Models: set objects instead of directly using ids

This was always inconsistent - I've been setting objects in some models,
and ids in other ones. Using ids can cause various errors, especially in
cases where one of the objects involved hasn't been committed to the
database yet and so hasn't been assigned its id.

tildes/tildes/models/comment/comment.py

@@ -131,13 +131,9 @@ class Comment(DatabaseModel):
     ):
         """Create a new comment."""
         self.topic = topic
-        self.user_id = author.user_id
-        if parent_comment:
-            self.parent_comment_id = parent_comment.comment_id
-        else:
-            self.parent_comment_id = None
-
+        self.user = author
         self.markdown = markdown
+        self.parent_comment = parent_comment
 
         incr_counter("comments")
 

tildes/tildes/models/comment/comment_label.py

@@ -58,8 +58,8 @@ class CommentLabel(DatabaseModel):
         reason: Optional[str] = None,
     ):
         """Add a new label to a comment."""
-        self.comment_id = comment.comment_id
-        self.user_id = user.user_id
+        self.comment = comment
+        self.user = user
         self.label = label
         self.weight = weight
         self.reason = reason

tildes/tildes/models/comment/comment_notification.py

@@ -99,15 +99,15 @@ class CommentNotification(DatabaseModel):
 
         for user in users_to_mention:
             # prevent the user from mentioning themselves
-            if comment.user_id == user.user_id:
+            if comment.user == user:
                 continue
 
             if parent_comment:
                 # prevent comment replies from mentioning that comment's poster
-                if parent_comment.user_id == user.user_id:
+                if parent_comment.user == user:
                     continue
             # prevent top-level comments from mentioning the thread creator
-            elif comment.topic.user_id == user.user_id:
+            elif comment.topic.user == user:
                 continue
 
             mention_notification = cls(

tildes/tildes/models/message/message.py

@@ -111,9 +111,9 @@ class MessageConversation(DatabaseModel):
 
     def __init__(self, sender: User, recipient: User, subject: str, markdown: str):
         """Create a new message conversation between two users."""
-        self.sender_id = sender.user_id
-        self.recipient_id = recipient.user_id
-        self.unread_user_ids = [self.recipient_id]
+        self.sender = sender
+        self.recipient = recipient
+        self.unread_user_ids = [self.recipient.user_id]
         self.subject = subject
         self.markdown = markdown
         self.rendered_html = convert_markdown_to_safe_html(markdown)
@@ -231,12 +231,15 @@ class MessageReply(DatabaseModel):
     markdown: str = deferred(Column(Text, nullable=False))
     rendered_html: str = Column(Text, nullable=False)
 
+    conversation: MessageConversation = relationship(
+        "MessageConversation", innerjoin=True
+    )
     sender: User = relationship("User", lazy=False, innerjoin=True)
 
     def __init__(self, conversation: MessageConversation, sender: User, markdown: str):
         """Add a new reply to a message conversation."""
-        self.conversation_id = conversation.conversation_id
-        self.sender_id = sender.user_id
+        self.conversation = conversation
+        self.sender = sender
         self.markdown = markdown
         self.rendered_html = convert_markdown_to_safe_html(markdown)
 

tildes/tildes/models/topic/topic.py

@@ -196,8 +196,8 @@ class Topic(DatabaseModel):
     def _create_base_topic(cls, group: Group, author: User, title: str) -> "Topic":
         """Create the "base" for a new topic."""
         new_topic = cls()
-        new_topic.group_id = group.group_id
-        new_topic.user_id = author.user_id
+        new_topic.group = group
+        new_topic.user = author
 
         # if the title is all caps, convert to title case
         if title.isupper():

tildes/tildes/models/user/user_invite_code.py

@@ -8,6 +8,7 @@ import string
 from datetime import datetime
 
 from sqlalchemy import CheckConstraint, Column, ForeignKey, Integer, Text, TIMESTAMP
+from sqlalchemy.orm import relationship
 from sqlalchemy.sql.expression import text
 
 from tildes.lib.string import separate_string
@@ -39,6 +40,8 @@ class UserInviteCode(DatabaseModel):
     )
     invitee_id: int = Column(Integer, ForeignKey("users.user_id"))
 
+    user: User = relationship("User", innerjoin=True, foreign_keys=[user_id])
+
     def __str__(self) -> str:
         """Format the code into a more easily readable version."""
         return separate_string(self.code, "-", 5)
@@ -49,7 +52,7 @@ class UserInviteCode(DatabaseModel):
         Note that uniqueness is not confirmed here, so there is the potential to create
         duplicate codes (which will fail to commit to the database).
         """
-        self.user_id = user.user_id
+        self.user = user
 
         code_chars = random.choices(self.ALPHABET, k=self.LENGTH)
         self.code = "".join(code_chars)