We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Links to unpublished sources should not appear on Provenance detail pages
Example: visit http://206.12.93.196/provenance/3665 (while logged out), click on first link. We get a 403 Forbidden error, since the source is unpublished.

Unpublished sources should not be listed on the Provenance Detail page.

Credit to @zhannaklimanova and her link checker script for catching this bug!

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `django/cantusdb_project/main_app/views/provenance.py`
Content:
```
1 from django.views.generic import DetailView
2 from main_app.models import Provenance
3 
4 
5 class ProvenanceDetailView(DetailView):
6     model = Provenance
7     context_object_name = "provenance"
8     template_name = "provenance_detail.html"
9
```

Path: `django/cantusdb_project/main_app/views/century.py`
Content:
```
1 from django.views.generic import DetailView
2 from main_app.models import Century, Source
3 from typing import Any
4 
5 
6 class CenturyDetailView(DetailView):
7     model = Century
8     context_object_name = "century"
9     template_name = "century_detail.html"
10 
11     def get_context_data(self, **kwargs: Any) -> dict[str, Any]:
12         context = super().get_context_data(**kwargs)
13         century = self.get_object()
14         user = self.request.user
15         display_unpublished = user.is_authenticated
16         sources = Source.objects.filter(century=century)
17         if not display_unpublished:
18             sources = sources.filter(published=True)
19         sources = sources.only("title", "id")
20         context["sources"] = sources
21         return context
22
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/django/cantusdb_project/main_app/views/century.py b/django/cantusdb_project/main_app/views/century.py
--- a/django/cantusdb_project/main_app/views/century.py
+++ b/django/cantusdb_project/main_app/views/century.py
@@ -16,6 +16,6 @@
         sources = Source.objects.filter(century=century)
         if not display_unpublished:
             sources = sources.filter(published=True)
-        sources = sources.only("title", "id")
+        sources = sources.only("title", "id", "siglum")
         context["sources"] = sources
         return context
diff --git a/django/cantusdb_project/main_app/views/provenance.py b/django/cantusdb_project/main_app/views/provenance.py
--- a/django/cantusdb_project/main_app/views/provenance.py
+++ b/django/cantusdb_project/main_app/views/provenance.py
@@ -1,8 +1,21 @@
 from django.views.generic import DetailView
-from main_app.models import Provenance
+from main_app.models import Provenance, Source
+from typing import Any
 
 
 class ProvenanceDetailView(DetailView):
     model = Provenance
     context_object_name = "provenance"
     template_name = "provenance_detail.html"
+
+    def get_context_data(self, **kwargs: Any) -> dict[str, Any]:
+        context = super().get_context_data(**kwargs)
+        provenance = self.get_object()
+        user = self.request.user
+        display_unpublished = user.is_authenticated
+        sources = Source.objects.filter(provenance=provenance)
+        if not display_unpublished:
+            sources = sources.filter(published=True)
+        sources = sources.only("title", "id", "siglum")
+        context["sources"] = sources
+        return context

{"golden_diff": "diff --git a/django/cantusdb_project/main_app/views/century.py b/django/cantusdb_project/main_app/views/century.py\n--- a/django/cantusdb_project/main_app/views/century.py\n+++ b/django/cantusdb_project/main_app/views/century.py\n@@ -16,6 +16,6 @@\n         sources = Source.objects.filter(century=century)\n         if not display_unpublished:\n             sources = sources.filter(published=True)\n-        sources = sources.only(\"title\", \"id\")\n+        sources = sources.only(\"title\", \"id\", \"siglum\")\n         context[\"sources\"] = sources\n         return context\ndiff --git a/django/cantusdb_project/main_app/views/provenance.py b/django/cantusdb_project/main_app/views/provenance.py\n--- a/django/cantusdb_project/main_app/views/provenance.py\n+++ b/django/cantusdb_project/main_app/views/provenance.py\n@@ -1,8 +1,21 @@\n from django.views.generic import DetailView\n-from main_app.models import Provenance\n+from main_app.models import Provenance, Source\n+from typing import Any\n \n \n class ProvenanceDetailView(DetailView):\n     model = Provenance\n     context_object_name = \"provenance\"\n     template_name = \"provenance_detail.html\"\n+\n+    def get_context_data(self, **kwargs: Any) -> dict[str, Any]:\n+        context = super().get_context_data(**kwargs)\n+        provenance = self.get_object()\n+        user = self.request.user\n+        display_unpublished = user.is_authenticated\n+        sources = Source.objects.filter(provenance=provenance)\n+        if not display_unpublished:\n+            sources = sources.filter(published=True)\n+        sources = sources.only(\"title\", \"id\", \"siglum\")\n+        context[\"sources\"] = sources\n+        return context\n", "issue": "Links to unpublished sources should not appear on Provenance detail pages\nExample: visit http://206.12.93.196/provenance/3665 (while logged out), click on first link. We get a 403 Forbidden error, since the source is unpublished.\r\n\r\nUnpublished sources should not be listed on the Provenance Detail page.\r\n\r\nCredit to @zhannaklimanova and her link checker script for catching this bug!\n", "before_files": [{"content": "from django.views.generic import DetailView\nfrom main_app.models import Provenance\n\n\nclass ProvenanceDetailView(DetailView):\n    model = Provenance\n    context_object_name = \"provenance\"\n    template_name = \"provenance_detail.html\"\n", "path": "django/cantusdb_project/main_app/views/provenance.py"}, {"content": "from django.views.generic import DetailView\nfrom main_app.models import Century, Source\nfrom typing import Any\n\n\nclass CenturyDetailView(DetailView):\n    model = Century\n    context_object_name = \"century\"\n    template_name = \"century_detail.html\"\n\n    def get_context_data(self, **kwargs: Any) -> dict[str, Any]:\n        context = super().get_context_data(**kwargs)\n        century = self.get_object()\n        user = self.request.user\n        display_unpublished = user.is_authenticated\n        sources = Source.objects.filter(century=century)\n        if not display_unpublished:\n            sources = sources.filter(published=True)\n        sources = sources.only(\"title\", \"id\")\n        context[\"sources\"] = sources\n        return context\n", "path": "django/cantusdb_project/main_app/views/century.py"}], "after_files": [{"content": "from django.views.generic import DetailView\nfrom main_app.models import Provenance, Source\nfrom typing import Any\n\n\nclass ProvenanceDetailView(DetailView):\n    model = Provenance\n    context_object_name = \"provenance\"\n    template_name = \"provenance_detail.html\"\n\n    def get_context_data(self, **kwargs: Any) -> dict[str, Any]:\n        context = super().get_context_data(**kwargs)\n        provenance = self.get_object()\n        user = self.request.user\n        display_unpublished = user.is_authenticated\n        sources = Source.objects.filter(provenance=provenance)\n        if not display_unpublished:\n            sources = sources.filter(published=True)\n        sources = sources.only(\"title\", \"id\", \"siglum\")\n        context[\"sources\"] = sources\n        return context\n", "path": "django/cantusdb_project/main_app/views/provenance.py"}, {"content": "from django.views.generic import DetailView\nfrom main_app.models import Century, Source\nfrom typing import Any\n\n\nclass CenturyDetailView(DetailView):\n    model = Century\n    context_object_name = \"century\"\n    template_name = \"century_detail.html\"\n\n    def get_context_data(self, **kwargs: Any) -> dict[str, Any]:\n        context = super().get_context_data(**kwargs)\n        century = self.get_object()\n        user = self.request.user\n        display_unpublished = user.is_authenticated\n        sources = Source.objects.filter(century=century)\n        if not display_unpublished:\n            sources = sources.filter(published=True)\n        sources = sources.only(\"title\", \"id\", \"siglum\")\n        context[\"sources\"] = sources\n        return context\n", "path": "django/cantusdb_project/main_app/views/century.py"}]}