chore: 1.4.0

Steam's helper script is only patched when the patch keeps the file at the
length Steam wrote down. Where the comments cannot pay for the argument,
nothing is written at all: a file of the wrong length costs the whole client
package downloaded and installed again, and a client that quits at the end of
it instead of coming up.

With no such patch left to prop up, -noverifyfiles is gone from everything that
carried it - Steam's launcher entry, its autostart entry, the shortcut on the
desktop and the ones Steam writes for single games. Steam repairs its own
installation again, and nothing of this program's is on its command line. A
patch an earlier version appended is rebuilt to fit at the next apply, or taken
back if it cannot be.

A script somebody puts in front of the client to add a switch of its own is
recognised as a way of starting Steam, rather than as an application to hand
the flag to.

A desktop entry edited in place that the ledger has lost is written again from
the copy kept beside it. Without that, an entry from an older version kept an
older answer for good - a browser patched that way stayed on the flag that
shows the "unsupported command-line flag" bar while every other browser moved
off it in 1.3.0.

Makefile

@@ -8,7 +8,7 @@
 # Overridable so a packager can pass the version it is actually building
 # (`make VERSION=$pkgver`). The literal below is the fallback for builds
 # straight from a checkout, and is what a release tag has to carry.
-VERSION      ?= 1.3.0
+VERSION      ?= 1.4.0
 
 PREFIX       ?= /usr
 DESTDIR      ?=

README.md

@@ -122,13 +122,18 @@ same thing manually.
 
 Steam's web UI supports autoscroll but has no way to pass extra arguments to its
 helper, so the program patches the script that starts it. Steam checks its own
-files at every start and repairs whatever looks changed, so the patch is written
-to look unchanged.
+files against its manifest - by size and timestamp - and reinstalls the whole
+client package over anything that differs, so the patch is written to look
+unchanged: the bytes the argument costs are taken back out of the script's
+comments and the timestamp is put back.
 
-As a fallback, for the case where that isn't possible, `-noverifyfiles` goes on
-everything that starts Steam: its launcher, its autostart entry, and the
-shortcuts it writes for single games. That one means Steam won't auto-repair
-damaged files on its own just so you're aware of that.
+If that can't be done - a script with no comments left to pay for the argument,
+or one this version doesn't recognise - nothing is written and Steam is left
+alone. A file of the wrong length costs the client package downloaded and
+installed again, and a Steam that quits at the end of it instead of coming up;
+no autoscroll in Steam is the smaller problem. Nothing is added to Steam's
+launcher entry or to the shortcuts it writes for games, and Steam keeps
+repairing its own installation.
 
 ## Commands
 

doc/middleclick-autoscroll.1.scd

@@ -142,23 +142,22 @@ that checks its files finds nothing to repair, and the argument survives
 however Steam was started - from the menu, from a game shortcut, from a
 launcher like Heroic or Lutris, from a terminal.
 
-That is what has to work, because there is no way to make every possible way of
-starting Steam carry an argument. *-noverifyfiles* is the second line rather
-than the first: it covers the case where the script has no comments left to pay
-for the argument and the patch has to grow the file. It goes on Steam's
-launcher entry, on its entry in _~/.config/autostart_, which Steam writes as
-soon as it is set to run at login, and on the shortcuts Steam writes for single
-games, on the desktop and in the menu alike. A game is not an application this
-program has anything to offer and none of them is listed under *Applications*,
-but starting one is a Steam start like any other. The trade-off of the switch
-is that Steam no longer repairs a damaged installation on its own; that is why
-Steam is a switch of its own in the settings.
+That is what has to work, because it is the only thing that does. A patch that
+changes the length is never written, whatever else could be done to cover for
+it: Steam checks its files at the shutdown it runs itself as well as at a start
+it was given arguments for, and that one carries no arguments of anybody's. One
+wrong length costs the whole client package downloaded, extracted and installed
+again, and a client that quits at the end of it instead of coming up.
 
-A patch that does change the size is still held back while the client is
-running: Steam puts its own copy back, the two would only undo each other, and
-the helper is started once, at the start, so patching again would not help that
-session anyway. It goes in at the next apply with Steam closed. A patch that
-keeps the size has nothing to wait for and goes in either way.
+So where the comments cannot pay for the argument, or a client update has
+changed how the helper is started, nothing is written and the status screen
+says Steam is not patched. Nothing goes on Steam's launcher entry, its
+autostart entry or the shortcuts it writes for single games either, and Steam
+goes on repairing its own installation.
+
+An installation patched by an earlier version, which appended where the
+comments were short, is written again to fit at the next apply, or taken back
+if it cannot be made to.
 
 A client update brings a new version of the script. The watcher notices and
 patches it again, and the copy kept for undoing is replaced with the new

po/de.po

@@ -43,9 +43,6 @@ msgstr "nicht erkennbar"
 msgid "not patched yet"
 msgstr "noch nicht gepatcht"
 
-msgid "waiting until Steam is closed"
-msgstr "wartet, bis Steam geschlossen ist"
-
 
 #. Status block
 msgid "Autoscroll"
@@ -155,9 +152,6 @@ msgstr "Autoscroll ist für %d Anwendungen an."
 msgid "Applications that are already running pick this up when they are restarted."
 msgstr "Bereits laufende Anwendungen übernehmen das nach einem Neustart."
 
-msgid "Steam's launcher now skips its file check, which is what keeps the change from being undone at every start."
-msgstr "Steams Startereintrag überspringt jetzt die Dateiprüfung – nur so bleibt die Änderung bei jedem Start erhalten."
-
 msgid "Could not start the watcher for newly installed applications."
 msgstr "Die Überwachung neu installierter Anwendungen konnte nicht gestartet werden."
 
@@ -179,11 +173,11 @@ msgstr "Auf %d Anwendungen angewendet."
 msgid "Already applied to %d applications."
 msgstr "Bereits auf %d Anwendungen angewendet."
 
-msgid "Steam starts its interface in a way this version does not recognise; leaving it alone."
-msgstr "Steam startet seine Oberfläche auf eine Art, die diese Version nicht kennt; Steam bleibt unangetastet."
+msgid "Steam starts its interface in a way this version cannot change without Steam noticing; leaving it alone."
+msgstr "Steam startet seine Oberfläche auf eine Art, die diese Version nicht ändern kann, ohne dass Steam es merkt; Steam bleibt unangetastet."
 
-msgid "Steam is running and has put its own file back; the change waits until Steam is closed."
-msgstr "Steam läuft und hat seine eigene Datei wiederhergestellt; die Änderung wird nachgeholt, sobald Steam geschlossen ist."
+msgid "Steam's interface cannot be given the flag without leaving a file Steam would reinstall; the change has been taken back."
+msgstr "Steams Oberfläche lässt sich das Flag nicht geben, ohne eine Datei zu hinterlassen, die Steam neu installieren würde; die Änderung wurde zurückgenommen."
 
 
 #. Help

po/middleclick-autoscroll.pot

@@ -43,9 +43,6 @@ msgstr ""
 msgid "not patched yet"
 msgstr ""
 
-msgid "waiting until Steam is closed"
-msgstr ""
-
 
 #. Status block
 msgid "Autoscroll"
@@ -155,9 +152,6 @@ msgstr ""
 msgid "Applications that are already running pick this up when they are restarted."
 msgstr ""
 
-msgid "Steam's launcher now skips its file check, which is what keeps the change from being undone at every start."
-msgstr ""
-
 msgid "Could not start the watcher for newly installed applications."
 msgstr ""
 
@@ -179,10 +173,10 @@ msgstr ""
 msgid "Already applied to %d applications."
 msgstr ""
 
-msgid "Steam starts its interface in a way this version does not recognise; leaving it alone."
+msgid "Steam starts its interface in a way this version cannot change without Steam noticing; leaving it alone."
 msgstr ""
 
-msgid "Steam is running and has put its own file back; the change waits until Steam is closed."
+msgid "Steam's interface cannot be given the flag without leaving a file Steam would reinstall; the change has been taken back."
 msgstr ""
 
 

src/lib/apply.sh

@@ -103,7 +103,9 @@ mca_apply() {
 				mca_desktop_apply "$id" "$file" "$(mca_flags "$kind")"
 				;;
 			steam)
-				mca_steam_desktop_apply "$id" "$file" "$packaging"
+				# Nothing is done to the entry itself: what Steam needs is
+				# in its own installation, and the same patch serves every
+				# way of starting the client.
 				if (( ! steam_done )); then
 					mca_steam_apply
 					steam_done=1
@@ -118,30 +120,16 @@ mca_apply() {
 		mca_steam_apply
 	fi
 
-	# The shortcuts Steam writes for single games. They are not applications
-	# and are not offered as ones, but starting a game with Steam closed is a
-	# Steam start like any other: without the switch the client finds the
-	# patched helper script, puts its own back, and the interface loses
-	# autoscroll for the rest of the session.
-	if [[ $CFG_STEAM == yes ]]; then
-		for i in "${!MCA_STEAM_LINKS[@]}"; do
-			mca_steam_desktop_apply "${MCA_STEAM_LINKS[i]}" \
-				"${MCA_STEAM_LINK_FILES[i]}" "${MCA_STEAM_LINK_PACK[i]}"
-		done
-	fi
-
-	# Steam's autostart entry carries Steam's own switch and follows the Steam
-	# setting, not this one - leaving it out while Steam is patched is what puts
-	# the client in an update loop - so both are checked inside.
-	if [[ $CFG_AUTOSTART == yes || $CFG_STEAM == yes ]]; then
+	# Autostart entries. A Chromium application that starts itself at login
+	# points straight at its binary and never reads the entry in the menu, so
+	# Discord at login used to behave differently from Discord from the menu.
+	if [[ $CFG_AUTOSTART == yes ]]; then
 		mca_autostart_apply
 	fi
 
-	# Shortcuts on the desktop itself. Nothing above has seen them - the XDG
-	# search path does not go there - and a game started from one starts Steam
-	# without its switch, which is the difference between autoscroll working
-	# and autoscroll working most of the time. Each entry is gated on its own,
-	# so there is nothing to check out here.
+	# Shortcuts on the desktop itself, which nothing above has seen: the XDG
+	# search path does not go there. Each entry is gated on its own, so there is
+	# nothing to check out here.
 	mca_shortcuts_apply
 
 	[[ $CFG_SPOTIFY == yes ]] && mca_spotify_apply

src/lib/common.sh

@@ -45,10 +45,14 @@ MCA_BROWSER_FLAG="--enable-features=MiddleClickAutoscroll,HeliumMiddleClickAutos
 MCA_FEATURE="MiddleClickAutoscroll"
 MCA_BROWSER_FEATURES="MiddleClickAutoscroll,HeliumMiddleClickAutoscroll"
 
-# Bumped when the flags above change. An installation that was set up by a
-# version with a different answer is taken back and done again once, because a
-# file that is already patched is otherwise left alone. See mca_apply.
-MCA_FLAG_SCHEME=2
+# Bumped when the flags above change, and when what gets written where does.
+# An installation that was set up by a version with a different answer is taken
+# back and done again once, because a file that is already patched is otherwise
+# left alone. See mca_apply.
+#
+# 3 is what takes -noverifyfiles back out of the Steam entries an older version
+# put it in.
+MCA_FLAG_SCHEME=3
 
 MCA_LIBDIR="${MCA_LIBDIR:-@LIBDIR@}"
 MCA_LOCALEDIR="${MCA_LOCALEDIR:-@LOCALEDIR@}"
@@ -289,6 +293,16 @@ mca_ledger_add() {
 	printf '%s\t%s\t%s\n' "$kind" "$path" "$detail" >> "$MCA_LEDGER"
 }
 
+# mca_ledger_has <path>
+# Whether the ledger still knows about that file. Worth asking because the copy
+# kept beside it is named after the path and outlives a ledger that was lost or
+# truncated: a file nothing has a record of any more is one nothing would ever
+# look at again.
+mca_ledger_has() {
+	[[ -f $MCA_LEDGER ]] || return 1
+	awk -F'\t' -v p="$1" '$2 == p { found = 1 } END { exit !found }' "$MCA_LEDGER"
+}
+
 mca_ledger_forget() {
 	local path="$1" tmp
 	[[ -f $MCA_LEDGER ]] || return 0

src/lib/detect.sh

@@ -223,6 +223,46 @@ mca_exec_is_steam_link() {
 	mca_prog_is_steam "$prog"
 }
 
+# _mca_prog_is_steam_name <program>
+# The launcher under one of the names Valve and the distributions give it.
+_mca_prog_is_steam_name() {
+	case "${1##*/}" in
+		steam|steam-runtime|steam-native|steam-jupiter) return 0 ;;
+	esac
+	return 1
+}
+
+# _mca_prog_is_steam_wrapper <program>
+# Whether a script in front of the client is a way of starting Steam. People
+# put one there to add a switch of their own, and an entry pointing at it is a
+# Steam start like any other - but the script is not named after Steam, so
+# nothing above recognises it.
+#
+# Getting this wrong is worse than it sounds: such a script tends to mention
+# the flag it is there to add, which is one of the markers that say "Chromium"
+# to the hint scan. The entry then ends up being handled as an application and
+# is given the flag on its command line, where Steam ignores it, instead of
+# being handed to the Steam module that knows how to reach the web helper.
+#
+# Only the handover is followed, and only one step of it: the client's own
+# launcher is already recognised by name, so a wrapper in front of it is the
+# whole of what is left.
+_mca_prog_is_steam_wrapper() {
+	local prog="$1" head='' target
+
+	[[ $prog == /* && -f $prog && -r $prog ]] || return 1
+
+	# Two characters, read in the shell: the scan asks this about every program
+	# on the system, and most of them are binaries whose first line is the whole
+	# file.
+	read -r -N 2 head < "$prog" 2>/dev/null || return 1
+	[[ $head == '#!' ]] || return 1
+
+	target="$(_mca_script_target "$prog")" || return 1
+	[[ -n $target ]] || return 1
+	_mca_prog_is_steam_name "$target"
+}
+
 # mca_prog_is_steam <program>
 # Whether running this program starts the Steam client. Every packaging is in
 # here and every name Valve and the distributions give the launcher, because
@@ -234,10 +274,9 @@ mca_exec_is_steam_link() {
 mca_prog_is_steam() {
 	local prog="$1"
 
-	case "${prog##*/}" in
-		steam|steam-runtime|steam-native|steam-jupiter) return 0 ;;
-	esac
-	[[ $prog == flatpak:com.valvesoftware.Steam || $prog == snap:steam ]]
+	_mca_prog_is_steam_name "$prog" && return 0
+	[[ $prog == flatpak:com.valvesoftware.Steam || $prog == snap:steam ]] && return 0
+	_mca_prog_is_steam_wrapper "$prog"
 }
 
 # ---------------------------------------------------------------------------
@@ -576,16 +615,6 @@ MCA_PROGS=()      # resolved program, or a Flatpak app id or a snap name
 MCA_KINDS=()      # app | browser | steam | unknown | no
 MCA_PACKAGING=()  # native | flatpak | snap
 
-# The shortcuts Steam writes for single games. Not applications of their own - a
-# game is whatever engine it was built with, and none of those reads a Chromium
-# argument - so they are kept apart from the list rather than listed as
-# something that got switched on. They do start Steam, which is why they are
-# kept at all: the Steam module gives them Steam's own switch.
-MCA_STEAM_LINKS=()       # desktop file id
-MCA_STEAM_LINK_FILES=()  # the entry that is in effect for it
-MCA_STEAM_LINK_PACK=()   # native | flatpak | snap, which decides where the
-                         # switch goes on the command line
-
 # A scan reads every desktop entry on the system, so the menu does it once and
 # then redraws from what it found. Applying rescans on its own, so nothing else
 # has to remember to invalidate this.
@@ -603,7 +632,6 @@ mca_scan() {
 
 	MCA_IDS=(); MCA_FILES=(); MCA_NAMES=(); MCA_PROGS=(); MCA_KINDS=()
 	MCA_PACKAGING=()
-	MCA_STEAM_LINKS=(); MCA_STEAM_LINK_FILES=(); MCA_STEAM_LINK_PACK=()
 
 	# Pass one: read the entries and work out what each of them starts. No
 	# detection yet - that needs a stat per program, and those are collected so
@@ -643,18 +671,12 @@ mca_scan() {
 				prog="snap:$MCA_PROG"
 			fi
 
-			if mca_exec_is_steam_link "$exec_line" "$prog"; then
-				MCA_STEAM_LINKS+=("$id")
-				MCA_STEAM_LINK_FILES+=("$file")
-				if [[ $prog == flatpak:* ]]; then
-					MCA_STEAM_LINK_PACK+=(flatpak)
-				elif [[ $prog == snap:* ]]; then
-					MCA_STEAM_LINK_PACK+=(snap)
-				else
-					MCA_STEAM_LINK_PACK+=(native)
-				fi
-				continue
-			fi
+			# The shortcuts Steam writes for single games are not
+			# applications of their own - a game is whatever engine it was
+			# built with, and none of those reads a Chromium argument - and
+			# starting the client through one needs nothing on its command
+			# line either.
+			mca_exec_is_steam_link "$exec_line" "$prog" && continue
 
 			c_ids+=("$id"); c_files+=("$file"); c_names+=("$name")
 			c_progs+=("$prog")

src/lib/menu.sh

@@ -178,9 +178,6 @@ mca_ui_status() {
 	if mca_steam_installed; then
 		if mca_steam_patched; then
 			_mca_row "$(mca_msg "Steam")" "$(_mca_onoff yes)"
-		elif [[ $CFG_STEAM == yes && $CFG_ENABLED == yes ]] && mca_steam_waiting; then
-			_mca_row "$(mca_msg "Steam")" \
-				"${MCA_C_DIM}$(mca_msg "waiting until Steam is closed")${MCA_C_RESET}"
 		elif [[ $CFG_STEAM == yes && $CFG_ENABLED == yes ]]; then
 			_mca_row "$(mca_msg "Steam")" \
 				"${MCA_C_YELLOW}$(mca_msg "not patched yet")${MCA_C_RESET}"

src/lib/patch.sh

@@ -410,15 +410,6 @@ mca_desktop_apply() {
 #   The desktop folder, where a shortcut somebody dragged out of the menu -
 #   or asked Steam for - lives and nowhere else.
 #
-# Steam is in both, even though it is not a Chromium process itself: its
-# entries need -noverifyfiles exactly like the menu one. The autostart entry is
-# the one most likely to exist, because Steam writes it as soon as "run at
-# startup" is ticked; without it a Steam started at login restores the patched
-# web helper script and the watcher patches it back, over and over. The desktop
-# ones are the gap behind "autoscroll works, except sometimes": starting a game
-# from the desktop is a Steam start like any other, and a Steam start without
-# the switch costs the interface its autoscroll for the rest of the session.
-#
 # Neither can be shadowed from anywhere, so both are edited where they stand,
 # with the original kept.
 
@@ -426,16 +417,27 @@ mca_desktop_apply() {
 # One desktop entry that lives outside the XDG search path, edited where it is
 # because there is nowhere to shadow it from.
 #
-# Anything that starts Steam gets Steam's own switch; a Chromium application
-# gets the flag. What decides whether a Chromium application here is in scope
-# differs by where the entry came from, which is what the gate says: an
-# autostart entry follows the autostart setting, a shortcut follows the same
-# rules as the application it is a shortcut to.
+# What decides whether an application here is in scope differs by where the
+# entry came from, which is what the gate says: an autostart entry follows the
+# autostart setting, a shortcut follows the same rules as the application it is
+# a shortcut to.
 _mca_entry_patch_inplace() {
 	local file="$1" gate="$2"
-	local id prog packaging=native content backup kind
+	local id prog packaging=native content backup kind copy
 
-	grep -q "^$MCA_MARK_INPLACE=" "$file" 2>/dev/null && return 0
+	# Already ours, and normally that is the end of it: what is in there is what
+	# this version put there. Not so for a file the ledger has no record of -
+	# nothing would ever look at that one again, neither the undo a change of
+	# flags goes through nor this, which leaves a marked file alone, and it would
+	# keep an answer from an older version for good. The copy taken before the
+	# edit is named after the path and is still there, so the file goes back to
+	# what it was and is written again below.
+	if grep -q "^$MCA_MARK_INPLACE=" "$file" 2>/dev/null; then
+		mca_ledger_has "$file" && return 0
+		copy="$MCA_BACKUPDIR/$(mca_backup_name "$file")"
+		[[ -f $copy ]] || return 0
+		cp -p -- "$copy" "$file" 2>/dev/null || return 0
+	fi
 
 	_mca_desktop_read "$file"
 	[[ -n $DE_EXEC ]] || return 0
@@ -456,11 +458,11 @@ _mca_entry_patch_inplace() {
 		packaging=snap
 	fi
 
-	if mca_prog_is_steam "$prog"; then
-		[[ $CFG_STEAM == yes ]] || return 0
-		content="$(_mca_desktop_transform "$file" "$MCA_MARK_INPLACE" \
-			"$MCA_STEAM_LAUNCH_FLAG" "$(mca_steam_flag_position "$packaging")")"
-	else
+	# An entry that starts Steam is left where it is. Steam takes nothing
+	# from a command line that would help, and what it does take belongs to
+	# the web helper script in its own installation.
+	mca_prog_is_steam "$prog" && return 0
+
 	case "$packaging" in
 		flatpak) mca_flatpak_is_chromium "${prog#flatpak:}" || return 0 ;;
 		snap)    mca_snap_is_chromium "${prog#snap:}" || return 0 ;;
@@ -478,7 +480,6 @@ _mca_entry_patch_inplace() {
 
 	content="$(_mca_desktop_transform "$file" "$MCA_MARK_INPLACE" \
 		"$(mca_flags "$kind")")"
-	fi
 
 	[[ -n $content ]] || return 0
 	[[ "$content" == "$(< "$file")" ]] && return 0

src/lib/steam.sh

@@ -18,25 +18,19 @@
 # and the flag survives however Steam was started - from the menu, from a game
 # shortcut, from a launcher like Heroic, from a terminal.
 #
-# That is the part that has to work, because there is no way to make every
-# possible way of starting Steam carry an argument. -noverifyfiles on the
-# launcher entries is the second line rather than the first: it covers the case
-# where the script has no comments left to pay for the flag and the patch has
-# to grow the file. The trade-off is real and belongs to the user, so it is a
-# switch of its own rather than part of the general application handling: with
-# verification off, Steam no longer repairs a damaged installation by itself.
-#
-# A patch that does change the size still has to stay out of the way of a
-# client that is already running, or the two programs spend the session undoing
-# each other: Steam restores the script, the watcher patches it again, Steam
-# restores it again, and the client never gets past its update dialog. A patch
-# that keeps the size is invisible to that check and goes in either way.
+# A patch that changes the length is not an option, and no switch covers for
+# one. Steam checks its files at a start it was given arguments for, but also
+# at the shutdown it runs itself - and that one has no -noverifyfiles on its
+# command line, whatever the session was started with. What a single wrong
+# length costs is the whole client package downloaded, extracted and installed
+# again, and a client that quits at the end of it instead of coming up. So the
+# flag either fits in the space the comments give back, or it is not written at
+# all: no autoscroll in the interface is a smaller thing than a client that
+# reinstalls itself.
 #
 # The file comes back on every client update, and the watcher re-applies the
 # patch when that happens.
 
-MCA_STEAM_LAUNCH_FLAG='-noverifyfiles'
-
 # Every place a Steam installation is known to live, resolved and de-duplicated
 # because ~/.steam/steam is normally a symlink into ~/.local/share.
 #
@@ -88,24 +82,6 @@ mca_steam_installed() {
 	return 1
 }
 
-# mca_steam_running
-# Steam records its own process id beside its installation while it runs. The
-# file outlives a crash, so the id is checked rather than believed.
-mca_steam_running() {
-	local f pid
-	for f in \
-		"$HOME/.steam/steam.pid" \
-		"$HOME/.var/app/com.valvesoftware.Steam/.steam/steam.pid" \
-		"$HOME/snap/steam/common/.steam/steam.pid"
-	do
-		[[ -r $f ]] || continue
-		pid="$(< "$f")"
-		[[ $pid =~ ^[0-9]+$ ]] || continue
-		kill -0 "$pid" 2>/dev/null && return 0
-	done
-	return 1
-}
-
 # mca_steam_script_patched <script>
 mca_steam_script_patched() {
 	grep -q -- "$MCA_FEATURE" "$1" 2>/dev/null
@@ -120,26 +96,6 @@ mca_steam_patched() {
 	return 1
 }
 
-# mca_steam_deferred <script>
-# Whether the patch is being held back rather than simply missing: the script
-# was patched before, its own copy is back, and Steam is still running. See
-# mca_steam_apply for why that is left alone.
-mca_steam_deferred() {
-	[[ -e "$MCA_BACKUPDIR/$(mca_backup_name "$1")" ]] && mca_steam_running
-}
-
-# mca_steam_waiting
-# The same question for the status screen, which has no script in hand.
-mca_steam_waiting() {
-	local root script
-	while IFS= read -r root; do
-		script="$(mca_steam_script "$root")" || continue
-		mca_steam_script_patched "$script" && continue
-		mca_steam_deferred "$script" && return 0
-	done < <(mca_steam_roots)
-	return 1
-}
-
 # _mca_steam_exec_line <script>
 # The line number of the command that starts the web helper: the last
 # uncommented line that both names steamwebhelper and forwards "$@". Both the
@@ -154,27 +110,25 @@ _mca_steam_exec_line() {
 	' "$1" 2>/dev/null
 }
 
-# _mca_steam_build <script> <flags> <reclaim: 0|1>
+# _mca_steam_build <script> <flags>
 # The patched script on stdout: the flags appended to the line that starts the
-# web helper, and - when asked for - the same number of bytes taken back out of
-# the script's comments, so that the file Steam finds is the length Steam wrote
-# down. Everything else - setting up the container runtime, deciding whether
-# the sandbox can be used - is left alone.
+# web helper, and the same number of bytes taken back out of the script's
+# comments, so that the file Steam finds is the length Steam wrote down.
+# Everything else - setting up the container runtime, deciding whether the
+# sandbox can be used - is left alone.
 #
 # Comments are eaten from the bottom up, so the header that says what the
 # script is for is the last thing to lose anything, and the '#' itself always
 # stays: a line that loses it stops being a comment and starts being a command.
 # Fails when the comments are too short to pay for the flags.
 _mca_steam_build() {
-	local script="$1" flags="$2" reclaim="$3" lineno need=0
+	local script="$1" flags="$2" lineno need
 
 	lineno="$(_mca_steam_exec_line "$script")"
 	[[ -n $lineno ]] || return 1
 
-	if (( reclaim )); then
 	need="$(printf '%s' " $flags" | wc -c)"
 	need="${need//[^0-9]/}"
-	fi
 
 	# LC_ALL=C so awk counts bytes: a comment with an accent in it is shorter
 	# in characters than it is on disk, and it is the disk that Steam measures.
@@ -222,29 +176,29 @@ _mca_steam_refresh_backup() {
 	cp -p -- "$script" "$MCA_BACKUPDIR/$name" 2>/dev/null || true
 }
 
-# _mca_steam_reneutralise <script> <flags>
-# An earlier version of this program patched by appending and left the script
-# longer than Steam expects, which is a patch that only survives because
-# -noverifyfiles is there to stop Steam looking. If the same flags can be made
-# to fit, they are: the file goes back to the length and the timestamp Steam
-# wrote down and stops depending on that switch.
+# _mca_steam_settle <script> <flags>
+# The script is already patched. Whether that is a patch Steam can live with is
+# a question of length: an earlier version of this program appended the flag
+# where the comments could not pay for it, which leaves the script longer than
+# the file Steam wrote down - and a client that checks its files reinstalls
+# itself over that, then quits instead of starting.
 #
-# The new copy is built from the untouched original that was kept when the
-# script was first patched, never from the patched file - patching a patched
-# file is how a flag ends up in there twice.
-_mca_steam_reneutralise() {
+# Rebuilt from the untouched original kept when the script was first patched,
+# never from the patched file, the flag either fits this time or the original
+# goes back and Steam is left with a client it recognises.
+_mca_steam_settle() {
 	local script="$1" flags="$2" name copy out
 
 	name="$(mca_backup_name "$script")"
 	copy="$MCA_BACKUPDIR/$name"
-	[[ -f $copy ]] || return 1
 
-	# Already the length Steam expects: there is nothing to gain.
-	(( $(wc -c < "$script") == $(wc -c < "$copy") )) && return 1
+	# Nothing to compare against, so nothing can be said about the length.
+	[[ -f $copy ]] || return 0
 
-	out="$(_mca_steam_build "$copy" "$flags" 1)" || return 1
-	_mca_steam_same_size "$copy" "$out" || return 1
+	# Already the length Steam expects: the patch is a good one.
+	(( $(wc -c < "$script") == $(wc -c < "$copy") )) && return 0
 
+	if out="$(_mca_steam_build "$copy" "$flags")" && _mca_steam_same_size "$copy" "$out"; then
 		if mca_write_if_changed "$script" "$out"$'\n'; then
 			MCA_CHANGES=$(( MCA_CHANGES + 1 ))
 		fi
@@ -252,14 +206,20 @@ _mca_steam_reneutralise() {
 		touch -r "$copy" -- "$script" 2>/dev/null || true
 		mca_ledger_add steam "$script" "$name"
 		return 0
+	fi
+
+	mca_steam_revert "$script" "$name"
+	mca_ledger_forget "$script"
+	mca_note "$(mca_msg "Steam's interface cannot be given the flag without leaving a file Steam would reinstall; the change has been taken back.")"
+	return 0
 }
 
 # mca_steam_apply
-# Puts the flags into every Steam installation that has the script, preferring
-# the patch that keeps the file's size and falling back to the one that does
-# not. Returns 1 when there is no Steam to patch at all.
+# Puts the flags into every Steam installation that has the script, and only
+# where that can be done without changing how long the file is. Returns 1 when
+# there is no Steam to patch at all.
 mca_steam_apply() {
-	local root script backup flags found=0 out neutral
+	local root script backup flags found=0 out
 
 	flags="$(mca_flags)"
 
@@ -268,35 +228,21 @@ mca_steam_apply() {
 		found=1
 
 		if mca_steam_script_patched "$script"; then
-			_mca_steam_reneutralise "$script" "$flags" || true
+			_mca_steam_settle "$script" "$flags"
 			continue
 		fi
 
 		_mca_steam_refresh_backup "$script"
 
-		neutral=1
-		if ! { out="$(_mca_steam_build "$script" "$flags" 1)" \
+		# Either the comments can pay for the flag or nothing is written.
+		# A longer file is one Steam reinstalls itself over; a client update
+		# that changed how the helper is started leaves no line to patch at
+		# all. Both end here, and this script is what starts Steam's entire
+		# interface, so leaving it alone is the only safe answer to either.
+		if ! { out="$(_mca_steam_build "$script" "$flags")" \
 			&& _mca_steam_same_size "$script" "$out"; }
 		then
-			neutral=0
-			out="$(_mca_steam_build "$script" "$flags" 0)" || {
-				# A client update changed how the helper is started. Leaving
-				# the file alone is the only safe answer: this script is what
-				# starts Steam's entire interface.
-				mca_note "$(mca_msg "Steam starts its interface in a way this version does not recognise; leaving it alone.")"
-				continue
-			}
-		fi
-
-		# The patch has to grow the file, and it is not patched now but was
-		# before: Steam has just put its own copy back. Patching it again
-		# while the client watches is what turns one size mismatch into an
-		# endless update dialog, and it would not help this session anyway -
-		# the helper is started once, at the start. The patch waits for the
-		# next apply with Steam closed. A patch that keeps the size has
-		# nothing to wait for.
-		if (( ! neutral )) && mca_steam_deferred "$script"; then
-			mca_note "$(mca_msg "Steam is running and has put its own file back; the change waits until Steam is closed.")"
+			mca_note "$(mca_msg "Steam starts its interface in a way this version cannot change without Steam noticing; leaving it alone.")"
 			continue
 		fi
 
@@ -339,23 +285,3 @@ mca_steam_revert() {
 	chmod +x -- "$script" 2>/dev/null || true
 	return 0
 }
-
-# mca_steam_flag_position <packaging>
-# Where Steam's own switch goes on a command line. Straight after the program
-# for a native or snap entry, because Steam reads its options before the
-# steam:// argument that the right-click actions pass. For a Flatpak the first
-# token is flatpak itself, which would take the switch for one of its own and
-# refuse to start, so there it goes at the end of the arguments - after the
-# application id, where flatpak hands everything on to Steam.
-mca_steam_flag_position() {
-	[[ ${1:-native} == flatpak ]] && { printf 'before-fields\n'; return; }
-	printf 'after-program\n'
-}
-
-# mca_steam_desktop_apply <id> <source entry> [packaging]
-# Steam restores its own files at every start unless it is told not to verify
-# them, so the launcher entry carries that switch.
-mca_steam_desktop_apply() {
-	mca_desktop_apply "$1" "$2" "$MCA_STEAM_LAUNCH_FLAG" \
-		"$(mca_steam_flag_position "${3:-native}")"
-}

src/middleclick-autoscroll

@@ -56,10 +56,6 @@ mca_do_enable() {
 
 	mca_ok "$(mca_msg "Autoscroll is on for %d applications." "$MCA_N_ON")"
 
-	if [[ $CFG_STEAM == yes ]] && mca_steam_installed; then
-		mca_note "$(mca_msg "Steam's launcher now skips its file check, which is what keeps the change from being undone at every start.")"
-	fi
-
 	mca_note "$(mca_msg "Applications that are already running pick this up when they are restarted.")"
 }