Added unit tests for LIST responses with NIL (or "") directory separa…

…tors
jstedfast · Dec 31, 2023 · 9a1c39c · 9a1c39c
1 parent 6ad1c01
commit 9a1c39c
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Showing 4 changed files with 117 additions and 4 deletions.
diff --git a/MailKit/Net/Imap/ImapFolder.cs b/MailKit/Net/Imap/ImapFolder.cs
@@ -1627,6 +1627,13 @@ ImapCommand QueueGetSubfoldersCommand (StatusItems items, bool subscribedOnly, C
 		{
 			CheckState (false, false);
 
+			// Any folder with a nil directory separator cannot have children.
+			if (DirectorySeparator == '\0') {
+				status = false;
+				list = null;
+				return null;
+			}
+
 			// Note: folder names can contain wildcards (including '*' and '%'), so replace '*' with '%'
 			// in order to reduce the list of folders returned by our LIST command.
 			var pattern = new StringBuilder (EncodedName.Length + 2);
@@ -1769,6 +1776,9 @@ public override IList<IMailFolder> GetSubfolders (StatusItems items, bool subscr
 		{
 			var ic = QueueGetSubfoldersCommand (items, subscribedOnly, cancellationToken, out var list, out var status);
 
+			if (ic == null)
+				return Array.Empty<IMailFolder> ();
+
 			Engine.Run (ic);
 
 			var children = ProcessGetSubfoldersResponse (ic, list, out var unparented);
@@ -1823,6 +1833,9 @@ public override async Task<IList<IMailFolder>> GetSubfoldersAsync (StatusItems i
 		{
 			var ic = QueueGetSubfoldersCommand (items, subscribedOnly, cancellationToken, out var list, out var status);
 
+			if (ic == null)
+				return Array.Empty<IMailFolder> ();
+
 			await Engine.RunAsync (ic).ConfigureAwait (false);
 
 			var children = ProcessGetSubfoldersResponse (ic, list, out var unparented);
@@ -1852,6 +1865,15 @@ ImapCommand QueueGetSubfolderCommand (string name, CancellationToken cancellatio
 
 			CheckState (false, false);
 
+			// Any folder with a nil directory separator cannot have children.
+			if (DirectorySeparator == '\0') {
+				encodedName = null;
+				fullName = null;
+				folder = null;
+				list = null;
+				return null;
+			}
+
 			fullName = FullName.Length > 0 ? FullName + DirectorySeparator + name : name;
 			encodedName = Engine.EncodeMailboxName (fullName);
 
@@ -1931,7 +1953,7 @@ public override IMailFolder GetSubfolder (string name, CancellationToken cancell
 			var ic = QueueGetSubfolderCommand (name, cancellationToken, out var list, out var fullName, out var encodedName, out var folder);
 
 			if (ic == null)
-				return folder;
+				return folder ?? throw new FolderNotFoundException (name);
 
 			Engine.Run (ic);
 
@@ -1993,7 +2015,7 @@ public override async Task<IMailFolder> GetSubfolderAsync (string name, Cancella
 			var ic = QueueGetSubfolderCommand (name, cancellationToken, out var list, out var fullName, out var encodedName, out var folder);
 
 			if (ic == null)
-				return folder;
+				return folder ?? throw new FolderNotFoundException (name);
 
 			await Engine.RunAsync (ic).ConfigureAwait (false);
 

diff --git a/MailKit/Net/Imap/ImapUtils.cs b/MailKit/Net/Imap/ImapUtils.cs
@@ -646,7 +646,7 @@ public static void ParseFolderList (ImapEngine engine, List<ImapFolder> list, bo
 			if (token.Type == ImapTokenType.QString) {
 				var qstring = (string) token.Value;
 
-				delim = qstring[0];
+				delim = qstring.Length > 0 ? qstring[0] : '\0';
 			} else if (token.Type == ImapTokenType.Nil) {
 				delim = '\0';
 			} else {
@@ -755,7 +755,7 @@ public static async Task ParseFolderListAsync (ImapEngine engine, List<ImapFolde
 			if (token.Type == ImapTokenType.QString) {
 				var qstring = (string) token.Value;
 
-				delim = qstring[0];
+				delim = qstring.Length > 0 ? qstring[0] : '\0';
 			} else if (token.Type == ImapTokenType.Nil) {
 				delim = '\0';
 			} else {

diff --git a/UnitTests/Net/Imap/ImapFolderTests.cs b/UnitTests/Net/Imap/ImapFolderTests.cs
@@ -572,6 +572,93 @@ public async Task TestLiteralFolderNamesAsync ()
 			}
 		}
 
+		static IList<ImapReplayCommand> CreateNilDirectorySeparatorCommands ()
+		{
+			return new List<ImapReplayCommand> {
+				new ImapReplayCommand ("", "common.basic-greeting.txt"),
+				new ImapReplayCommand ("A00000000 CAPABILITY\r\n", "common.capability.txt"),
+				new ImapReplayCommand ("A00000001 LOGIN username password\r\n", ImapReplayCommandResponse.OK),
+				new ImapReplayCommand ("A00000002 CAPABILITY\r\n", "common.capability.txt"),
+				new ImapReplayCommand ("A00000003 LIST \"\" \"\"\r\n", "common.list-namespace.txt"),
+				new ImapReplayCommand ("A00000004 LIST \"\" \"INBOX\"\r\n", "common.list-inbox.txt"),
+				new ImapReplayCommand ("A00000005 LIST \"\" \"%\"\r\n", "common.list-nil-folder-delim.txt"),
+			};
+		}
+
+		[Test]
+		public void TestNilDirectorySeparator ()
+		{
+			var commands = CreateNilDirectorySeparatorCommands ();
+
+			using (var client = new ImapClient () { TagPrefix = 'A' }) {
+				try {
+					client.Connect (new ImapReplayStream (commands, false), "localhost", 143, SecureSocketOptions.None);
+				} catch (Exception ex) {
+					Assert.Fail ($"Did not expect an exception in Connect: {ex}");
+				}
+
+				try {
+					client.Authenticate ("username", "password");
+				} catch (Exception ex) {
+					Assert.Fail ($"Did not expect an exception in Authenticate: {ex}");
+				}
+
+				var personal = client.GetFolder (client.PersonalNamespaces[0]);
+				var subfolders = personal.GetSubfolders (false);
+
+				Assert.That (subfolders.Count, Is.EqualTo (3), "Count");
+				Assert.That (subfolders[0].Name, Is.EqualTo ("INBOX"));
+				Assert.That (subfolders[1].Name, Is.EqualTo ("Folder1"));
+				Assert.That (subfolders[1].DirectorySeparator, Is.EqualTo ('\0'));
+				Assert.That (subfolders[2].Name, Is.EqualTo ("Folder2"));
+				Assert.That (subfolders[2].DirectorySeparator, Is.EqualTo ('\0'));
+
+				Assert.Throws<FolderNotFoundException> (() => subfolders[1].GetSubfolder ("Subfolder"));
+
+				var empty = subfolders[1].GetSubfolders (false);
+				Assert.That (empty.Count, Is.EqualTo (0), "GetSubfolders when DirectorySeparator is nil");
+
+				client.Disconnect (false);
+			}
+		}
+
+		[Test]
+		public async Task TestNilDirectorySeparatorAsync ()
+		{
+			var commands = CreateNilDirectorySeparatorCommands ();
+
+			using (var client = new ImapClient () { TagPrefix = 'A' }) {
+				try {
+					await client.ConnectAsync (new ImapReplayStream (commands, true), "localhost", 143, SecureSocketOptions.None);
+				} catch (Exception ex) {
+					Assert.Fail ($"Did not expect an exception in Connect: {ex}");
+				}
+
+				try {
+					await client.AuthenticateAsync ("username", "password");
+				} catch (Exception ex) {
+					Assert.Fail ($"Did not expect an exception in Authenticate: {ex}");
+				}
+
+				var personal = client.GetFolder (client.PersonalNamespaces[0]);
+				var subfolders = await personal.GetSubfoldersAsync (false);
+
+				Assert.That (subfolders.Count, Is.EqualTo (3), "Count");
+				Assert.That (subfolders[0].Name, Is.EqualTo ("INBOX"));
+				Assert.That (subfolders[1].Name, Is.EqualTo ("Folder1"));
+				Assert.That (subfolders[1].DirectorySeparator, Is.EqualTo ('\0'));
+				Assert.That (subfolders[2].Name, Is.EqualTo ("Folder2"));
+				Assert.That (subfolders[2].DirectorySeparator, Is.EqualTo ('\0'));
+
+				Assert.ThrowsAsync<FolderNotFoundException> (() => subfolders[1].GetSubfolderAsync ("Subfolder"));
+
+				var empty = await subfolders[1].GetSubfoldersAsync (false);
+				Assert.That (empty.Count, Is.EqualTo (0), "GetSubfolders when DirectorySeparator is nil");
+
+				await client.DisconnectAsync (false);
+			}
+		}
+
 		static IList<ImapReplayCommand> CreateAppendLimitCommands ()
 		{
 			return new List<ImapReplayCommand> {

diff --git a/UnitTests/Net/Imap/Resources/common/list-nil-folder-delim.txt b/UnitTests/Net/Imap/Resources/common/list-nil-folder-delim.txt
@@ -0,0 +1,4 @@
+* LIST () "/" INBOX
+* LIST (\HasNoChildren) NIL "Folder1"
+* LIST (\HasNoChildren) "" "Folder2"
+A######## OK LIST Completed