fix: only warn on endpoint-less sessionAuth when it carries more than refreshOn (#148)

[garretpremo]

Closes #148

Summary

The session.endpoint warning added in #147 was over-broad. It fired whenever rawSessionAuth existed without session.endpoint — but an endpoint-less sessionAuth: { refreshOn: [401] } block is a configuration #135 deliberately supports, since refreshOn is sourced from rawSessionAuth precisely so it survives the mergedSessionAuth narrowing. A correctly-configured project on that route printed the warning on every single CLI invocation.

The warning's actual target is the typo case — a block carrying handshake keys with no reachable endpoint (sessions: for session:). Gating on "carries some key other than refreshOn" keeps that diagnostic and goes quiet for the intentional config.

What changes

src/auth/refresh-wiring.ts — gate the warning, and say what was found

if (rawSessionAuth && !mergedSessionAuth) {
    const foundKeys = Object.keys(rawSessionAuth).filter(
        key => key !== 'refreshOn' && (rawSessionAuth as Record<string, unknown>)[key] !== undefined,
    );

    if (foundKeys.length > 0) {
        console.warn(
            `[apijack] sessionAuth is set but missing session.endpoint — SessionAuthStrategy will not be used. Found: ${foundKeys.join(', ')}.`,
        );
    }
}

The !== undefined clause is load-bearing, not defensive padding: deepMergeSessionAuth always assigns onChallenge = overrideFn ?? baseFn, so the key is present-but-undefined on every merged block. Without the clause, a refreshOn-only config would still warn.

Naming the found keys is what makes the diagnostic actionable — a sessions: typo now reports Found: sessions, cookies instead of leaving the user to diff their config against the docs.

JSDoc no longer claims purity

The function grew an I/O side effect in #147 while its docstring still read "Kept pure so both sites stay in lockstep". The lockstep rationale stands and is kept; the purity claim is replaced with a note about the diagnostic.

Acceptance criteria

• A deliberate endpoint-less sessionAuth: { refreshOn: [...] } block produces no warning
• A block with handshake keys but no reachable session.endpoint (the typo case) still warns
• The warning names the offending block's top-level keys
• refreshOn behavior from sessionAuth.refreshOn is unreachable for projects using a custom AuthStrategy #135 is unchanged in both cases
• The refresh-wiring.ts JSDoc no longer claims purity

Test plan

• bun test — 1043 pass / 0 fail (up from 1041 on dev)
• bun run lint — 0 errors (118 pre-existing warnings, unchanged)

New coverage in tests/auth/refresh-wiring.test.ts:

• refreshOn-only block is silent; typo'd block warns and the message names sessions and cookies but not refreshOn ('sessions' isn't a substring of 'session.endpoint', so that assertion is real rather than incidental)
• both cases still assert mergedSessionAuth === undefined and refreshOn === [401], so sessionAuth.refreshOn is unreachable for projects using a custom AuthStrategy #135's behavior is pinned in both directions
• a third test pins the onChallenge case (see below)

Every clause of the new filter was mutation-tested during review — reverting the gate, inverting it, dropping !== undefined, or dropping key !== 'refreshOn' each fails at least one test, and dropping the refreshOn exclusion fails both.

Known behavior, deliberately kept

bin/apijack.ts:130-132 and src/run-routine.ts:140-142 inject onChallenge from .apijack/auth.ts into the sessionAuth object. A project with a refreshOn-only block and a custom onChallenge export therefore still warns, reporting Found: onChallenge — a key the user never wrote into that block. This is left as-is and pinned by a test: onChallenge is consumed only by SessionAuthStrategy, which is never constructed without an endpoint, so in that configuration the hook is genuinely dead and the warning is pointing at a real mistake. Excluding it from foundKeys would discard a legitimate diagnostic.

[garretpremo]

🤖 Automated review by claude — generated by the review-issue skill. Treat as advisory; a human still owns the merge decision.

The gate is correct and every acceptance criterion in #148 is met: the refreshOn-only block goes silent, the typo'd-handshake-key block still warns and now names what it found, refreshOn is pinned in both directions, and the JSDoc purity claim is gone. Scope is tight — two files, no drive-by edits — and all 11 checks are green on 55c0284.

I verified the two load-bearing claims in the description independently:

• deepMergeSessionAuth really does always assign onChallenge (src/auth/config-merge.ts:24, result.onChallenge = overrideFn ?? baseFn), and structuredClone({ ...base, onChallenge: undefined }) preserves the key with an undefined value — so Object.keys sees onChallenge on every merged block and the !== undefined clause is genuinely required, not padding.
• The onChallenge injection at bin/apijack.ts and src/run-routine.ts is guarded by if (sessionAuth && projectOnChallenge), so it only lands when a project actually exports the hook. Acceptance criterion 1 therefore holds on the real shared-binary path, not just in the unit test.

Non-blocking observations

• The Found: onChallenge case is reasoned about well and pinned by a test, but the message a user actually sees names a key they never typed into their config — they wrote refreshOn and a .apijack/auth.ts export, and got told sessionAuth is set but missing session.endpoint ... Found: onChallenge. The diagnostic is pointing at a real dead hook, so keeping it is the right call; the phrasing just doesn't connect the key back to where it came from. A future tweak could special-case it (Found: onChallenge (injected from .apijack/auth.ts)). Not worth blocking on, and not in #148's scope.
• foundKeys filters on !== undefined only, so a JSON env config with an explicit "cookies": null counts as a found key and gets named. That's arguably correct — an explicit null is still something the user wrote — but it's a slightly different notion of "present" than the undefined case the filter was written for.
• No caller asserts on the new Found: suffix outside the unit test; tests/cli-builder-refresh-wiring.integration.test.ts covers the wiring but not the message. Fine as-is given the message is a diagnostic rather than API surface.

Nitpicks

• The message ends at Found: sessions, cookies. without a hint at the fix. For the typo case the found-key list is usually enough to spot sessions vs session, so this is marginal.
• The description's mutation-testing note is a good signal to have in the PR body — worth keeping that habit, since it's the part of the test suite that's hardest to verify from the diff alone.

[garretpremo]

🤖 Final review by claude — generated by the final-review skill. CI is green, no blockers, soak window elapsed. Marking approved and merging.

Approved.

Outstanding observations from first-pass review

• The Found: onChallenge case is reasoned about well and pinned by a test, but the message a user actually sees names a key they never typed into their config — they wrote refreshOn and a .apijack/auth.ts export, and got told sessionAuth is set but missing session.endpoint ... Found: onChallenge. The diagnostic is pointing at a real dead hook, so keeping it is the right call; the phrasing just doesn't connect the key back to where it came from. A future tweak could special-case it (Found: onChallenge (injected from .apijack/auth.ts)). Not worth blocking on, and not in #148's scope. (#150)
• foundKeys filters on !== undefined only, so a JSON env config with an explicit "cookies": null counts as a found key and gets named. That's arguably correct — an explicit null is still something the user wrote — but it's a slightly different notion of "present" than the undefined case the filter was written for. (#150)
• No caller asserts on the new Found: suffix outside the unit test; tests/cli-builder-refresh-wiring.integration.test.ts covers the wiring but not the message. Fine as-is given the message is a diagnostic rather than API surface.