Show what a run is doing, and record when one is cut short

A run that held back a blocker then upgraded 214 packages printed one line and
then nothing for nearly five minutes while pacman downloaded and installed. It
looked hung, so it got killed - during pacman's uninterruptible commit phase,
which meant the packages landed but our bookkeeping never did. The menu then
kept showing a failure from a previous run on a fully up-to-date machine.

pacman, the AUR helper and flatpak now stream their output when a person is
watching, and the progress bar is left enabled for that case. Timer runs are
unchanged: quiet, --noprogressbar, everything captured in the log.

Interactivity is decided once at startup rather than tested at the point of
use. cau_pacman_flags runs inside a process substitution, so its stdout is
always a pipe and a -t 1 check there would have silently always been false.

INT/TERM/HUP now record last_result=interrupted, so a run that is stopped says
so instead of leaving the previous verdict standing.

src/lib/common.sh

@@ -91,7 +91,14 @@ cau_msg_in() {
 # Output and logging
 # ---------------------------------------------------------------------------
 
-if [[ -t 1 && -z ${NO_COLOR:-} ]]; then
+# Is a person watching? Decided once, here, while stdout is still whatever the
+# process was started with. Testing `-t 1` at the point of use is unreliable:
+# any function called through $(...) or <(...) sees a pipe on stdout and would
+# conclude nobody is there.
+CAU_INTERACTIVE=''
+[[ -t 1 ]] && CAU_INTERACTIVE=1
+
+if [[ -n $CAU_INTERACTIVE && -z ${NO_COLOR:-} ]]; then
 	CAU_C_RESET=$'\033[0m'
 	CAU_C_BOLD=$'\033[1m'
 	CAU_C_DIM=$'\033[2m'
@@ -132,10 +139,19 @@ cau_log_open() {
 	CAU_LOG_OPEN=1
 }
 
-# Runs a command, streaming its combined output into the run log. Returns the
+# Runs a command, capturing its combined output in the run log. Returns the
 # command's exit status.
+#
+# When a person is watching - `cachy-auto-update run` from a terminal - the
+# output is shown as well. Building an AUR package or pulling a few hundred
+# megabytes of Flatpak can take minutes, and silence for that long is
+# indistinguishable from a hang.
 cau_run_logged() {
 	if [[ -n ${CAU_LOG_OPEN:-} ]]; then
+		if [[ -n $CAU_INTERACTIVE ]]; then
+			"$@" 2>&1 | tee -a "$CAU_RUNLOG"
+			return "${PIPESTATUS[0]}"
+		fi
 		"$@" >> "$CAU_RUNLOG" 2>&1
 	else
 		"$@" >&2

src/lib/menu.sh

@@ -81,6 +81,10 @@ cau_ui_status() {
 		printf '\n  %s%s%s\n' "$CAU_C_YELLOW" \
 			"$(cau_msg "The last run reported a problem - see 'cachy-auto-update log'.")" \
 			"$CAU_C_RESET"
+	elif [[ $result == interrupted ]]; then
+		printf '\n  %s%s%s\n' "$CAU_C_YELLOW" \
+			"$(cau_msg "The last run was stopped before it finished.")" \
+			"$CAU_C_RESET"
 	fi
 	if [[ $reboot == 1 ]]; then
 		printf '\n  %s%s%s\n' "$CAU_C_YELLOW" \

src/lib/pkg_pacman.sh

@@ -15,13 +15,35 @@ CAU_PACMAN_HELD=''
 
 # Base flags for every unattended pacman invocation.
 cau_pacman_flags() {
-	printf '%s\n' --noconfirm --color never --noprogressbar --disable-download-timeout
+	printf '%s\n' --noconfirm --color never --disable-download-timeout
+
+	# A progress bar is worth having when somebody is watching a `run` from a
+	# terminal; in the timer's log it is only carriage-return noise.
+	[[ -n $CAU_INTERACTIVE ]] || printf '%s\n' --noprogressbar
+
 	local pkg
 	for pkg in $CFG_IGNORE_PKG; do
 		printf '%s\n' --ignore "$pkg"
 	done
 }
 
+# _cau_pacman_exec <logfile> <pacman args...>
+# Captures pacman's output for classification, and streams it as well when a
+# person is watching. Upgrading a few hundred packages takes minutes; without
+# this an interactive run shows one line and then nothing at all, which is
+# indistinguishable from a hang and invites someone to kill it mid-transaction.
+_cau_pacman_exec() {
+	local log="$1"
+	shift
+
+	if [[ -n $CAU_INTERACTIVE ]]; then
+		pacman "$@" 2>&1 | tee "$log"
+		return "${PIPESTATUS[0]}"
+	fi
+
+	pacman "$@" > "$log" 2>&1
+}
+
 # cau_pacman_pending
 # Fills CAU_PACMAN_PENDING and returns 1 when there is nothing to do.
 cau_pacman_pending() {
@@ -121,7 +143,7 @@ cau_pacman_update() {
 	local attempt=0 b
 
 	while true; do
-		if pacman -Syu "${flags[@]}" "${extra[@]}" > "$log" 2>&1; then
+		if _cau_pacman_exec "$log" -Syu "${flags[@]}" "${extra[@]}"; then
 			cat "$log" >> "$CAU_RUNLOG" 2>/dev/null
 			grep -E '^(removing|replacing) ' "$log" 2>/dev/null \
 				| while read -r line; do cau_info "  $line"; done