tooling: pr-reviews polls past the second poll; stale harness lock names its fix

improvise-7epn: two cases on the one-tick-per-read clock. One resolves on
poll 3, and one times out after polling up to the deadline. Replacing the
post-poll deadline check with `break` now fails exactly those two
(23 passed, 2 failed), where before it left the suite 23/23.

improvise-lnsh: when `cargo metadata --locked` refuses the opfs-contract
lock, build.sh now says not to remove --locked and names
`cargo update -w --manifest-path harness/opfs-contract/Cargo.toml`.
Checked by hand against a lock with pest pinned to 2.9.1. Evidence is in
context/test-evidence/tooling.md.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze

context/test-evidence/tooling.md

@@ -763,3 +763,50 @@ to spare a harness directory. `opfs.spec.js` instead asserts `/opfs/index.html`
 is served, naming the fix. Injected by running `web/assemble.sh harness/serve`
 alone: 4 chromium failures, each carrying that message, where it used to fail
 with no hint of the cause.
+
+### Polling past the second poll — `scripts/pr-reviews-test.sh` (improvise-7epn)
+
+**What was unguarded.** Every multi-poll fixture resolved on poll 2, and the
+timeout case expects exit 1 whether the loop polls twice or twenty times. So
+replacing the post-poll deadline check with an unconditional `break` left the
+suite at 23 passed, 0 failed, and `--wait N` would have polled at most twice.
+
+**Two cases, both on the one-tick-per-read clock.** "a review arriving on the
+third poll is seen" empties polls 1 and 2 and puts an inline comment at the head
+in `last`, with `--wait 10`, and asserts exit 0 *and* exactly 3 polls. "--wait
+keeps polling until its deadline" runs the empty fixture with `--wait 5` and
+asserts exit 1 after at least 5 polls. The second one is the timeout path. Its
+exit code alone cannot tell a loop that stopped early from one that reached the
+deadline, so it counts polls.
+
+**Rival, injected and watched.** `break` in place of
+`[ "$(date +%s)" -lt "$deadline" ] || break`: 23 passed, 2 failed. The failures
+were exactly the two new cases, each "exit 1 after 2 polls". The first attempt
+to inject used `sed -i ''`, which the GNU sed on this PATH read as a filename.
+Nothing changed and the suite passed 25/25, which looks like a vacuous rival.
+The second attempt asserted the replacement landed before running.
+
+**Still not covered.** Deleting the check outright makes the timeout case loop
+forever rather than fail. The suite has no wall-clock guard, so that fault shows
+as a hang, not a FAIL.
+
+### A stale harness lock names its remedy — `harness/build.sh` (improvise-lnsh)
+
+**What broke.** With a stale `harness/opfs-contract/Cargo.lock`, `build.sh`
+exited 101 and printed only cargo's text, whose `help:` line says to remove
+`--locked`. That is the one change that brings improvise-mkbp back. The real
+remedy was only in a source comment.
+
+**Reproduced, then fixed, by hand.** Changing `pest`'s locked version from
+`2.9.2` to `2.9.1` in the lock reproduces the stale state. Before the fix:
+exit 101 and cargo's hint only. After: exit 1, and the script's own two lines
+follow cargo's, telling the reader not to remove `--locked` and naming
+`cargo update -w --manifest-path harness/opfs-contract/Cargo.toml`. The lock
+was untouched both times. Running that command on the stale lock restored it
+byte for byte (`cmp` against the committed file). With the committed lock,
+`build.sh` still runs to "harness/serve ready".
+
+**Not automated.** There is no suite for `harness/build.sh`. A test would have
+to corrupt a tracked file and call cargo, which needs the crates.io index, from
+`checkers.sh`, whose environment is scrubbed. The by-hand run above is the
+evidence.

harness/build.sh

@@ -22,7 +22,11 @@ serve="$root/harness/serve"
 # re-resolves the lock itself before any `-- --locked` reaches cargo build.
 # Fix a failure with `cargo update -w` in harness/opfs-contract, and commit it.
 cargo metadata --locked --format-version 1 \
-  --manifest-path "$root/harness/opfs-contract/Cargo.toml" >/dev/null
+  --manifest-path "$root/harness/opfs-contract/Cargo.toml" >/dev/null || {
+  echo "harness/build.sh: harness/opfs-contract/Cargo.lock is stale. Do not remove --locked." >&2
+  echo "  Run: cargo update -w --manifest-path harness/opfs-contract/Cargo.toml, and commit the lock." >&2
+  exit 1
+}
 
 "$root/web/build.sh" >/dev/null
 "$root/web/assemble.sh" "$serve" harness >/dev/null

scripts/pr-reviews-test.sh

@@ -217,6 +217,39 @@ got=$?
 [ "$got" = 0 ] && ok "a second passing before the first re-poll does not skip it" \
   || bad "a second passing before the first re-poll does not skip it" "exit $got, wanted 0"
 
+# Every fixture above resolves by poll 2, so a loop that stops after one
+# re-poll passed them all (improvise-7epn). This one resolves on poll 3.
+d3="$work/arrives-third"
+for n in 1 2; do
+  mk "$d3" "$n.pr.json" <<EOF
+{"headRefOid":"$HEAD","reviews":[]}
+EOF
+  mk "$d3" "$n.inline.json" <<'EOF'
+[]
+EOF
+  mk "$d3" "$n.issue.json" <<'EOF'
+[]
+EOF
+done
+cp -f "$d/last.pr.json" "$d/last.inline.json" "$d/last.issue.json" "$d3/"
+rm -f "$d3/.poll" "$work/ticks"
+CLOCK_TICKS="$work/ticks" PATH="$clock:$PATH" PR_REVIEWS_FIXTURE_DIR="$d3" \
+  "$REVIEWS" 1 --wait 10 --interval 1 > "$work/out" 2>&1
+got=$?
+polls=$(cat "$d3/.poll" 2>/dev/null || echo 0)
+[ "$got" = 0 ] && [ "$polls" = 3 ] && ok "a review arriving on the third poll is seen" \
+  || bad "a review arriving on the third poll is seen" "exit $got after $polls polls, wanted 0 after 3"
+
+# The timeout path: nothing ever arrives, so --wait 5 on a clock that ticks
+# once per read must keep polling until the deadline, then report exit 1.
+rm -f "$work/empty/.poll" "$work/ticks"
+CLOCK_TICKS="$work/ticks" PATH="$clock:$PATH" PR_REVIEWS_FIXTURE_DIR="$work/empty" \
+  "$REVIEWS" 1 --wait 5 --interval 1 > "$work/out" 2>&1
+got=$?
+polls=$(cat "$work/empty/.poll" 2>/dev/null || echo 0)
+[ "$got" = 1 ] && [ "$polls" -ge 5 ] && ok "--wait keeps polling until its deadline" \
+  || bad "--wait keeps polling until its deadline" "exit $got after $polls polls, wanted 1 after 5 or more"
+
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