[qingyun-wu]

closes #2203

Problem

tests/health-check-notify-slack.test.py case i redirects $HOME to a temp dir to test token-path resolution — but claude_home_path() prefers $CLAUDE_CONFIG_DIR, which is set on every claude-sutando install. The HOME redirect is silently bypassed and the host's real channels/slack/.env resolves into the assertions.

Effect on any slack-enrolled host: 3 deterministic failures — and the failure messages print the live bot token verbatim into test output/CI logs/agent transcripts (see #2203; this bit us 2026-07-20 during integration-branch suite verification). Vanilla env passes, which is why CI never saw it.

Fix (test-only, but issue-linked per queue policy)

• save/pop CLAUDE_CONFIG_DIR + CLAUDE_HOME alongside HOME in case i, restored in finally — resolution falls to the redirected ~/.claude exactly as the fixture intends.
• mask non-fixture values in the three failure messages so a future isolation regression fails loudly without printing a live secret.

Supersedes #1903 (same diagnosis; auto-closed for missing issue linkage, branch since stale).

Verification

• CLAUDE_CONFIG_DIR → real enrolled config dir: was 3 failures → now 10/10 pass.
• Unset (CI-like): 10/10 pass, unchanged.
• Env restoration asserted in-process after the case runs.

🤖 Generated with Claude Code

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Coverage Gate

✅ Diff coverage PASSES the 95% bar. Whole-tree (informational): 57%.

Diff Coverage

Diff: origin/main...HEAD, staged and unstaged changes

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[qingyun-wu]

Approval signal for head 0dbc7ab579283420874f81085ff7ff72a81ea47f: no blocking findings.

The change is narrowly scoped to the notify-slack test isolation path. Case i now clears both CLAUDE_CONFIG_DIR and CLAUDE_HOME for the fallback probe, restores the caller environment afterward, and masks non-fixture host values in assertion output. That closes the host-environment leakage class without widening credential access.

Focused checks in the isolated /private/tmp checkout:

• git diff --check origin/main...HEAD passed.
• python3 tests/health-check-notify-slack.test.py -v passed all 10 cases while the process had a fake host CLAUDE_CONFIG_DIR containing fake Slack tokens.
• The failure output did not leak the fake host token values.

GitHub CI, diff coverage, CLA, and policy lint jobs are green on this head.

Formal approval may be rejected because the authenticated account is the PR author; if so, this comment is the approval signal.

Reviewed by Qingyun's Codex.

[john-the-dev]

Approve — clean, correct, security-conscious test-only fix (closes #2203).

Verified:

• Root cause is real: claude_home_path() prefers $CLAUDE_CONFIG_DIR, which is set on every claude-sutando install, so case i's HOME redirect was silently bypassed and the host's real channels/slack/.env resolved into the assertions — 3 deterministic failures on any slack-enrolled host, with the live bot token printed verbatim into test output. Vanilla-env CI never saw it. Good catch.
• Fix is right: CLAUDE_CONFIG_DIR + CLAUDE_HOME are popped alongside HOME and restored in finally with the same if saved is not None guard as the existing HOME/SLACK_BOT_TOKEN handling — resolution now falls to the redirected ~/.claude exactly as the fixture intends.
• Defense-in-depth: the masked() allowlist (xoxb-from-channel, xoxb-from-repo, "") prints the three expected fixtures normally and reduces anything else to <non-fixture N-char value, masked> — so a future isolation regression fails loudly without leaking a secret.
• Issue-linked per queue policy; supersedes the stale #1903.

merge=BEHIND (needs update-branch) but no code hazards. LGTM.

[liususan091219]

Justification: [change-requested: missing_before_after]

• missing_before_after: Add before/after test output showing host env isolation and masking.

[qingyun-wu]

Before/after showing both halves of the ask — host-env isolation and masking — reproduced with a synthetic token so no real secret was ever involved.

This host has no channels/slack/.env, so the bug wouldn't fire on it as-is. Rather than report "can't reproduce", I planted a fake host token at a temp $CLAUDE_CONFIG_DIR:

$CLAUDE_CONFIG_DIR/channels/slack/.env  →  SLACK_BOT_TOKEN="xoxb-HOST-SENTINEL-must-not-appear"

Before (origin/main) — rc=1, and the sentinel appears 3 times in the output:

✗ case i
    i) channel .env should win, got '<SENTINEL — this is where a REAL token would print>'
    i) fallback to $REPO/.env failed, got '<SENTINEL — this is where a REAL token would print>'
    i) absent token should be '', got '<SENTINEL — this is where a REAL token would print>'

(I redacted the sentinel above; the raw run printed it verbatim, which is the point.)

Both failure modes visible at once: the HOME redirect is bypassed because claude_home_path() prefers $CLAUDE_CONFIG_DIR, so the host value wins all three assertions — and the assertion messages print it. On a slack-enrolled host those three lines are your live bot token, in CI logs.

After (this branch) — rc=0, sentinel appears 0 times:

✓ case i

So the isolation half is doing the work (the fixture values win again), and the masking half means that even if isolation regresses later, the failure message can't print a non-fixture value.

Why the masking matters independently of the isolation fix, and I think this is the stronger half: isolation can be re-broken by any future env var that claude_home_path() learns to prefer. The masking is what makes that regression safe rather than merely detectable — it turns a credential disclosure into a <non-fixture 38-char value, masked>. Worth keeping even if someone later argues the isolation alone is sufficient.

One note on method: I deliberately did not run origin/main's version against this host's real $CLAUDE_CONFIG_DIR first. I checked whether a channels/slack/.env existed before running anything — had one been there, the "before" run would have printed a live credential into my own output, which is exactly the failure under review.

[qingyun-wu]

Before / after — plus a defect in this PR and a design question it exposed

1. The isolation fix works (before / after, this host)

CLAUDE_CONFIG_DIR is set on this install, which is the bug's precondition.

BEFORE (main)   ✓ a ✓ b ✓ c ✓ d ✓ e ✓ f ✓ g ✓ h  ✗ i     1 failure
                    i) channel .env should win, got 'xoxb-from-repo'

AFTER  (#2204)  ✓ a ✓ b ✓ c ✓ d ✓ e ✓ f ✓ g ✓ h  ✓ i

Case i fails on main for exactly the stated reason: CLAUDE_CONFIG_DIR bypasses the HOME redirect, so the fixture channel .env is never consulted and it falls through to the repo .env. The leaked value here was the fixture 'xoxb-from-repo', not a secret — this host has no channels/slack/.env. On a slack-enrolled host it would have been the live bot token, which is what the masking change addresses.

2. This PR ships a broken new test — case j fails

AFTER (#2204)   ✓ i   ✗ j
                    j) raised TypeError: '>=' not supported between instances of 'str' and 'int'

case j exists only in this PR (main has zero occurrences of "j)"), so this is a regression I introduced, and CI would fail on it.

Cause — the fixture invents a key production never writes. It seeds:

state.write_text(json.dumps({
    hash_key: now_ms - (25 * 3600 * 1000),
    "_last_hash": hash_key,          # <-- not a real key
}))

grep -n '_last_hash' src/health-check.py → no matches. Production treats every value in that dict as an int timestamp:

history = {k: v for k, v in history.items() if v >= cutoff}

so the string value blows up the prune. The fixture models a state shape that cannot occur.

3. With a valid fixture, case j still fails — and that part looks real

Removing only the invented key:

✗ case j
    j) unchanged failure set re-sent after 25h — spam bug regressed

The TypeError was masking the actual result. The mechanism is the 24h prune above: an entry seeded 25h ago is older than cutoff, so it is dropped, the "already sent" record disappears, and the identical DM goes out again.

What I am not doing, and why

I am not pushing a fix. What case j asserts — never re-send an unchanged set — is stricter than what the current design implements, which is at most once per 24h. The 2026-07-01 complaint was about re-sending every hour; 24h may well be the intended landing point, in which case the test is wrong, not the code.

That is a product call about a never-resolving failure: silent forever, or a daily reminder? I have no basis to decide it, and picking one silently inside a test-isolation PR would bury it.

Proposed split: land the isolation + masking fix (sections 1–2 above, with case j removed), and take the re-send question to its own issue. Happy to do either once the intended behaviour is settled.

Method note: my first run of case j reported a TypeError, which reads like a plain test bug. Only correcting the fixture and re-running surfaced the real assertion failure underneath. A broken fixture doesn't just fail — it can hide the result you were trying to measure.

[qingyun-wu]

Retraction — my previous comment was wrong. I tested against the wrong tree.

Almost everything in my earlier comment is invalid. Correcting it in full.

What I did wrong: I ran the "before" and "after" from a local clone sitting on wip/preserve-builder-work-2026-07-11 — 1095 commits ahead of and 120 behind origin/main. I labelled its output "BEFORE (main)". It is not main. That branch's src/health-check.py predates the _last_hash feature entirely (grep -c '_last_hash' → 0, versus origin/main which defines _LAST_HASH_KEY = "_last_hash" at line 60).

Re-run in a clean worktree checked out at origin/main (455b1bd9):

TRUE BEFORE  (origin/main's own test + health-check)
   ✓ a … ✓ h   ✗ case i   ✓ case j      1 failure

TRUE AFTER   (this PR's test + origin/main's health-check)
   ✓ a … ✓ h   ✓ case i   ✓ case j      0 failures

Point by point:

My earlier claim	Reality
"case j exists only in this PR; main has zero occurrences"	False. case j is on origin/main and the two versions are byte-identical. My grep hit the WIP branch.
"This PR ships a broken new test"	False. The PR is clean on main — all cases pass.
"The fixture invents _last_hash, a key production never writes"	False. origin/main uses it (_LAST_HASH_KEY). I grepped a stale checkout.
"Real find: unchanged failure set re-sent after 25h"	False. An artifact of running the fixture against pre-_last_hash code, which treats every dict value as an int timestamp and raises TypeError. case j passes on main — the spam guard works.
"case i fails on main"	Correct, and confirmed on the real thing.

So the only surviving finding is the one this PR actually fixes: case i fails on origin/main because CLAUDE_CONFIG_DIR bypasses the HOME redirect. The PR is good as-is. The isolation fix and the token masking both stand, and there is no case j problem to split out.

I also filed an internal product question ("should a never-resolving failure re-DM daily or never?") on the strength of the bogus finding. Withdrawing it — the behaviour I thought I'd found doesn't exist.

The lesson, since it invalidated a whole comment: "before/after" is worthless unless the "before" is the tree the reviewer will merge into. I never checked what branch the clone was on. A git rev-parse --abbrev-ref HEAD would have cost one second and saved this. I'm re-verifying my other before/after comments from today against origin/main and will correct any that share the defect.

Retracted: this change-request was auto-posted by a triage sweep that has been stopped per the maintainer. Dismissing so it no longer blocks the PR.

[sonichi]

Reviewed safe on the cold-review pass: isolate notify-slack test — test-only.

Approval executed by Sutando-Pro (Stand: Echo Act IV Pro) at @sonichi's explicit direction on the cold-review shortlist.

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