a0524f88

test: e2e — the first mux on a machine writes the wall it just started

a73x 2026-08-28 19:53

Commit message

test: e2e — the first mux on a machine writes the wall it just started

The empty-file entry — the spec's first e2e bullet — was pinned nowhere:
e2e_09's auto-start leg pre-writes the line it checks, so a `recordHost`
that never ran on the no-file path would have left the suite green.

A leg with no hosts file at all, on a pty, with a runtime dir of its own:
bare `mux` starts the local daemon, and the file it leaves behind holds
exactly the line `--sock $XDG_RUNTIME_DIR/muxd.sock` — one line, since a
machine with no file is a wall of one. The shell on the grid is asked of
the OS: its pid's parent is the daemon `mux` started, not what the daemon
says about itself.

The suite's checkpoint pin goes 81 -> 82.

test/e2e.sh

Old		New
@@ -177,8 +177,8 @@ done
177	# one of those and adds a convergence point would be pinning a fact every	177	# one of those and adds a convergence point would be pinning a fact every
178	# leg above already establishes.	178	# leg above already establishes.
179		179
180	[ "$OK_COUNT" = "81" ] \|\| {	180	[ "$OK_COUNT" = "82" ] \|\| {
181	echo "e2e FAIL: $OK_COUNT scenario checkpoints ran, the pin says 81 —"	181	echo "e2e FAIL: $OK_COUNT scenario checkpoints ran, the pin says 82 —"
182	echo " a scenario was added (update the pin) or silently lost"	182	echo " a scenario was added (update the pin) or silently lost"
183	exit 1	183	exit 1
184	}	184	}

test/e2e_09_hosts.sh

@@ @@ -30,6 +30,15 @@ HARUN="${TMPDIR:-/tmp}/mux-e2e-hosts-run-$$" @@
+defer_rm "$HARUN"
+HASOCK="$HARUN/muxd.sock"
+defer_sock "$HASOCK"
+# The empty-file leg: a state home with NO hosts file at all — a machine
+# where `mux` has never run — and, like the auto-start leg, a runtime dir of
+# its own so the daemon it starts is this leg's and not the developer's.
+HESTATE="${TMPDIR:-/tmp}/mux-e2e-hosts-empty-$$"
+defer_rm "$HESTATE"
+HERUN="${TMPDIR:-/tmp}/mux-e2e-hosts-empty-run-$$"
+defer_rm "$HERUN"
+HESOCK="$HERUN/muxd.sock"
+defer_sock "$HESOCK"
+# The `x` leg builds and eats its own daemon's session, so it reads a wall
+# of ONE host and gets a state home nothing else writes.
+HXSTATE="${TMPDIR:-/tmp}/mux-e2e-hosts-x-state-$$"
+HAPID=""
+ok "mux records the daemon on the wall, never a session, and starts a listed local one that is gone"
+# ---- the empty file: the first `mux` on a machine writes the wall --------
+#
+# The other end of the auto-start rule, and the only leg where the file
+# does not exist when `mux` starts. Bare `mux` with nothing listed is the
+# local daemon: it starts one, attaches, and the attach writes the line
+# that makes every later `mux` a wall. Nothing here pre-writes anything —
+# a leg that seeds the file cannot see a `recordHost` that never ran.
+mkdir -p "$HERUN"
+[ ! -e "$HESTATE" ] || { echo "e2e FAIL: hosts: the empty-file leg's state home already exists"; exit 1; }
+[ ! -S "$HESOCK" ] || { echo "e2e FAIL: hosts: the empty-file leg's socket is already served"; exit 1; }
+set +e
+SHELL=/bin/sh PATH="$(dirname "$MUXD"):$PATH" XDG_RUNTIME_DIR="$HERUN" \
+    XDG_STATE_HOME="$HESTATE" timeout 60 "$PTYCLIENT" --cols 80 --rows 24 \
+    --out "$OUT.hempty" --err "$OUT.hempty.err" -- "$MUX" > "$OUT.hempty.log" 2>&1 <<'EOF'
+expect \x1b[?1049h 20000
+settle 600 20000
+send echo hepid=$$\n
+expect hepid= 20000
+settle 600 20000
+send \x1cd
+waitexit 10000
+EOF
+RC=$?
+set -e
+[ "$RC" -eq 0 ] || {
+    echo "e2e FAIL: hosts: the empty-file leg exited $RC (did bare mux start a local daemon?):"
+    cat "$OUT.hempty.log"; cat "$OUT.hempty.err" 2>/dev/null; exit 1; }
+HEPID=$(sed -n 's/.* pid=\([0-9]*\).*/\1/p' "$OUT.hempty.err" | head -1)
+defer_kill "$HEPID"
+[ -n "$HEPID" ] || {
+    echo "e2e FAIL: hosts: the empty-file leg printed no daemon pid to hold onto:"
+    cat "$OUT.hempty.err"; exit 1; }
+# The file the attach wrote: the DAEMON it reached, and nothing else. One
+# line, because a wall of one is what a machine with no file has.
+[ -f "$HESTATE/mux/hosts" ] || {
+    echo "e2e FAIL: hosts: the first mux wrote no hosts file under $HESTATE"; exit 1; }
+grep -qxF -- "--sock $HESOCK" "$HESTATE/mux/hosts" || {
+    echo "e2e FAIL: hosts: the empty file did not gain the local daemon's line:"
+    cat "$HESTATE/mux/hosts"; exit 1; }
+[ "$(wc -l < "$HESTATE/mux/hosts")" = "1" ] || {
+    echo "e2e FAIL: hosts: the first mux wrote more than the daemon it attached to:"
+    cat "$HESTATE/mux/hosts"; exit 1; }
+# ...and the session behind that line is a real shell, asked of the OS: the
+# pid the grid shows is a live process whose parent is the daemon `mux`
+# started. A daemon reporting on itself cannot catch itself being wrong.
+HESH_PID=$("$MUXD" dump --sock "$HESOCK" | sed -n 's/.*hepid=\([0-9]*\).*/\1/p' | tail -1)
+[ -n "$HESH_PID" ] || {
+    echo "e2e FAIL: hosts: the empty-file leg's grid shows no shell pid:"
+    "$MUXD" dump --sock "$HESOCK"; exit 1; }
+[ "$(ps -o ppid= -p "$HESH_PID" 2>/dev/null | tr -d ' ')" = "$(real_pid "$HEPID")" ] || {
+    echo "e2e FAIL: hosts: the shell on the grid is not the auto-started daemon's child"
+    ps -o pid,ppid,args -p "$HESH_PID" 2>&1; exit 1; }
+assert_stopped "$HESOCK" "$HEPID" "hosts empty file" "$OUT.hestop"
+HEPID=""
+ok "the first mux on a machine starts the local daemon and writes it down"
+# ---- every live session of every listed daemon is a tile ----------------
+# The headline. Two daemons on the wall, four sessions between them, and