Code review and testing fixes:

- fix(dm-share): kotlin-review fixes (alias dot-boundary match + transient feed doc)
- fix(dm-share): address code-review findings (intent consume, media helper, manifest sync)
- fix(dm-share): make the picker one-shot so backing out doesn't duplicate drafts
- fix(dm): avoid duplicate drafts on abort by rotating draft tag after the async save

amethyst/src/main/AndroidManifest.xml

@@ -218,6 +218,9 @@
             </intent-filter>
         </activity>
 
+        <!-- "Send as DM" share target. The android:name simple class ("ShareAsDMAlias")
+             is matched at runtime by ShareIntentRouting.SHARE_AS_DM_ALIAS_SIMPLE_NAME;
+             keep the two in sync when renaming. -->
         <activity-alias
             android:name=".ui.ShareAsDMAlias"
             android:exported="true"

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/actions/uploads/SharedMediaResolver.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.actions.uploads
+
+import android.content.Context
+import androidx.core.net.toUri
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+/**
+ * Resolves a shared content-URI string (from an Android SEND intent) into a
+ * [SelectedMedia] by reading its MIME type off the main thread. Returns null for
+ * a null/blank URI. Shared by the share-to-compose pre-fill paths (DM chatroom,
+ * group DM, …) so the URI→MIME→SelectedMedia logic lives in one place.
+ */
+suspend fun resolveSharedMedia(
+    context: Context,
+    uriString: String?,
+): SelectedMedia? =
+    uriString?.ifBlank { null }?.toUri()?.let { uri ->
+        withContext(Dispatchers.IO) {
+            SelectedMedia(uri, context.contentResolver.getType(uri))
+        }
+    }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/AppNavigation.kt

@@ -625,6 +625,14 @@ private fun NavigateIfIntentRequested(
         } else {
             nav.newStack(Route.NewShortNote(message = message, attachment = media.toString()))
         }
+
+        // Consume the launch intent so a later recomposition can't re-fire
+        // newStack for the same share (the isBaseRoute guard is a non-reactive
+        // snapshot and stops guarding once we navigate past the destination,
+        // e.g. into a chat via the one-shot picker). Clearing the action also
+        // lets the else-branch register the onNewIntent listener for the rest
+        // of this session.
+        activity.intent.action = null
     } else {
         var newAccount by remember { mutableStateOf<String?>(null) }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/ShareIntentRouting.kt

@@ -26,8 +26,13 @@ package com.vitorpamplona.amethyst.ui.navigation
  * component class name of the launching intent (the activity-alias name).
  */
 object ShareIntentRouting {
-    /** Simple class name of the activity-alias declared in AndroidManifest.xml. */
+    /**
+     * Simple class name of the `<activity-alias>` declared in AndroidManifest.xml
+     * (android:name=".ui.ShareAsDMAlias"). MUST stay in sync with the manifest —
+     * renaming the alias there without updating this constant silently routes
+     * "Send as DM" shares to the New Post composer (no build error).
+     */
     const val SHARE_AS_DM_ALIAS_SIMPLE_NAME = "ShareAsDMAlias"
 
-    fun isShareAsDm(componentClassName: String?): Boolean = componentClassName?.endsWith(SHARE_AS_DM_ALIAS_SIMPLE_NAME) == true
+    fun isShareAsDm(componentClassName: String?): Boolean = componentClassName?.endsWith(".$SHARE_AS_DM_ALIAS_SIMPLE_NAME") == true
 }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/privateDM/ChatroomView.kt

@@ -31,10 +31,9 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
-import androidx.core.net.toUri
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.event.EventFinderFilterAssemblerSubscription
-import com.vitorpamplona.amethyst.ui.actions.uploads.SelectedMedia
+import com.vitorpamplona.amethyst.ui.actions.uploads.resolveSharedMedia
 import com.vitorpamplona.amethyst.ui.feeds.WatchLifecycleAndUpdateModel
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.note.LoadAddressableNote
@@ -50,9 +49,7 @@ import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip17Dm.base.ChatroomKey
 import com.vitorpamplona.quartz.nip17Dm.settings.ChatMessageRelayListEvent
 import kotlinx.collections.immutable.persistentListOf
-import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
 
 @Composable
 fun ChatroomView(
@@ -122,11 +119,8 @@ fun ChatroomView(
     val context = LocalContext.current
     if (attachmentUri != null) {
         LaunchedEffect(key1 = attachmentUri) {
-            attachmentUri.ifBlank { null }?.toUri()?.let { uri ->
-                withContext(Dispatchers.IO) {
-                    val mediaType = context.contentResolver.getType(uri)
-                    newPostModel.pickedMedia(persistentListOf(SelectedMedia(uri, mediaType)))
-                }
+            resolveSharedMedia(context, attachmentUri)?.let {
+                newPostModel.pickedMedia(persistentListOf(it))
             }
         }
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/privateDM/send/PrivateMessageEditFieldRow.kt

@@ -114,9 +114,15 @@ fun PrivateMessageEditFieldRow(
         if (channelScreenModel.message.text.isNotBlank()) {
             accountViewModel.launchSigner {
                 channelScreenModel.sendDraftSync()
+                // Rotate the draft tag only AFTER the async save completes. Doing it
+                // synchronously here (before launchSigner runs) would make sendDraftSync
+                // persist under a freshly-rotated tag, duplicating the draft. See the
+                // matching order in NewGroupDMScreen.
+                channelScreenModel.cancel()
             }
+        } else {
+            channelScreenModel.cancel()
         }
-        channelScreenModel.cancel()
         nav.popBack()
     }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/share/ShareToDMNav.kt

@@ -36,6 +36,14 @@ class ShareToDMNav(
     private val attachment: String?,
 ) : INav by delegate {
     override fun nav(route: Route) {
-        delegate.nav(ShareToDMRouteRewriter.rewrite(route, message, attachment))
+        val rewritten = ShareToDMRouteRewriter.rewrite(route, message, attachment)
+        if (route is Route.Room) {
+            // One-shot: replace the picker in the back stack so backing out of the
+            // chat exits the share flow instead of returning to the picker, which
+            // would re-inject the shared text on re-tap and create duplicate drafts.
+            delegate.popUpTo(rewritten, Route.ShareToDM::class)
+        } else {
+            delegate.nav(rewritten)
+        }
     }
 }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/share/ShareToDMScreen.kt

@@ -55,6 +55,12 @@ fun ShareToDMScreen(
     accountViewModel: AccountViewModel,
     nav: INav,
 ) {
+    // Deliberately a screen-scoped, transient FeedContentState (not wired into
+    // AccountFeedContentStates like dmKnown/dmNew). The share picker is a one-shot,
+    // short-lived screen, so it owns its feed via viewModelScope and relies on
+    // WatchLifecycleAndUpdateModel to load/refresh on entry and resume rather than
+    // on the always-on additive update loop. Account switch recreates it (the
+    // remember key), which is correct for a transient picker.
     val feedContentState =
         remember(accountViewModel) {
             FeedContentState(
@@ -85,7 +91,7 @@ fun ShareToDMScreen(
                         .clickable(
                             role = Role.Button,
                             onClickLabel = stringRes(R.string.share_to_dm_start_new),
-                        ) { nav.nav(Route.NewGroupDM(message = message, attachment = attachment)) }
+                        ) { nav.popUpTo(Route.NewGroupDM(message = message, attachment = attachment), Route.ShareToDM::class) }
                         .padding(16.dp),
             )
 

amethyst/src/test/java/com/vitorpamplona/amethyst/navigation/ShareIntentRoutingTest.kt

@@ -46,4 +46,9 @@ class ShareIntentRoutingTest {
     fun rejectsNull() {
         assertFalse(ShareIntentRouting.isShareAsDm(null))
     }
+
+    @Test
+    fun rejectsSuffixThatIsNotASimpleName() {
+        assertFalse(ShareIntentRouting.isShareAsDm("com.evil.XShareAsDMAlias"))
+    }
 }