Merge #5001 from justinmk/t_colors

TUI: infer 256 colors more liberally; listen to unibilium in other cases

4 files changed, 9 insertions, 8 deletions

diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 42fde50bee..7f91903106 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -414,7 +414,7 @@ EXTERN int provider_call_nesting INIT(= 0);
 EXTERN char_u hash_removed;
 
 
-EXTERN int t_colors INIT(= 0);              /* int value of T_CCO */
+EXTERN int t_colors INIT(= 256);                // int value of T_CCO
 
 /*
  * When highlight_match is TRUE, highlight a match, starting at the cursor
diff --git a/src/nvim/main.c b/src/nvim/main.c
index a876a0ad21..5cd1dbb467 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -276,7 +276,6 @@ int main(int argc, char **argv)
     printf(_("%d files to edit\n"), GARGCOUNT);
 
   full_screen = true;
-  t_colors = 256;
   check_tty(&params);
 
   /*
@@ -1671,8 +1670,6 @@ static bool do_user_initialization(void)
 }
 
 /// Source startup scripts
-///
-/// @param[in]
 static void source_startup_scripts(const mparm_T *const parmp)
   FUNC_ATTR_NONNULL_ALL
 {
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 020a119fd3..a844c4ed80 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -4404,6 +4404,7 @@ bool get_tty_option(char *name, char **value)
 
   if (is_tty_option(name)) {
     if (value) {
+      // XXX: All other t_* options were removed in 3baba1e7.
       *value = xstrdup("");
     }
     return true;
diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index 50558e644a..d220df508a 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -135,6 +135,8 @@ static void terminfo_start(UI *ui)
     data->ut = unibi_dummy();
   }
   fix_terminfo(data);
+  // Set 't_Co' from the result of unibilium & fix_terminfo.
+  t_colors = unibi_get_num(data->ut, unibi_max_colors);
   // Enter alternate screen and clear
   unibi_out(ui, unibi_enter_ca_mode);
   unibi_out(ui, unibi_clear_screen);
@@ -786,6 +788,7 @@ static void fix_terminfo(TUIData *data)
   unibi_term *ut = data->ut;
 
   const char *term = os_getenv("TERM");
+  const char *colorterm = os_getenv("COLORTERM");
   if (!term) {
     goto end;
   }
@@ -831,10 +834,10 @@ static void fix_terminfo(TUIData *data)
 #define XTERM_SETAB \
   "\x1b[%?%p1%{8}%<%t4%p1%d%e%p1%{16}%<%t10%p1%{8}%-%d%e48;5;%p1%d%;m"
 
-  if (os_getenv("COLORTERM") != NULL
-      && (!strcmp(term, "xterm") || !strcmp(term, "screen"))) {
-    // probably every modern terminal that sets TERM=xterm supports 256
-    // colors(eg: gnome-terminal). Also do it when TERM=screen.
+  if ((colorterm && strstr(colorterm, "256"))
+      || strstr(term, "256")
+      || strstr(term, "xterm")) {
+    // Assume TERM~=xterm or COLORTERM~=256 supports 256 colors.
     unibi_set_num(ut, unibi_max_colors, 256);
     unibi_set_str(ut, unibi_set_a_foreground, XTERM_SETAF);
     unibi_set_str(ut, unibi_set_a_background, XTERM_SETAB);