Show live per-run rows during runs, hidden before the summary

Display the script's per-run timing rows as progress while the benchmark
runs. On a tty without --details they are shown on the alternate screen and
discarded when we switch back to the main screen just before the summary, so
they never clutter the final output regardless of how much scrolls. With
--details they stay on the main screen; off a tty they are suppressed
(summary only). dtest's own output is captured, not shown.

Replaces the old transient per-run rows, whose ANSI line-clearing could not
erase content that had scrolled off-screen.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: tameware

benchmark.sh

@@ -55,6 +55,12 @@ BRANCH_TMP=""
 BUILD_LOG=""
 
 cleanup() {
+  # Leave the alternate screen first so any restore/error messages and the shell
+  # prompt land on the normal screen.
+  if [[ "${ALT_SCREEN_ACTIVE:-0}" == "1" ]]; then
+    printf '\033[?1049l' >/dev/tty 2>/dev/null || true
+    ALT_SCREEN_ACTIVE=0
+  fi
   if [[ -n "$ORIG_BRANCH" ]]; then
     local cur
     cur="$(git -C "$ROOT" symbolic-ref --quiet --short HEAD 2>/dev/null \
@@ -468,6 +474,7 @@ run_dtest() {
   # Wrap with `time -p` so we can capture wall-clock elapsed for this run. Its
   # "real/user/sys" lines go to the merged output but do not collide with the
   # dtest lines parse_dtest_output looks for.
+  #
   local out
   if ! out="$(/usr/bin/time -p "${cmd[@]}" 2>&1)"; then
     echo "error: dtest failed: ${cmd[*]}" >&2
@@ -487,40 +494,18 @@ run_dtest() {
   echo "$parsed $wall"
 }
 
-progress_lines=0
-TRANSIENT_PROGRESS=0
 show_run_lines=1
 
 print_run_table_header() {
   printf "%-6s %-13s %7s %8s %8s %10s %6s %s\n" \
     "solver" "file" "ver" "user_ms" "sys_ms" "avg_user" "ratio" "run"
   printf "%-6s %-13s %7s %8s %8s %10s %6s %s\n" \
     "------" "-------------" "-------" "--------" "--------" "----------" "------" "---"
-  if [[ "$TRANSIENT_PROGRESS" == "1" ]]; then
-    progress_lines=$((progress_lines + 2))
-  fi
 }
 
 print_run_row() {
   printf "%-6s %-13s %7s %8s %8s %10s %6s %s\n" \
     "$1" "$2" "$3" "$4" "$5" "$6" "$7" "$8"
-  if [[ "$TRANSIENT_PROGRESS" == "1" ]]; then
-    progress_lines=$((progress_lines + 1))
-  fi
-}
-
-clear_transient_progress() {
-  if [[ "$TRANSIENT_PROGRESS" != "1" || $progress_lines -le 0 ]]; then
-    return
-  fi
-  # Cursor rests on a blank line below the last row; erase it, then each table line.
-  # Do not move up after clearing the topmost line (would hit the header above).
-  printf '\033[2K'
-  local i
-  for (( i = 0; i < progress_lines; i++ )); do
-    printf '\033[1A\033[2K'
-  done
-  progress_lines=0
 }
 
 echo "DDS dtest benchmark"
@@ -572,16 +557,28 @@ if ((${#DTEST_EXTRA[@]} > 0)); then
 fi
 echo
 
+# The per-run rows are the script's live progress. With --details they are kept
+# in the final output. Without --details, on a tty, they are shown on the
+# alternate screen so the user sees progress, then discarded when we switch back
+# to the main screen just before the summary; off a tty they are suppressed
+# (summary only), since there is nothing to hide them.
 show_run_lines=0
-TRANSIENT_PROGRESS=0
-# Per-run rows are detail: show them only with --details. Without it they are
-# suppressed entirely (no transient progress table, which could otherwise scroll
-# off-screen and leave residue). The summary is always shown regardless.
-if [[ "$DETAILS" == "1" ]]; then
-  show_run_lines=1
+ALT_SCREEN=0
+if [[ "$DRY_RUN" != "1" ]]; then
+  if [[ "$DETAILS" == "1" ]]; then
+    show_run_lines=1
+  elif [[ -t 1 ]]; then
+    show_run_lines=1
+    ALT_SCREEN=1
+  fi
 fi
 
-if [[ "$DRY_RUN" != "1" && ( "$show_run_lines" == "1" || "$TRANSIENT_PROGRESS" == "1" ) ]]; then
+if [[ "$ALT_SCREEN" == "1" ]]; then
+  printf '\033[?1049h\033[H\033[2J' >/dev/tty   # enter alt screen, home, clear
+  ALT_SCREEN_ACTIVE=1
+fi
+
+if [[ "$DRY_RUN" != "1" && "$show_run_lines" == "1" ]]; then
   print_run_table_header
 fi
 
@@ -611,7 +608,7 @@ for solver in "${SOLVERS[@]}"; do
 
         read -r user sys avg ratio wall < <(run_dtest "$bin" "$solver" "$hands")
 
-        if [[ "$show_run_lines" == "1" || "$TRANSIENT_PROGRESS" == "1" ]]; then
+        if [[ "$show_run_lines" == "1" ]]; then
           print_run_row "$solver" "$file" "$ver" "$user" "$sys" "$avg" "$ratio" "$run_label"
         fi
 
@@ -623,7 +620,12 @@ for solver in "${SOLVERS[@]}"; do
   done
 done
 
-clear_transient_progress
+# Return to the normal screen, discarding the live dtest output, before the
+# summary so the final output is just the header and the summary.
+if [[ "$ALT_SCREEN" == "1" ]]; then
+  printf '\033[?1049l' >/dev/tty
+  ALT_SCREEN_ACTIVE=0
+fi
 
 if [[ -n "${COMPARE:-}" && "$DRY_RUN" != "1" ]]; then
   echo  # compare summary (two binaries)