Implement cancellable hook mechanism and error isolation #87

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opened 2026-03-15 04:13:06 +00:00 by freemo · 0 comments

freemo commented

2026-03-15 04:13:06 +00:00

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Metadata

Commit Message: feat(lifecycle): add hook cancellation and error isolation
Branch: feature/m1-lifecycle-hooks

Background and Context

The specification requires that hooks support cancellation (a handler can prevent
downstream handlers from running) and error isolation (one failing handler must not
crash the server or prevent other handlers from executing).

Expected Behavior

A handler can call event.cancel! to set cancelled = true
Subsequent handlers in the same hook see event.cancelled? and can choose to skip
The emit method wraps each handler in a begin/rescue block, logging errors at
Logger::Medium without re-raising
Cancellation and errors are tracked in the HookEvent for diagnostic purposes

Acceptance Criteria

HookEvent#cancel! and HookEvent#cancelled? methods
LifecycleHooks.emit respects cancellation flag
Error isolation with logging for each handler invocation
BDD scenarios for cancellation and error recovery

Subtasks

Add cancel! and cancelled? to HookEvent
Update emit to check cancellation between handlers
Wrap handler calls in error isolation
Write Cucumber scenarios for cancellation and error cases

Definition of Done

This issue is complete when:

All subtasks above are completed and checked off.
A Git commit is created where the first line of the commit message matches the
Commit Message in Metadata exactly.
The commit is pushed to the remote on the branch matching the Branch in Metadata.
The commit is submitted as a pull request to master, reviewed, and merged.

## Metadata - **Commit Message**: `feat(lifecycle): add hook cancellation and error isolation` - **Branch**: `feature/m1-lifecycle-hooks` ## Background and Context The specification requires that hooks support cancellation (a handler can prevent downstream handlers from running) and error isolation (one failing handler must not crash the server or prevent other handlers from executing). ## Expected Behavior - A handler can call `event.cancel!` to set `cancelled = true` - Subsequent handlers in the same hook see `event.cancelled?` and can choose to skip - The `emit` method wraps each handler in a `begin/rescue` block, logging errors at `Logger::Medium` without re-raising - Cancellation and errors are tracked in the `HookEvent` for diagnostic purposes ## Acceptance Criteria - `HookEvent#cancel!` and `HookEvent#cancelled?` methods - `LifecycleHooks.emit` respects cancellation flag - Error isolation with logging for each handler invocation - BDD scenarios for cancellation and error recovery ## Subtasks - [ ] Add `cancel!` and `cancelled?` to HookEvent - [ ] Update `emit` to check cancellation between handlers - [ ] Wrap handler calls in error isolation - [ ] Write Cucumber scenarios for cancellation and error cases ## Definition of Done This issue is complete when: - All subtasks above are completed and checked off. - A Git commit is created where the **first line** of the commit message matches the Commit Message in Metadata exactly. - The commit is pushed to the remote on the branch matching the **Branch** in Metadata. - The commit is submitted as a **pull request** to `master`, reviewed, and **merged**.