Avoid crashing if opening browse with unavailable source

app/src/main/java/eu/kanade/presentation/browse/BrowseSourceScreen.kt

@@ -1,6 +1,7 @@
 package eu.kanade.presentation.browse
 
 import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.outlined.HelpOutline
@@ -11,6 +12,7 @@ import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.SnackbarResult
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.paging.LoadState
 import androidx.paging.compose.LazyPagingItems
@@ -18,19 +20,22 @@ import eu.kanade.data.source.NoResultsException
 import eu.kanade.presentation.browse.components.BrowseSourceComfortableGrid
 import eu.kanade.presentation.browse.components.BrowseSourceCompactGrid
 import eu.kanade.presentation.browse.components.BrowseSourceList
+import eu.kanade.presentation.components.AppBar
 import eu.kanade.presentation.components.EmptyScreen
 import eu.kanade.presentation.components.EmptyScreenAction
 import eu.kanade.presentation.components.LoadingScreen
+import eu.kanade.presentation.components.Scaffold
 import eu.kanade.tachiyomi.R
-import eu.kanade.tachiyomi.source.CatalogueSource
 import eu.kanade.tachiyomi.source.LocalSource
+import eu.kanade.tachiyomi.source.Source
+import eu.kanade.tachiyomi.source.SourceManager
 import kotlinx.coroutines.flow.StateFlow
 import tachiyomi.domain.library.model.LibraryDisplayMode
 import tachiyomi.domain.manga.model.Manga
 
 @Composable
 fun BrowseSourceContent(
-    source: CatalogueSource?,
+    source: Source?,
     mangaList: LazyPagingItems<StateFlow<Manga>>,
     columns: GridCells,
     displayMode: LibraryDisplayMode,
@@ -139,3 +144,24 @@ fun BrowseSourceContent(
         }
     }
 }
+
+@Composable
+fun MissingSourceScreen(
+    source: SourceManager.StubSource,
+    navigateUp: () -> Unit,
+) {
+    Scaffold(
+        topBar = { scrollBehavior ->
+            AppBar(
+                title = source.name,
+                navigateUp = navigateUp,
+                scrollBehavior = scrollBehavior,
+            )
+        },
+    ) { paddingValues ->
+        EmptyScreen(
+            message = source.getSourceNotInstalledException().message!!,
+            modifier = Modifier.padding(paddingValues),
+        )
+    }
+}

app/src/main/java/eu/kanade/presentation/browse/components/BrowseSourceToolbar.kt

@@ -20,15 +20,15 @@ import eu.kanade.presentation.components.DropdownMenu
 import eu.kanade.presentation.components.RadioMenuItem
 import eu.kanade.presentation.components.SearchToolbar
 import eu.kanade.tachiyomi.R
-import eu.kanade.tachiyomi.source.CatalogueSource
 import eu.kanade.tachiyomi.source.LocalSource
+import eu.kanade.tachiyomi.source.Source
 import tachiyomi.domain.library.model.LibraryDisplayMode
 
 @Composable
 fun BrowseSourceToolbar(
     searchQuery: String?,
     onSearchQueryChange: (String?) -> Unit,
-    source: CatalogueSource?,
+    source: Source?,
     displayMode: LibraryDisplayMode,
     onDisplayModeChange: (LibraryDisplayMode) -> Unit,
     navigateUp: () -> Unit,

app/src/main/java/eu/kanade/tachiyomi/source/SourceManager.kt

@@ -152,6 +152,6 @@ class SourceManager(
         }
     }
 
-    inner class SourceNotInstalledException(val sourceString: String) :
+    inner class SourceNotInstalledException(sourceString: String) :
         Exception(context.getString(R.string.source_not_installed, sourceString))
 }

app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/BrowseSourceScreen.kt

@@ -39,6 +39,7 @@ import cafe.adriel.voyager.core.screen.uniqueScreenKey
 import cafe.adriel.voyager.navigator.LocalNavigator
 import cafe.adriel.voyager.navigator.currentOrThrow
 import eu.kanade.presentation.browse.BrowseSourceContent
+import eu.kanade.presentation.browse.MissingSourceScreen
 import eu.kanade.presentation.browse.components.BrowseSourceToolbar
 import eu.kanade.presentation.browse.components.RemoveMangaDialog
 import eu.kanade.presentation.components.ChangeCategoryDialog
@@ -48,7 +49,9 @@ import eu.kanade.presentation.components.Scaffold
 import eu.kanade.presentation.util.AssistContentScreen
 import eu.kanade.presentation.util.padding
 import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.source.CatalogueSource
 import eu.kanade.tachiyomi.source.LocalSource
+import eu.kanade.tachiyomi.source.SourceManager
 import eu.kanade.tachiyomi.source.online.HttpSource
 import eu.kanade.tachiyomi.ui.browse.source.browse.BrowseSourceScreenModel.Listing
 import eu.kanade.tachiyomi.ui.category.CategoryScreen
@@ -73,17 +76,10 @@ data class BrowseSourceScreen(
 
     @Composable
     override fun Content() {
-        val navigator = LocalNavigator.currentOrThrow
-        val scope = rememberCoroutineScope()
-        val context = LocalContext.current
-        val haptic = LocalHapticFeedback.current
-        val uriHandler = LocalUriHandler.current
-
         val screenModel = rememberScreenModel { BrowseSourceScreenModel(sourceId, listingQuery) }
         val state by screenModel.state.collectAsState()
 
-        val snackbarHostState = remember { SnackbarHostState() }
+        val navigator = LocalNavigator.currentOrThrow
-
         val navigateUp: () -> Unit = {
             when {
                 !state.isUserQuery && state.toolbarQuery != null -> screenModel.setToolbarQuery(null)
@@ -91,8 +87,21 @@ data class BrowseSourceScreen(
             }
         }
 
-        val onHelpClick = { uriHandler.openUri(LocalSource.HELP_URL) }
+        if (screenModel.source is SourceManager.StubSource) {
+            MissingSourceScreen(
+                source = screenModel.source,
+                navigateUp = navigateUp,
+            )
+            return
+        }
 
+        val scope = rememberCoroutineScope()
+        val context = LocalContext.current
+        val haptic = LocalHapticFeedback.current
+        val uriHandler = LocalUriHandler.current
+        val snackbarHostState = remember { SnackbarHostState() }
+
+        val onHelpClick = { uriHandler.openUri(LocalSource.HELP_URL) }
         val onWebViewClick = f@{
             val source = screenModel.source as? HttpSource ?: return@f
             navigator.push(
@@ -147,7 +156,7 @@ data class BrowseSourceScreen(
                                 Text(text = stringResource(R.string.popular))
                             },
                         )
-                        if (screenModel.source.supportsLatest) {
+                        if ((screenModel.source as CatalogueSource).supportsLatest) {
                             FilterChip(
                                 selected = state.listing == Listing.Latest,
                                 onClick = {

app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/BrowseSourceScreenModel.kt

@@ -103,9 +103,10 @@ class BrowseSourceScreenModel(
 
     var displayMode by sourcePreferences.sourceDisplayMode().asState(coroutineScope)
 
-    val source = sourceManager.get(sourceId) as CatalogueSource
+    val source = sourceManager.getOrStub(sourceId)
 
     init {
+        if (source is CatalogueSource) {
             mutableState.update {
                 var query: String? = null
                 var listing = it.listing
@@ -122,6 +123,7 @@ class BrowseSourceScreenModel(
                 )
             }
         }
+    }
 
     /**
      * Sheet containing filter items.
@@ -164,6 +166,8 @@ class BrowseSourceScreenModel(
     }
 
     fun resetFilters() {
+        if (source !is CatalogueSource) return
+
         mutableState.update { it.copy(filters = source.getFilterList()) }
     }
 
@@ -172,6 +176,8 @@ class BrowseSourceScreenModel(
     }
 
     fun search(query: String? = null, filters: FilterList? = null) {
+        if (source !is CatalogueSource) return
+
         val input = state.value.listing as? Listing.Search
             ?: Listing.Search(query = null, filters = source.getFilterList())
 
@@ -187,6 +193,8 @@ class BrowseSourceScreenModel(
     }
 
     fun searchGenre(genreName: String) {
+        if (source !is CatalogueSource) return
+
         val defaultFilters = source.getFilterList()
         var genreExists = false