startup: add init.lua as an alternative user config, fixes #7895

2 files changed, 40 insertions, 2 deletions

diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 0a3c30134b..97f6d5bd31 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -1244,6 +1244,23 @@ void ex_luafile(exarg_T *const eap)
   }
 }
 
+bool load_init_lua(const char *script_path)
+{
+  lua_State *const lstate = nlua_enter();
+
+  if (luaL_loadfile(lstate, script_path)) {
+    nlua_error(lstate, _("E5112: Error while creating lua chunk: %.*s"));
+    return false;
+  }
+
+  if (lua_pcall(lstate, 0, 0, 0)) {
+    nlua_error(lstate, _("E5113: Error while calling lua chunk: %.*s"));
+    return false;
+  }
+
+  return true;
+}
+
 static void nlua_add_treesitter(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
 {
   tslua_init(lstate);
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 63249416b1..2835174ac6 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -1770,6 +1770,23 @@ static bool do_user_initialization(void)
     do_exrc = p_exrc;
     return do_exrc;
   }
+
+  char_u *init_lua_path = (char_u *)stdpaths_user_conf_subpath("init.lua");
+  if (os_path_exists(init_lua_path)
+      && load_init_lua((const char *)init_lua_path)) {
+    os_setenv("MYVIMRC", (const char *)init_lua_path, 1);
+    char_u *vimrc_path = (char_u *)stdpaths_user_conf_subpath("init.vim");
+
+    if (os_path_exists(vimrc_path)) {
+      EMSG3(_("Conflicting configs: \"%s\" \"%s\""), init_lua_path, vimrc_path);
+    }
+
+    xfree(vimrc_path);
+    xfree(init_lua_path);
+    return false;
+  }
+  xfree(init_lua_path);
+
   char_u *user_vimrc = (char_u *)stdpaths_user_conf_subpath("init.vim");
   if (do_source(user_vimrc, true, DOSO_VIMRC) != FAIL) {
     do_exrc = p_exrc;
@@ -1829,8 +1846,12 @@ static void source_startup_scripts(const mparm_T *const parmp)
         || strequal(parmp->use_vimrc, "NORC")) {
       // Do nothing.
     } else {
-      if (do_source((char_u *)parmp->use_vimrc, false, DOSO_NONE) != OK) {
-        EMSG2(_("E282: Cannot read from \"%s\""), parmp->use_vimrc);
+      if (path_with_extension(parmp->use_vimrc, "lua")) {
+        load_init_lua(parmp->use_vimrc);
+      } else {
+        if (do_source((char_u *)parmp->use_vimrc, false, DOSO_NONE) != OK) {
+          EMSG2(_("E282: Cannot read from \"%s\""), parmp->use_vimrc);
+        }
       }
     }
   } else if (!silent_mode) {