Merge #5001 from justinmk/t_colors

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

6 files changed, 70 insertions, 13 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);
diff --git a/test/functional/options/defaults_spec.lua b/test/functional/options/defaults_spec.lua
index ed978cd17e..a36939b0bd 100644
--- a/test/functional/options/defaults_spec.lua
+++ b/test/functional/options/defaults_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
-local clear, eval, eq  = helpers.clear, helpers.eval, helpers.eq
+local eval, eq = helpers.eval, helpers.eq
 local execute = helpers.execute
 
 local function init_session(...)
@@ -15,10 +15,6 @@ local function init_session(...)
 end
 
 describe('startup defaults', function()
-  before_each(function()
-    clear()
-  end)
-
   describe(':filetype', function()
     local function expect_filetype(expected)
       local screen = Screen.new(48, 4)
diff --git a/test/functional/terminal/tui_spec.lua b/test/functional/terminal/tui_spec.lua
index 91789d6575..4bae9a8d02 100644
--- a/test/functional/terminal/tui_spec.lua
+++ b/test/functional/terminal/tui_spec.lua
@@ -301,3 +301,63 @@ describe('tui focus event handling', function()
     ]])
   end)
 end)
+
+-- These tests require `thelpers` because --headless/--embed
+-- does not initialize the TUI.
+describe("tui 't_Co' (terminal colors)", function()
+  local screen
+
+  local function assert_term_colors(term, colorterm, maxcolors)
+    helpers.clear({env={TERM=term}, args={}})
+    -- This is ugly because :term/termopen() forces TERM=xterm-256color.
+    -- TODO: Revisit this after jobstart/termopen accept `env` dict.
+    screen = thelpers.screen_setup(0, string.format(
+      [=[['sh', '-c', 'TERM=%s %s %s -u NONE -i NONE --cmd "silent set noswapfile"']]=],
+      term,
+      (colorterm ~= nil and "COLORTERM="..colorterm or ""),
+      helpers.nvim_prog))
+
+    thelpers.feed_data(":echo &t_Co\n")
+    screen:expect(string.format([[
+      {1: }                                                 |
+      ~                                                 |
+      ~                                                 |
+      ~                                                 |
+      [No Name]                                         |
+      %-3s                                               |
+      -- TERMINAL --                                    |
+    ]], tostring(maxcolors and maxcolors or "")))
+  end
+
+  it("unknown TERM sets empty 't_Co'", function()
+    assert_term_colors("yet-another-term", nil, nil)
+  end)
+
+  it("unknown TERM with COLORTERM=screen-256color uses 256 colors", function()
+    assert_term_colors("yet-another-term", "screen-256color", 256)
+  end)
+
+  it("TERM=linux uses 8 colors", function()
+    assert_term_colors("linux", nil, 8)
+  end)
+
+  it("TERM=screen uses 8 colors", function()
+    assert_term_colors("screen", nil, 8)
+  end)
+
+  it("TERM=screen COLORTERM=screen-256color uses 256 colors", function()
+    assert_term_colors("screen", "screen-256color", 256)
+  end)
+
+  it("TERM=yet-another-term COLORTERM=screen-256color uses 256 colors", function()
+    assert_term_colors("screen", "screen-256color", 256)
+  end)
+
+  it("TERM=xterm uses 256 colors", function()
+    assert_term_colors("xterm", nil, 256)
+  end)
+
+  it("TERM=xterm-256color uses 256 colors", function()
+    assert_term_colors("xterm-256color", nil, 256)
+  end)
+end)