Fixed vi mode cursor shape!

fish.configlink/config.fish

@@ -11,12 +11,12 @@ if status --is-interactive
 
     # Use `vi` in the shell
     fish_vi_key_bindings
-    set XTERM_VERSION hello
+    set -g fish_vi_force_cursor
+    set -g fish_cursor_default block
+    set -g fish_cursor_insert line
+    set -g fish_cursor_visual block
+    set -g fish_cursor_replace_one underscore
     fish_vi_cursor
-    set fish_cursor_default block
-    set fish_cursor_insert line
-    set fish_cursor_replace_one underscore
-    set fish_cursor_visual block
 
     # Turn off greeting
     set fish_greeting ""

fish.configlink/functions/fish_vi_cursor.fish

@@ -0,0 +1,122 @@
+#!/usr/local/bin/fish
+
+function fish_vi_cursor -d 'Set cursor shape for different vi modes'
+    # If we're not interactive, there is effectively no bind mode.
+    if not status is-interactive
+        return
+    end
+
+    # This is hard to test in expect, since the exact sequences depend on the environment.
+    # Instead disable it.
+    if set -q FISH_UNIT_TESTS_RUNNING
+        return
+    end
+
+    # If this variable is set, skip all checks
+    if not set -q fish_vi_force_cursor
+
+        # Emacs Makes All Cursors Suck
+        if set -q INSIDE_EMACS
+            return
+        end
+
+        # vte-based terms set $TERM = xterm*, but only gained support in 2015.
+        # From https://bugzilla.gnome.org/show_bug.cgi?id=720821, it appears it was version 0.40.0
+        if set -q VTE_VERSION
+            and test "$VTE_VERSION" -lt 4000 2>/dev/null
+            return
+        end
+
+        # Similarly, genuine XTerm can do it since v280.
+        if set -q XTERM_VERSION
+            and not test (string replace -r "XTerm\((\d+)\)" '$1' -- "$XTERM_VERSION") -ge 280 2>/dev/null
+            return
+        end
+
+        # We need one of these terms.
+        # It would be lovely if we could rely on terminfo, but:
+        # - The "Ss" entry isn't a thing in macOS' old and crusty terminfo
+        # - It is set for xterm, and everyone and their dog claims to be xterm
+        #
+        # So we just don't care about $TERM, unless it is one of the few terminals that actually have their own entry.
+        #
+        # Note: Previous versions also checked $TMUX, and made sure that then $TERM was screen* or tmux*.
+        # We don't care, since we *cannot* handle term-in-a-terms 100% correctly.
+        if not set -q KONSOLE_PROFILE_NAME
+            and not test -n "$KONSOLE_VERSION" -a "$KONSOLE_VERSION" -ge 200400 # konsole, but new.
+            and not set -q ITERM_PROFILE
+            and not set -q VTE_VERSION # which version is already checked above
+            and not set -q WT_PROFILE_ID
+            and not set -q XTERM_VERSION
+            and not string match -rq '^st(-.*)$' -- $TERM
+            and not string match -q 'xterm-kitty*' -- $TERM
+            and not string match -q 'rxvt*' -- $TERM
+            and not string match -q 'alacritty*' -- $TERM
+            return
+        end
+
+        # HACK: Explicitly disable on ITERM because of #3696, which is weirdness with multi-line prompts.
+        # --force-iterm is now deprecated; set $fish_vi_force_cursor instead
+        if contains -- $argv[1] --force-iterm
+            set -e argv[1]
+        else if set -q ITERM_PROFILE
+            return
+        end
+    end
+
+    set -l terminal $argv[1]
+    set -q terminal[1]
+    or set terminal auto
+
+    set -l function
+    switch "$terminal"
+        case auto
+            # Nowadays, konsole does not set $KONSOLE_PROFILE_NAME anymore,
+            # and it uses the xterm sequences.
+            if set -q KONSOLE_PROFILE_NAME
+                set function __fish_cursor_konsole
+            else if set -q ITERM_PROFILE
+                set function __fish_cursor_1337
+            else
+                set function __fish_cursor_xterm
+            end
+        case konsole
+            set function __fish_cursor_konsole
+        case xterm
+            set function __fish_cursor_xterm
+    end
+
+    set -l tmux_prefix
+    set -l tmux_postfix
+    if set -q TMUX
+        set tmux_prefix echo -ne "'\ePtmux;\e'"
+        set tmux_postfix echo -ne "'\e\\\\'"
+    end
+
+    set -q fish_cursor_unknown
+    or set -g fish_cursor_unknown block blink
+
+    echo "
+          function fish_vi_cursor_handle --on-variable fish_bind_mode --on-event fish_postexec --on-event fish_focus_in
+              set -l varname fish_cursor_\$fish_bind_mode
+              if not set -q \$varname
+                set varname fish_cursor_unknown
+              end
+              $tmux_prefix
+              $function \$\$varname
+              $tmux_postfix
+          end
+         " | source
+
+    echo "
+          function fish_vi_cursor_handle_preexec --on-event fish_preexec
+              set -l varname fish_cursor_default
+              if not set -q \$varname
+                set varname fish_cursor_unknown
+              end
+              $tmux_prefix
+              $function \$\$varname
+              $tmux_postfix
+          end
+         " | source
+end