Merge #6789 from ZyX-I/lua-path

lua: Add paths from &runtimepath to package.path and package.cpath

src/nvim/lua/executor.c

@@ -14,6 +14,7 @@
 #include "nvim/api/vim.h"
 #include "nvim/vim.h"
 #include "nvim/ex_getln.h"
+#include "nvim/ex_cmds2.h"
 #include "nvim/message.h"
 #include "nvim/memline.h"
 #include "nvim/buffer_defs.h"
@@ -284,7 +285,9 @@ static int nlua_state_init(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
 ///
 /// Crashes NeoVim if initialization fails. Should be called once per lua
 /// interpreter instance.
-static lua_State *init_lua(void)
+///
+/// @return New lua interpreter instance.
+static lua_State *nlua_init(void)
   FUNC_ATTR_NONNULL_RET FUNC_ATTR_WARN_UNUSED_RESULT
 {
   lua_State *lstate = luaL_newstate();
@@ -297,7 +300,43 @@ static lua_State *init_lua(void)
   return lstate;
 }
 
-static lua_State *global_lstate = NULL;
+/// Enter lua interpreter
+///
+/// Calls nlua_init() if needed. Is responsible for pre-lua call initalization
+/// like updating `package.[c]path` with directories derived from &runtimepath.
+///
+/// @return Interprter instance to use. Will either be initialized now or taken
+///         from previous initalization.
+static lua_State *nlua_enter(void)
+  FUNC_ATTR_NONNULL_RET FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  static lua_State *global_lstate = NULL;
+  if (global_lstate == NULL) {
+    global_lstate = nlua_init();
+  }
+  lua_State *const lstate = global_lstate;
+  // Last used p_rtp value. Must not be dereferenced because value pointed to
+  // may already be freed. Used to check whether &runtimepath option value
+  // changed.
+  static const void *last_p_rtp = NULL;
+  if (last_p_rtp != (const void *)p_rtp) {
+    // stack: (empty)
+    lua_getglobal(lstate, "vim");
+    // stack: vim
+    lua_getfield(lstate, -1, "_update_package_paths");
+    // stack: vim, vim._update_package_paths
+    if (lua_pcall(lstate, 0, 0, 0)) {
+      // stack: vim, error
+      nlua_error(lstate, _("E5117: Error while updating package paths: %.*s"));
+      // stack: vim
+    }
+    // stack: vim
+    lua_pop(lstate, 1);
+    // stack: (empty)
+    last_p_rtp = (const void *)p_rtp;
+  }
+  return lstate;
+}
 
 /// Execute lua string
 ///
@@ -308,11 +347,7 @@ static lua_State *global_lstate = NULL;
 void executor_exec_lua(const String str, typval_T *const ret_tv)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (global_lstate == NULL) {
-    global_lstate = init_lua();
-  }
-
-  NLUA_CALL_C_FUNCTION_2(global_lstate, nlua_exec_lua_string, 0,
+  NLUA_CALL_C_FUNCTION_2(nlua_enter(), nlua_exec_lua_string, 0,
                          (void *)&str, ret_tv);
 }
 
@@ -551,11 +586,7 @@ void executor_eval_lua(const String str, typval_T *const arg,
                        typval_T *const ret_tv)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (global_lstate == NULL) {
-    global_lstate = init_lua();
-  }
-
-  NLUA_CALL_C_FUNCTION_3(global_lstate, nlua_eval_lua_string, 0,
+  NLUA_CALL_C_FUNCTION_3(nlua_enter(), nlua_eval_lua_string, 0,
                          (void *)&str, arg, ret_tv);
 }
 
@@ -570,12 +601,8 @@ void executor_eval_lua(const String str, typval_T *const arg,
 /// @return Return value of the execution.
 Object executor_exec_lua_api(const String str, const Array args, Error *err)
 {
-  if (global_lstate == NULL) {
-    global_lstate = init_lua();
-  }
-
   Object retval = NIL;
-  NLUA_CALL_C_FUNCTION_4(global_lstate, nlua_exec_lua_string_api, 0,
+  NLUA_CALL_C_FUNCTION_4(nlua_enter(), nlua_exec_lua_string_api, 0,
                          (void *)&str, (void *)&args, &retval, err);
   return retval;
 }
@@ -609,9 +636,6 @@ void ex_lua(exarg_T *const eap)
 void ex_luado(exarg_T *const eap)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (global_lstate == NULL) {
-    global_lstate = init_lua();
-  }
   if (u_save(eap->line1 - 1, eap->line2 + 1) == FAIL) {
     EMSG(_("cannot save undo information"));
     return;
@@ -621,7 +645,7 @@ void ex_luado(exarg_T *const eap)
     .data = (char *)eap->arg,
   };
   const linenr_T range[] = { eap->line1, eap->line2 };
-  NLUA_CALL_C_FUNCTION_2(global_lstate, nlua_exec_luado_string, 0,
+  NLUA_CALL_C_FUNCTION_2(nlua_enter(), nlua_exec_luado_string, 0,
                          (void *)&cmd, (void *)range);
 }
 
@@ -633,9 +657,6 @@ void ex_luado(exarg_T *const eap)
 void ex_luafile(exarg_T *const eap)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (global_lstate == NULL) {
-    global_lstate = init_lua();
-  }
-  NLUA_CALL_C_FUNCTION_1(global_lstate, nlua_exec_lua_file, 0,
+  NLUA_CALL_C_FUNCTION_1(nlua_enter(), nlua_exec_lua_file, 0,
                          (void *)eap->arg);
 }

src/nvim/lua/vim.lua

@@ -1,2 +1,64 @@
 -- TODO(ZyX-I): Create compatibility layer.
-return {}
+--{{{1 package.path updater function
+-- Last inserted paths. Used to clear out items from package.[c]path when they
+-- are no longer in &runtimepath.
+local last_nvim_paths = {}
+local function _update_package_paths()
+  local cur_nvim_paths = {}
+  local rtps = vim.api.nvim_list_runtime_paths()
+  local sep = package.config:sub(1, 1)
+  for _, key in ipairs({'path', 'cpath'}) do
+    local orig_str = package[key] .. ';'
+    local pathtrails_ordered = {}
+    local orig = {}
+    -- Note: ignores trailing item without trailing `;`. Not using something
+    -- simpler in order to preserve empty items (stand for default path).
+    for s in orig_str:gmatch('[^;]*;') do
+      s = s:sub(1, -2)  -- Strip trailing semicolon
+      orig[#orig + 1] = s
+    end
+    if key == 'path' then
+      -- /?.lua and /?/init.lua
+      pathtrails_ordered = {sep .. '?.lua', sep .. '?' .. sep .. 'init.lua'}
+    else
+      local pathtrails = {}
+      for _, s in ipairs(orig) do
+        -- Find out path patterns. pathtrail should contain something like
+        -- /?.so, \?.dll. This allows not to bother determining what correct
+        -- suffixes are.
+        local pathtrail = s:match('[/\\][^/\\]*%?.*$')
+        if pathtrail and not pathtrails[pathtrail] then
+          pathtrails[pathtrail] = true
+          pathtrails_ordered[#pathtrails_ordered + 1] = pathtrail
+        end
+      end
+    end
+    local new = {}
+    for _, rtp in ipairs(rtps) do
+      if not rtp:match(';') then
+        for _, pathtrail in pairs(pathtrails_ordered) do
+          local new_path = rtp .. sep .. 'lua' .. pathtrail
+          -- Always keep paths from &runtimepath at the start:
+          -- append them here disregarding orig possibly containing one of them.
+          new[#new + 1] = new_path
+          cur_nvim_paths[new_path] = true
+        end
+      end
+    end
+    for _, orig_path in ipairs(orig) do
+      -- Handle removing obsolete paths originating from &runtimepath: such
+      -- paths either belong to cur_nvim_paths and were already added above or
+      -- to last_nvim_paths and should not be added at all if corresponding
+      -- entry was removed from &runtimepath list.
+      if not (cur_nvim_paths[orig_path] or last_nvim_paths[orig_path]) then
+        new[#new + 1] = orig_path
+      end
+    end
+    package[key] = table.concat(new, ';')
+  end
+  last_nvim_paths = cur_nvim_paths
+end
+--{{{1 Module definition
+return {
+  _update_package_paths = _update_package_paths,
+}