fix: Keep the sole GPS segment when a trip is stopped after one recorded point

[TaduJR]

Explanation of Change

Standing still while tracking records only one location, because the app records a new location only after you move 100 m. When you tapped Stop, the app removed the last section of the trip if it had one location or none. That's right for a section added by Resume that recorded nothing useful, but it also happened when that section was the whole trip. The app treats a trip with no locations as one that never started, so the trip disappeared: no Resume or Save, no distance or addresses, and the button went back to Start.

Stop now only removes a short section when there's an earlier section to fall back on. So stopping without moving keeps the trip with Resume and Save, and tapping Save shows the existing "Can't create expense" message. The same applies when a trip is stopped from "View trip" after reopening the app, or by switching to Expensify Classic.

Keeping that one location makes a few new situations possible, and this PR handles them:

• The map pins assumed every section has a start and an end, so a section with one location made the last pin show as a normal waypoint instead of the stop. Pins are now picked by where they sit in their section, on both the trip screen and the Edit stop screen.
• A trip too short to trim, like one that never moved, no longer shows the Edit button.
• A trip can now be discarded right after its first location, while its start address is still being looked up. When that lookup finished, it saved the address and the discarded trip came back. It now saves nothing if the trip is gone.
• For a trip with a single location, the map now centers on it at the zoom used for a single pin, instead of trying to fit its view around a route that has no size.

This is a regression from #88609. The check that kept a trip's only section was lost when the logic was split into a helper before that PR merged.

Fixed Issues

$ #100938
PROPOSAL:

Tests

1. Tap FAB, then Track distance, then the GPS tab.
2. Tap Start and allow any location prompts.
3. Wait until Distance shows 0.00, your address appears under Start, and Tracking distance... appears under Stop.
4. Without moving, tap Stop.
5. Verify the trip stays on screen: Distance 0.00, your address under both Start and Stop, a trash icon next to the distance, no pencil icon, and Resume and Save buttons.
6. Verify the map is centered on your location at a normal zoom where nearby streets are visible, not zoomed in all the way.
7. Drag the map away, then tap the crosshair button at the top right of the map. Verify the map returns to your location at the same normal zoom.
8. Tap Save. Verify a "Can't create expense" message says "You can't create an expense with the same start and stop location."
9. Tap Got it. Verify the trip is still on screen and no expense was created.

• Verify that no errors appear in the JS console

Offline tests

Same as tests

QA Steps

// TODO: These must be filled out, or the issue title must include "[No QA]."
Same as tests

• Verify that no errors appear in the JS console

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
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• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Screen.Recording.2026-09-12.at.7.51.01.PM.mov

Android: mWeb Chrome

iOS: Native

Screen.Recording.2026-09-12.at.7.58.04.PM.mov

iOS: mWeb Safari

MacOS: Chrome / Safari

[melvin-bot]

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[chatgpt-codex-connector]

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Codex Review: Didn't find any major issues. 🚀

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[MelvinBot]

🤖 Done — all five of my comments on this PR are now hidden as resolved:

Comment	Pass
5647386443	Initial review at 2c80098
5647713052	Withdrew the refactor, raised the .value finding
5647815991	Re-review at a5c7fcf
5648186152	Re-review at 72026b8
5648667453	Re-review at 8f5852e

Correcting my last reply: I said there was nothing to resolve because these were top-level comments rather than inline review threads. That was wrong — GitHub's Hide comment → Resolved works on top-level comments too, and that's what I've applied.

Head is still 8f5852e, the commit my last pass cleared, so nothing has changed since. The two inline review threads from chatgpt-codex-connector were already resolved and I left them alone.

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[codecov]

Codecov Report

❌ Looks like you've decreased code coverage for some files. Please write tests to increase, or at least maintain, the existing level of code coverage. See our documentation here for how to interpret this table.

Files with missing lines	Coverage Δ
src/components/MapView/utils.ts	92.10% <100.00%> (+2.91%)	⬆️
src/libs/GPSDraftDetailsUtils.ts	87.50% <100.00%> (+28.09%)	⬆️
src/libs/actions/GPSDraftDetails.ts	57.47% <100.00%> (+55.19%)	⬆️
...OURequestStepDistanceGPS/useGPSWaypointMarkers.tsx	100.00% <100.00%> (+100.00%)	⬆️
...tup/backgroundLocationTrackingTask/index.native.ts	82.05% <100.00%> (+79.34%)	⬆️
...estStepDistanceGPS/Waypoints/EditGPSTripButton.tsx	0.00% <0.00%> (ø)
src/components/MapView/GPSMapView.tsx	2.46% <0.00%> (-0.17%)	⬇️
... and 16 files with indirect coverage changes

[TaduJR]

@MelvinBot @codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Keep them coming!

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[MelvinBot]

🤖 Re-reviewed at d854560. The branch was rewritten since my last pass (8f5852e is no longer an ancestor — the three commits here are new), so this is a fresh read rather than a delta. CI is fully green. Two findings.

Test step 3 now contradicts the code

Step 3 still says to verify "trash and pencil icons next to the distance". Commit 77648b2 deliberately hides the pencil for exactly that trip: EditGPSTripButton now gates on canGpsTripBeTrimmed, and a stopped trip with one point has distanceInMeters === 0, so it returns null. QA will fail that step on correct behavior.

While you're in there — the steps only exercise the first commit. Nothing covers the map centering on a single point, the stop marker on a segment that holds one point, or the Edit button disappearing. QA Steps say "Same as tests", so both sections inherit the gap.

The rewrite dropped the addressFromGpsPoint fix

The previous revision changed GPSPointUtils.ts:21 to return address || null. That file is not in this PR any more, and main still has the bare return address.

It matters here specifically. Line 19 builds the address as formattedAddress ?? [name, city, region].filter(Boolean).join(', ') — a geocode result with a location object whose fields are all null yields '', not null. updateStartAddress gates on address !== null, so {value: '', type: 'address'} gets written. Then Waypoints/index.tsx:49-50 reads !address?.value, '' is falsy, and both rows render the '...' spinner with nothing to ever resolve them.

That's a latent bug on main, not one you introduced. But before this PR a one-point trip was deleted on Stop, so the stuck rows were never on screen. Keeping the trip is what makes it reachable — which is presumably why the earlier revision fixed it. Worth pulling back.

Nits

• The caller-side if is now redundant. GPSDraftDetailsUtils.ts:143-147 guards on gpsPoints.length > 1, and removeLastSegment:68 now returns early on length <= 1 itself. Both branches of the outer if fall to the same return, so dropping it leaves behavior identical. Your earlier reason for keeping it — the sole segment continuing into the address logic — no longer applies to this code.
• getSinglePointCoordinate([], undefined) returns undefined by accident. getBounds on empty input gives southWest: [Infinity, Infinity] and northEast: [-Infinity, -Infinity], so the equality check happens to fail. The test asserting this passes for a reason a reader would not guess. An explicit empty check would say it.
• getBounds runs twice per render. GPSMapView.tsx:48 walks every coordinate, then getWaypointBounds walks them again on the same inputs — a third time in the focus effect. Computing the bounds once and deriving singlePointCoordinate from them would collapse all three.
• The discard guard doesn't cover a restart. index.native.ts:82 catches the discard, but if a new trip is started during the lookup, updatedGpsDraftDetails is truthy and the stale tripSegmentIndex from line 72 writes the old trip's address onto the new one. Nearly always harmless since both points sit in the same place, but it's the same race the commit is about.

What I checked and found correct

canGpsTripBeTrimmed's threshold is exact, not approximate. > GPS_DISTANCE_INTERVAL_METERS matches Slider.tsx:33, where minRatio = GPS_DISTANCE_INTERVAL_METERS / totalDistanceMeters. At exactly one interval minRatio is 1, so the slider's min equals its max and there is genuinely nothing to trim. I went looking for an off-by-one here and there isn't one.

The .catch(() => undefined) on the draft read is unreachable, which makes the new guard unambiguous. getGpsDraftDetails wraps Onyx.connectWithoutView in a promise with no reject path, so !updatedGpsDraftDetails can only mean "no draft". Good — the branch can't silently swallow a read failure.

removeLastSegment owning the invariant is the change I asked for two passes ago, and the tests now assert real Onyx state instead of mock call counts, including the [[]] and resumed-segment cases.

useGPSWaypointMarkers — isLastWaypointSegmentStart uses findLast((segment) => segment.length > 0), which matches the segment.length < 1 skip inside getGPSWaypoints, so the index arithmetic stays aligned. The two trimmed cases I flagged as untested last round are now covered, including segmentIndex: 1.

Onyx array semantics. Onyx.merge replaces arrays rather than merging them, so stopGpsTrip writing its stale gpsPoints parameter can still clobber a point that lands during the awaits. Unchanged from main and not something this PR makes worse, so I'm not reopening it — noting it only because the backgroundLocationTrackingTask commit fixes the same class of race one file over.

CI. All 8 test jobs pass, along with typecheck, ESLint check, React Compiler Compliance, Oxfmt check, spellcheck, Storybook tests and both perf jobs. The only red checks are Check independent approval and checklist, neither of which reflects the code.

I did not run the app — this flow is native-only and isn't reproducible on web, so I reviewed statically against green CI.

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[TaduJR]

@MelvinBot The bug is already on main branch. I can make a follow-up. Addressing here will bloat up the PR. For now make the comment your wrote as resolved including all the others.

[MelvinBot]

🤖 Nothing left to resolve — and my main point is already fixed on your branch.

All three inline review threads are already resolved, and no review is in a blocking state. My review was posted as a top-level PR comment, which GitHub gives no resolve control for. Treat it as closed out — I'm not holding anything open.

You already applied the cleanup I asked for. At src/libs/actions/GPSDraftDetails.ts:66-70, removeLastSegment now early-returns on gpsPoints.length <= 1. The clear-to-[[]] branch that was the actual bug is gone, so the invariant lives in one place. That was the only thing I flagged as "should fix."

Agreed on the follow-up for the rest — the remaining ... endpoint edge cases predate this PR, and widening the diff to chase them here is the wrong trade.

One optional leftover whenever you touch this next: the if (gpsPoints.length > 1) guard at src/libs/GPSDraftDetailsUtils.ts:144 is now redundant with the one inside removeLastSegment. Harmless as defense in depth — just not worth a push on its own.

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