vim: enable true color inside tmux

nvim/.config/nvim/lua/fs/options.lua

@@ -1,5 +1,5 @@
--- vim.cmd('let &t_8f = "\\e[38:2:%lu:%lu:%lum"')
--- vim.cmd('let &t_8b = "\\e[48:2:%lu:%lu:%lum"')
+vim.cmd([[let &t_8f = "\<ESC>[38:2:%lu:%lu:%lum"]])
+vim.cmd([[let &t_8b = "\<ESC>[48:2:%lu:%lu:%lum"]])
 
 local set_options = function(options)
     local opt = vim.opt

tmux/.config/tmux/tmux.conf

@@ -31,12 +31,19 @@ unbind-key -T   copy-mode-vi MouseDragEnd1Pane # Stay in copy mode on drag end
 #
 set -gs escape-time         50                  # avoid delays with ESC in vim
 set -g base-index           1                   # start window numbering from 1
-set -g default-terminal     "screen-256color"   # display 256 colors
 set -g history-limit        20000               # remember longer history
 setw -g automatic-rename    on                  # automatically rename windows
 setw -g mouse               on                  # enable mouse support
 setw -g pane-base-index     1                   # start pane numbering from 1
 
+# Set $TERM and force 256 colors.
+# https://github.com/tmux/tmux/wiki/FAQ#how-do-i-use-a-256-colour-terminal
+set -g default-terminal 'screen-256color'
+
+# Report true color support to programs.
+# https://github.com/tmux/tmux/wiki/FAQ#how-do-i-use-rgb-colour
+set -ga terminal-overrides ',*-256col*:Tc'
+
 # The shell will increment SHLVL by one when it is started -> unsetting this
 # variable here removes any memory of nesting before tmux was executed and will
 # cause shells to start with level 1 again within the session.