IMAP move operation should ignore expunge policy

Because the original IMAP specification doesn't include a move operation, we implement it as copy, followed by deleting the source message. Deleting messages in IMAP is a two stage process. First a message is marked as deleted, then the EXPUNGE command is issued. However, the EXPUNGE command will remove all messages in a folder marked as deleted. For a move operation, we don't want to remove other messages, and therefore won't issue the EXPUNGE command. However, if the server supports the UIDPLUS extension, we can specify which messages exactly should be expunged. So if that extension is available, we will use the UID EXPUNGE command on the source message of a move operation. Since the EXPUNGE command removes all messages marked as deleted, K-9 Mail has a setting that controls when the command is issued (when deleting a message, when polling, manually via a menu option). Previously this setting was also used for move operations. However, that probably should have never been the case.
thunderbird · Nov 18, 2023 · 8b66b04 · 8b66b04
1 parent 9fe2c68
commit 8b66b04
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Showing 3 changed files with 38 additions and 8 deletions.
diff --git a/app/core/src/main/java/com/fsck/k9/controller/MessagingController.java b/app/core/src/main/java/com/fsck/k9/controller/MessagingController.java
@@ -893,11 +893,6 @@ void processPendingMoveOrCopy(Account account, long srcFolderId, long destFolder
         }
 
         if (operation != MoveOrCopyFlavor.COPY) {
-            if (backend.getSupportsExpunge() && account.getExpungePolicy() == Expunge.EXPUNGE_IMMEDIATELY) {
-                Timber.i("processingPendingMoveOrCopy expunging folder %s:%s", account, srcFolderServerId);
-                backend.expungeMessages(srcFolderServerId, uids);
-            }
-
             destroyPlaceholderMessages(localSourceFolder, uids);
         }
 

diff --git a/mail/protocols/imap/src/main/java/com/fsck/k9/mail/store/imap/RealImapFolder.kt b/mail/protocols/imap/src/main/java/com/fsck/k9/mail/store/imap/RealImapFolder.kt
@@ -320,8 +320,11 @@ internal class RealImapFolder(
             return null
         }
 
+        val uids = messages.map { it.uid }
+
         val uidMapping = copyMessages(messages, folder)
         setFlags(messages, setOf(Flag.DELETED), true)
+        expungeUidsOnly(uids)
 
         return uidMapping
     }
@@ -1080,8 +1083,15 @@ internal class RealImapFolder(
         }
     }
 
-    @Throws(MessagingException::class)
     override fun expungeUids(uids: List<String>) {
+        expungeUids(uids, fullExpungeFallback = true)
+    }
+
+    private fun expungeUidsOnly(uids: List<String>) {
+        expungeUids(uids, fullExpungeFallback = false)
+    }
+
+    private fun expungeUids(uids: List<String>, fullExpungeFallback: Boolean) {
         require(uids.isNotEmpty()) { "expungeUids() must be called with a non-empty set of UIDs" }
 
         open(OpenMode.READ_WRITE)
@@ -1091,8 +1101,10 @@ internal class RealImapFolder(
             if (connection!!.isUidPlusCapable) {
                 val longUids = uids.map { it.toLong() }.toSet()
                 connection!!.executeCommandWithIdSet(Commands.UID_EXPUNGE, "", longUids)
-            } else {
+            } else if (fullExpungeFallback) {
                 executeSimpleCommand("EXPUNGE")
+            } else {
+                Timber.v("Server doesn't support expunging individual messages: %s", uids)
             }
         } catch (ioe: IOException) {
             throw ioExceptionHandler(connection, ioe)

diff --git a/mail/protocols/imap/src/test/java/com/fsck/k9/mail/store/imap/RealImapFolderTest.kt b/mail/protocols/imap/src/test/java/com/fsck/k9/mail/store/imap/RealImapFolderTest.kt
@@ -48,6 +48,8 @@ import org.mockito.kotlin.doReturn
 import org.mockito.kotlin.doThrow
 import org.mockito.kotlin.eq
 import org.mockito.kotlin.mock
+import org.mockito.kotlin.never
+import org.mockito.kotlin.stub
 import org.mockito.kotlin.whenever
 
 class RealImapFolderTest {
@@ -312,16 +314,37 @@ class RealImapFolderTest {
     }
 
     @Test
-    fun moveMessages_shouldDeleteMessagesFromSourceFolder() {
+    fun `moveMessages() should delete messages from source folder but not issue EXPUNGE command`() {
         val sourceFolder = createFolder("Folder")
         prepareImapFolderForOpen(OpenMode.READ_WRITE)
+        imapConnection.stub {
+            on { isUidPlusCapable } doReturn false
+        }
         val destinationFolder = createFolder("Destination")
         val messages = listOf(createImapMessage("1"))
         sourceFolder.open(OpenMode.READ_WRITE)
 
         sourceFolder.moveMessages(messages, destinationFolder)
 
         assertCommandWithIdsIssued("UID STORE 1 +FLAGS.SILENT (\\Deleted)")
+        verify(imapConnection, never()).executeSimpleCommand("EXPUNGE")
+    }
+
+    @Test
+    fun `moveMessages() should delete messages from source folder and issue UID EXPUNGE command when available`() {
+        val sourceFolder = createFolder("Folder")
+        prepareImapFolderForOpen(OpenMode.READ_WRITE)
+        imapConnection.stub {
+            on { isUidPlusCapable } doReturn true
+        }
+        val destinationFolder = createFolder("Destination")
+        val messages = listOf(createImapMessage("1"))
+        sourceFolder.open(OpenMode.READ_WRITE)
+
+        sourceFolder.moveMessages(messages, destinationFolder)
+
+        assertCommandWithIdsIssued("UID STORE 1 +FLAGS.SILENT (\\Deleted)")
+        assertCommandWithIdsIssued("UID EXPUNGE 1")
     }
 
     @Test