argv[0]), -1);
+  init_path(argv[0]);
 
   event_init();
   /*
@@ -1194,9 +1192,27 @@ static void check_and_set_isatty(mparm_T *paramp)
   paramp->err_isatty = os_isatty(fileno(stderr));
   TIME_MSG("window checked");
 }
-/*
- * Get filename from command line, given that there is one.
- */
+
+// Sets v:progname and v:progpath. Also modifies $PATH on Windows.
+static void init_path(char *exename)
+{
+  char exepath[MAXPATHL] = { 0 };
+  size_t exepathlen = MAXPATHL;
+  // Make v:progpath absolute.
+  if (os_exepath(exepath, &exepathlen) != 0) {
+    EMSG2(e_intern2, "init_path()");
+  }
+  set_vim_var_string(VV_PROGPATH, exepath, -1);
+  set_vim_var_string(VV_PROGNAME, (char *)path_tail((char_u *)exename), -1);
+
+#ifdef WIN32
+  // Append the process start directory to $PATH, so that ":!foo" finds tools
+  // shipped with Windows package. This also mimics SearchPath().
+  os_setenv_append_path(exepath);
+#endif
+}
+
+/// Get filename from command line, if any.
 static char_u *get_fname(mparm_T *parmp, char_u *cwd)
 {
 #if !defined(UNIX)