feat(map-maplibre): offline terrain (hillshade + contours) for MapLibre - #7012
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…e, contours) New :feature:map-terrain module — pure computation for the offline hillshade + elevation-contour terrain layer, ported from the sibling iOS app's spec-018 implementation, shared by both Android flavors' upcoming wiring (MapLibre: native raster-dem + GeoJSON contours; Google: pre-rendered hillshade PNGs + Polyline contours). - Terrarium WebP elevation decode, with platform actuals guarding against premultiplied-alpha corruption of the RGB-encoded elevation bits on both Android (BitmapFactory) and JVM/Desktop (Skia). - Horn's-method hillshade with the three cleanup passes iOS added against real Puget Sound artifacts: median despike, sea-level fade, local-relief fade. - Marching-squares contour generation with saddle-case disambiguation and segment chaining into polylines. - The zoom-banded contour interval table, verified against iOS source rather than approximated. - Contour styling as shared simplestyle-spec property values (stroke/ stroke-width/stroke-opacity), so both flavors' existing generic simplestyle consumers (MapLibre's CustomLayers.kt style expressions, Google's applySimpleStyleSpec()) style contours identically without per-flavor color logic. jvm()+android() targets only — nothing here is consumed by iOS — but the shared KMP convention plugin adds Kotlin/Native targets regardless, so decodeTerrariumTile's nativeMain actual intentionally throws; see its doc comment.
…estrate) Adds the pieces that get terrain data from Mapterhorn onto disk: - TerrainTileMath: self-contained Web Mercator tile math (this module intentionally has no dependency in either direction on flavor code). - MapterhornEndpoints: the two-tier PMTiles layout (global archive always, regional archive only when a region fits one z6 tile). - TerrainTileFetcher: expect/actual wrapping ch.poole.geo.pmtiles.Reader (androidMain/jvmMain, duplicated rather than shared since the library has no KMP-common home; nativeMain throws, same as the elevation decoder's own stub). - TerrainTileStore: Okio-based file-hierarchy tile storage, not SQLite — this module must also work on Desktop, unlike the base offline layer's Android-only archive. - TerrainRegionExtractor: orchestrates a bounded two-tier download into the store, one tile per request like the base layer's own extractor. pmtiles-reader and kotlinx-serialization-protobuf catalog entries are duplicated from the not-yet-merged feat/map-google-pmtiles-offline branch (#7000) — expected, not a mistake; identical values either way.
Wires the shared :feature:map-terrain math core into the MapLibre flavor: an OfflineTerrainRepository tracking a single downloaded region (manifest + tile store under the platform files dir), download/delete UI matching OfflineMapsSection's shape, two-tier rasterDemSource hillshade via file:// tile templates, and contour lines decoded from Terrarium tiles and rendered through the existing simplestyle LineLayer pattern. Adds TerrainTileMath.lonLatAt, the inverse of the existing forward tile transform, needed to place contour vertices in real coordinates. Confirmed MapLibre's own rasterDemSource handling does the Horn's-method shading internally from raw tiles, so Hillshade.shade() in map-terrain is Google-flavor-only and unused here. Does not touch androidApp or the Google flavor.
TerrainLayers.kt's two rememberRasterDemSource calls had no attributionHtml, so the map's ExpandingAttributionButton never surfaced Mapterhorn's credit for offline hillshade/contours — the only place either can appear, since GeoJsonOptions (the contour source) has no attribution field of its own. MapterhornEndpoints.ATTRIBUTION/ATTRIBUTION_URL also didn't exist yet on this branch's copy of :feature:map-terrain — added, matching the Google flavor's branch verbatim (the two copies are intentionally duplicated pending merge; see that module's own commit history for why).
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📝 WalkthroughWalkthroughThe pull request adds a new multiplatform terrain module. It supports terrain math, elevation decoding, hillshade, contours, PMTiles downloads, offline storage, MapLibre rendering, UI controls, localization, tests, and build integration. ChangesOffline terrain maps
Estimated code review effort: 5 (Critical) | ~120 minutes Merge Risk: 🟠 High · up to This PR adds terrain downloads and local hillshade/contour rendering, but the current implementation can exhaust memory or storage, omit or misreport terrain for some regions, leave failed downloads stuck or unreadable, and fail for valid local paths containing reserved characters. These are concrete correctness and availability risks, so the PR is not ready to merge until they are fixed or explicitly accepted. 🚥 Pre-merge checks | ✅ 6 | ❌ 2❌ Failed checks (2 warnings)
✅ Passed checks (6 passed)
Full details: Sibling Call Sites And Presence SemanticsExplanation PASS — The PR does not change RSSI, temperature, current, voltage, particulate, or SNR field presence semantics. The new nullable terrain state is handled at every production call site: both Full details: Tests Prove The Path, Not The End StateExplanation Several added tests match the prohibited patterns. Resolution Replace fake round-trip assertions with observable side-effect checks. Verify the expected filesystem path and raw bytes after Full details: Regression Coverage For Changed BehaviorExplanation Regression coverage is incomplete for the new download, decode, UI, and MapLibre rendering paths. - Impacted code path: Resolution Add the missing tests described above. Provide test seams for the extractor, repository, decoder, and repository singleton where required. Run the shared tests plus the JVM and Android host/device coverage. Run at least one real MapLibre render smoke test on F-Droid Android and Desktop before treating the local Full details: Moved Code Diffed Against Its OriginalExplanation PASS — the PR contains one actual extraction: the Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
Missing entry meant kmpSmokeCompile and Dokka/Kover aggregation silently never touched this module's iOS target — CI's own root-module-list drift check caught it on push. Same gap fixed identically on the Google-flavor branch's copy of this file.
CI's own coverage-drift check caught it: the module has commonTest sources but no allTests/koverXmlReport entry in reusable-check.yml, so its tests would never have run in CI. Same fix applied identically on the Google- flavor branch.
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Inline comments:
In
`@feature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/component/OfflineTerrainSection.kt`:
- Around line 148-152: The composite labels in OfflineTerrainSection must use
locale-controlled string-resource templates instead of concatenated separators.
Add one resource template for the estimate and zoom-level values at lines
148-152, and one template for cache size and tile count at lines 198-202; update
the corresponding stringResource calls while preserving the existing values.
- Line 200: Update the megabyte substitution in OfflineTerrainSection around
stringResource and region.byteSize.megabytes() to pre-format the floating-point
value with NumberFormatter.format(), then pass the resulting string to the
resource’s %s placeholder instead of supplying the raw number.
In
`@feature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainRepository.kt`:
- Line 215: Update both catch paths in readManifest() that currently return null
to delete the unreadable manifest and its associated tile directory before
returning. Ensure OfflineTerrainRepository cleanup removes both artifacts on
every manifest-read failure.
- Line 189: Update OfflineTerrainRepository.tileUrlTemplate() to URI-encode
reserved characters in the base directory and path components before
constructing the file URI template, while preserving the existing tile
placeholders and behavior. Add coverage verifying paths containing spaces, #,
and % produce a valid encoded template consumed by rememberRasterDemSource().
- Line 224: Update OfflineTerrainRepository.writeManifest and the download flow
so manifest storage failures are caught before completion, partial tiles and the
manifest are cleaned up, and
TerrainDownloadState.Failed(TerrainDownloadFailure.IO_ERROR) is emitted instead
of leaving downloadState in progress. Ensure startDownload propagates or handles
the failure consistently with existing error paths.
In
`@feature/map-maplibre/src/commonTest/kotlin/org/meshtastic/feature/map/maplibre/terrain/TerrainDownloadEstimateTest.kt`:
- Line 60: Update the test named `zero or negative maxZoom counts nothing` to
reflect that only negative maxZoom values count no tiles, or add an explicit
assertion confirming `estimateTerrainTiles(bounds, 0)` includes the z0 tile;
ensure the test name matches the behavior it verifies.
In
`@feature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/ElevationTile.kt`:
- Line 38: Update the ElevationTile constructor validation before the
elevations-size check to require width and height are positive, and validate the
multiplication cannot overflow Int before comparing against elevations.size.
Preserve construction only for grids with a safe positive width*height matching
the elevation array.
In
`@feature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/Hillshade.kt`:
- Around line 104-105: Restrict the despiking loops in the terrain processing
flow to the output area rather than the full padded tile dimensions. Update the
loops around shadeOnePixel() so the one-pixel padding ring remains unchanged and
its supplied neighbor samples are used by output-edge kernels.
In
`@feature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/TerrainRegionExtractor.kt`:
- Line 118: Update the extraction flow around fetchTile() and store.writeTile()
so completed/progress tracking counts processed requests separately, while the
persisted tile counter increments only after a non-null tile is successfully
written. Ensure Complete.tileCount reports stored tiles and does not include
missing archive tiles.
- Line 52: Update the tile generation in TerrainRegionExtractor around
globalTiles and the corresponding regional tile collection to enforce MAX_TILES
before materializing large lists. Count or lazily generate candidate tiles with
an early stop, and return TILE_LIMIT_EXCEEDED once the cap is reached instead of
allowing full flatMap allocation.
In
`@feature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileMath.kt`:
- Line 59: Update the tile enumeration around the X-range loop in
TerrainTileMath to handle GeoBounds crossing the antimeridian: split the wrapped
X range at the tile boundary and enumerate both segments, or explicitly reject
such bounds before enumeration. Ensure valid non-crossing bounds retain the
existing range behavior and never report a successful zero-tile download for a
crossing bounds.
In
`@feature/map-terrain/src/jvmMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileFetcher.jvm.kt`:
- Line 38: Limit decoded GZIP output before materializing tiles in the gunzip
implementation used by TerrainTileFetcher.fetchTile. Apply the same explicit
maximum decoded tile size to TerrainTileFetcher.jvm.kt lines 38-38 and
TerrainTileFetcher.android.kt lines 38-38, ensuring decompression stops or fails
once the limit is exceeded while preserving valid tiles within the limit.
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.github/workflows/reusable-check.yml.skills/compose-ui/strings-index.txtbuild-logic/convention/src/main/kotlin/RootConventionPlugin.ktcore/resources/src/commonMain/composeResources/values/strings.xmlfeature/map-maplibre/build.gradle.ktsfeature/map-maplibre/src/androidMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainStorage.android.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/MeshMap.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/component/MapLayersButton.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/component/OfflineTerrainSection.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/geojson/ContourFeatureKeys.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/geojson/ContourFeatures.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/layers/TerrainLayers.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainRegion.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainRepository.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainStorage.ktfeature/map-maplibre/src/commonMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/TerrainDownloadEstimate.ktfeature/map-maplibre/src/commonTest/kotlin/org/meshtastic/feature/map/maplibre/geojson/ContourFeaturesTest.ktfeature/map-maplibre/src/commonTest/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainRegionTest.ktfeature/map-maplibre/src/commonTest/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainRepositoryTest.ktfeature/map-maplibre/src/commonTest/kotlin/org/meshtastic/feature/map/maplibre/terrain/TerrainDownloadEstimateTest.ktfeature/map-maplibre/src/iosMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainStorage.ios.ktfeature/map-maplibre/src/jvmMain/kotlin/org/meshtastic/feature/map/maplibre/terrain/OfflineTerrainStorage.jvm.ktfeature/map-terrain/build.gradle.ktsfeature/map-terrain/src/androidMain/kotlin/org/meshtastic/feature/map/terrain/ElevationTile.android.ktfeature/map-terrain/src/androidMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileFetcher.android.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/ContourGenerator.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/ContourIntervals.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/ContourStyle.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/ElevationTile.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/Hillshade.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/MapterhornEndpoints.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/TerrainRegionExtractor.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileFetcher.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileMath.ktfeature/map-terrain/src/commonMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileStore.ktfeature/map-terrain/src/commonTest/kotlin/org/meshtastic/feature/map/terrain/ContourGeneratorTest.ktfeature/map-terrain/src/commonTest/kotlin/org/meshtastic/feature/map/terrain/ContourIntervalsTest.ktfeature/map-terrain/src/commonTest/kotlin/org/meshtastic/feature/map/terrain/ElevationTileTest.ktfeature/map-terrain/src/commonTest/kotlin/org/meshtastic/feature/map/terrain/HillshadeTest.ktfeature/map-terrain/src/commonTest/kotlin/org/meshtastic/feature/map/terrain/MapterhornEndpointsTest.ktfeature/map-terrain/src/commonTest/kotlin/org/meshtastic/feature/map/terrain/TerrainTileMathTest.ktfeature/map-terrain/src/commonTest/kotlin/org/meshtastic/feature/map/terrain/TerrainTileStoreTest.ktfeature/map-terrain/src/jvmMain/kotlin/org/meshtastic/feature/map/terrain/ElevationTile.jvm.ktfeature/map-terrain/src/jvmMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileFetcher.jvm.ktfeature/map-terrain/src/nativeMain/kotlin/org/meshtastic/feature/map/terrain/ElevationTile.native.ktfeature/map-terrain/src/nativeMain/kotlin/org/meshtastic/feature/map/terrain/TerrainTileFetcher.native.ktgradle/libs.versions.tomlsettings.gradle.kts
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… offline terrain
- Add proper string templates for composite labels (tile estimate detail,
cache size detail) instead of concatenating stringResource() calls with
literal separators.
- Percent-encode reserved characters (space, #, %) when building the
tileUrlTemplate() file:// URL from baseDir, preserving {z}/{x}/{y}
literally.
- readManifest() now deletes the corrupt manifest and its tile directory
instead of just returning null and leaking disk usage.
- Wrap the manifest write in download() so a full-disk/permission failure
surfaces as Failed(IO_ERROR) instead of an uncaught exception, cleaning
up the just-fetched tiles on failure.
- Rename the maxZoom=-1 estimate test to reflect what it actually covers,
and add a real maxZoom=0 case (z0 tile is a nonzero, valid count).
- Guard ElevationTile's constructor against zero-dimension grids, which
previously passed the size check but crashed elevationAt() later.
- Bound Hillshade's despike pass to the interior only, so it no longer
corrupts the 1px margin ring that carries real neighbor-tile data into
edge-pixel shading.
- Restructure TerrainRegionExtractor to count tiles cheaply via a new
TerrainTileMath.tileCountAt() (shared with the map-maplibre estimate)
before materializing any TileIndex list, avoiding an OOM risk on
oversized regional requests. Split the progress counter from the
stored-tile counter so sparse archive coverage no longer inflates
Complete.tileCount.
- Fix TerrainTileMath.tilesAt() to enumerate tiles across the antimeridian
instead of silently returning zero for a crossing bounding box.
- Cap GZIPInputStream decompression in TerrainTileFetcher.jvm.kt/.android.kt
at 8MB to guard against a zip-bomb from a compromised/MITM'd response.
Left feature/map-maplibre's OfflineMapTarget.kt untouched (CodeRabbit's
byteSize.megabytes() finding was a false positive — it already formats via
NumberFormatter.format()).
Six real bugs CodeRabbit found in the shared, intentionally-duplicated :feature:map-terrain module were fixed there first (PR #7012); porting the identical fixes here since this branch carries its own copy of the module: - TerrainTileMath.tilesAt(): antimeridian-crossing bounds (Fiji, Chukotka/ Alaska) silently enumerated zero tiles instead of wrapping. New xRangesAt()/tileCountAt() helpers fix this and add a cheap tile-count path. - TerrainRegionExtractor.download(): MAX_TILES was checked only after fully materializing every TileIndex — real OOM risk at deep regional zoom. Restructured to count via tileCountAt() before materializing anything, and split the progress counter from the stored-tile counter so sparse archive coverage no longer inflates Complete.tileCount. - Hillshade despike(): iterated the full padded tile including the 1px margin ring that's supposed to carry real neighbor-tile elevation data, corrupting it before edge-pixel shading read it. Bounded to the interior. - ElevationTile: added a require() guard against degenerate 0-dimension grids, which previously passed construction and crashed on first access. - TerrainTileFetcher.jvm.kt/.android.kt: capped GZIP decompression at 8MB against a zip-bomb from a compromised/MITM'd response. Also updated this branch's own TerrainDownloadPlanner.kt (Google-flavor-only, no MapLibre equivalent) to use the new tileCountAt() instead of its own .tilesAt(...).size — same class of fix, applied locally.
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A comment line drifted past ktlint's wrap width during the CodeRabbit-fix pass; local spotlessApply runs on the whole module didn't re-touch it because nothing else in the file changed after that edit. Caught by CI, not locally.
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… branch Both found by CodeRabbit on PR #7000 and verified real; the module is duplicated verbatim across the two branches, so the fixes land here too: - Hillshade.despike() allocated a fresh 9-float array per interior pixel (~64k allocations per tile, on every cache miss). One scratch buffer per call now; median-of-9 semantics unchanged. - TerrainRegionExtractor reported hasRegionalDetail = true whenever a regional archive URL resolved, even if zero regional tiles were actually stored (sparse coverage) — consumers then clamped to REGIONAL_MAX_ZOOM and read an empty directory. Stored counts are now tracked per tier and the flag means what it says. Adds an openArchive seam (defaulted, existing call sites untouched) and a TerrainRegionExtractorTest covering both cases.
… state startDownload() launched download() with no handler, so an IOException from the disk work that runs before the extractor (clearing the previous region) escaped the flow: downloadState stuck mid-way, and on Android an uncaught exception in the repository's own SupervisorJob scope. Catch it there and report Failed(IO_ERROR), matching how the extractor's and manifest's own failures already surface. CodeRabbit follow-up on the same thread. Also: ElevationTile compares size against width×height in Long, so a product that wraps in Int (65536², say) can no longer match an empty array. Ported identically to the Google-flavor branch.
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Summary
Offline terrain — hillshade + elevation contours — for the MapLibre flavor (F-Droid + Desktop), the sibling piece to #7000's Google-flavor equivalent. Closes the standout Android-vs-iOS map gap: the sibling iOS app ships Mapterhorn-sourced hillshade and contours for its offline regions; Android had zero offline terrain on either flavor before this and #7000.
Wires the shared math core in
:feature:map-terrain(Terrarium decode, Horn's-method hillshade, marching-squares contour generation, zoom-banded contour intervals — purecommonMain, unit-tested independently of either flavor) into this flavor:OfflineTerrainRepository— tracks a single downloaded region (manifest + tile store under the platform files dir), matchingOfflineMapsSection's existing shape and UX.rememberRasterDemSourcepointed at localfile:///.../terrain/tiles/{tier}/{z}/{x}/{y}.webptemplates — MapLibre does its own Horn's-method shading internally from raw Terrarium tiles, soHillshade.shade()in:feature:map-terrainis Google-flavor-only and unused here.LineLayerviarememberGeoJsonSource, decoded from the same downloaded Terrarium tiles, styled through the existing simplestyle (stroke/stroke-width/stroke-opacity) patternCustomLayers.ktalready uses for imported overlays.TileSetOptionsso MapLibre's ownExpandingAttributionButtonpicks it up automatically — the only place either hillshade or contours can carry a credit, sinceGeoJsonOptions(the contour source) has no attribution field of its own.Full design rationale, including why contours bypass
rememberFeatureSourceforrememberGeoJsonSourcedirectly (a stale-cache bug in the wrapper otherwise), is in the relevant files' own doc comments (TerrainLayers.kt,OfflineTerrainRepository.kt).Does not touch
androidAppor the Google flavor.:feature:map-terrainis presently duplicated verbatim (module + version-catalog entries) between this branch and #7000's — see that module's own commit history for why that's deliberate, low-conflict-risk duplication pending whichever merges first, not an oversight. One real divergence:TerrainTileMath.lonLatAt/LonLatexist only here (needed to place contour vertices in real coordinates forGeoJsonSource); the Google flavor doesn't need it since it already has its own equivalent conversion inWebMercatorTileMath.Why draft
Not visually verified on a real device or desktop build — no display was available in this development environment. The
file://+ raster-dem combination is architecturally sound (confirmed via direct inspection ofmaplibre-native's C++ resource-loading source: tile-URL-template substitution inResource::tile()happens before scheme dispatch, sofile://should behave the same asmbtiles:///https://) but this is evidence, not an on-device test. Also unverified: MapLibre's behavior when afile://source is asked for a tile the store doesn't have on disk (a viewport partially outside the downloaded region, or a zoom between the two tiers) — noted inTerrainLayers.kt's own doc comment.Marking ready for review once someone can actually look at this on a phone or the desktop app.
Legal
Mapterhorn: no API key, no documented rate limit (Cloudflare R2-backed). On-screen attribution per above; see
MapterhornEndpoints.ATTRIBUTION's own doc comment for why it's a generic credit rather than an enumerated per-source list (100+ regional datasets under a mix of licenses, no single blanket license).Test plan
TerrainTileMathTest(the newlonLatAtinverse transform),OfflineTerrainRegionTest,OfflineTerrainRepositoryTest,TerrainDownloadEstimateTest,ContourFeaturesTest— all passing../gradlew spotlessApply spotlessCheck detekt assembleDebug test allTests kmpSmokeCompile— full repo baseline, pass (three transient shared-Gradle-daemon failures on first run, confirmed environmental by serial re-run, not code)./gradlew :core:konsist:testAndroidHostTest— pass, including the new:feature:map-terrainmodule./gradlew :androidApp:compileFdroidDebugKotlin :desktopApp:compileKotlin— pass (confirms this doesn't touch the Google flavor)Summary by CodeRabbit