From 9d3e3a1dfdd24ef5cc107542397aa1e3060c84d6 Mon Sep 17 00:00:00 2001
From: James Rich <2199651+jamesarich@users.noreply.github.com>
Date: Fri, 10 Jul 2026 12:02:36 -0500
Subject: [PATCH] fix(firmware): never offer an alpha release older than
 current stable (#6198)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
---
 .../repository/FirmwareReleaseRepositoryImpl.kt    | 14 +++++++++++++-
 .../FirmwareReleaseRepositoryImplTest.kt           | 12 ++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/core/data/src/commonMain/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImpl.kt b/core/data/src/commonMain/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImpl.kt
index da3b53e35..287f2fc2b 100644
--- a/core/data/src/commonMain/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImpl.kt
+++ b/core/data/src/commonMain/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImpl.kt
@@ -75,7 +75,8 @@ open class FirmwareReleaseRepositoryImpl(
     private fun getLatestFirmware(releaseType: FirmwareReleaseType): Flow<FirmwareRelease?> = staleWhileRevalidateFlow(
         loadFromCache = {
             ensureSeeded()
-            localDataSource.getLatestRelease(releaseType)?.asExternalModel()
+            val latest = localDataSource.getLatestRelease(releaseType)?.asExternalModel()
+            if (releaseType == FirmwareReleaseType.ALPHA) latest.notBelowStable() else latest
         },
         shouldFetch = { cached ->
             cached == null || localDataSource.getLatestRelease(releaseType)?.isStale() != false
@@ -93,6 +94,17 @@ open class FirmwareReleaseRepositoryImpl(
         localDataSource.deleteAllFirmwareReleases()
     }
 
+    /**
+     * After a stable promotion the alpha channel lags behind stable — never offer a downgrade. Reads the cached stable
+     * row (every refresh writes both types together, so it is as fresh as the alpha row) rather than combining with
+     * [stableRelease], which would run a second revalidate pipeline — and potentially a duplicate network refresh — for
+     * every alpha collector.
+     */
+    private suspend fun FirmwareRelease?.notBelowStable(): FirmwareRelease? {
+        val stable = localDataSource.getLatestRelease(FirmwareReleaseType.STABLE)?.asExternalModel()
+        return if (this != null && stable != null && asDeviceVersion() < stable.asDeviceVersion()) stable else this
+    }
+
     /**
      * Applies the bundled snapshot per release type whenever it is newer than what is cached for that type — not just
      * when the cache is empty. The bundle is refreshed weekly in CI, so an app update carries fresh data even for users
diff --git a/core/data/src/jvmTest/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImplTest.kt b/core/data/src/jvmTest/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImplTest.kt
index 393755b85..5b9cc0b54 100644
--- a/core/data/src/jvmTest/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImplTest.kt
+++ b/core/data/src/jvmTest/kotlin/org/meshtastic/core/data/repository/FirmwareReleaseRepositoryImplTest.kt
@@ -228,6 +228,18 @@ class FirmwareReleaseRepositoryImplTest {
         )
     }
 
+    @Test
+    fun alphaChannelNeverOffersVersionBelowStable() = runBlocking {
+        // After a promotion the newest alpha (2.7.25) is older than stable (2.7.26) — offer stable instead.
+        dao.insert(FirmwareReleaseEntity(id = "v2.7.26.54e0d8d", releaseType = FirmwareReleaseType.STABLE))
+        dao.insert(FirmwareReleaseEntity(id = "v2.7.25.104df5f", releaseType = FirmwareReleaseType.ALPHA))
+        assertEquals("v2.7.26.54e0d8d", repository.alphaRelease.toList().last()?.id)
+
+        // A genuinely newer alpha is still offered.
+        dao.insert(FirmwareReleaseEntity(id = "v2.7.27.abc1234", releaseType = FirmwareReleaseType.ALPHA))
+        assertEquals("v2.7.27.abc1234", repository.alphaRelease.toList().last()?.id)
+    }
+
     @Test
     fun olderBundledSnapshotNeverRegressesCache() = runBlocking {
         // A successful network refresh left the cache newer than the (weekly) bundle.