Django Blog url error NoReverseMatch at / - django

Question

I git this error home.html page when I but the url to user posts page the url is work fine in other pages
but in home page I get this error
Reverse for 'user-posts' with arguments '('',)' not found. 1 pattern(s) tried: ['user/(?P[^/]+)/$']
I don't know if their something I need to but in home.html to let me access the post.author.usernname
home.html
{% extends "blog/base.html" %}
{% block content %}
<h1>Blog Home!</h1>
{% for post in posts %}
<article class="media content-section">
<img class = "rounded-circle article-img" src = "{{ post.author.profile.image.url }}">
<div class="media-body">
<div class="article-metadata">
<a class="mr-2" href="{% url 'user-posts' post.author.username %}">{{ post.author }}</a>
<small class="text-muted">{{ post.date_posted|date:"F d, Y" }}</small>
</div>
<h2><a class="article-title" href="{% url 'post-detail' post.id %}">{{ post.title }}</a></h2>
<p class="article-content">{{ post.content }}</p>
</div>
</article>
{% endfor %}
{% if is_paginated %}
{% if page_obj.has_previous %}
<a class = "btn btn-outline-info mb-4" href="?page=1">First</a>
<a class = "btn btn-outline-info mb-4" href="?page={{ page_obj.previous_page_number }}">Previous</a>
{% endif %}
{% for num in page_obj.paginator.page_range %}
{% if page_obj.number == num %}
<a class = "btn btn-info mb-4" href="?page={{ num }}">{{ num }}</a>
{% elif num > page_obj.number|add:'-4' and num < page_obj.number|add:'4' %}
<a class = "btn btn-outline-info mb-4" href="?page={{ num }}">{{ num }}</a>
{% endif %}
{% endfor %}
{% if page_obj.has_next %}
<a class = "btn btn-outline-info mb-4" href="?page={{ page_obj.next_page_number }}">Next</a>
<a class = "btn btn-outline-info mb-4" href="?page={{ page_obj.paginator.num_pages }}">Last</a>
{% endif %}
{% endif %}
{% endblock %}
url.py
from django.urls import path
from .views import (
PostListView,
PostDetailView,
PostCreateView,
PostUpdateView,
PostDeleteView,
UserPostListView
)
from . import views
urlpatterns = [
path('', PostListView.as_view(), name= "blog-home"),
path('user/<str:username>/', UserPostListView.as_view(), name= "user-posts"),
path('post/<int:pk>/', PostDetailView.as_view(), name= "post-detail"),
path('post/new/', PostCreateView.as_view(), name= "post-create"),
path('post/<int:pk>/update/', PostUpdateView.as_view(), name= "post-update"),
path('post/<int:pk>/delete/', PostDeleteView.as_view(), name= "post-delete"),
path('about/', views.about, name= "blog-about"),
]
the views.py
from django.shortcuts import render, get_object_or_404
from django.contrib.auth.models import User
from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
from django.views.generic import (
ListView,
DetailView,
CreateView,
UpdateView,
DeleteView
)
from .models import Post
def home(request):
content = {
'posts':Post.objects.all()
}
return render(request, 'blog/home.html', content)
class PostListView(ListView):
model = Post
template_name = 'blog/home.html'
context_object_name = 'posts'
ordering = ['-date_posted']
paginate_by = 5
class UserPostListView(ListView):
model = Post
template_name = 'blog/user_posts.html'
context_object_name = 'posts'
paginate_by = 5
def get_queryset(self):
user = get_object_or_404(User, username = self.kwargs.get('username'))
return Post.objects.filter(author = user).order_by('-date_posted')
class PostDetailView(DetailView):
model = Post
class PostCreateView(LoginRequiredMixin, CreateView):
model = Post
fields = ['title', 'content']
def form_valid(self, form):
form.instance.author = self.request.user
return super().form_valid(form)
class PostUpdateView(LoginRequiredMixin, UserPassesTestMixin, UpdateView):
model = Post
fields = ['title', 'content']
def form_valid(self, form):
form.instance.author = self.request.user
return super().form_valid(form)
def test_func(self):
post = self.get_object()
if self.request.user == post.author:
return True
return False
class PostDeleteView(LoginRequiredMixin, UserPassesTestMixin, DeleteView):
model = Post
success_url = '/'
def test_func(self):
post = self.get_object()
if self.request.user == post.author:
return True
return False
def about(request):
return render(request, 'blog/about.html', {'title': 'About'})
the models.py
from django.db import models
from django.utils import timezone
from django.contrib.auth.models import User
from django.urls import reverse
class Post(models.Model):
title = models.CharField(max_length = 100)
content = models.TextField()
date_posted = models.DateTimeField(default=timezone.now)
author = models.ForeignKey(User, on_delete = models.CASCADE, db_constraint=False)
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse('post-detail', kwargs = {'pk':self.pk})