fix: sub-habits no longer inherit the parent's frequency when the user picks one-time

[thomasluizon]

Summary

• Adds an explicit InheritParentFrequency flag to CreateSubHabitCommand, defaulted false. The REST endpoint (used by both orbit-ui-mobile web and mobile) never sets it, so an omitted FrequencyUnit/FrequencyQuantity always means the user's explicit "one-time" choice — it no longer silently falls back to the parent's cadence.
• The AI chat tool (CreateSubHabitTool) opts in via InheritParentFrequency: true, preserving its documented "unspecified frequency = match the parent" contract.

Root cause

CreateSubHabitCommandHandler unconditionally did request.FrequencyUnit ?? parent.FrequencyUnit. Both the REST API (meaning "one-time" by omission) and the AI tool (meaning "inherit" by omission) shared the same ambiguous null, so the handler could not distinguish the two intents.

Repro (before the fix)

1. Parent habit: recurring, 1 day, Mon–Fri.
2. Open "Criar sub-hábito" — frequency correctly mirrors the parent (Recorrente).
3. Switch the sub-habit's frequency to "Tarefa única" (one-time) and create.
4. Bug: the sub-habit was created as recurring (Day, quantity 1) with no days selected, instead of one-time.

Confirmed via a local repro against a running instance + direct DB inspection before/after.

Test plan

• dotnet test tests/Orbit.Application.Tests — 40/40 passing, including 2 new regression tests (Handle_OneTimeChildUnderRecurringParent_DoesNotInheritParentFrequency, Handle_InheritParentFrequencyWithNoOverride_UsesParentCadence)
• dotnet build — clean
• Live repro against local API + Postgres, verified fixed (DB row shows FrequencyUnit=NULL, Days={} for the one-time sub-habit)

Paired with orbit-ui-mobile PR (frontend timing bug for the same sub-habit-creation flow, bug #1 in that PR's description).

https://claude.ai/code/session_01VsTmCprkkcg9o3meMrET8W

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[claude]

Code Review: fix/sub-habit-frequency-inheritance

Scope: PR #426 in thomasluizon/orbit-api
Recommendation: APPROVE

Summary

Small, well-scoped fix for a real bug: CreateSubHabitCommandHandler used to unconditionally fall back to the parent's frequency whenever the request omitted one, so a user picking "one-time" for a sub-habit was silently coerced back to the parent's recurring cadence. The fix introduces an explicit InheritParentFrequency flag (default false), so REST clients (whose omitted frequency always means an explicit "one-time" choice) get their real intent, while the AI chat tool opts in explicitly since its contract is "unspecified = match the parent." Two focused regression tests cover both branches.

Findings

Critical

None.

High

None.

Medium

None.

Low / Info

None — nothing rises to the concretely-actionable bar; the diff is small, targeted, and doesn't introduce new patterns worth flagging.

Subagents

Agent	Verdict
security-reviewer	PASS — InheritParentFrequency is hardcoded true in CreateSubHabitTool.cs, not read from AI-tool JSON args, so it isn't attacker-controllable via prompt injection; REST DTO has no matching field so REST always defaults to false; parent-habit ownership check (h.UserId == request.UserId) still gates the read of parent.FrequencyUnit/FrequencyQuantity; no new logging/authz/injection surface.
contract-aligner	N/A — no DTO, Controller route, or packages/shared type changed in this diff (the new InheritParentFrequency param is Application-internal only; CreateSubHabitRequest/HabitsController.CreateSubHabit are untouched, confirmed by reading HabitsController.cs:537-558).

Validation

Check	Result
Build (dotnet)	N/A — covered by separate required CI check per this run's adaptation
Tests (dotnet)	N/A — covered by separate required CI check per this run's adaptation

Deferred — N/A dimensions & files not verdicted

• Dimension 8 (DESIGN.md/AI-slop): N/A — no apps/* files in this diff.
• Dimension 9 (Parity) / 10 (i18n): N/A — backend-only diff, and both are frontend-only dimensions owned by the orbit-ui-mobile-side review; not verifiable in this checkout.
• Dimension 14 (FEATURES.md parity): N/A — this is a bugfix restoring documented behavior, not a new/changed/removed feature surface (rubric explicitly excludes pure bugfixes).
• All three changed files (CreateSubHabitTool.cs, CreateSubHabitCommand.cs, CreateSubHabitCommandHandlerTests.cs) were read in full and given a verdict — nothing deferred there.

What's good

• Correctly root-causes the ambiguity (a shared null meaning two different things for two callers) instead of patching around it — no workaround, no special-casing by caller type.
• The new XML-doc on InheritParentFrequency clearly states the contract and why each caller sets it the way it does — exactly the kind of WHY note the comment policy wants.
• Two new regression tests pin both branches (one-time child overrides parent cadence; explicit inherit opt-in still matches parent), and both assert on the actual persisted Habit fields via AddAsync interception rather than the Result alone.
• Verified locally against a running instance + DB inspection per the PR description, in addition to the new unit tests.

Recommendation

Safe to merge as-is.