Logged in user information incorrectly dispalyed - django

Question

I have created a page to update User profile. If I try to update a value of user with existing user, error is thrown as expected, however the variable user.username in profile.html shows the value I am trying to update. My query is why {{ user.username }} is picking up the incorrect value even though the save() method is not called.
profile.html
<div class="content p-3">
<div><img class="rounded-circle" src="{{ user.profile.image.url }}" width="100" height="100"></div>
<div>{{ user.username }}</div>
<div>{{ user.email }}</div>
</div>
<div class="w-25">
<form method="POST" enctype="multipart/form-data">
{% csrf_token %}
<fieldset>
<legend>Profile Info</legend>
{{ user_form | crispy }}
{{ profile_form | crispy }}
</fieldset>
<input class="mt-3" type="submit" value="Update">
</form>
</div>
forms.py
class UserUpdateForm(forms.ModelForm):
email = forms.EmailField()
class Meta:
model = User
fields = ['username', 'email']
class ProfileUpdateForm(forms.ModelForm):
class Meta:
model = Profile
fields = ['image']
views.py
#login_required
def profile(request):
if (request.method == "POST"):
user_form = UserUpdateForm(request.POST, instance=request.user)
profile_form = ProfileUpdateForm(request.POST,
request.FILES,
instance=request.user.profile)
if (user_form.is_valid() and profile_form.is_valid()):
user_form.save()
profile_form.save()
messages.success(request, f"Your profile is updated successfully")
return redirect("profile")
else:
messages.error(request, f"Failed to update profile")
else:
user_form = UserUpdateForm(instance=request.user)
profile_form = ProfileUpdateForm(instance=request.user.profile)
return render(request, 'User/profile.html', {'user_form': user_form, 'profile_form': profile_form}

Answer 1

The ModelForm updating the instance as part of validation is strange/unwanted behaviour, maybe you have found a "bug"
A work around would be to pass a copy of request.user using copy.copy into the ModelForm so that any changes made as part of validation happen on the copy
user_form = UserUpdateForm(request.POST, instance=copy.copy(request.user))

Answer 2

When you write user_form = UserUpdateForm(request.POST, instance=request.user),
your user_form update itself using the values received from front-end. In this case, username is 'newuser2'.
Since this username is taken, user_form.is_valid() returns false and below render function is returned:
return render(request, 'User/profile.html', {'user_form': user_form, 'profile_form': profile_form}
Please note that this instance of user_form has username as "newuser2". Thats why you see username as "newuser2" instead of your current logged in user.
Apologies for the brevity, I'm learning to post answers.