fix: Ctrl-D at a confirm prompt aborts out loud, not in silence (#111)

confirm() and uninstall_confirm() read the operator's answer with a bare
'read -r reply'. Ctrl-D makes read return non-zero, set -euo pipefail ends
the run on that line, and the case below — the only thing that ever says
"aborted." — is never reached. box exits 1 having printed nothing after
the question it just asked.

The cure is one token in each, 'read -r reply || die "aborted."', the same
one heavy-duty/rig#43 applied to rig's credential prompts.

The three answers a human can give (y, n, Ctrl-D) are now driven on a real
pty via util-linux 'script'. They were structurally untested before —
'[ -t 0 ]' sends a terminal-less suite to the refusal branch, so every
existing check stopped there, which is how this survived four releases.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -79,6 +79,31 @@ which records not just what changed but what each drill run proved.
   misnumbered one, and an operator sent to correct a version number that is
   already right will not find the real problem. Matches
   heavy-duty/rig#67, so the three repos agree.
+- **Ctrl-D at a confirmation prompt aborts out loud, instead of exiting
+  in silence** (#111) — `confirm()` and `uninstall_confirm()` both took
+  the operator's answer with a bare `read -r reply`. Every answer a
+  human can type routes through the `case` below it and ends at a
+  `return` or at `die "aborted."` — every answer except EOF. Ctrl-D
+  makes `read` return non-zero, `set -euo pipefail` ends the run on that
+  line, and the `case` is never reached: box exits 1 having printed
+  nothing at all after the question it just asked. It fails closed,
+  which is why this is a small fix and not an incident — nothing is
+  destroyed, the abort is real. The damage is that the tool goes mute at
+  the one moment it had the operator's full attention, and someone who
+  Ctrl-Ds out of `box rm work` cannot tell from the output whether the
+  box is still there. The cure is one token in each function,
+  `read -r reply || die "aborted."`, the same one heavy-duty/rig#43
+  applied to rig's credential prompts so the two repos read alike. The
+  bug predates everything it touches — `rm` has carried a confirm gate
+  for as long as the verb has existed — but #105 took the number of
+  verbs reaching that line from one to two, and both are irreversible,
+  which is the argument for closing it now rather than the next time
+  someone notices. The three answers a human can actually give (`y`,
+  `n`, and Ctrl-D) are now driven for real on a pty via util-linux
+  `script`: they were structurally untested before, because `[ -t 0 ]`
+  sends a terminal-less suite to the refusal branch and every existing
+  check stopped there — which is exactly how this survived four
+  releases.
 - **`box restore` asks before it destroys — and the confirmation prompt is
   now the row's, not rm's** (#105) — `restore` and `rm` both irreversibly
   discard user state, and only one of them asked. The table gave `restore`

bin/box

@@ -823,7 +823,9 @@ confirm() {   # $1 = prompt. --force, or a TTY to ask on, or we refuse.
   [ -t 0 ] || usage_error "refusing to $1 without --force (no terminal to confirm on)"
   local reply
   printf 'box: %s? this cannot be undone. [y/N] ' "$1"
-  read -r reply
+  # EOF (Ctrl-D) is an answer, and it means no. Unguarded, 'read' returns
+  # non-zero and 'set -e' ends the run in silence — heavy-duty/rig#43.
+  read -r reply || die "aborted."
   case "$reply" in y|Y|yes|YES|Yes) return 0 ;; *) die "aborted." ;; esac
 }
 
@@ -1651,7 +1653,8 @@ uninstall_confirm() {   # $1 = question. --force, or BOX_YES=1, or a TTY.
   [ -t 0 ] || usage_error "refusing to $1 without --force (no terminal to confirm on; BOX_YES=1 also means yes)"
   local reply
   printf 'box: %s? [y/N] ' "$1"
-  read -r reply
+  # Same EOF cure as confirm() above — Ctrl-D must abort out loud.
+  read -r reply || die "aborted."
   case "$reply" in y|Y|yes|YES|Yes) return 0 ;; *) die "aborted." ;; esac
 }
 

test/cli.sh

@@ -890,6 +890,54 @@ check "dispatch: the confirm prompt comes from the row, not a constant (#105)" 0
 # Pinned here because the rehearsal itself needs a daemon and this suite has none.
 check "rehearsal: the unattended restore passes --force (#105)" 0 "" \
   grep -qF 'box restore mine s1 --force' "$ROOT/drill/multiuser.sh"
+# --- the three answers a human can give — DRIVEN ON A REAL PTY (#111) -------
+# Everything above stops at the no-TTY refusal, because confirm() branches on
+# '[ -t 0 ]' and this suite has no terminal. So the interactive half — 'y',
+# 'n', and Ctrl-D — had never been executed here at all, which is precisely
+# how #111 survived: an unguarded 'read' returns non-zero on EOF, 'set -e'
+# ends the run before the 'case', and the abort happens in total silence.
+#
+# 'script' from util-linux gives the child a pty, so box takes the interactive
+# branch for real and reads the answer we write to the master side. This does
+# NOT hang a suite run from a terminal: script's own stdin is a file or
+# /dev/null on every run below, never the developer's tty, so the answer (or
+# the EOF) is always already waiting.
+if command -v script >/dev/null 2>&1 && script --version 2>/dev/null | grep -q util-linux; then
+  PWORK="$(mktemp -d)"; PLOG="$PWORK/pty.log"
+  printf 'y\n' > "$PWORK/yes"; printf 'n\n' > "$PWORK/no"
+  # Invoked through a file so 'script -c' needs no quoting of its own; the log
+  # path and the shim PATH ride the environment script hands to the child.
+  cat > "$PWORK/run" <<RUNNER
+#!/usr/bin/env bash
+exec env PATH="$CSHIM:\$PATH" "$BOX" rm work
+RUNNER
+  chmod +x "$PWORK/run"
+  ptybox() {  # ptybox <answers-file> — 'box rm work' on a pty, answered
+    : > "$PLOG"
+    FAKE_INCUS_LOG="$PLOG" script -qec "$PWORK/run" /dev/null < "$1"
+  }
+  # The load-bearing assertion is the MESSAGE, not the exit code: before the
+  # fix Ctrl-D also exited 1, just without ever saying why. Asserting on the
+  # code alone would pass against the bug.
+  check "rm: Ctrl-D at the prompt aborts OUT LOUD, not in silence (#111)" \
+    1 "aborted." ptybox /dev/null
+  check "rm: ...and the Ctrl-D abort really deleted nothing (#111)" 1 "" \
+    grep -qF 'incus delete' "$PLOG"
+  check "rm: 'n' at the prompt aborts (#111)" 1 "aborted." ptybox "$PWORK/no"
+  check "rm: ...and 'n' really deleted nothing (#111)" 1 "" \
+    grep -qF 'incus delete' "$PLOG"
+  # The accept path, so the pty rig is proven to be able to reach the work —
+  # three checks that can only ever refuse would pass against a box that
+  # refuses everything.
+  check "rm: 'y' at the prompt goes through (#111)" 0 "removed work" \
+    ptybox "$PWORK/yes"
+  check "rm: ...and 'y' really reached 'incus delete -f' (#111)" 0 "" \
+    grep -qF 'incus delete -f work' "$PLOG"
+  rm -rf "$PWORK"
+else
+  echo "skip: the interactive confirm answers (no util-linux 'script' here; CI has it)"
+fi
+
 rm -rf "$CSHIM" "$CWORK"
 
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