Don't reframe the route on ordinary arrivals polls (#1895)

[bmander]

Summary

Fixes #1895. In stop + route focus, an ordinary background arrivals poll
reframed the camera to the whole route's extent, throwing away the pan/zoom the
rider had set.

Root cause

HomeViewModel.onArrivalsLoaded runs on every arrivals load. When a route
is selected within a focused stop, it re-emits MapDirective.ShowRoute(..., stopScoped = true, frameRoute = !preserveViewport). On an ordinary poll
preserveViewport is false, so frameRoute was true. That routes through
MapViewModel.toRoute → RouteMapController.reframe(frameRoute = true) →
host.frameRoute(), re-fitting the camera to the whole route on every poll.

(The retained-FramingIntent.Route theory in the issue was a red herring — the
real trigger is the per-poll ShowRoute re-emission.)

Fix

Frame the selected route only when the load is the initial (restore /
deep-link) focus establishment:

val frameSelectedRoute = pendingMapFocus && !preserveViewportForPendingMapFocus

• Ordinary poll → pendingMapFocus == false → frameSelectedRoute == false.
  The ShowRoute re-emission still refreshes presentation, but reframe() is a
  no-op (direction unchanged, no focusTripId), so the camera stays put.
• Initial pending-focus establishment without a saved viewport → frames (unchanged).
• Pending focus that carries a saved viewport → still declines to frame (unchanged).

The initial route selection continues to frame via selectStopRoute's default
frameRoute = true; the back/undo restore paths already pass their own explicit
frameRoute, so they're unaffected.

Tests

Added an ordinary arrivals poll refreshes the selected route without reframing
to HomeViewModelTest: selects a route in stop focus (asserts the initial
ShowRoute frames), then a subsequent onArrivalsLoaded with no pending focus
re-shows the route with frameRoute = false.

• ./gradlew :onebusaway-android:testObaGoogleDebugUnitTest --tests 'org.onebusaway.android.ui.home.*' --tests 'org.onebusaway.android.map.*' -PwarningsAsErrors=true

Note

Root cause was found by reading the code, not reproduced on-device — worth a
manual confirmation on the shared phone before merge.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved map behavior when refreshing arrivals for a selected route.
  • Prevented the map from unnecessarily reframing to the full route during routine arrivals updates.
  • Preserved the initial map focus when selecting a route or restoring a focused stop.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 3750e193-2090-4b85-a80b-f00750e83008

📥 Commits

Reviewing files that changed from the base of the PR and between 2049fdb and 8981164.

📒 Files selected for processing (2)

• onebusaway-android/src/main/java/org/onebusaway/android/ui/home/HomeViewModel.kt
• onebusaway-android/src/test/java/org/onebusaway/android/ui/home/HomeViewModelTest.kt

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📝 Walkthrough

Walkthrough

The home view model now reframes a selected route only during initial map focus. Subsequent arrivals polls refresh the route without reframing the camera, with a unit test covering both behaviors.

Changes

Route framing refresh control

Layer / File(s)	Summary
Focus framing and poll validation onebusaway-android/src/main/java/org/onebusaway/android/ui/home/HomeViewModel.kt, onebusaway-android/src/test/java/org/onebusaway/android/ui/home/HomeViewModelTest.kt	onArrivalsLoaded uses initial focus state to control route framing, and the test verifies that later arrivals polls re-show the selected route without reframing it.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly states the main change: preventing route reframing on ordinary arrivals polls.
Linked Issues check	✅ Passed	The code and test match #1895 by suppressing route framing on ordinary arrivals refreshes while preserving initial focus framing.
Out of Scope Changes check	✅ Passed	The changes stay focused on the route-framing fix and its test, with no unrelated modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/no-reframe-on-arrivals-poll

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