message: sanitize maildir

Remove trailing '/' in maildirs, since people have that (like "/foo/"),
and earlier version didn't complain about that.

Fixes #2298

lib/message/mu-message.cc

@@ -800,14 +800,22 @@ Message::cache_path(Option<size_t> index) const
 		return Ok(std::string{priv_->cache_path});
 }
 
+// for now this only remove stray '/' at the end
+std::string
+Message::sanitize_maildir(const std::string& mdir)
+{
+	if (mdir.size() > 1 && mdir.at(mdir.length()-1) == '/')
+		return mdir.substr(0, mdir.length() - 1);
+	else
+		return mdir;
+}
 
 Result<void>
 Message::update_after_move(const std::string& new_path,
 			   const std::string& new_maildir,
 			   Flags new_flags)
 {
-	const auto statbuf{get_statbuf(new_path)};
-	if (!statbuf)
+	if (auto statbuf{get_statbuf(new_path)}; !statbuf)
 		return Err(statbuf.error());
 	else
 		priv_->ctime = statbuf->st_ctime;
@@ -820,7 +828,7 @@ Message::update_after_move(const std::string& new_path,
 
 	set_flags(new_flags);
 
-	if (const auto res = set_maildir(new_maildir); !res)
+	if (const auto res = set_maildir(sanitize_maildir(new_maildir)); !res)
 		return res;
 
 	return Ok();

lib/message/mu-message.hh

@@ -208,6 +208,16 @@ public:
 	 */
 	Result<void> set_maildir(const std::string& maildir);
 
+	/**
+	 * Clean up the maildir. This is for internal use, but exposed for testing.
+	 * For now cleaned-up means "stray trailing / removed".
+	 *
+	 * @param maildir some maildir
+	 *
+	 * @return a cleaned-up version
+	 */
+	static std::string sanitize_maildir(const std::string& maildir);
+
 	/**
 	 * Get the subject of this message
 	 *

lib/message/test-mu-message.cc

@@ -823,6 +823,14 @@ test_message_fail ()
 	}
 }
 
+static void
+test_message_sanitize_maildir()
+{
+	assert_equal(Message::sanitize_maildir("/"), "/");
+	assert_equal(Message::sanitize_maildir("/foo/bar"), "/foo/bar");
+	assert_equal(Message::sanitize_maildir("/foo/bar/cuux/"), "/foo/bar/cuux");
+}
+
 int
 main(int argc, char* argv[])
 {
@@ -844,6 +852,8 @@ main(int argc, char* argv[])
 			test_message_calendar);
 	g_test_add_func("/message/message/fail",
 			test_message_fail);
+	g_test_add_func("/message/message/sanitize-maildir",
+			test_message_sanitize_maildir);
 
 	return g_test_run();
 }