hyprcosmic-session/data/start-hyprcosmic

#!/usr/bin/bash
#
# Launch a HyprCosmic session: cosmic-comp for window management, HyDE's shell
# on top.
#
# Deliberately separate from /usr/bin/start-cosmic rather than patching it.
# The stock COSMIC session entry keeps working untouched, so a broken
# HyprCosmic config is always one logout away from being escaped — which
# matters when the thing you are replacing is your desktop.

set -e

# Re-exec through the user's login shell, before anything else runs.
#
# The greeter starts this script with a minimal environment: what pam and
# systemd put there, and nothing from /etc/profile or the user's own login
# files. start-cosmic re-execs itself through $SHELL to pick those up, and not
# doing the same here is why the two sessions disagree about the environment.
# see: https://github.com/pop-os/cosmic-session/issues/23
#
# The measurable difference on this machine is XDG_DATA_DIRS. Without this pass
# it arrives empty; /etc/profile.d/flatpak.sh is what appends the two flatpak
# exports directories, and those are where flatpak applications keep the
# .desktop files and icons the launcher looks for. PATH is untouched either way
# -- /etc/profile only appends what is missing -- so this adds and does not
# rearrange.
#
# First in the file, deliberately. The login files are allowed to set
# XDG_CACHE_HOME, which is where the log below decides to go, so this has to
# happen while there is still nothing to lose. The cost is one extra process
# and, measured here, about 35ms.
#
# The guard is an exported variable rather than start-cosmic's positional
# `--in-login-shell`. A flag has to survive being quoted through another shell
# to be seen on the way back in; if it ever failed to, the script would re-exec
# itself forever and the login would hang instead of failing. An exported
# variable survives exec by definition, so the recursion cannot happen.
#
# `exec -l` is bash's own flag and this script is bash, so start-cosmic's extra
# `bash -c` hop buys nothing. The inner `exec` means the login shell replaces
# itself with the session rather than sitting there as its parent for the rest
# of the login.
#
# Whatever goes wrong here is unlogged, because the log does not exist yet --
# hence checking that the shell is real and runnable first rather than finding
# out from a session that dies silently.
if [[ -z "${HYPRCOSMIC_LOGIN_SHELL:-}" && -n "${SHELL:-}" && -x "${SHELL}" ]]; then
    case "${SHELL##*/}" in
        nologin | false)
            # An account with no usable login shell still gets a desktop.
            ;;
        *)
            export HYPRCOSMIC_LOGIN_SHELL=1
            exec -l "${SHELL}" -c "exec $(printf '%q' "$0")"
            ;;
    esac
fi

# The binaries, under their own names. HyprCosmic installs beside COSMIC rather
# than over it: these are this fork's builds, and /usr/bin/cosmic-session and
# /usr/bin/cosmic-comp are left to the distribution's packages.
#
# That is what keeps the stock session on the greeter's menu and working. The
# alternative -- taking the cosmic-* names -- means erasing the distribution's
# compositor and session to install this, which on Fedora also means erasing
# cosmic-greeter, which is the display manager. A fork that can only be tried by
# removing the desktop it forked is a fork nobody can back out of.
#
# cosmic-session takes the compositor as argv[1], so the pairing is arranged
# here and needs no patch: see the exec at the end of this file.
#
# Still named in variables rather than called bare. Two reasons: the check below
# can then say which path was missing, and both stay overridable from the
# environment, which is how the session is run out of a build tree without
# installing it.
HYPRCOSMIC_SESSION_BIN="${HYPRCOSMIC_SESSION_BIN:-/usr/bin/hyprcosmic-session}"
HYPRCOSMIC_COMP_BIN="${HYPRCOSMIC_COMP_BIN:-/usr/bin/hyprcosmic-comp}"

if [[ ! -x "$HYPRCOSMIC_SESSION_BIN" ]]; then
    echo "start-hyprcosmic: $HYPRCOSMIC_SESSION_BIN is missing or not executable" >&2
    echo "start-hyprcosmic: log out and choose the stock COSMIC session" >&2
    exit 1
fi

# Capture this session's output to a file that outlives it.
#
# A session that fails drops you straight back to the greeter, taking its
# stderr with it -- and by then you cannot read the journal from inside a
# session that no longer exists. A plain file in the cache directory is still
# there afterwards, whatever happened.
#
# A plain redirect, not `tee` into a process substitution: tee would be a child
# process the session writes through, so if it ever died the session would take
# a SIGPIPE. Nothing about diagnostics should be able to kill the desktop.
#
# Every step is guarded. If any of it fails the session starts anyway with no
# log -- losing diagnostics is an inconvenience, refusing to log in is not.
#
# The previous log is kept as .1, so a second attempt does not erase the
# evidence from the first.
HYPRCOSMIC_LOG="${XDG_CACHE_HOME:-$HOME/.cache}/hyprcosmic/session.log"
if mkdir -p "$(dirname "$HYPRCOSMIC_LOG")" 2>/dev/null; then
    if [[ -f "$HYPRCOSMIC_LOG" ]]; then
        mv -f "$HYPRCOSMIC_LOG" "${HYPRCOSMIC_LOG}.1" 2>/dev/null || true
    fi
    if : >>"$HYPRCOSMIC_LOG" 2>/dev/null; then
        exec >>"$HYPRCOSMIC_LOG" 2>&1
        echo "=== hyprcosmic session starting $(date -Is) ==="
        echo "    session bin: $HYPRCOSMIC_SESSION_BIN"
        echo "    comp bin:    $HYPRCOSMIC_COMP_BIN"
        echo "    autostart:   ${XDG_CONFIG_HOME:-$HOME/.config}/hyprcosmic/autostart"
    fi
fi

# Selects the component set in cosmic-session's profile module: cosmic-panel,
# cosmic-launcher, cosmic-app-library, cosmic-workspaces, cosmic-bg and
# cosmic-files-applet are skipped; waybar and friends come from
# ~/.config/hyprcosmic/autostart.
export HYPRCOSMIC_PROFILE=hyprcosmic

# Keep COSMIC's identity: portals, cosmic-settings and any COSMIC app still
# key off this, and the compositor underneath really is COSMIC.
export XDG_CURRENT_DESKTOP="${XDG_CURRENT_DESKTOP:-COSMIC}"
export XDG_SESSION_DESKTOP="${XDG_SESSION_DESKTOP:-hyprcosmic}"
export XDG_SESSION_TYPE="${XDG_SESSION_TYPE:-wayland}"

# Toolkit hints, same set start-cosmic exports.
#
# These are what make non-GTK applications behave under a Wayland session at
# all: Firefox on Wayland rather than XWayland, Qt preferring the Wayland
# platform plugin and falling back to xcb, and Java AWT not expecting a
# reparenting window manager (without it, Swing windows come up blank or
# mispositioned). Nothing here is COSMIC-specific -- it is the generic Wayland
# session contract, and leaving it out is why Qt and Java apps looked different
# under HyprCosmic than under the stock session.
#
# `:-` rather than a plain assignment, matching the XDG lines above: if
# something in the environment already made a deliberate choice, it keeps it.
export _JAVA_AWT_WM_NONREPARENTING="${_JAVA_AWT_WM_NONREPARENTING:-1}"
export GDK_BACKEND="${GDK_BACKEND:-wayland,x11}"
export MOZ_ENABLE_WAYLAND="${MOZ_ENABLE_WAYLAND:-1}"
export QT_QPA_PLATFORM="${QT_QPA_PLATFORM:-wayland;xcb}"
export QT_AUTO_SCREEN_SCALE_FACTOR="${QT_AUTO_SCREEN_SCALE_FACTOR:-1}"
export QT_ENABLE_HIGHDPI_SCALING="${QT_ENABLE_HIGHDPI_SCALING:-1}"

# Qt platform theme: CuteCosmic if it is installed, qt6ct/qt5ct if not.
#
# Kept pointing at COSMIC's theme rather than HyDE's, because this fork themes
# GTK/waybar/rofi and has no Qt pipeline: switching to qt5ct here would hand Qt
# apps to a configuration nothing in this project writes. CuteCosmic at least
# follows the COSMIC palette that cosmic.conf does drive.
if [[ -z "${QT_QPA_PLATFORMTHEME:-}" ]]; then
    export QT_QPA_PLATFORMTHEME=cosmic
    for qt_plugin_path in /usr/lib{*,/*}/qt6/plugins; do
        if [[ -f "${qt_plugin_path}/platformthemes/libcutecosmictheme.so" ]]; then
            export QT_QPA_PLATFORMTHEME=cosmic
            break
        elif [[ -f "${qt_plugin_path}/platformthemes/libqt6ct.so" ]] ||
             [[ -f "${qt_plugin_path}/platformthemes/libqt5ct.so" ]]; then
            # Keep looking; CuteCosmic later in the glob still wins.
            # "qt5ct" is the value both qt5ct and qt6ct answer to.
            export QT_QPA_PLATFORMTHEME=qt5ct
        fi
    done
    unset qt_plugin_path
fi

# dconf profile, which is where COSMIC's own settings live.
#
# The profile file -- `user-db:cosmic` layered above the usual user and system
# databases -- is shipped by the cosmic-session package, under
# /usr/share/dconf/profile/cosmic on Fedora.
#
# Naming a profile that cannot be found is not a soft failure. dconf logs
# "using null configuration" and then every GSettings read falls back to schema
# defaults while writes go nowhere: a whole desktop's settings, apparently
# blank. Measured here -- a missing profile dumps zero keys where the default
# profile dumps a full set -- which is why this is guarded and start-cosmic's
# unconditional export is not copied.
#
# The bare name is used rather than an absolute path. start-cosmic has its
# prefix rewritten in at install time by the Justfile, but dconf searches
# /etc/dconf/profile first and XDG_DATA_DIRS after, so the bare name keeps an
# administrator's /etc override working instead of pinning one prefix.
dconf_profile_found=""
IFS=: read -r -a xdg_data_dirs <<<"${XDG_DATA_DIRS:-/usr/local/share:/usr/share}" || :
for dir in /etc "${xdg_data_dirs[@]}"; do
    if [[ -f "${dir}/dconf/profile/cosmic" ]]; then
        dconf_profile_found=1
        break
    fi
done
if [[ -n "${dconf_profile_found}" ]]; then
    export DCONF_PROFILE=cosmic
else
    echo "start-hyprcosmic: no dconf profile 'cosmic' found; leaving DCONF_PROFILE unset" >&2
fi
unset dconf_profile_found xdg_data_dirs dir

# gnome-keyring, and the SSH agent it provides.
#
# PAM starts the daemon at login but brings up only its `control` socket, so
# without this a HyprCosmic session has no ssh-agent at all: SSH_AUTH_SOCK is
# unset, anything over SSH asks for the passphrase every time, and callers of
# the secrets API find nothing listening. `--start` attaches to the daemon that
# is already running and brings up whichever components are missing.
#
# The daemon writes `NAME=value` to stdout and chatter like
# "discover_other_daemon: 1" to stderr, so the 2>/dev/null is load-bearing for
# the parse, not just for tidiness.
#
# start-cosmic evals that stdout, but its eval is
# `eval "$(... > /dev/null 2>&1)"` -- the redirect is *inside* the substitution,
# so the eval always runs on an empty string and the block works only because
# of the socket checks that follow it. Rather than repair that by evaluating
# whatever a daemon chooses to write to stdout, read out the one variable we
# actually want.
if [[ -d "/run/user/$(id -u)/keyring" ]]; then
    keyring_ssh_sock=""
    if command -v gnome-keyring-daemon >/dev/null 2>&1; then
        keyring_ssh_sock="$(
            gnome-keyring-daemon --start --components=pkcs11,secrets,ssh 2>/dev/null |
                sed -n 's/^SSH_AUTH_SOCK=//p' | tail -n1
        )"
    else
        echo "start-hyprcosmic: gnome-keyring-daemon not found in PATH" >&2
    fi

    # start-cosmic's rule, kept: set the correct socket or set none at all,
    # never a wrong one. The daemon's own answer goes first because it is
    # authoritative about where it just put the socket; the two fixed paths are
    # the fallback for when it told us nothing.
    for candidate in \
        "${keyring_ssh_sock}" \
        "/run/user/$(id -u)/gcr/ssh" \
        "/run/user/$(id -u)/keyring/ssh"
    do
        if [[ -n "${candidate}" && -S "${candidate}" ]]; then
            export SSH_AUTH_SOCK="${candidate}"
            break
        fi
    done
    unset keyring_ssh_sock candidate
fi

# Same hygiene as start-cosmic: a failed unit left by a previous graphical
# session will otherwise block this one from starting.
if command -v systemctl >/dev/null; then
    for unit in $(systemctl --user --no-legend --state=failed --plain list-units | cut -f1 -d' '); do
        partof="$(systemctl --user show -p PartOf --value "$unit")"
        for target in cosmic-session.target graphical-session.target; do
            if [ "$partof" = "$target" ]; then
                systemctl --user reset-failed "$unit"
                break
            fi
        done
    done

    # Hand the session's identity to `systemd --user`, which is what actually
    # launches the portal.
    #
    # Exporting XDG_CURRENT_DESKTOP above only reaches processes started *by
    # this script*. The user manager is older than the session and has its own
    # environment block, so anything it activates -- xdg-desktop-portal, and
    # through it xdg-desktop-portal-cosmic, which is `SystemdService=` in its
    # D-Bus service file -- never saw the variable.
    #
    # xdg-desktop-portal picks a backend by matching the `UseIn=` line of
    # /usr/share/xdg-desktop-portal/portals/*.portal against
    # XDG_CURRENT_DESKTOP. With the variable unset, `UseIn=COSMIC` did not
    # match, no backend loaded, and org.freedesktop.portal.Screenshot was never
    # exported -- so pressing PrtScr made cosmic-screenshot unwrap an error and
    # abort with "COSMIC screenshot crashed". Nothing logged a missing portal;
    # the only symptom was the crash.
    #
    # Ordering is fine: xdg-desktop-portal.service is `After=` and
    # `Requisite=graphical-session.target`, which cosmic-session brings up
    # later, so the portal cannot start before this import.
    #
    # SSH_AUTH_SOCK rides along for the same reason: a user unit or a
    # systemd-activated app that wants the agent has to find it in the manager's
    # environment, not in this script's. It is skipped harmlessly when the
    # keyring block above declined to set it.
    #
    # `||:` throughout -- losing a portal is bad, refusing to log in is worse.
    systemctl --user import-environment \
        XDG_CURRENT_DESKTOP XDG_SESSION_DESKTOP XDG_SESSION_TYPE \
        DCONF_PROFILE SSH_AUTH_SOCK ||:
fi

# Same variables again for dbus-daemon's own activation environment, which
# covers any backend whose .service file has no `SystemdService=` line.
#
# Only when a bus already exists. In the dbus-run-session branch below the bus
# is created *after* this point, so calling it here would talk to the wrong bus
# or none at all. That branch is the fallback path anyway; a normal graphical
# login arrives with DBUS_SESSION_BUS_ADDRESS already set.
if [[ -n "${DBUS_SESSION_BUS_ADDRESS}" ]] && command -v dbus-update-activation-environment >/dev/null; then
    dbus-update-activation-environment \
        XDG_CURRENT_DESKTOP XDG_SESSION_DESKTOP XDG_SESSION_TYPE \
        DCONF_PROFILE SSH_AUTH_SOCK ||:
fi

# cosmic-session takes the compositor to launch as its first argument
# (main.rs: `args.next().unwrap_or_else(|| String::from("cosmic-comp"))`),
# which is how a forked cosmic-comp gets used without replacing the system one.
if [[ -z "${DBUS_SESSION_BUS_ADDRESS}" ]]; then
    exec /usr/bin/dbus-run-session -- "${HYPRCOSMIC_SESSION_BIN}" "${HYPRCOSMIC_COMP_BIN}"
else
    exec "${HYPRCOSMIC_SESSION_BIN}" "${HYPRCOSMIC_COMP_BIN}"
fi