refactor: create constant for limit, move repr creation into pprint()

django/template/defaultfilters.py

@@ -30,6 +30,9 @@ from .library import Library
 
 register = Library()
 
+# The number of characters that will be printed
+# before trimming while printing an exception in reports.
+EXCEPTION_PRINT_LIMIT = 4096
 
 #######################
 # STRING DECORATOR    #
@@ -970,16 +973,14 @@ def phone2numeric_filter(value):
     return phone2numeric(value)
 
 
-PRINT_LIMIT = 4096
-repr_instance = DjangoRepr()
-repr_instance.config(PRINT_LIMIT)
-
-
 @register.filter(is_safe=True)
 def pprint(v):
+    repr_instance = DjangoRepr()
+    repr_instance.config(limit=EXCEPTION_PRINT_LIMIT)
+
     try:
-        if isinstance(v, Sized) and len(v) > PRINT_LIMIT:
-            diff = len(v) - PRINT_LIMIT
+        if isinstance(v, Sized) and len(v) > EXCEPTION_PRINT_LIMIT:
+            diff = len(v) - EXCEPTION_PRINT_LIMIT
             repr_instance.fillvalue = "...<trimmed %d bytes string>" % diff
         v = repr_instance.repr(v)
 

django/views/debug.py

@@ -17,7 +17,6 @@ from django.utils.datastructures import MultiValueDict
 from django.utils.encoding import force_str
 from django.utils.module_loading import import_string
 from django.utils.regex_helper import _lazy_re_compile
-from django.utils.repr import DjangoRepr
 from django.utils.version import PY311, get_docs_version
 from django.views.decorators.debug import coroutine_functions_to_sensitive_variables
 
@@ -311,9 +310,6 @@ class SafeExceptionReporterFilter:
 class ExceptionReporter:
     """Organize and coordinate reporting on exceptions."""
 
-    repr_instance = DjangoRepr()
-    PRINT_LIMIT = 4096
-
     @property
     def html_template_path(self):
         return builtin_template_path("technical_500.html")
@@ -334,8 +330,6 @@ class ExceptionReporter:
         self.template_does_not_exist = False
         self.postmortem = None
 
-        self.repr_instance.config(limit=ExceptionReporter.PRINT_LIMIT)
-
     def _get_raw_insecure_uri(self):
         """
         Return an absolute URI from variables available in this request. Skip

tests/view_tests/tests/test_debug.py

@@ -17,6 +17,7 @@ from django.db import DatabaseError, connection
 from django.http import Http404, HttpRequest, HttpResponse
 from django.shortcuts import render
 from django.template import TemplateDoesNotExist
+from django.template.defaultfilters import EXCEPTION_PRINT_LIMIT
 from django.test import RequestFactory, SimpleTestCase, override_settings
 from django.test.utils import LoggingCaptureMixin
 from django.urls import path, reverse
@@ -1084,7 +1085,7 @@ class ExceptionReporterTests(SimpleTestCase):
         html = reporter.get_traceback_html()
         self.assertEqual(len(html) // 1024 // 128, 0)  # still fit in 128Kb
         trim_msg = "<trimmed %d bytes string>" % (
-            large - ExceptionReporter.PRINT_LIMIT + repr_of_str_adds,
+            large - EXCEPTION_PRINT_LIMIT + repr_of_str_adds,
         )
         self.assertIn(trim_msg, html)
 
@@ -1108,7 +1109,7 @@ class ExceptionReporterTests(SimpleTestCase):
                 ls = eval(v[:i] + "]")
 
                 # Check if length of trimmed list is our limit
-                self.assertEqual(len(ls), ExceptionReporter.PRINT_LIMIT)
+                self.assertEqual(len(ls), EXCEPTION_PRINT_LIMIT)
                 break
 
     def test_non_sizable_object(self):