Getting a ValueError when trying to alter a Django model field related to a ManyToManyField

I'm encountering an issue while trying to make alterations to a Django model field in my project. Specifically, I'm attempting to modify the 'likes' field in the 'Tweet' model. However, I'm receiving the following error:

"ValueError: Cannot alter field tweets.Tweet.likes into tweets.Tweet.likes - they are not compatible types (you cannot alter to or from M2M fields, or add or remove through= on M2M fields)"

Here are the relevant parts of my code:

import random
from django.conf import settings
from django.db import models

User = settings.AUTH_USER_MODEL

class TweetLike(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    tweet = models.ForeignKey("Tweet", on_delete=models.CASCADE)
    timestamp = models.DateTimeField(auto_now_add=True)

class Tweet(models.Model):
    # id = models.AutoField(primary_key=True)
    parent = models.ForeignKey("self", null=True, on_delete=models.SET_NULL)
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name="tweets")
    likes = models.ManyToManyField(User, related_name='tweet_user', blank=True, through=TweetLike)
    content = models.TextField(blank=True, null=True)
    image = models.FileField(upload_to='images/', blank=True, null=True)
    timestamp = models.DateTimeField(auto_now_add=True)

class Meta:
    ordering = ['-id']

I'm not quite sure how to proceed and would appreciate any guidance on how to resolve this error.

Thank you for your help!

I attempted to modify the 'likes' field directly in the model, but it resulted in the error mentioned above.

Solution

you're trying to alter a ManyToManyField called likes in your Tweet model, which has a through parameter defined, indicating the intermediary model TweetLike

When you alter a field in Django, there are certain limitations and restrictions, and altering a ManyToManyField with a custom intermediary model can be one of those cases where altering is more complex.

If your goal is to add a new field to the likes relationship (for example, to capture additional information about the like, such as a comment), you should create a new model for that purpose. You can't directly alter the likes field without removing the through parameter.

class Like(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    tweet = models.ForeignKey(Tweet, on_delete=models.CASCADE)
    timestamp = models.DateTimeField(auto_now_add=True)
    comment = models.TextField(blank=True, null=True)  # Add any additional fields you need

class Tweet(models.Model):
    # Your existing fields
    likes = models.ManyToManyField(User, related_name='tweet_user', blank=True, through=Like)