Generate the Android Sheet renderer (Material 3 ModalBottomSheet) - #36
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Companion to the mob repo's Mob.UI.sheet/2 (MOB-101). MobNode.kt needed zero changes — parsing is fully generic, no per-type allowlist. MobBridge.kt gets: - "sheet" dispatch -> MobSheet(node), deliberately NOT threading the nodeModifier(node.props)-derived `m` through, since ModalBottomSheet owns its own containerColor/shape the same way Button already does (via constructor params, not a Modifier chain) -- passing `m` would double-apply background/corner_radius. - Detent logic: medium-only sheets reject Expanded via confirmValueChange. Material 3 can omit the PartiallyExpanded anchor when content is shorter than half the viewport, which would leave a medium-only sheet with no valid anchor and stuck hidden -- fixed by forcing content to slightly over half the measured viewport height in that case only (BoxWithConstraints + heightIn), never allowing Expanded. - Exactly-once dismissal via a remembered per-presentation flag. - New structural lint (sheet_content_modifier_not_double_applied/1) guarding both halves of the double-application fix -- the dispatch arm not passing `m`, and MobSheet actually stripping background/corner_radius before building its content modifier. Neither half is something a compiler catches. New androidTest instrumentation scaffolding (first in this template -- build.gradle.eex had zero test deps before this) + MediumOnlySheetTest, covering the medium-only short-content fix. Confirmed 1/1 pass on a real emulator against a freshly generated project. MOB-101 Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
detentsProp() was `(node.props["detents"] as? List<*>)` — MobNode's parser hands JSON array props through as org.json.JSONArray, not Kotlin List, so the cast silently failed on every real BEAM-sent tree and fell through to the hardcoded ["medium", "large"] default. The medium-only detent feature — this PR's headline addition — could never actually trigger from production data, only from a hand-built MobNode in a test. Follows the same JSONArray-branch pattern already proven correct for :tabs (tabDefsProp). MediumOnlySheetTest now builds its MobNode via JSONObject(...).toMobNode() (the real parsing path) instead of a hand-built Kotlin listOf(...), so it exercises the code path the bug actually lived in. Re-verified 1/1 pass on a real Pixel emulator against a freshly generated project. Also: dedupe function_span/2 and mob_bridge_span/1's shared find-anchor-then-matching-brace logic into span_after_anchor/2. Verified dismissSent is not redundant with `visible` (a second onDismissRequest firing before recomposition removes the sheet isn't gated by visible alone) — no change made there. Not merged/released — awaiting review per standing instruction. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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Summary
Mob.UI.sheet/2native modal Sheet primitive (MOB-101).MobNode.ktneeded zero changes — parsing is fully generic, no per-type allowlist anywhere.MobBridge.kt:"sheet"dispatch →MobSheet(node), Material 3ModalBottomSheetwith detent logic (medium-only rejectsExpandedviaconfirmValueChange), custom drag indicator, exactly-once dismissal via a remembered per-presentation flag.PartiallyExpandedanchor when content is shorter than half the viewport, which would leave a medium-only sheet with no valid anchor and stuck hidden.BoxWithConstraints+heightIn(min = maxHeight * 0.5f + 1.dp)forces just enough height when (and only when)mediumOnly— never allowsExpanded.ModalBottomSheetownscontainerColor/shapeas constructor params (same reasonButtonalready readsbackground/corner_radiusdirectly instead of viaModifier— they don't compose through a modifier chain). The"sheet"dispatch arm deliberately does not pass thenodeModifier(node.props)-derivedmthrough;MobSheetbuilds its content modifier fromnode.props - listOf("background", "corner_radius"). New structural lintMobNew.Templates.Lint.sheet_content_modifier_not_double_applied/1guards both halves against regression (neither is something a compiler catches).androidTestinstrumentation scaffolding — first added to this template (build.gradle.eexhad zero test deps before this: Compose UI test + Espresso +ui-test-manifest) — plusMediumOnlySheetTest.MobNativeViewRegistry.render()'s-1-sentinel guard was written but never shipped in an earlier session — released separately as mob_new 0.4.23, unrelated to this PR's diff.Test plan
mix test(withMOB_DIR/MOB_DEV_DIRset per this repo's worktree convention) — 335 passed, including newdescribe "sheet_content_modifier_not_double_applied/1"inlint_test.exsand aproject_generator_test.exspin asserting the dispatch arm, imports, detent logic, the double-application guard, and exactly-once dismissal are all present in generated outputmix format/mix credo --strict/mix test --only lint(generate + ktlint) — all cleanMediumOnlySheetTestviaadb shell am instrumenton a real emulator — 1/1 pass. Full main APK also builds and installs cleanly.decisions/2026-08-26-native-sheet-primitive.md(mob repo) as a verification limitation worth another look on a different device/BOM, not swept under the rug.Linear: MOB-101 (cross-repo — see mob#86 for the Elixir + iOS side)