patch 9.0.1073: using "xterm-kitty" for 'term' causes problemsv9.0.1073

Problem:    Using "xterm-kitty" for 'term' causes problems.
Solution:   Remove the "xterm-" part when 'term' is set from $TERM.  Detect a
            few kitty-specific properties based on the version response
            instead of the terminal name.

1 files changed, 20 insertions, 0 deletions

diff --git a/runtime/doc/term.txt b/runtime/doc/term.txt
index f7b65ea74..50ba187ab 100644
--- a/runtime/doc/term.txt
+++ b/runtime/doc/term.txt
@@ -294,6 +294,26 @@ When Vim receives a response to the |t_RV| (request version) sequence and it
 starts with CSI, it assumes that the terminal is in 8-bit mode and will
 convert all key sequences to their 8-bit variants.
 
+						*xterm-kitty* *kitty-terminal*
+The Kitty terminal is a special case.  Mainly because it works different from
+most other terminals, but also because, instead of trying the fit in and make
+it behave like other terminals by default, it dictates how applications need
+to work when using Kitty.  This makes it very difficult for Vim to work in a
+Kitty terminal.  Some exceptions have been hard coded, but it is not at all
+nice to have to make exceptions for one specific terminal.
+
+One of the problems is that the value for $TERM is set to "xterm-kitty".  For
+Vim this is an indication that the terminal is xterm-compatible and the
+builtin xterm termcap entries should be used.  Many other terminals depend on
+this.  However, Kitty is not fully xterm compatible.  The author suggested to
+ignore the "xterm-" prefix and use the terminfo entry anyway, but that
+conflicts with what is needed for other terminals.  Therefore Vim removes the
+"xterm-" prefix from "xterm-kitty" when it comes from $TERM.
+
+Note that using the kitty keyboard protocol is a separate feature, see
+|kitty-keyboard-protocol|.
+
+
 ==============================================================================
 2. Terminal options		*terminal-options* *termcap-options* *E436*