tui: expose terminal type in 'term' option

runtime/doc/vim_diff.txt

@@ -333,9 +333,11 @@ terminal capabilities. Instead Nvim treats the terminal as any other UI. For
 example, 'guicursor' sets the terminal cursor style if possible.
 
 						  *'term'* *E529* *E530* *E531*
-The 'term' option has a fixed value, present only for script compatibility and
-intentionally not the same as any known terminal type name.  It should be a
-rare case in Nvim where one needs |term-dependent-settings|.
+'term' reflects the terminal type derived from |$TERM| and other environment
+checks.  For debugging only; not reliable during startup. >
+	:echo &term
+"builtin_x" means one of the |builtin-terms| was chosen, because the expected
+terminfo file was not found on the system.
 
 								*termcap*
 Nvim never uses the termcap database, only |terminfo| and |builtin-terms|.

src/nvim/option.c

@@ -105,6 +105,9 @@ typedef enum {
  */
 #define VAR_WIN ((char_u *)-1)
 
+static char *p_term = NULL;
+static char *p_ttytype = NULL;
+
 /*
  * These are the global values for options which are also local to a buffer.
  * Only to be used in option.c!
@@ -4530,13 +4533,17 @@ int findoption_len(const char *const arg, const size_t len)
 bool is_tty_option(const char *name)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  return (name[0] == 't' && name[1] == '_') || strcmp(name, "term") == 0;
+  return (name[0] == 't' && name[1] == '_')
+    || strequal(name, "term")
+    || strequal(name, "ttytype");
 }
 
 #define TCO_BUFFER_SIZE 8
+/// @param name TUI-related option
+/// @param[out,allocated] value option string value
 bool get_tty_option(char *name, char **value)
 {
-  if (!strcmp(name, "t_Co")) {
+  if (strequal(name, "t_Co")) {
     if (value) {
       if (t_colors <= 1) {
         *value = xstrdup("");
@@ -4548,9 +4555,16 @@ bool get_tty_option(char *name, char **value)
     return true;
   }
 
-  if (!strcmp(name, "term") || !strcmp(name, "ttytype")) {
+  if (strequal(name, "term")) {
     if (value) {
-      *value = xstrdup("nvim");
+      *value = p_term ? xstrdup(p_term) : xstrdup("nvim");
+    }
+    return true;
+  }
+
+  if (strequal(name, "ttytype")) {
+    if (value) {
+      *value = p_ttytype ? xstrdup(p_ttytype) : xstrdup("nvim");
     }
     return true;
   }
@@ -4566,25 +4580,25 @@ bool get_tty_option(char *name, char **value)
   return false;
 }
 
-bool set_tty_option(const char *name, const char *value)
+bool set_tty_option(const char *name, char *value)
 {
-  if (!strcmp(name, "t_Co")) {
-    int colors = atoi(value);
-
-    // Only reinitialize colors if t_Co value has really changed to
-    // avoid expensive reload of colorscheme if t_Co is set to the
-    // same value multiple times
-    if (colors != t_colors) {
-      t_colors = colors;
-      // We now have a different color setup, initialize it again.
-      init_highlight(true, false);
+  if (strequal(name, "term")) {
+    if (p_term) {
+      xfree(p_term);
     }
+    p_term = value;
+    return true;
+  }
 
+  if (strequal(name, "ttytype")) {
+    if (p_ttytype) {
+      xfree(p_ttytype);
+    }
+    p_ttytype = value;
     return true;
   }
 
-  return (is_tty_option(name) || !strcmp(name, "term")
-          || !strcmp(name, "ttytype"));
+  return false;
 }
 
 /// Find index for an option
@@ -4597,54 +4611,50 @@ static int findoption(const char *const arg)
   return findoption_len(arg, strlen(arg));
 }
 
-/*
- * Get the value for an option.
- *
- * Returns:
- * Number or Toggle option: 1, *numval gets value.
- *	     String option: 0, *stringval gets allocated string.
- * Hidden Number or Toggle option: -1.
- *	     hidden String option: -2.
- *		   unknown option: -3.
- */
-int 
-get_option_value (
+/// Gets the value for an option.
+///
+/// @returns:
+/// Number or Toggle option: 1, *numval gets value.
+///           String option: 0, *stringval gets allocated string.
+/// Hidden Number or Toggle option: -1.
+///           hidden String option: -2.
+///                 unknown option: -3.
+int get_option_value(
     char_u *name,
     long *numval,
-    char_u **stringval,            /* NULL when only checking existence */
+    char_u **stringval,            ///< NULL when only checking existence
     int opt_flags
 )
 {
   if (get_tty_option((char *)name, (char **)stringval)) {
     return 0;
   }
 
-  int opt_idx;
-  char_u      *varp;
-
-  opt_idx = findoption((const char *)name);
+  int opt_idx = findoption((const char *)name);
   if (opt_idx < 0) {  // Unknown option.
     return -3;
   }
 
-  varp = get_varp_scope(&(options[opt_idx]), opt_flags);
+  char_u *varp = get_varp_scope(&(options[opt_idx]), opt_flags);
 
   if (options[opt_idx].flags & P_STRING) {
-    if (varp == NULL)                       /* hidden option */
+    if (varp == NULL) {  // hidden option
       return -2;
+    }
     if (stringval != NULL) {
       *stringval = vim_strsave(*(char_u **)(varp));
     }
     return 0;
   }
 
-  if (varp == NULL)                 /* hidden option */
+  if (varp == NULL) {  // hidden option
     return -1;
-  if (options[opt_idx].flags & P_NUM)
+  }
+  if (options[opt_idx].flags & P_NUM) {
     *numval = *(long *)varp;
-  else {
-    /* Special case: 'modified' is b_changed, but we also want to consider
-     * it set when 'ff' or 'fenc' changed. */
+  } else {
+    // Special case: 'modified' is b_changed, but we also want to consider
+    // it set when 'ff' or 'fenc' changed.
     if ((int *)varp == &curbuf->b_changed) {
       *numval = curbufIsChanged();
     } else {
@@ -4791,8 +4801,8 @@ char *set_option_value(const char *const name, const long number,
                        const char *const string, const int opt_flags)
   FUNC_ATTR_NONNULL_ARG(1)
 {
-  if (set_tty_option(name, string)) {
-    return NULL;
+  if (is_tty_option(name)) {
+    return NULL;  // Fail silently; many old vimrcs set t_xx options.
   }
 
   int opt_idx;

src/nvim/tui/terminfo.c

@@ -9,6 +9,7 @@
 #include <unibilium.h>
 
 #include "nvim/log.h"
+#include "nvim/memory.h"
 #include "nvim/tui/terminfo.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
@@ -94,51 +95,72 @@ bool terminfo_is_term_family(const char *term, const char *family)
 /// Loads a built-in terminfo db when we (unibilium) failed to load a terminfo
 /// record from the environment (termcap systems, unrecognized $TERM, …).
 /// We do not attempt to detect xterm pretenders here.
-static unibi_term *terminfo_builtin(const char *term)
+///
+/// @param term $TERM value
+/// @param[out,allocated] termname decided builtin 'term' name
+/// @return [allocated] terminfo structure
+static unibi_term *terminfo_builtin(const char *term, char **termname)
 {
   if (terminfo_is_term_family(term, "xterm")) {
+    *termname = xstrdup("builtin_xterm");
     return unibi_from_mem((const char *)xterm_256colour_terminfo,
                           sizeof xterm_256colour_terminfo);
   } else if (terminfo_is_term_family(term, "screen")) {
+    *termname = xstrdup("builtin_screen");
     return unibi_from_mem((const char *)screen_256colour_terminfo,
                           sizeof screen_256colour_terminfo);
   } else if (terminfo_is_term_family(term, "tmux")) {
+    *termname = xstrdup("builtin_tmux");
     return unibi_from_mem((const char *)tmux_256colour_terminfo,
                           sizeof tmux_256colour_terminfo);
   } else if (terminfo_is_term_family(term, "rxvt")) {
+    *termname = xstrdup("builtin_rxvt");
     return unibi_from_mem((const char *)rxvt_256colour_terminfo,
                           sizeof rxvt_256colour_terminfo);
   } else if (terminfo_is_term_family(term, "putty")) {
+    *termname = xstrdup("builtin_putty");
     return unibi_from_mem((const char *)putty_256colour_terminfo,
                           sizeof putty_256colour_terminfo);
   } else if (terminfo_is_term_family(term, "linux")) {
+    *termname = xstrdup("builtin_linux");
     return unibi_from_mem((const char *)linux_16colour_terminfo,
                           sizeof linux_16colour_terminfo);
   } else if (terminfo_is_term_family(term, "interix")) {
+    *termname = xstrdup("builtin_interix");
     return unibi_from_mem((const char *)interix_8colour_terminfo,
                           sizeof interix_8colour_terminfo);
   } else if (terminfo_is_term_family(term, "iterm")
              || terminfo_is_term_family(term, "iterm2")
              || terminfo_is_term_family(term, "iTerm.app")
              || terminfo_is_term_family(term, "iTerm2.app")) {
+    *termname = xstrdup("builtin_iterm");
     return unibi_from_mem((const char *)iterm_256colour_terminfo,
                           sizeof iterm_256colour_terminfo);
   } else if (terminfo_is_term_family(term, "st")) {
+    *termname = xstrdup("builtin_st");
     return unibi_from_mem((const char *)st_256colour_terminfo,
                           sizeof st_256colour_terminfo);
   } else if (terminfo_is_term_family(term, "gnome")
              || terminfo_is_term_family(term, "vte")) {
+    *termname = xstrdup("builtin_vte");
     return unibi_from_mem((const char *)vte_256colour_terminfo,
                           sizeof vte_256colour_terminfo);
   } else {
+    *termname = xstrdup("builtin_ansi");
     return unibi_from_mem((const char *)ansi_terminfo,
                           sizeof ansi_terminfo);
   }
 }
 
-unibi_term *terminfo_from_builtin(const char *term)
+/// @param term $TERM value
+/// @param[out,allocated] termname decided builtin 'term' name
+/// @return [allocated] terminfo structure
+unibi_term *terminfo_from_builtin(const char *term, char **termname)
 {
-  unibi_term *ut = terminfo_builtin(term);
+  unibi_term *ut = terminfo_builtin(term, termname);
+  if (*termname == NULL) {
+    *termname = xstrdup("builtin_?");
+  }
   // Disable BCE by default (for built-in terminfos). #7624
   // https://github.com/kovidgoyal/kitty/issues/160#issuecomment-346470545
   unibi_set_bool(ut, unibi_back_color_erase, false);

src/nvim/tui/tui.c

@@ -23,6 +23,7 @@
 #include "nvim/map.h"
 #include "nvim/main.h"
 #include "nvim/memory.h"
+#include "nvim/option.h"
 #include "nvim/api/vim.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/event/loop.h"
@@ -166,6 +167,13 @@ static size_t unibi_pre_fmt_str(TUIData *data, unsigned int unibi_index,
   return unibi_run(str, data->params, buf, len);
 }
 
+static void termname_set_event(void **argv)
+{
+  char *termname = argv[0];
+  set_tty_option("term", termname);
+  // Do not free termname, it is freed by set_tty_option.
+}
+
 static void terminfo_start(UI *ui)
 {
   TUIData *data = ui->data;
@@ -190,12 +198,20 @@ static void terminfo_start(UI *ui)
   data->unibi_ext.reset_cursor_style = -1;
   data->out_fd = 1;
   data->out_isatty = os_isatty(data->out_fd);
-  // setup unibilium
+
+  // Set up unibilium/terminfo.
   const char *term = os_getenv("TERM");
   data->ut = unibi_from_env();
+  char *termname = NULL;
   if (!data->ut) {
-    data->ut = terminfo_from_builtin(term);
+    data->ut = terminfo_from_builtin(term, &termname);
+  } else {
+    termname = xstrdup(term);
   }
+  // Update 'term' option.
+  loop_schedule_deferred(&main_loop,
+                         event_create(termname_set_event, 1, termname));
+
   // None of the following work over SSH; see :help TERM .
   const char *colorterm = os_getenv("COLORTERM");
   const char *termprg = os_getenv("TERM_PROGRAM");
@@ -344,7 +360,7 @@ static void tui_scheduler(Event event, void *d)
 {
   UI *ui = d;
   TUIData *data = ui->data;
-  loop_schedule(data->loop, event);
+  loop_schedule(data->loop, event);  // `tui_loop` local to tui_main().
 }
 
 #ifdef UNIX

test/functional/helpers.lua

@@ -603,6 +603,15 @@ local function get_pathsep()
   return funcs.fnamemodify('.', ':p'):sub(-1)
 end
 
+-- Returns a valid, platform-independent $NVIM_LISTEN_ADDRESS.
+-- Useful for communicating with child instances.
+local function new_pipename()
+  -- HACK: Start a server temporarily, get the name, then stop it.
+  local pipename = nvim_eval('serverstart()')
+  funcs.serverstop(pipename)
+  return pipename
+end
+
 local function missing_provider(provider)
   if provider == 'ruby' then
     local prog = funcs['provider#' .. provider .. '#Detect']()
@@ -732,6 +741,7 @@ local module = {
   missing_provider = missing_provider,
   alter_slashes = alter_slashes,
   hexdump = hexdump,
+  new_pipename = new_pipename,
 }
 
 return function(after_each)