improvise/context/test-evidence/tooling.md

Test evidence — the repository's own gates

Evidence for the checks in scripts/ and for the tests that hold CI's shape. The arguments behind the checkers themselves are in context/code/tooling.md; this file records what fault each test was watched to catch.

Note what is deliberately absent. scripts/check-comment-runs.py --self-test, scripts/kb-test.sh and scripts/assemble-stamp-test.sh are check-the-checker suites whose cases are already injected faults, and none of their case names is a Rust fn or a JS test( the evidence checker could resolve — so their evidence is the case list itself plus context/code/tooling.md, and inventing headings for them here would be headings naming nothing.

"no test in web/tests/ reaches for a built bundle"

The js CI job runs node --test web/tests/*.test.js and installs nothing; the browser job runs web/tests/bundle/*.test.js after three wasm-pack builds. The moment a flat web/tests/ file reads web/pkg/, the fast job inherits the slow one's dependency — and the likely repair is to add a build step to it, silently spending the ~4m30s the split exists to avoid. Until improvise-4ktt that constraint was a directory convention and a glob, checked by nothing, and it failed in the direction that looks like ordinary breakage: a confusing ENOENT in CI on a machine where the bundle happens not to be built.

Fault injected, 2026-09-21: appended const injected = readFileSync("../pkg/improvise_wasm_client.js"); to web/tests/grid_plan.test.js. The test failed naming that file and pointing at web/tests/bundle/. Reverted; green again.

Two things the test does that a simpler one would not. It asserts its own filename is among the files it scans, so it cannot become the one place a violation may hide. And it strips comments before matching, because this file's own header and the test's header both name the directory in prose — a lexical grep over raw text would have had to exempt them, and an exemption is where the next violation goes.

What it cannot see, stated because the check itself uses the evasion: a path assembled at runtime ("../" + "p" + "kg") is invisible to a lexical match, and the test's own FORBIDDEN constant is built exactly that way to stay out of its own scan. That is a deliberate, disclosed hole — closing it needs a parser, and the failure it would catch is one somebody has to write on purpose, where this gate exists for the one written by accident.

"the subdirectory that MAY use a bundle is not the one being checked"

The companion, and the one that stops the first from passing vacuously. If web/tests/bundle/ were emptied or its files stopped touching the bundle, the first test would still be green while having nothing to be scoped against — "no flat test uses the bundle" is uninteresting if no test anywhere does. This asserts the other half of the split exists and really does what the flat half is forbidden to do.

Fault injected, 2026-09-21: moved web/tests/bundle/wasm_surface.test.js out of the tree. The test failed with "web/tests/bundle/ is empty — the split lost its other half" rather than passing. Restored; green again.

"no test in web/tests/ imports a module that reaches the bundle"

The companion to the lexical check above, and the reason that one is not enough: import "../app.js" needs the bundle transitively and names nothing forbidden, so the js job breaks loudly but unattributed. app.js and worker.js are the two entry points that load the bundle; shell.js and serial.js do not, and serial.test.js imports one legitimately.

Fault injected, 2026-09-21: appended import "../app.js"; to web/tests/grid_plan.test.js. The lexical test stayed green; this one failed naming the file. Reverted.

Note — the checker's own blockers, found by review of PR #83

Two gates in scripts/check-comment-runs.py produced a pass while not doing what their prose said. Both were in the mode the same PR rewrote, which is the part worth keeping: writing the doctrine down does not exempt the writer.

A leaf name is not an identity. Six leaf names collide in this workspace and two were cited in evidence. Renaming ui::project::tests::a_load_that_fails_is_not_a_rebase — the one its entry describes — left the checker printing all name a test that runs, exit 0, with the heading answered by the ui::host::tests namesake. Now an ambiguous leaf is refused with both candidates named, and the two entries are qualified. Re-verified both ways, 2026-09-21: the refusal fires on the unqualified headings and names exactly those two; with the heading qualified, the same rename is reported as an orphan rather than absorbed.

--rust-tests was strictly more permissive and said the same words. It called cargo_test_names with one argument, so the --ignored subtraction never ran, and the success line was byte-identical to the honest path's. Injecting ### eyeball_the_rendered_hints_and_pages orphaned on the default path and passed on the flag's. Now the flag requires --rust-tests-ignored (one alone exits 2) and the success line names its source.

A missing evidence directory exited 0. The early return preceded the citation scan, so deleting context/test-evidence/ reported nothing while 170 citations pointed at a directory that was not there. Verified 2026-09-21 by moving the directory aside: exit 1, 170 tests cite context/test-evidence and have no entry there.

Note — the flag that selected the cap away (improvise-ijql)

scripts/check-comment-runs.py --check-evidence early-returned in main, so the flagged run never answered the comment-run cap and printed nothing about having skipped it. The reviewer's position when it was first raised was that CI runs all three spellings (ci.yml, the three check-comment-runs.py steps in the test job) so this was documentation only. The counter that carried is that the flagged form is the expensive one — it needs a compiled workspace — which makes it the one a human runs alone; three agents hit it independently in one campaign, and in one case a local gate went green while CI went red on a three-line doc comment.

Reproduced before the fix, 2026-09-21, in a temporary tree holding one .rs file with a four-line comment run:

$ check-comment-runs.py src --check-evidence --rust-tests … --rust-tests-ignored …
test-evidence: 0 entries, all name a test that runs …
EXIT=0
$ check-comment-runs.py src
1 comment runs longer than 2 lines:
  src/bad.rs:1  4 lines
EXIT=1

Two invocations over one tree, opposite verdicts, and the one that exits 0 is the one a human is more likely to run by itself.

The guard is _dispatch_self_test, which runs the script as a subprocess — the only level at which this is visible, since every unit in the file was correct and the defect was in main's dispatch. Both arms were demonstrated:

injected fault	what failed
restore the --check-evidence early return	DISPATCH: --check-evidence: exited 0 over a four-line comment run
make the cap always report a violation	DISPATCH: bare: refused a clean tree and the same for --check-evidence

The second arm is what stops an always-failing cap from satisfying the first, and it is why SELF_TEST_DISPATCH asserts a clean tree passes as well as a dirty one failing. Why the fix is additive rather than a printed disclaimer, and why --self-test/--list-doctests are excluded from the table rather than exempted from the rule: context/code/tooling.md §2, "A flag adds a question".

Note — the stamp gate's discrimination, measured

scripts/assemble-stamp-test.sh separates three outcomes rather than two, which is what makes it evidence rather than a smoke test. Measured 2026-09-21 over its nine cases: the real script passes 9; deleting the final test -z "$missing" (the PR #69 injection, which the inline version survived at exit 0) passes 4 and fails 5; a script that does nothing passes 2; one that always fails passes 0.

The PR body first cited "4 of 9" for the middle row, from a run taken when the suite had eight cases. A figure is what the next reader checks, so it is recorded here where it can be re-measured rather than only in a message nothing can audit (design-principles §6).

Note — the stamp gate matches literally

scripts/assemble-stamp.sh greps with -F. As a regex, the . in improvise_wasm_client.js?v=abc matches any character, so a stamp corrupted in exactly that position reads as present — a pass in the one direction a guard must not fail in. Inherited from the inline version this was extracted from, and found by reading the extraction rather than by anything failing.

Fault injected, 2026-09-21: dropping the -F makes improvise_wasm_clientXjs?v=abc satisfy the pattern, and a pattern is matched literally, not as a regex goes from pass to fail.

Note — the doc site's derived checks

scripts/build-doc-site.mjs carries two gates that no test names, because the generator is the test: it runs on every assembly and exits non-zero.

Faults injected, 2026-09-21, each observed:

injected	reported
a new context/code/newarea.md	context/code/newarea.md is neither published nor a named omission
context/plan.md moved out of the tree	context/plan.md is listed as omitted but does not exist
a line appended below the generator in web/assemble.sh	web/assemble.sh must invoke this generator LAST, naming the offending command
a trailing echo "see scripts/build-doc-site.mjs"	the same, once the check asks for an INVOCATION rather than a mention — .includes had accepted it (review, PR #83)

scripts/check-ci-graph.py is the third, and it is a script rather than a stanza because its own refusals need checking: adding a zz-new-check: job to ci.yml reports pages-deploy does not need zz-new-check and exits 1, where before the rule was prose and nothing noticed. Its five self-test graphs include the one a naive parse gets wrong — another job's needs: read as the deploy's.

The second arm is the one that would not get written first, and it is the point: without it, deleting or renaming an omitted file leaves an entry asserting a reason for a file nobody can find — the same failure as a dead ticket id, which AGENTS.md already calls worse than no id.

The first arm was filed as latent and was live when it was written: context/code/kb-tool.md had been unpublished, unargued and unnoticed since it was added.

Duplicate evidence headings — SELF_TEST_DUPLICATES

improvise-hsoe. --check-evidence verified that a heading names a test that runs, and a duplicate heading names one just as well, so both copies pass. PR #92 shipped two entries under a_layout_change_moves_the_layout_version_and_no_record, and two more pairs sat in tui.md — one of them asserting that THE_MEMBERSHIP_CORRECT_SPANS was "a live tripwire, do not remove it" some four hundred lines above the entry recording that improvise-gd83 had removed it. A reader meeting the older copy first takes it as current, which is worse than an orphan: an orphan announces itself as broken.

The fault is injected by the six cases in SELF_TEST_DUPLICATES, and three of them are the ones that would not get written first. Two different tests sharing a leaf must come back ambiguous and not duplicate, because the wrong diagnosis files the wrong repair. A prose heading must be free to repeat, because it claims no test. And the bare and module-qualified spellings of one test must collide — grouping by the string rather than by the resolved test would have missed exactly the case improvise-rm4s's qualification repair creates, which is the first way this would have come back.

The live tree was itself the first injection: before the three merges the check exited 1 naming all three pairs with both line numbers; after them it exits 0. The clean arms (two headings naming two tests, and prose repeated) are what stop an always-refuse from satisfying the rest.

The PR review reader's own suite — scripts/pr-reviews-test.sh

improvise-xgra. Like kb-test.sh and pr-watch-test.sh, its cases are already injected faults and none of their names is a Rust fn the evidence checker could resolve, so the case list is the evidence. What is recorded here is the five faults it was watched to fail against, and which case caught each — a suite that only asked "did it print something" passes all five.

Fault 1, the inline surface dropped entirely, which is the live bug as it shipped: inline: [] in both fetch paths. Eight cases fail, including both --wait arms. This is the one that matters, because the old script's behaviour was this fault and it exited 0 on PR #122's review body while printing none of the five rulings underneath it.

Fault 2, an inline comment counted rather than compared: ((.inline|length) > 0) in place of the commit_id == head test. One case fails, an inline comment at an EARLIER head does not satisfy --wait, and that is the pair the two inline fixtures exist to discriminate — the at-head case passes under this fault, so on its own it proves nothing.

Fault 3, the time sort dropped (| . for | sort_by(.at)). Only the three surfaces interleave in time order fails: it reads the three bodies back as SECOND THIRD FIRST, the per-endpoint concatenation order. Every content assertion still passes, because each body is still printed.

Fault 4, no original_line fallback. Only the outdated-comment case fails. line is null exactly when the line has moved under the comment, so a renderer reading .line alone prints draw.rs:null on precisely the comments whose location is hardest to recover by hand.

Fault 5, --wait widened to any issue-level comment. Only an issue-level comment does not satisfy --wait fails. That is the fault a well-meaning repair would introduce — "wait for anyone to say anything" — and the fixture that separates it is a PR thread comment with no commit_id at all.

Two cases are there for the contract rather than the bug: a review body at the current head still satisfies --wait and --wait 0 over an empty PR is success, because other briefs depend on exit 0 and exit 1 meaning what they did before. no PR number is exit 4 pins the third code, which is distinguishable from 1 only if nothing collapses them.

the usage warns about a trailing $? reader asserts a sentence rather than a behaviour, which is unusual and deliberate: the ; echo "exit=$?" trap costs a wrong diagnosis every time it is hit, the warning is the only guard against it, and a header is exactly the thing a later edit trims without noticing.

Three more cases were added after ChatGPT Codex reviewed PR #133, and the pair of bugs it found is the reason the suite has to run in CI rather than only on the author's machine. Both produce exit 2 with no output whatsoever, which is jq refusing an invalid --argjson — so a shell fault at the top of the script arrives wearing jq's exit code, and 17 of 19 cases failed identically with nothing to read.

The first, a multi-assignment local whose third clause reads its first, is fine on macOS's bash 3.2 and fatal on bash 5 under set -u. The suite passed 19/19 locally and 2/19 in CI on the same commit, which is the case for wiring it into the kb job in the same change rather than afterwards.

The second is gh api --paginate emitting one array per page. Fault 6 removes | pages_to_array from the fixture path and exactly the three new cases fail — a comment on the first page survives pagination, …the second page…, and a paginated thread still satisfies --wait (exit 2, the live signature). The fixture carries two concatenated arrays and both paths flatten through the same helper; a fixture holding one array could not have caught this, because it would exercise a shape the live fetch never produces. No PR in this repo has yet had enough inline comments to reach a second page, so the test is the only thing that will ever see it before a user does.

The checker runner's own suite — scripts/checkers-test.sh

The bug behind improvise-f9qf was invisible to a local run, so the evidence that matters here is not "the suite is green" but "the suite goes red when the fault is put back, in the place the fault was not seen."

The fault, injected against the real script. Restoring pr-reviews' multi-assignment local — the exact text 051f541 replaced — and running the suite three ways on one machine in one sitting:

gate	result
sh scripts/pr-reviews-test.sh (the old local gate)	22 passed, 0 failed
direnv exec . ./scripts/pr-reviews-test.sh	22 passed, 0 failed
./scripts/checkers.sh pr-reviews	2 passed, 20 failed, exit 1

The middle row is the one that earns the design. The dev shell supplies the correct bash and would still have shipped this, because pkgs.mkShell exports name and the broken clause read $name. Only scrubbing the environment as well as pinning the shell makes the fault visible, and the 2/20 shape matches the 2/19 CI actually reported.

checkers-test.sh itself is twelve cases, and each injects rather than asserts. The two that carry the argument:

• a suite reading an inherited dev-shell variable fails under the runner — a fixture suite whose body is echo "$name" under set -euo pipefail, run with name=nix-shell-env exported, exactly as direnv leaves it. It is paired with and passes when run directly with that variable exported, which asserts the same fixture passes the old way. Without that pair the first case is a test of set -u and proves nothing about the runner.
• a bash-3.2-only construct fails under the runner's pinned bash — a fixture suite containing local a="$1" b="$a/x", which is the bug's shape reduced to two lines. Green on bash 3.2, fatal on bash 5.

The rest separate the runner's outcomes from each other: a #!/bin/sh script in the directory is refused and the same sandbox passes once it is removed (so the refusal is not standing in for some other complaint); a failing suite fails and a passing one passes; an old bash with no nix is exit 3 rather than a quiet run; an unknown suite name is exit 4 rather than a silent no-op; and --list names exactly the suites present, including the case where an X-test.sh has no X beside it — scripts/node-test.sh is a test runner, and the first version of the glob ran it as a suite, where it printed its usage inside a green gate.

What is asserted about the runner's own environment, and what is not. The allowlist is checked only in the sense that seven real suites pass through it; there is no case asserting a particular name is absent beyond name. A suite that grows a dependency on some other inherited variable will fail loudly on first run rather than be caught here. Stated rather than guarded.

The two-workspace fmt gate — scripts/fmt-workspaces-test.sh

The bug (improvise-b4ks) was a gate decoupled from what it checks while wearing the exit code of a real failure. From the repo root, cargo fmt -p opfs-contract -- --check exits 1 with package 'opfs-contract' is not a member of the workspace — --check never runs. A caller reading $? cannot tell "this crate is misformatted" from "nothing was checked", so the gate could neither report success when the crate was dirty nor failure when it was clean. Reproduced at 7cef9f8, exit 1, before any fix.

scripts/fmt-workspaces.sh replaces it: it discovers every [workspace] root and checks each with -p <member> scoped by that root's own --manifest-path. Exit 2 is a usage error or a cargo that could not run; 1 is a formatting verdict; they are never the same number.

Why -p and not the two obvious spellings — both were measured, and both fail in a direction that looks like success:

• --manifest-path <root> --all crosses the workspace boundary. --all formats "all packages, and also their local path-based dependencies", and harness/opfs-contract depends on improvise-io by path, so the inner root reports the outer tree's files. Measured: an injected fault in src/draw.rs was reported by the harness root's own invocation.
• --manifest-path <root> bare is blind to the members. The repo root is a package (improvise) as well as a workspace, so the bare form checks only that package. Measured: an injected fault in crates/improvise-core/src/format.rs exited 0.

Four rivals were injected into the script and each failed the suite: --all for -p (the boundary leak, caught by counting — the outer file must be named exactly once); the bare manifest-path (caught by the outer-fault case); return 2 collapsed to return 1 on the usage arms (two cases); and "no workspace root found" returning 0 instead of 2.

The fixture had to be made faithful twice, and each vacuity was found only by injecting the rival — not by reading. The suite passed under a rival at both stages, which is the only reason the gaps were visible:

• The first fixture's nested crate had no path dependency into the outer tree, so --all had nothing to leak through and the boundary rival passed.
• The first fixture's outer root was a virtual manifest with no [package], where the bare form happens to reach every member, so that rival passed too.

Both are properties this repo really has, and a fixture that omits them tests a repository that does not exist. That is the generalisable point: a check_the_checker's fixture must reproduce the structural features the hazard depends on, and the only way to know it does is to inject the rival and watch it fail. A green suite over a simplified fixture is the same non-evidence as a green suite over a vacuous assertion.

What is not covered. The script asks cargo metadata for members, so a root whose metadata succeeds but whose member list is wrong is not detectable here. Narrowed by improvise-90ea, below: a list that omits a package in the tree is now refused; one that names a package it should not is still not detected. And harness/opfs-contract's own cargo fmt -p opfs-contract step in the harness-lint job is left as it is: it resolves correctly because that step sets working-directory, and the ticket's own note confirms CI as written was never the broken caller.

The exit contract, narrowed after review — scripts/fmt-workspaces-test.sh

ChatGPT Codex on PR #159 found that the contract above promised more than the script maintained: both formatter invocations end || rc=1, so any failure after the cargo fmt --version probe was reported as "misformatted" even though no verdict had been produced. The finding was correct and was measured rather than assumed:

• an unparseable source (pub fn a( {{{) exits 1 — identical to a diff;
• an unknown rustfmt.toml option is only a warning, and exits 0.

Of the two remedies offered, the contract was narrowed rather than the failure re-classified, because parsing rustfmt's prose to tell a diff from a parse error is precisely the check-adjacent-to-its-subject this repo keeps getting wrong. The line the split actually needs is "did the gate run":

• exit 1 — rustfmt did not certify a root clean. A diff or a refusal to parse; either way a file is named and the tree is what is wrong.
• exit 2 — the gate did not run. Usage, no cargo, no rustfmt, cargo metadata failed, no [workspace] root. No source file is named. Every such cause is checked above the loop, which is what makes the narrowing true rather than hopeful. (Since improvise-90ea, a package no root reaches is also exit 2, and it names that package's Cargo.toml, which is the reason no verdict exists. The line is "no verdict", not "no output"; improvise-ximf.)

Both directions are now pinned, and two further rivals were injected:

• deleting the cargo fmt --version probe;
• turning || rc=1 into || return 2, which collapses a verdict into the usage code — the mirror of the original bug, and caught by three cases.

The first of those exposed a vacuous test, again only by injection. The original stub was a cargo that failed for every argument — but such a cargo also breaks cargo metadata, so the run exited 2 on the metadata arm and the probe could be deleted with the suite still green. A missing rustfmt component is cargo metadata succeeding while only cargo fmt fails, so the stub now delegates every other subcommand to the real cargo and fails fmt alone. Both stubs are kept, because they exercise different arms.

That is the third fixture correction on this one checker, all three found the same way: the suite passed under a rival. The generalisable rule is that a stub must fail in the shape of the real fault, not merely fail — a stub that breaks more than the real thing breaks satisfies the test through the wrong arm, and reads exactly like coverage.

The root package, and why the fourth fix is structural — scripts/fmt-workspaces-test.sh

A post-merge review of PR #159 found a fourth fixture vacuity (improvise-90ea). The fixture's outer root is a package (root-pkg) as well as a workspace, which is right, but no case ever dirtied the root package's own src/lib.rs. Only the member a/ and nested/ were dirtied. So a script that formats every member except the root package passed 17/17. In this repo the root package is improvise, the whole TUI. Reproduced at 40b8913 with the review's rival in members_of (drop the package whose manifest sits at workspace_root): the suite passed 17/17 and --list left improvise out.

Adding one more hand-picked case would have fixed the fourth and not the fifth. Four vacuities in one checker all have the same cause: the cases were chosen by hand, one per hazard somebody had thought of. So the fix is structural, and it has two halves because it has to cover two sets of packages:

• Every package the fixture has. The two hand-picked fault cases are replaced by a loop over every [package] manifest in the fixture. Each one gets its own misformatted src/lib.rs, must exit 1, and must be named exactly once, so the --all boundary check now covers every package rather than one. The enumeration is a grep for [package], deliberately not the script's [workspace] + cargo metadata discovery, since that discovery is what is under test. A count assertion (three packages) stops the loop going vacuous if the fixture loses a package. A package added to the fixture gets its case automatically.
• Every package the tree has. The loop proves only that the script handles the fixture's shapes. A real tree can hold a package no root lists (an excluded crate, say), and nothing in the fixture would say so. So the gate itself now checks an invariant before it formats anything: every [package] manifest the find reaches must be a member of some root, or it exits 2 and names the package. That is exit 2 and not 1 because no verdict was produced for that package, which is what exit 2 means here. Paths are compared through realpath, because on macOS mktemp lives under /var while cargo reports /private/var.

Rivals injected, and where each failed (the suite went from 17 to 21 cases):

• The review's skip-the-root rival. It now fails the fixture at a fault in src/lib.rs is reported (exit 0). With the invariant in place it fails six cases (exit 2, "no workspace root reaches"). It also fails the real repo with no fixture involved: fmt-workspaces.sh exits 2 naming Cargo.toml. That last one is the property worth having. The gate refuses its own blindness in CI, not only in its test suite.
• Disabling the invariant (if false). It fails a package no workspace root reaches is exit 2, not a pass with exit 0, even though that package's src/lib.rs is misformatted. That exit 0 is the hazard: an unreached package is silently clean.
• The two earlier rivals, re-run against the loop. --all for -p fails both a/src/lib.rs and src/lib.rs "named exactly once". The second of those was not predicted: the nested root's --all also reaches the root package. The bare manifest-path form fails a fault in a/src/lib.rs is reported.

The real-repo control from the ticket still holds: a misformatted fn appended to src/ui/text.rs is reported (Diff in …/src/ui/text.rs:72).

What is still not covered. A root whose member list includes something it should not is not detected, and a package in a directory the find excludes (target/, .claude/, node_modules/) is outside the invariant by construction.

The kb tool's completeness guard and atomic write — scripts/kb-test.sh cases 18–22

improvise-usus: scripts/kb add wrote onto a working-tree kb.pl that had lost 276 of its 801 clauses, and kb_consistent passed. The argument for the fix (compare with HEAD by key, record kb rm removals in a ledger, publish by rename) is in context/code/kb-tool.md. This entry covers what each case was watched to catch.

Reproduced at 40b8913 before any fix. A copy of HEAD's kb.pl with 34 of its 35 location/3 facts removed still passes kb_consistent, and kb add onto it printed 775 before, 1 in delta, 776 after and exited 0. Against the unfixed tool, the new cases gave 33 passed, 5 failed: 18, 19, 20b, 21 and 22 failed. Case 20 passed there because an rm followed by an add has no guard to trip.

The fixture has to fail in the incident's shape. The ticket's "truncate to half" fixture also breaks kb_consistent, because the rules live in the second half. So the unfixed tool refused it too, by the wrong guard. Removing a whole predicate is an existence error, and removing cited clauses fails the citation check. Case 18 keeps one location/3 fact and asserts that the fixture passes kb_consistent before using it. Case 19 keeps the ticket's half-truncation, and said() is what makes it evidence: the completeness guard runs first and must be the one that answers.

Rivals injected into scripts/kb, one at a time. Each failed only its own case:

• baseline taken from the file's own pre-write state rather than HEAD: 18, 19 and 20b failed (35/38 passed). This is the guard that would have passed the real incident.
• ledger never consulted: 20 and 20b failed. A legitimate rm then blocks every later write.
• guard stands down whenever the ledger is non-empty: 20b failed.
• candidate built by plain mktemp in $TMPDIR: 22 failed on the directory check.
• candidate copied over kb.pl before the publish point: 22 failed as modified.
• unreadable baseline exiting 1 rather than 3: 21 failed.

A rival can fail wider than its fault. The first form of the "stands down" rival skipped merge complete altogether. That also skipped writing $cand.ledger, so the later mv crashed under set -e and five unrelated cases failed. It proved nothing until it was rewritten to carry the ledger forward.

Checked by hand, not in the suite: the ledger prunes an entry once the key is re-added and once HEAD stops having it (a committed removal).

The kb completeness guard's follow-ups — scripts/kb-test.sh cases 19b, 20b, 23–25

improvise-ih3k, improvise-yea8 and improvise-za97, filed by the review of PR #166. The argument is in context/code/kb-tool.md. This entry covers what each case was watched to catch.

Reproduced at f909cad before any fix. The new cases 23, 23c and 24 gave 40 passed, 3 failed. 23 failed because an add onto a kb that had lost one of two work_done(<fixture id>,bug_fix,…) clauses exited 0. 23c failed because rm of that paired key was refused as "a clause was dropped": its expected total assumed one clause per key. The tickets did not predict that one, and it meant a pair could not be resolved through the tool at all. 24 failed because the stale ledger entry excused the loss.

The ticket's own reproduction defeats a content stamp. The first fix stamped the ledger with the kb's sha256, and case 24 still failed. kb.pl is canonical, so grep -v of one clause from HEAD is byte-identical to what kb rm of that clause writes. The stamp therefore also carries the inode and the nanosecond mtime.

Case 20b had to change, and why that is not a weakening. It made its second loss with sed -i on the kb. Under the fix, any edit outside the tool voids the ledger, so 20b then refused two clauses instead of one and failed on its "1 of" assertion. It was testing the new voiding rather than what its comment names. The second loss now comes from giving the baseline an extra clause (KB_BASELINE). The kb file stays exactly as the tool wrote it, the ledger stays valid, and the case again isolates "excuses only what it names". It also now asserts the unexcused clause is named.

Rivals injected, one at a time. Each failed only the cases listed:

• keys compared as a set (min(1, N) per key) in complete: 23 only.
• rm's expected total back to before - |delta|: 23c's rm step only.
• ledger pruned by key presence rather than count: 23c's final write only.
• ledger honoured whenever it exists: 24 and 25.
• ledger stamped by content alone: 24 only. 25 cannot see it, because its intervening add makes the restored-then-lost file differ in content anyway. 24 is the case that carries identity.
• ledger re-stamped only by rm, keeping the old stamp on other writes: 24b (as named), 20b and 23c. All three write again after an add.
• ledger stamped with the kb as read rather than the candidate: 20, 20b, 23c, 24b and 25. That is wider than any one case, as expected, since no later write can ever match.
• the gh/main scripts/kb (old refusal text, no stamp): 19b, 24 and 25.

Case 25 is the first to run the production paths. Every other case sets KB_FILE, so ledger_path's git rev-parse --git-path branch and baseline_to's git show HEAD were unexercised. It copies the tool into a throwaway git init repo and checks four things. rm records to the git-path ledger. git status shows only kb.pl modified, so the ledger is invisible to git. A later add is excused. After git checkout -- and a hand loss, the add is refused.

Checked by hand, not in the suite: a SIGKILL at the publish point (the KB_TEST_KILL seam) on a copy inside prolog-sessions/ leaves the candidate, its .base, .ledger, .removed and .stamped siblings and .lock. git status --untracked-files=all and git add -A --dry-run both show none of them, and git check-ignore -v names .gitignore:40 (prolog-sessions/*).

The pr-watch mergeability cases — scripts/pr-watch-test.sh

improvise-edpl. The cases are injected faults in themselves. Like the other scripts/ suites, none of their names is a Rust fn, so the case list is the evidence. The reasoning is in context/code/tooling.md, "pr-watch and mergeability".

The bug, reproduced before the fix. Against the script as it stood at ae96b8c, 19 of the 34 new cases failed and all 19 exited 0. UNKNOWN that resolves to CONFLICTING fails is PR #172's shape exactly: every check green, UNKNOWN/UNKNOWN on the first poll, CONFLICTING/DIRTY on the second. The old script broke out of the loop on the first poll and passed. The fixtures are hand-built. They are the subset of the gh pr view --json shape that the script reads: headRefOid, the two mergeability fields, and the rollup's status and conclusion. They are not a captured payload. A stub that errors instead would have exited 4, a wider shape than the fault.

Rival 1: treat UNKNOWN as an answer. The wait condition was replaced with if true. 13 cases fail: every UNKNOWN row of the table, MERGEABLE/UNKNOWN, the timeout case, and UNKNOWN that resolves to MERGEABLE/CLEAN passes. That last one exits 1 under this rival, so the fix cannot pass by refusing everything uncertain. It has to wait. UNKNOWN that resolves to CONFLICTING fails still passes under this rival, because the allowlist refuses UNKNOWN as well. Rival 2 does not separate it either: its first poll is UNKNOWN, which rival 2 still waits on. What separates it is the original fault, which combined both rivals. An earlier version of this entry said rival 2 separated it. That was wrong.

Rival 2: the old verdict. The allowlist was replaced with exit 0 after the MERGEABLE test. Five cases fail: MERGEABLE/BEHIND, DIRTY, DRAFT, SOMETHING_NEW and null. These are the states that look mergeable by the flag and are not. At 128a2a0 it was six, with BLOCKED among them. Since improvise-zlj2, BLOCKED is waited on, so this rival never reaches the verdict for it. The entry below covers that.

a failed check fails without waiting on mergeability runs at --timeout 0. A script that waited on UNKNOWN before reading the rollup would report that known red as exit 3.

The pr-watch needs-gap and pinned-head cases — scripts/pr-watch-test.sh

improvise-zlj2 and improvise-h3ni. These were found by review of PR #186 at 128a2a0, which was ruled do-not-merge.

zlj2: a healthy PR exited 1. The required Browser harness check run exists only after the build job completes (needs: build). In that gap GitHub reports MERGEABLE/BLOCKED while every registered check is green, and the #186 rule refused BLOCKED. The rollup in the new cases is PR #189's, captured verbatim with gh pr view --json. It has thirteen entries with every field GitHub returns. Each gap state drops or rewinds entries of that rollup with jq. Against 128a2a0 three cases failed, all with exit 1:

• the needs-gap before the required check registers is not a failure: the healthy sequence should exit 0.
• a required check that never registers is a timeout: should exit 3.
• table: MERGEABLE/BLOCKED: should exit 3, not 1.

Rival for zlj2: remove MERGEABLE/BLOCKED from the wait. The same three cases fail with exit 1. That rival is 128a2a0's code.

h3ni: nothing pinned the head across the UNKNOWN wait. The case is a head that moves during the UNKNOWN wait is not a pass. Its polls are UNKNOWN@a, then UNKNOWN@b, then CLEAN@b, and it must exit 2. It passed on the first run, so it is a guard for behaviour the script already has, not a reproduction.

Rival for h3ni: re-pin the head whenever mergeable is UNKNOWN. That case alone fails, exiting 0. All 44 others pass. That is the review's point: the older a head that moves mid-wait is not a pass starts from MERGEABLE, so it cannot see this rival.

Every JSON parser reads numbers exactly (improvise-dz8c)

every_crate_that_can_parse_json_enables_float_roundtrip

It replaces a check over three crates listed by hand. It reads cargo metadata --no-deps and fails naming every workspace package, and every target-specific entry, whose normal serde_json dependency lacks float_roundtrip. The rule and why it was chosen over the alternatives are in context/code/protocol.md. It is red at 1158c23, naming improvise, improvise-command, improvise-io and improvise-protocol.

Faults injected, each run:

• The feature removed from improvise-io alone. The check fails naming improvise-io (all targets), and so does a_legacy_json_workbook_loads_its_numbers_bit_for_bit. a_json_import_stores_its_numbers_bit_for_bit stays green, because improvise-command enables the feature and unification reaches io in its build.
• The feature removed from improvise-command alone. The check fails naming improvise-command (all targets). The command crate's own import test stays green: cargo tree -p improvise-command shows io's declaration switching the feature on. So the manifest check is the only guard that sees this case. It is also the case the retired build-graph check would have passed.
• A throwaway workspace member, zz-throwaway, with normal dependencies on improvise-protocol and serde_json and no feature (the lockfile updated, as a real new crate would be). The check fails naming zz-throwaway (all targets). With the unconditional dependency carrying the feature and a cfg(target_arch = "wasm32") one lacking it, the check fails naming zz-throwaway (cfg(target_arch = "wasm32")). That is stricter than the build needs, since a wasm build unifies the two entries, and cheap to satisfy. The crate was then removed.

The checked.len() >= 2 assertion is the positive signal. If a cargo change renamed the metadata fields, the check would find no serde_json dependency and pass vacuously without it.