From 7fb992dba3f04381364c5236b858c792d979ef6e Mon Sep 17 00:00:00 2001
From: Steve Howell <showell30@yahoo.com>
Date: Tue, 4 Oct 2016 08:35:36 -0700
Subject: [PATCH] Simplify and "fix" render_old_messages management command.

The command to render old messages now looks for all messages
not matching the bugdown version, and it no longer directly calls
into model code.  We should still be extremely cautious about
using this code.
---
 zerver/lib/message.py                            | 16 ++++++++++++++++
 zerver/models.py                                 | 16 ----------------
 .../management/commands/render_old_messages.py   |  6 ++++--
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/zerver/lib/message.py b/zerver/lib/message.py
index 01c034040f..42b737cb25 100644
--- a/zerver/lib/message.py
+++ b/zerver/lib/message.py
@@ -213,3 +213,19 @@ class MessageDict(object):
 
         return obj
 
+def re_render_content_for_management_command(message):
+    # type: (Message) -> None
+
+    '''
+    Please avoid using this function, as its only used in a management command that
+    is somewhat deprecated.
+    '''
+    assert Message.need_to_render_content(message.rendered_content,
+                                          message.rendered_content_version,
+                                          bugdown.version)
+
+    rendered_content = message.render_markdown(message.content)
+    message.rendered_content = rendered_content
+    message.rendered_content_version = bugdown.version
+    message.save_rendered_content()
+
diff --git a/zerver/models.py b/zerver/models.py
index bbfd280971..a942c7d300 100644
--- a/zerver/models.py
+++ b/zerver/models.py
@@ -878,22 +878,6 @@ class Message(ModelReprMixin, models.Model):
         # type: () -> None
         self.save(update_fields=["rendered_content", "rendered_content_version"])
 
-    def maybe_render_content(self, domain, save = False):
-        # type: (Optional[text_type], bool) -> bool
-        """Render the markdown if there is no existing rendered_content"""
-        # TODO: see #1379 to eliminate bugdown dependencies
-        global bugdown
-        if bugdown is None:
-            import zerver.lib.bugdown as bugdown
-            # 'from zerver.lib import bugdown' gives mypy error in python 3 mode.
-
-        if Message.need_to_render_content(self.rendered_content,
-                                          self.rendered_content_version,
-                                          bugdown.version):
-            return self.set_rendered_content(self.render_markdown(self.content, domain), save)
-        else:
-            return True
-
     @staticmethod
     def need_to_render_content(rendered_content, rendered_content_version, bugdown_version):
         # type: (Optional[text_type], int, int) -> bool
diff --git a/zilencer/management/commands/render_old_messages.py b/zilencer/management/commands/render_old_messages.py
index 7a4b15e790..34125a26fc 100644
--- a/zilencer/management/commands/render_old_messages.py
+++ b/zilencer/management/commands/render_old_messages.py
@@ -5,6 +5,8 @@ from typing import Any
 
 from django.core.management.base import BaseCommand
 
+import zerver.lib.bugdown as bugdown
+from zerver.lib.message import re_render_content_for_management_command
 from zerver.models import Message
 import datetime
 import time
@@ -18,11 +20,11 @@ Usage: python manage.py render_old_messages"""
         # type: (*Any, **Any) -> None
         total_rendered = 0
         while True:
-            messages = Message.objects.filter(rendered_content_version=None)[0:100]
+            messages = Message.objects.exclude(rendered_content_version=bugdown.version)[0:100]
             if len(messages) == 0:
                 break
             for message in messages:
-                message.maybe_render_content(None, save=True)
+                re_render_content_for_management_command(message)
             total_rendered += len(messages)
             print(datetime.datetime.now(), total_rendered)
             # Put in some sleep so this can run safely on low resource machines