Reverted "Fixed #27818 -- Replaced try/except/pass with contextlib.suppress()."

This reverts commit 550cb3a365dee4edfdd1563224d5304de2a57fda
because try/except performs better.

7 files changed, 48 insertions, 24 deletions

diff --git a/django/utils/autoreload.py b/django/utils/autoreload.py
index a872d42d65..2784a89aeb 100644
--- a/django/utils/autoreload.py
+++ b/django/utils/autoreload.py
@@ -34,7 +34,6 @@ import subprocess
 import sys
 import time
 import traceback
-from contextlib import suppress
 
 import _thread
 
@@ -44,8 +43,10 @@ from django.core.signals import request_finished
 
 # This import does nothing, but it's necessary to avoid some race conditions
 # in the threading module. See http://code.djangoproject.com/ticket/2330 .
-with suppress(ImportError):
+try:
     import threading  # NOQA
+except ImportError:
+    pass
 
 try:
     import termios
@@ -53,7 +54,7 @@ except ImportError:
     termios = None
 
 USE_INOTIFY = False
-with suppress(ImportError):
+try:
     # Test whether inotify is enabled and likely to work
     import pyinotify
 
@@ -61,6 +62,8 @@ with suppress(ImportError):
     if fd >= 0:
         USE_INOTIFY = True
         os.close(fd)
+except ImportError:
+    pass
 
 RUN_RELOADER = True
 
@@ -207,8 +210,10 @@ def code_changed():
             continue
         if mtime != _mtimes[filename]:
             _mtimes = {}
-            with suppress(ValueError):
+            try:
                 del _error_files[_error_files.index(filename)]
+            except ValueError:
+                pass
             return I18N_MODIFIED if filename.endswith('.mo') else FILE_MODIFIED
     return False
 
@@ -287,15 +292,19 @@ def restart_with_reloader():
 def python_reloader(main_func, args, kwargs):
     if os.environ.get("RUN_MAIN") == "true":
         _thread.start_new_thread(main_func, args, kwargs)
-        with suppress(KeyboardInterrupt):
+        try:
             reloader_thread()
+        except KeyboardInterrupt:
+            pass
     else:
-        with suppress(KeyboardInterrupt):
+        try:
             exit_code = restart_with_reloader()
             if exit_code < 0:
                 os.kill(os.getpid(), -exit_code)
             else:
                 sys.exit(exit_code)
+        except KeyboardInterrupt:
+            pass
 
 
 def jython_reloader(main_func, args, kwargs):
diff --git a/django/utils/datastructures.py b/django/utils/datastructures.py
index 7713b08e8c..127c6dc774 100644
--- a/django/utils/datastructures.py
+++ b/django/utils/datastructures.py
@@ -1,6 +1,5 @@
 import copy
 from collections import OrderedDict
-from contextlib import suppress
 
 
 class OrderedSet:
@@ -19,8 +18,10 @@ class OrderedSet:
         del self.dict[item]
 
     def discard(self, item):
-        with suppress(KeyError):
+        try:
             self.remove(item)
+        except KeyError:
+            pass
 
     def __iter__(self):
         return iter(self.dict)
diff --git a/django/utils/dateformat.py b/django/utils/dateformat.py
index d811e83965..d3f586aacf 100644
--- a/django/utils/dateformat.py
+++ b/django/utils/dateformat.py
@@ -14,7 +14,6 @@ import calendar
 import datetime
 import re
 import time
-from contextlib import suppress
 
 from django.utils.dates import (
     MONTHS, MONTHS_3, MONTHS_ALT, MONTHS_AP, WEEKDAYS, WEEKDAYS_ABBR,
@@ -82,9 +81,11 @@ class TimeFormat(Formatter):
         if not self.timezone:
             return ""
 
-        with suppress(NotImplementedError):
+        try:
             if hasattr(self.data, 'tzinfo') and self.data.tzinfo:
                 return self.data.tzname() or ''
+        except NotImplementedError:
+            pass
         return ""
 
     def f(self):
@@ -165,11 +166,13 @@ class TimeFormat(Formatter):
             return ""
 
         name = None
-        with suppress(Exception):
+        try:
+            name = self.timezone.tzname(self.data)
+        except Exception:
             # pytz raises AmbiguousTimeError during the autumn DST change.
             # This happens mainly when __init__ receives a naive datetime
             # and sets self.timezone = get_default_timezone().
-            name = self.timezone.tzname(self.data)
+            pass
         if name is None:
             name = self.format('O')
         return str(name)
diff --git a/django/utils/formats.py b/django/utils/formats.py
index 33865d93a8..f19449ec1e 100644
--- a/django/utils/formats.py
+++ b/django/utils/formats.py
@@ -1,7 +1,6 @@
 import datetime
 import decimal
 import unicodedata
-from contextlib import suppress
 from importlib import import_module
 
 from django.conf import settings
@@ -80,8 +79,10 @@ def iter_format_modules(lang, format_module_path=None):
         locales.append(locale.split('_')[0])
     for location in format_locations:
         for loc in locales:
-            with suppress(ImportError):
+            try:
                 yield import_module('%s.formats' % (location % loc))
+            except ImportError:
+                pass
 
 
 def get_format_modules(lang=None, reverse=False):
@@ -109,8 +110,10 @@ def get_format(format_type, lang=None, use_l10n=None):
     if use_l10n and lang is None:
         lang = get_language()
     cache_key = (format_type, lang)
-    with suppress(KeyError):
+    try:
         return _format_cache[cache_key]
+    except KeyError:
+        pass
 
     # The requested format_type has not been cached yet. Try to find it in any
     # of the format_modules for the given lang if l10n is enabled. If it's not
diff --git a/django/utils/http.py b/django/utils/http.py
index 0870f1f180..07b6ae246a 100644
--- a/django/utils/http.py
+++ b/django/utils/http.py
@@ -5,7 +5,6 @@ import re
 import unicodedata
 import warnings
 from binascii import Error as BinasciiError
-from contextlib import suppress
 from email.utils import formatdate
 from urllib.parse import (
     ParseResult, SplitResult, _coerce_args, _splitnetloc, _splitparams, quote,
@@ -166,8 +165,10 @@ def parse_http_date_safe(date):
     """
     Same as parse_http_date, but return None if the input is invalid.
     """
-    with suppress(Exception):
+    try:
         return parse_http_date(date)
+    except Exception:
+        pass
 
 
 # Base 36 functions: useful for generating compact URLs
diff --git a/django/utils/translation/__init__.py b/django/utils/translation/__init__.py
index 4a6840782c..b4586885c4 100644
--- a/django/utils/translation/__init__.py
+++ b/django/utils/translation/__init__.py
@@ -3,7 +3,7 @@ Internationalization support.
 """
 import re
 import warnings
-from contextlib import ContextDecorator, suppress
+from contextlib import ContextDecorator
 
 from django.utils.deprecation import RemovedInDjango21Warning
 from django.utils.functional import lazy
@@ -126,9 +126,11 @@ def lazy_number(func, resultclass, number=None, **kwargs):
                     number_value = rhs
                 kwargs['number'] = number_value
                 translated = func(**kwargs)
-                # String may not contain a placeholder for the number.
-                with suppress(TypeError):
+                try:
                     translated = translated % rhs
+                except TypeError:
+                    # String doesn't contain a placeholder for the number.
+                    pass
                 return translated
 
         proxy = lazy(lambda **kwargs: NumberAwareString(), NumberAwareString)(**kwargs)
diff --git a/django/utils/translation/trans_real.py b/django/utils/translation/trans_real.py
index f36c21f0a1..6b3aeb127e 100644
--- a/django/utils/translation/trans_real.py
+++ b/django/utils/translation/trans_real.py
@@ -6,7 +6,6 @@ import re
 import sys
 import warnings
 from collections import OrderedDict
-from contextlib import suppress
 from threading import local
 
 from django.apps import apps
@@ -257,8 +256,10 @@ def get_language():
     """Return the currently selected language."""
     t = getattr(_active, "value", None)
     if t is not None:
-        with suppress(AttributeError):
+        try:
             return t.to_language()
+        except AttributeError:
+            pass
     # If we don't have a real translation object, assume it's the default language.
     return settings.LANGUAGE_CODE
 
@@ -424,8 +425,10 @@ def get_supported_language_variant(lang_code, strict=False):
     if lang_code:
         # If 'fr-ca' is not supported, try special fallback or language-only 'fr'.
         possible_lang_codes = [lang_code]
-        with suppress(KeyError):
+        try:
             possible_lang_codes.extend(LANG_INFO[lang_code]['fallback'])
+        except KeyError:
+            pass
         generic_lang_code = lang_code.split('-')[0]
         possible_lang_codes.append(generic_lang_code)
         supported_lang_codes = get_languages()
@@ -483,8 +486,10 @@ def get_language_from_request(request, check_path=False):
 
     lang_code = request.COOKIES.get(settings.LANGUAGE_COOKIE_NAME)
 
-    with suppress(LookupError):
+    try:
         return get_supported_language_variant(lang_code)
+    except LookupError:
+        pass
 
     accept = request.META.get('HTTP_ACCEPT_LANGUAGE', '')
     for accept_lang, unused in parse_accept_lang_header(accept):