Follow-ups from PR #82 review: context error strings, child deadline intersection, deterministic timer tests

[staheri14]

Deferred, non-blocking items from the review of #82 (IrrevocableContext deadline/timeout support). Points 1, 4, 6, 7 were addressed in that PR; the following were intentionally left as follow-ups.

2. Centralize the deadline/cancelled error strings (DRY)

run() and err() each construct "context deadline exceeded" / "context cancelled" ad hoc, and the tests assert on .contains("deadline exceeded") / .contains("context cancelled"). The strings currently match, but nothing prevents drift.

• Suggestion: small private helpers (e.g. deadline_err() / cancelled_err()) so the messages have a single source of truth.
• Priority: low (pure maintainability).

3. Allow a child to have a shorter deadline than its parent

child() inherits the parent's deadline verbatim; there is no way to give a child a tighter deadline. Go's context.WithTimeout on a child intersects deadlines (child gets min(parent, new)).

• Suggestion: a with_timeout-style constructor on an existing context that sets deadline = min(self.deadline, now + timeout); or at minimum document the current "inherit-only" behavior so callers don't assume Go-style intersection.
• Priority: low/medium (semantic gap vs. the Go model this is loosely based on); out of scope for feat: adds deadline/timeout support to IrrevocableContext #82.

5. Make the timer-based tests deterministic

test_run_respects_deadline, test_is_deadline_exceeded, and test_run_cancellation_beats_deadline rely on wall-clock timing (real sleeps with generous margins). These can flake under CI load.

• Suggestion: convert to #[tokio::test(start_paused = true)] + tokio::time::advance(..) for deterministic virtual time.
• Priority: low (margins are generous today), but paused-time is the robust pattern.

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Source: static review by Claude (@claude) on #82. Points renumbered per that review.

[claude]

Claude finished S T (@staheri14)'s task —— View job

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Blocker: PR #82's deadline/timeout support isn't present on this branch

• Read repo layout and locate IrrevocableContext
• Investigate prerequisites for points 2, 3, 5
• Point 2: Centralize error strings — blocked
• Point 3: with_timeout deadline intersection — blocked
• Point 5: Deterministic timer tests — blocked

What I found

All three follow-ups build directly on the deadline/timeout feature that PR #82 was supposed to add, but that code is not in this branch (claude/issue-83-…, based on main @ 14b902c).

Concretely, in src/core/context/mod.rs the current IrrevocableContext:

• has no deadline field, no Instant, no timeout constructor;
• run() (src/core/context/mod.rs:80) only does a select! between the future and cancelled(), emitting "context cancelled" — there is no "context deadline exceeded" path;
• there is no err() helper;
• child() (src/core/context/mod.rs:48) inherits only the cancellation token — no deadline to intersect.

And in src/core/context/context_test.rs the tests the issue names — test_run_respects_deadline, test_is_deadline_exceeded, test_run_cancellation_beats_deadline — don't exist.

The issue itself says points 1, 4, 6, 7 "were addressed in #82." Those aren't on this branch either, so it looks like #82 hasn't been merged into the base this branch was cut from (I don't have gh pr view access to confirm its state).

Why I stopped rather than implementing

Each follow-up references exact symbols/behavior from #82 (deadline_err()/cancelled_err(), min(parent, now+timeout) intersection, the three named timer tests). Implementing them here would require me to first re-create the entire #82 deadline feature by guessing its API, which would almost certainly diverge from the merged design and produce conflicts.

How to unblock

Please rebase/merge this branch onto the commit that contains #82 (or point me at that branch), and re-trigger me. Once the deadline/timeout code is present I can:

1. add deadline_err() / cancelled_err() private helpers and route run()/err() + tests through them (point 2);
2. add a with_timeout-style constructor that sets deadline = min(self.deadline, now + timeout) (point 3);
3. convert the three timer tests to #[tokio::test(start_paused = true)] + tokio::time::advance(..) (point 5).
   • claude/issue-83-20260718-2016