From 83a8afde16695073049846723744036988b4bb9b Mon Sep 17 00:00:00 2001
From: Valentin Lorentz <progval+git@progval.net>
Date: Thu, 7 May 2020 21:17:55 +0200
Subject: [PATCH] Add experimental support for +draft/reply client capability
 on outgoing messages.

---
 src/callbacks.py       |  8 ++++++
 src/conf.py            |  7 +++++
 test/test_callbacks.py | 64 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+)

diff --git a/src/callbacks.py b/src/callbacks.py
index 6a2151b5c..5c7f08ab3 100644
--- a/src/callbacks.py
+++ b/src/callbacks.py
@@ -236,6 +236,14 @@ def _makeReply(irc, msg, s,
     # Finally, we'll return the actual message.
     ret = msgmaker(target, s)
     ret.tag('inReplyTo', msg)
+    if 'msgid' in msg.server_tags \
+            and conf.supybot.protocols.irc.experimentalExtensions() \
+            and 'message-tags' in irc.state.capabilities_ack:
+        # In theory, msgid being in server_tags implies message-tags was
+        # negotiated, but the +reply spec requires it explicitly. Plus, there's
+        # no harm in doing this extra check, in case a plugin is replying
+        # across network (as it may happen with '@network command').
+        ret.server_tags['+draft/reply'] = msg.server_tags['msgid']
     return ret
 
 def error(*args, **kwargs):
diff --git a/src/conf.py b/src/conf.py
index a0b0bd269..e8ddbf3f1 100644
--- a/src/conf.py
+++ b/src/conf.py
@@ -1219,6 +1219,13 @@ registerGlobalValue(supybot.protocols.irc, 'strictRfc',
     requires you to message a nick such as services@this.network.server
     then you you should set this to False.""")))
 
+registerGlobalValue(supybot.protocols.irc, 'experimentalExtensions',
+    registry.Boolean(False, _("""Determines whether the bot will enable
+    draft/experimental extensions of the IRC protocol. Setting this to True
+    may break your bot at any time without warning and/or break your
+    configuration irreversibly. So keep it False unless you know what you are
+    doing.""")))
+
 registerGlobalValue(supybot.protocols.irc, 'certfile',
     registry.String('', _("""Determines what certificate file (if any) the bot
     will use connect with SSL sockets by default.""")))
diff --git a/test/test_callbacks.py b/test/test_callbacks.py
index 2b6fec9c0..4547eee0e 100644
--- a/test/test_callbacks.py
+++ b/test/test_callbacks.py
@@ -534,6 +534,70 @@ class PrivmsgTestCase(ChannelPluginTestCase):
         self.assertRegexp('help first firstcmd', 'First', 0) # no re.I flag.
         self.assertRegexp('help firstrepeat firstcmd', 'FirstRepeat', 0)
 
+    def testClientTagReply(self):
+        self.irc.addCallback(self.First(self.irc))
+
+        # no CAP, no msgid, no experimentalExtensions -> no +reply
+        self.irc.feedMsg(ircmsgs.IrcMsg(
+            command='PRIVMSG', prefix=self.prefix,
+            args=('#foo', '%s: firstcmd' % self.nick)))
+        msg = self.irc.takeMsg()
+        self.assertEqual(msg, ircmsgs.IrcMsg(
+            command='PRIVMSG', args=('#foo', '%s: foo' % self.nick)))
+
+        # CAP and msgid, not no experimentalExtensions -> no +reply
+        self.irc.feedMsg(ircmsgs.IrcMsg(
+            command='PRIVMSG', prefix=self.prefix,
+            args=('#foo', '%s: firstcmd' % self.nick),
+            server_tags={'msgid': 'foobar'}))
+        msg = self.irc.takeMsg()
+        self.assertEqual(msg, ircmsgs.IrcMsg(
+            command='PRIVMSG', args=('#foo', '%s: foo' % self.nick)))
+
+        with conf.supybot.protocols.irc.experimentalExtensions.context(True):
+            # no CAP, but msgid and experimentalExtensions -> no +reply
+            self.irc.feedMsg(ircmsgs.IrcMsg(
+                command='PRIVMSG', prefix=self.prefix,
+                args=('#foo', '%s: firstcmd' % self.nick),
+                server_tags={'msgid': 'foobar'}))
+            msg = self.irc.takeMsg()
+            self.assertEqual(msg, ircmsgs.IrcMsg(
+                command='PRIVMSG', args=('#foo', '%s: foo' % self.nick)))
+
+            # msgid and experimentalExtensions, but no CAP -> no +reply
+            # (note that in theory it's impossible to receive msgid without
+            # the CAP, but the +reply spec explicitly requires to check it)
+            self.irc.feedMsg(ircmsgs.IrcMsg(
+                command='PRIVMSG', prefix=self.prefix,
+                args=('#foo', '%s: firstcmd' % self.nick),
+                server_tags={'msgid': 'foobar'}))
+            msg = self.irc.takeMsg()
+            self.assertEqual(msg, ircmsgs.IrcMsg(
+                command='PRIVMSG', args=('#foo', '%s: foo' % self.nick)))
+
+            try:
+                self.irc.state.capabilities_ack.add('message-tags')
+
+                # no msgid, but CAP and experimentalExtensions -> no +reply
+                self.irc.feedMsg(ircmsgs.IrcMsg(
+                    command='PRIVMSG', prefix=self.prefix,
+                    args=('#foo', '%s: firstcmd' % self.nick)))
+                msg = self.irc.takeMsg()
+                self.assertEqual(msg, ircmsgs.IrcMsg(
+                    command='PRIVMSG', args=('#foo', '%s: foo' % self.nick)))
+
+                # all of CAP, msgid, experimentalExtensions -> yes +reply
+                self.irc.feedMsg(ircmsgs.IrcMsg(
+                    command='PRIVMSG', prefix=self.prefix,
+                    args=('#foo', '%s: firstcmd' % self.nick),
+                    server_tags={'msgid': 'foobar'}))
+                msg = self.irc.takeMsg()
+                self.assertEqual(msg, ircmsgs.IrcMsg(
+                    command='PRIVMSG', args=('#foo', '%s: foo' % self.nick),
+                    server_tags={'+draft/reply': 'foobar'}))
+            finally:
+                self.irc.state.capabilities_ack.remove('message-tags')
+
     class TwoRepliesFirstAction(callbacks.Plugin):
         def testactionreply(self, irc, msg, args):
             irc.reply('foo', action=True)