Add a stable URL for a patch that redirects to latest cf

Links to patches get outdated ever time we move it to new commitfest.

Author: JelteF

Diff for: pgcommitfest/commitfest/views.py

@@ -258,6 +258,12 @@ def global_search(request):
         'title': 'Patch search results',
     })
 
+def patch_redirect(request, patchid):
+    last_commitfest = PatchOnCommitFest.objects.select_related('commitfest').filter(patch_id=patchid).order_by('-commitfest__startdate').first()
+    if not last_commitfest:
+        raise Http404("Patch not found")
+    return HttpResponseRedirect(f'/{last_commitfest.commitfest_id}/{patchid}/')
+
 
 def patch(request, cfid, patchid):
     cf = get_object_or_404(CommitFest, pk=cfid)

Diff for: pgcommitfest/urls.py

@@ -19,6 +19,7 @@
     re_path(r'^(\d+)/$', views.commitfest),
     re_path(r'^(open|inprogress|current)/(.*)$', views.redir),
     re_path(r'^(?P<cfid>\d+)/activity(?P<rss>\.rss)?/$', views.activity),
+    re_path(r'^patch/(\d+)/$', views.patch_redirect),
     re_path(r'^(\d+)/(\d+)/$', views.patch),
     re_path(r'^(\d+)/(\d+)/edit/$', views.patchform),
     re_path(r'^(\d+)/new/$', views.newpatch),