feat: adding log for v2 schedule migration pathway

[davidporter-id-au]

What changed?

Adds a log for V2 schedules when they migrate, to differentiate between being created vs migrated

How did you test it?

• built
• run locally and tested manually
• covered by existing tests
• added new unit test(s)
• added new functional test(s)

Potential risks

low risk, just a log

[github-actions]

Claude finished @davidporter-id-au's task in 2m 47s —— View job

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Reviewed 2 files, 3 findings.
• feature/log-for-migration

[github-actions]

small — The event log is bounded and drops oldest-first, so this entry is the first one evicted; the created-vs-migrated signal disappears on exactly the schedules you'd want it for.

LogEvent keeps at most EventLogMaxEntries (30 by default, config.go:97) per component and drops the earliest entries beyond that. This event is written at construction, so it is always the first candidate for eviction from the Scheduler component's log. The same log also receives paused via API / unpaused via API (scheduler.go:228, :233), updated via API (:895), started migration to V1 (:840), schedule closed from idle timer (scheduler_tasks.go:57) and ignored-callback entries (completion.go:99). After 30 such events on a long-lived migrated schedule, there is no longer any way to tell it apart from one created through CreateScheduler, which logs nothing.

Distinguishing origin also relies on the absence of an event, which is ambiguous by construction: "created normally", "migrated but the entry aged out", and "created before this code shipped" all look identical.

Suggestion: If origin needs to survive, record it durably instead of (or in addition to) the event — e.g. a bool migrated_from_workflow on SchedulerState, set here and exposed in ListInfo/describe. If a best-effort breadcrumb is genuinely all that's wanted, log the counterpart on the CreateScheduler path too so the two paths are distinguished by a present event rather than a missing one.

[github-actions]

nit — getOrCreateEventLog re-checks a field that was just assigned unconditionally two lines above.

EventLog is set in the struct literal at line 311, so getOrCreateEventLog's TryGet-miss branch is unreachable here. The other call sites need it because they run against components that may have been loaded from persistence without an event log; this one does not.

Suggestion:

Suggested change

	sched.getOrCreateEventLog(ctx).LogEvent(ctx, "created via migration from V1")
	sched.EventLog.Get(ctx).LogEvent(ctx, "created via migration from V1")

[github-actions]

small — This test never calls CreateScheduler, and its whole body asserts an absence, so it will fail for reasons unrelated to migration.

setupSchedulerForTest calls scheduler.NewScheduler(...) with a nil patch (helper_test.go:633), not CreateScheduler, so the name points at a function the test does not exercise. TestCreateScheduler_InitialPauseState directly above does go through CreateScheduler, which makes the mismatch easy to misread.

The assertion is also a global claim about the create path rather than about migration: adding any event to NewScheduler — a future created via API counterpart, or an event from applyPausePatch if the helper ever passes a patch — breaks a test whose name says it is about migration events.

Suggestion: Name it for what it covers, and say what it protects:

Suggested change

	func TestCreateScheduler_NoMigrationEvent(t *testing.T) {
	sched, ctx, _ := setupSchedulerForTest(t)
	require.Empty(t, sched.EventLog.Get(ctx).Events)
	}
	// TestNewScheduler_LogsNoEvents verifies the non-migration create path leaves
	// the event log empty, so a "created via migration from V1" entry unambiguously
	// identifies a migrated schedule.
	func TestNewScheduler_LogsNoEvents(t *testing.T) {
	sched, ctx, _ := setupSchedulerForTest(t)
	require.Empty(t, sched.EventLog.Get(ctx).Events)
	}