Merge #18706 execute Lua with "nvim -l"

9 files changed, 169 insertions, 81 deletions

diff --git a/src/nvim/README.md b/src/nvim/README.md
index e710c3ef58..6876227e48 100644
--- a/src/nvim/README.md
+++ b/src/nvim/README.md
@@ -18,6 +18,12 @@ The source files use extensions to hint about their purpose.
 - `*.h.generated.h` - exported functions’ declarations.
 - `*.c.generated.h` - static functions’ declarations.
 
+Common structures
+-----------------
+
+- StringBuilder
+- kvec or garray.c for dynamic lists / vectors (use StringBuilder for strings)
+
 Logs
 ----
 
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 9c4df59819..bb7c519b7c 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -515,7 +515,7 @@ EXTERN int allbuf_lock INIT(= 0);
 /// not allowed then.
 EXTERN int sandbox INIT(= 0);
 
-/// Batch-mode: "-es" or "-Es" commandline argument was given.
+/// Batch-mode: "-es", "-Es", "-l" commandline argument was given.
 EXTERN int silent_mode INIT(= false);
 
 /// Start position of active Visual selection.
@@ -1042,7 +1042,7 @@ EXTERN int vim_ignored;
 
 // stdio is an RPC channel (--embed).
 EXTERN bool embedded_mode INIT(= false);
-// Do not start a UI nor read/write to stdio (unless embedding).
+// Do not start UI (--headless, -l) nor read/write to stdio (unless embedding).
 EXTERN bool headless_mode INIT(= false);
 
 // uncrustify:on
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 34b572f884..307b34a55c 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -323,6 +323,30 @@ static int nlua_thr_api_nvim__get_runtime(lua_State *lstate)
   return 1;
 }
 
+/// Copies args starting at `lua_arg0` into the Lua `arg` global.
+///
+/// Example (`lua_arg0` points to "--arg1"):
+///     nvim -l foo.lua --arg1 --arg2
+///
+/// @note Lua CLI sets arguments upto "-e" as _negative_ `_G.arg` indices, but we currently don't
+/// follow that convention.
+///
+/// @see https://www.lua.org/pil/1.4.html
+/// @see https://github.com/premake/premake-core/blob/1c1304637f4f5e50ba8c57aae8d1d80ec3b7aaf2/src/host/premake.c#L563-L594
+///
+/// @returns number of args
+static int nlua_init_argv(lua_State *const L, char **argv, int argc, int lua_arg0)
+{
+  lua_newtable(L);  // _G.arg
+  int i = 0;
+  for (; lua_arg0 >= 0 && i + lua_arg0 < argc; i++) {
+    lua_pushstring(L, argv[i + lua_arg0]);
+    lua_rawseti(L, -2, i + 1);  // _G.arg[i+1] = "arg1"
+  }
+  lua_setglobal(L, "arg");
+  return i;
+}
+
 static void nlua_schedule_event(void **argv)
 {
   LuaRef cb = (LuaRef)(ptrdiff_t)argv[0];
@@ -765,10 +789,8 @@ static bool nlua_state_init(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
   return true;
 }
 
-/// Initialize global lua interpreter
-///
-/// Crashes Nvim if initialization fails.
-void nlua_init(void)
+/// Initializes global Lua interpreter, or exits Nvim on failure.
+void nlua_init(char **argv, int argc, int lua_arg0)
 {
 #ifdef NLUA_TRACK_REFS
   const char *env = os_getenv("NVIM_LUA_NOTRACK");
@@ -789,10 +811,9 @@ void nlua_init(void)
   }
 
   luv_set_thread_cb(nlua_thread_acquire_vm, nlua_common_free_all_mem);
-
   global_lstate = lstate;
-
   main_thread = uv_thread_self();
+  nlua_init_argv(lstate, argv, argc, lua_arg0);
 }
 
 static lua_State *nlua_thread_acquire_vm(void)
@@ -1686,21 +1707,49 @@ void ex_luafile(exarg_T *const eap)
   nlua_exec_file((const char *)eap->arg);
 }
 
-/// execute lua code from a file.
+/// Executes Lua code from a file or "-" (stdin).
 ///
-/// Note: we call the lua global loadfile as opposed to calling luaL_loadfile
-/// in case loadfile has been overridden in the users environment.
+/// Calls the Lua `loadfile` global as opposed to `luaL_loadfile` in case `loadfile` was overridden
+/// in the user environment.
 ///
-/// @param  path  path of the file
+/// @param path Path to the file, may be "-" (stdin) during startup.
 ///
-/// @return  true if everything ok, false if there was an error (echoed)
+/// @return true on success, false on error (echoed) or user canceled (CTRL-c) while reading "-"
+/// (stdin).
 bool nlua_exec_file(const char *path)
   FUNC_ATTR_NONNULL_ALL
 {
   lua_State *const lstate = global_lstate;
+  if (!strequal(path, "-")) {
+    lua_getglobal(lstate, "loadfile");
+    lua_pushstring(lstate, path);
+  } else {
+    FileDescriptor *stdin_dup = file_open_stdin();
+
+    StringBuilder sb = KV_INITIAL_VALUE;
+    kv_resize(sb, 64);
+    ptrdiff_t read_size = -1;
+    // Read all input from stdin, unless interrupted (ctrl-c).
+    while (true) {
+      if (got_int) {  // User canceled.
+        return false;
+      }
+      read_size = file_read(stdin_dup, IObuff, 64);
+      if (read_size < 0) {  // Error.
+        return false;
+      }
+      kv_concat_len(sb, IObuff, (size_t)read_size);
+      if (read_size < 64) {  // EOF.
+        break;
+      }
+    }
+    kv_push(sb, NUL);
+    file_free(stdin_dup, false);
 
-  lua_getglobal(lstate, "loadfile");
-  lua_pushstring(lstate, path);
+    lua_getglobal(lstate, "loadstring");
+    lua_pushstring(lstate, sb.items);
+    kv_destroy(sb);
+  }
 
   if (nlua_pcall(lstate, 1, 2)) {
     nlua_error(lstate, _("E5111: Error calling lua: %.*s"));
diff --git a/src/nvim/main.c b/src/nvim/main.c
index b0da7f4500..9bb9eea4f6 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -279,8 +279,7 @@ int main(int argc, char **argv)
   // argument list "global_alist".
   command_line_scan(&params);
 
-  nlua_init();
-
+  nlua_init(argv, argc, params.lua_arg0);
   TIME_MSG("init lua interpreter");
 
   if (embedded_mode) {
@@ -363,8 +362,7 @@ int main(int argc, char **argv)
   debug_break_level = params.use_debug_break_level;
 
   // Read ex-commands if invoked with "-es".
-  if (!params.input_isatty && !params.input_neverscript
-      && silent_mode && exmode_active) {
+  if (!params.input_isatty && !params.input_istext && silent_mode && exmode_active) {
     input_start(STDIN_FILENO);
   }
 
@@ -409,14 +407,12 @@ int main(int argc, char **argv)
   init_default_autocmds();
   TIME_MSG("init default autocommands");
 
-  bool vimrc_none = params.use_vimrc != NULL && strequal(params.use_vimrc, "NONE");
+  bool vimrc_none = strequal(params.use_vimrc, "NONE");
 
   // Reset 'loadplugins' for "-u NONE" before "--cmd" arguments.
   // Allows for setting 'loadplugins' there.
-  if (vimrc_none) {
-    // When using --clean we still want to load plugins
-    p_lpl = params.clean;
-  }
+  // For --clean we still want to load plugins.
+  p_lpl = vimrc_none ? params.clean : p_lpl;
 
   // Execute --cmd arguments.
   exe_pre_commands(&params);
@@ -610,6 +606,12 @@ int main(int argc, char **argv)
     (void)eval_has_provider("clipboard");
   }
 
+  if (params.luaf != NULL) {
+    bool lua_ok = nlua_exec_file(params.luaf);
+    TIME_MSG("executing Lua -l script");
+    getout(lua_ok ? 0 : 1);
+  }
+
   TIME_MSG("before starting main loop");
   ILOG("starting main loop");
 
@@ -657,9 +659,8 @@ void getout(int exitval)
 {
   exiting = true;
 
-  // When running in Ex mode an error causes us to exit with a non-zero exit
-  // code.  POSIX requires this, although it's not 100% clear from the
-  // standard.
+  // On error during Ex mode, exit with a non-zero code.
+  // POSIX requires this, although it's not 100% clear from the standard.
   if (exmode_active) {
     exitval += ex_exitval;
   }
@@ -750,6 +751,7 @@ void getout(int exitval)
   if (did_emsg) {
     // give the user a chance to read the (error) message
     no_wait_return = false;
+    // TODO(justinmk): this may call getout(0), clobbering exitval...
     wait_return(false);
   }
 
@@ -773,10 +775,9 @@ void getout(int exitval)
   os_exit(exitval);
 }
 
-/// Preserve files and exit.
-/// @note IObuff must contain a message.
-/// @note This may be called from deadly_signal() in a signal handler, avoid
-///       unsafe functions, such as allocating memory.
+/// Preserve files, print contents of `IObuff`, and exit 1.
+///
+/// May be called from deadly_signal().
 void preserve_exit(void)
   FUNC_ATTR_NORETURN
 {
@@ -962,7 +963,7 @@ static bool edit_stdin(mparm_T *parmp)
 {
   bool implicit = !headless_mode
                   && !(embedded_mode && stdin_fd <= 0)
-                  && (!exmode_active || parmp->input_neverscript)
+                  && (!exmode_active || parmp->input_istext)
                   && !parmp->input_isatty
                   && parmp->scriptin == NULL;  // `-s -` was not given.
   return parmp->had_stdin_file || implicit;
@@ -993,9 +994,9 @@ static void command_line_scan(mparm_T *parmp)
       } else {
         parmp->commands[parmp->n_commands++] = &(argv[0][1]);
       }
-
-      // Optional argument.
     } else if (argv[0][0] == '-' && !had_minmin) {
+      // Optional argument.
+
       want_argument = false;
       char c = argv[0][argv_idx++];
       switch (c) {
@@ -1005,9 +1006,7 @@ static void command_line_scan(mparm_T *parmp)
           silent_mode = true;
           parmp->no_swap_file = true;
         } else {
-          if (parmp->edit_type != EDIT_NONE
-              && parmp->edit_type != EDIT_FILE
-              && parmp->edit_type != EDIT_STDIN) {
+          if (parmp->edit_type > EDIT_STDIN) {
             mainerr(err_too_many_args, argv[0]);
           }
           parmp->had_stdin_file = true;
@@ -1015,7 +1014,7 @@ static void command_line_scan(mparm_T *parmp)
         }
         argv_idx = -1;  // skip to next argument
         break;
-      case '-':    // "--" don't take any more option arguments
+      case '-':    // "--" No more option arguments.
         // "--help" give help message
         // "--version" give version message
         // "--noplugin[s]" skip plugins
@@ -1111,7 +1110,7 @@ static void command_line_scan(mparm_T *parmp)
         break;
       case 'E':    // "-E" Ex mode
         exmode_active = true;
-        parmp->input_neverscript = true;
+        parmp->input_istext = true;
         break;
       case 'f':    // "-f"  GUI: run in foreground.
         break;
@@ -1123,10 +1122,6 @@ static void command_line_scan(mparm_T *parmp)
         p_hkmap = true;
         set_option_value_give_err("rl", 1L, NULL, 0);
         break;
-      case 'l':    // "-l" lisp mode, 'lisp' and 'showmatch' on.
-        set_option_value_give_err("lisp", 1L, NULL, 0);
-        p_sm = true;
-        break;
       case 'M':    // "-M"  no changes or writing of files
         reset_modifiable();
         FALLTHROUGH;
@@ -1231,6 +1226,7 @@ static void command_line_scan(mparm_T *parmp)
         FALLTHROUGH;
       case 'S':    // "-S {file}" execute Vim script
       case 'i':    // "-i {shada}" use for ShaDa file
+      case 'l':    // "-l {file}" Lua mode
       case 'u':    // "-u {vimrc}" vim inits file
       case 'U':    // "-U {gvimrc}" gvim inits file
       case 'W':    // "-W {scriptout}" overwrite
@@ -1311,6 +1307,23 @@ static void command_line_scan(mparm_T *parmp)
           set_option_value_give_err("shadafile", 0L, argv[0], 0);
           break;
 
+        case 'l':    // "-l" Lua script: args after "-l".
+          headless_mode = true;
+          silent_mode = true;
+          p_verbose = 1;
+          parmp->no_swap_file = true;
+          parmp->use_vimrc = parmp->use_vimrc ? parmp->use_vimrc : "NONE";
+          if (p_shadafile == NULL || *p_shadafile == NUL) {
+            set_option_value_give_err("shadafile", 0L, "NONE", 0);
+          }
+          parmp->luaf = argv[0];
+          argc--;
+          if (argc > 0) {  // Lua args after "-l <file>".
+            parmp->lua_arg0 = parmp->argc - argc;
+            argc = 0;
+          }
+          break;
+
         case 's':    // "-s {scriptin}" read from script file
           if (parmp->scriptin != NULL) {
 scripterror:
@@ -1354,9 +1367,7 @@ scripterror:
       argv_idx = -1;  // skip to next argument
 
       // Check for only one type of editing.
-      if (parmp->edit_type != EDIT_NONE
-          && parmp->edit_type != EDIT_FILE
-          && parmp->edit_type != EDIT_STDIN) {
+      if (parmp->edit_type > EDIT_STDIN) {
         mainerr(err_too_many_args, argv[0]);
       }
       parmp->edit_type = EDIT_FILE;
@@ -1392,8 +1403,8 @@ scripterror:
     }
   }
 
-  if (embedded_mode && silent_mode) {
-    mainerr(_("--embed conflicts with -es/-Es"), NULL);
+  if (embedded_mode && (silent_mode || parmp->luaf)) {
+    mainerr(_("--embed conflicts with -es/-Es/-l"), NULL);
   }
 
   // If there is a "+123" or "-c" command, set v:swapcommand to the first one.
@@ -1421,6 +1432,8 @@ static void init_params(mparm_T *paramp, int argc, char **argv)
   paramp->listen_addr = NULL;
   paramp->server_addr = NULL;
   paramp->remote = 0;
+  paramp->luaf = NULL;
+  paramp->lua_arg0 = -1;
 }
 
 /// Initialize global startuptime file if "--startuptime" passed as an argument.
@@ -1554,19 +1567,7 @@ static void open_script_files(mparm_T *parmp)
   if (parmp->scriptin) {
     int error;
     if (strequal(parmp->scriptin, "-")) {
-      int stdin_dup_fd;
-      if (stdin_fd > 0) {
-        stdin_dup_fd = stdin_fd;
-      } else {
-        stdin_dup_fd = os_dup(STDIN_FILENO);
-#ifdef MSWIN
-        // Replace the original stdin with the console input handle.
-        os_replace_stdin_to_conin();
-#endif
-      }
-      FileDescriptor *const stdin_dup = file_open_fd_new(&error, stdin_dup_fd,
-                                                         kFileReadOnly|kFileNonBlocking);
-      assert(stdin_dup != NULL);
+      FileDescriptor *stdin_dup = file_open_stdin();
       scriptin[0] = stdin_dup;
     } else {
       scriptin[0] = file_open_new(&error, parmp->scriptin,
@@ -2133,7 +2134,7 @@ static void mainerr(const char *errstr, const char *str)
 static void version(void)
 {
   // TODO(bfred): not like this?
-  nlua_init();
+  nlua_init(NULL, 0, -1);
   info_message = true;  // use os_msg(), not os_errmsg()
   list_version();
   msg_putchar('\n');
@@ -2154,6 +2155,7 @@ static void usage(void)
   os_msg(_("  +                     Start at end of file\n"));
   os_msg(_("  --cmd <cmd>           Execute <cmd> before any config\n"));
   os_msg(_("  +<cmd>, -c <cmd>      Execute <cmd> after config and first file\n"));
+  os_msg(_("  -l <script> [args...] Execute Lua <script> (with optional args)\n"));
   os_msg("\n");
   os_msg(_("  -b                    Binary mode\n"));
   os_msg(_("  -d                    Diff mode\n"));
diff --git a/src/nvim/main.h b/src/nvim/main.h
index c39fc1ed4a..46d7217364 100644
--- a/src/nvim/main.h
+++ b/src/nvim/main.h
@@ -23,15 +23,18 @@ typedef struct {
   char cmds_tofree[MAX_ARG_CMDS];       // commands that need free()
   int n_pre_commands;                   // no. of commands from --cmd
   char *pre_commands[MAX_ARG_CMDS];     // commands from --cmd argument
+  char *luaf;                           // Lua script filename from "-l"
+  int lua_arg0;                         // Lua script args start index.
 
   int edit_type;                        // type of editing to do
   char *tagname;                        // tag from -t argument
   char *use_ef;                         // 'errorfile' from -q argument
 
   bool input_isatty;                    // stdin is a terminal
+  bool input_istext;                    // stdin is text, not executable (-E/-Es)
   bool output_isatty;                   // stdout is a terminal
   bool err_isatty;                      // stderr is a terminal
-  bool input_neverscript;               // never treat stdin as script (-E/-Es)
+
   int no_swap_file;                     // "-n" argument used
   int use_debug_break_level;
   int window_count;                     // number of windows to use
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 041e5ed6c3..118d144617 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -3003,31 +3003,36 @@ static int do_more_prompt(int typed_char)
 }
 
 #if defined(MSWIN)
-void os_errmsg(char *str)
+/// Headless (no UI) error message handler.
+static void do_msg(char *str, bool errmsg)
 {
+  static bool did_err = false;
   assert(str != NULL);
   wchar_t *utf16str;
   int r = utf8_to_utf16(str, -1, &utf16str);
-  if (r != 0) {
+  if (r != 0 && !did_err) {
+    did_err = true;
     fprintf(stderr, "utf8_to_utf16 failed: %d", r);
-  } else {
-    fwprintf(stderr, L"%ls", utf16str);
+    ELOG("utf8_to_utf16 failed: %d", r);
+  } else if (r == 0) {
+    if (errmsg) {
+      fwprintf(stderr, L"%ls", utf16str);
+    } else {
+      wprintf(L"%ls", utf16str);
+    }
     xfree(utf16str);
   }
 }
 
-/// Give a message.  To be used when the UI is not initialized yet.
+void os_errmsg(char *str)
+{
+  do_msg(str, true);
+}
+
+/// Headless (no UI) message handler.
 void os_msg(char *str)
 {
-  assert(str != NULL);
-  wchar_t *utf16str;
-  int r = utf8_to_utf16(str, -1, &utf16str);
-  if (r != 0) {
-    fprintf(stderr, "utf8_to_utf16 failed: %d", r);
-  } else {
-    wprintf(L"%ls", utf16str);
-    xfree(utf16str);
-  }
+  do_msg(str, false);
 }
 #endif  // MSWIN
 
diff --git a/src/nvim/os/fileio.c b/src/nvim/os/fileio.c
index bdea82f1ff..e93e1febcb 100644
--- a/src/nvim/os/fileio.c
+++ b/src/nvim/os/fileio.c
@@ -167,6 +167,30 @@ FileDescriptor *file_open_fd_new(int *const error, const int fd, const int flags
   return fp;
 }
 
+/// Opens standard input as a FileDescriptor.
+FileDescriptor *file_open_stdin(void)
+  FUNC_ATTR_MALLOC FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  int error;
+  int stdin_dup_fd;
+  if (stdin_fd > 0) {
+    stdin_dup_fd = stdin_fd;
+  } else {
+    stdin_dup_fd = os_dup(STDIN_FILENO);
+#ifdef MSWIN
+    // Replace the original stdin with the console input handle.
+    os_replace_stdin_to_conin();
+#endif
+  }
+  FileDescriptor *const stdin_dup = file_open_fd_new(&error, stdin_dup_fd,
+                                                     kFileReadOnly|kFileNonBlocking);
+  assert(stdin_dup != NULL);
+  if (error != 0) {
+    ELOG("failed to open stdin: %s", os_strerror(error));
+  }
+  return stdin_dup;
+}
+
 /// Close file and free its buffer
 ///
 /// @param[in,out]  fp  File to close.
diff --git a/src/nvim/testdir/test_startup.vim b/src/nvim/testdir/test_startup.vim
index ee0445c6b4..54b7636f69 100644
--- a/src/nvim/testdir/test_startup.vim
+++ b/src/nvim/testdir/test_startup.vim
@@ -962,6 +962,7 @@ endfunc
 
 " Test for enabling the lisp mode on startup
 func Test_l_arg()
+  throw 'Skipped: Nvim -l arg differs from Vim'
   let after =<< trim [CODE]
     let s = 'lisp=' .. &lisp .. ', showmatch=' .. &showmatch
     call writefile([s], 'Xtestout')
diff --git a/src/nvim/vim.h b/src/nvim/vim.h
index bfe75ef9f7..df24e423cf 100644
--- a/src/nvim/vim.h
+++ b/src/nvim/vim.h
@@ -245,12 +245,10 @@ enum { FOLD_TEXT_LEN = 51, };  //!< buffer size for get_foldtext()
 /// plus six following composing characters of three bytes each.
 #define MB_MAXBYTES    21
 
-// This has to go after the include of proto.h, as proto/gui.pro declares
-// functions of these names. The declarations would break if the defines had
-// been seen at that stage.  But it must be before globals.h, where error_ga
-// is declared.
 #ifndef MSWIN
+/// Headless (no UI) error message handler.
 # define os_errmsg(str)        fprintf(stderr, "%s", (str))
+/// Headless (no UI) message handler.
 # define os_msg(str)           printf("%s", (str))
 #endif