Drop support for ancient dulwich versions (#339)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: jelmer

klaus/repo.py

@@ -10,14 +10,7 @@
 from dulwich.errors import NotTreeError
 from dulwich.object_store import tree_lookup_path
 from dulwich.objects import S_ISGITLINK, Blob
-
-try:
-    from dulwich.refs import SymrefLoop
-except ImportError:  # dulwich < 0.20.46
-    InaccessibleRef = KeyError  # type: ignore
-else:
-    InaccessibleRef = (SymrefLoop, KeyError)  # type: ignore
-
+from dulwich.refs import SymrefLoop
 
 from klaus.diff import render_diff
 from klaus.utils import (
@@ -28,6 +21,7 @@
     repo_human_name,
 )
 
+InaccessibleRef = (SymrefLoop, KeyError)  # type: ignore
 NOT_SET = "__not_set__"
 
 

klaus/views.py

@@ -6,19 +6,12 @@
 import dulwich.config
 import dulwich.objects
 from dulwich.object_store import tree_lookup_path
+from dulwich.refs import SymrefLoop
 from flask import current_app, render_template, request, url_for
 from flask.views import View
 from werkzeug.exceptions import NotFound
 from werkzeug.wrappers import Response
 
-try:
-    from dulwich.refs import SymrefLoop
-except ImportError:  # dulwich < 0.20.46
-
-    class SymrefLoop(Exception):  # type: ignore
-        """Dummy exception."""
-
-
 try:
     import ctags
 except ImportError:

tests/test_contrib.py

@@ -1,11 +1,6 @@
 import os
-
-try:
-    from importlib import reload  # Python 3.4+
-except ImportError:
-    pass
-
 import subprocess
+from importlib import reload  # Python 3.4+
 
 import pytest
 import requests