app-shells/bash: revbump 5.2, 5.3 and 5.4 for improved title setting

This commit introduces the following versions.

- 5.2_p37-r5
- 5.3_p3-r3
- bash-5.4_alpha_pre20250918-r2 (replacing -r1)

They improve the window title setting behaviour by using the ${param@P}
form of expansion to expand "\u@\h \W" as a prompt string. A notable
consequence of this is that, upon switching to the home directory, the
current working directory will be shown as the <tilde> character again.

The value of PROMPT_DIRTRIM is now respected. If this variable is unset,
the use of the \W prompt string escape will prevail, with the current
working directory typically being shown as its basename. If set to 0 or
greater, \w will be used instead, which may be trimmed. This means that
the title can be made to show the full path by setting PROMPT_DIRTRIM=0.

Also, whitelist xterm-ghostty for XTWINOPS support.

Signed-off-by: Kerin Millar <kfm@plushkava.net>
Signed-off-by: Sam James <sam@gentoo.org>

2 files changed, 77 insertions, 29 deletions

diff --git a/app-shells/bash/files/bashrc-r1 b/app-shells/bash/files/bashrc-r1
deleted file mode 100644
index deb0ce97d4a7..000000000000
--- a/app-shells/bash/files/bashrc-r1
+++ /dev/null
@@ -1,29 +0,0 @@
-# /etc/bash/bashrc
-
-# Proceed no further in the case of a non-interactive shell.
-if [[ $- != *i* ]]; then
-	return
-fi
-
-# Disable errexit in case the user enabled it then chose to re-source this file.
-shopt -u -o errexit
-
-# Disable completion when the input buffer is empty. Mute STDERR because this
-# option is only present in the case that bash was built with readline support.
-shopt -s no_empty_cmd_completion 2>/dev/null &&
-
-# Append to HISTFILE rather than overwrite upon exiting, per bug #139609. This
-# option also requires for bash to have been built with readline support.
-shopt -s histappend
-
-# Initialise PROMPT_COMMAND as an array, which is permitted as of bash 5.1.
-PROMPT_COMMAND=()
-
-# Don't let the user influence the order of sourcing for bash 5.3 or greater.
-unset -v GLOBSORT
-
-for _ in /etc/bash/bashrc.d/*; do
-	if [[ $_ == *.@(bash|sh) && -r $_ ]]; then
-		source "$_"
-	fi
-done
diff --git a/app-shells/bash/files/bashrc.d/10-gentoo-title-r3.bash b/app-shells/bash/files/bashrc.d/10-gentoo-title-r3.bash
new file mode 100644
index 000000000000..186763d07d9d
--- /dev/null
+++ b/app-shells/bash/files/bashrc.d/10-gentoo-title-r3.bash
@@ -0,0 +1,77 @@
+# /etc/bash/bashrc.d/10-gentoo-title.bash
+
+# For information regarding the control sequences used, please refer to
+# https://invisible-island.net/xterm/ctlseqs/ctlseqs.html.
+
+genfun_set_win_title() {
+	# Advertise the fact that the presently running interactive shell will
+	# update the title. Doing so allows for its subprocesses to determine
+	# whether it is safe to set the title of their own accord. Note that 0
+	# refers to the value of Ps within the OSC Ps ; Pt BEL sequence.
+	export SHELL_SETS_TITLE=0
+
+	# Sets the window title with the Set Text Parameters control sequence.
+	# For screen, the sequence defines the hardstatus (%h) and for tmux, the
+	# pane_title (#T). For graphical terminal emulators, it is normal for
+	# the title bar to be affected.
+	genfun_set_win_title() {
+		local prompt
+
+		if [[ ${PROMPT_DIRTRIM} ]]; then
+			# Respect the value of PROMPT_DIRTRIM. If set as 0, the
+			# current working directory shall be shown in full.
+			prompt='\u@\h \w'
+		else
+			# Show the basename of the current working directory.
+			prompt='\u@\h \W'
+		fi
+		printf '\033]0;%s\007' "${prompt@P}"
+	}
+
+	genfun_set_win_title
+}
+
+unset -v SHELL_SETS_TITLE
+
+# Determine whether the terminal can handle the Set Text Parameters sequence.
+# The only terminals permitted here are those for which there is empirical
+# evidence that the sequence is supported and that the UTF-8 character encoding
+# is handled correctly. Quite rightly, this precludes many vintage terminals.
+case ${TERM} in
+	alacritty*|contour|foot*|tmux*|xterm-ghostty)
+		# The terminal emulator also supports XTWINOPS. If the PTY was
+		# created by sshd(8) then push the current window title to the
+		# stack and arrange for it to be popped upon exiting. Xterm also
+		# supports this but there are far too many terminal emulators
+		# that falsely identify as being xterm-compatible.
+		if [[ ${SSH_TTY} && ${SSH_TTY} == "$(tty)" ]]; then
+			trap 'printf "\033[23;0t"' EXIT
+			printf '\033[22;0t'
+		fi
+		;;
+	rxvt-unicode*|st-256color|xterm*)
+		# If the PTY was created by sshd(8) then proceed no further.
+		# Alas, there exist many operating environments in which the
+		# title would otherwise not be restored upon ssh(1) exiting.
+		# Those wanting for the title to be set regardless may adjust
+		# ~/.bashrc or create a bashrc.d drop-in to set PROMPT_COMMAND.
+		# For example, PROMPT_COMMAND=(genfun_set_win_title).
+		if [[ ${SSH_TTY} && ${SSH_TTY} == "$(tty)" ]]; then
+			return
+		fi
+		;;
+	screen*)
+		# If the PTY was created by sshd(8) and screen(1) was launched
+		# prior to the SSH session beginning, as opposed to afterwards,
+		# proceed no further. It is another case in which there would be
+		# no guarantee of the title being restored upon ssh(1) exiting.
+		if [[ ! ${WINDOW} && ${SSH_TTY} && ${SSH_TTY} == "$(tty)" ]]; then
+			return
+		fi
+		;;
+	*)
+		return
+esac
+
+# Arrange for the title to be updated each time the primary prompt is displayed.
+PROMPT_COMMAND+=('genfun_set_win_title')