From e49fec4001dd3d9d48da9ec229271a9e422dd7d1 Mon Sep 17 00:00:00 2001
From: Bob Halley <halley@dnspython.org>
Date: Sat, 26 Jul 2025 08:36:29 -0700
Subject: [PATCH] Specify the utf-8 encoding when opening files [#1188].

---
 dns/message.py     |  2 +-
 dns/resolver.py    |  2 +-
 dns/zone.py        |  2 +-
 dns/zonefile.py    |  2 +-
 tests/test_svcb.py |  9 ++++++---
 tests/test_zone.py | 10 +++++-----
 6 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/dns/message.py b/dns/message.py
index 77bec1e9..b6cc2103 100644
--- a/dns/message.py
+++ b/dns/message.py
@@ -1738,7 +1738,7 @@ def from_file(
     """
 
     if isinstance(f, str):
-        cm: contextlib.AbstractContextManager = open(f)
+        cm: contextlib.AbstractContextManager = open(f, "rt", encoding="utf-8")
     else:
         cm = contextlib.nullcontext(f)
     with cm as f:
diff --git a/dns/resolver.py b/dns/resolver.py
index fef9e84a..f7550cae 100644
--- a/dns/resolver.py
+++ b/dns/resolver.py
@@ -998,7 +998,7 @@ class BaseResolver:
         nameservers = []
         if isinstance(f, str):
             try:
-                cm: contextlib.AbstractContextManager = open(f)
+                cm: contextlib.AbstractContextManager = open(f, "rt", encoding="utf-8")
             except OSError:
                 # /etc/resolv.conf doesn't exist, can't be read, etc.
                 raise NoResolverConfiguration(f"cannot open {f}")
diff --git a/dns/zone.py b/dns/zone.py
index 7cba657d..18039791 100644
--- a/dns/zone.py
+++ b/dns/zone.py
@@ -1378,7 +1378,7 @@ def from_file(
     if isinstance(f, str):
         if filename is None:
             filename = f
-        cm: contextlib.AbstractContextManager = open(f)
+        cm: contextlib.AbstractContextManager = open(f, "rt", encoding="utf-8")
     else:
         cm = contextlib.nullcontext(f)
     with cm as f:
diff --git a/dns/zonefile.py b/dns/zonefile.py
index d6047cce..fd0f4642 100644
--- a/dns/zonefile.py
+++ b/dns/zonefile.py
@@ -537,7 +537,7 @@ class Reader:
                                 self.default_ttl_known,
                             )
                         )
-                        self.current_file = open(filename)
+                        self.current_file = open(filename, "rt", encoding="utf-8")
                         self.tok = dns.tokenizer.Tokenizer(self.current_file, filename)
                         self.current_origin = new_origin
                     elif c == "$GENERATE":
diff --git a/tests/test_svcb.py b/tests/test_svcb.py
index d2d8dd79..e92ec453 100644
--- a/tests/test_svcb.py
+++ b/tests/test_svcb.py
@@ -7,7 +7,6 @@ import dns.rdata
 import dns.rdtypes.svcbbase
 import dns.rrset
 from dns.tokenizer import Tokenizer
-
 from tests.util import here
 
 
@@ -303,9 +302,13 @@ class SVCBTestCase(unittest.TestCase):
 
     def test_svcb_spec_test_vectors(self):
         text_file = here("svcb_test_vectors.text")
-        text_tokenizer = Tokenizer(open(text_file), filename=text_file)
+        text_tokenizer = Tokenizer(
+            open(text_file, "rt", encoding="utf-8"), filename=text_file
+        )
         generic_file = here("svcb_test_vectors.generic")
-        generic_tokenizer = Tokenizer(open(generic_file), filename=generic_file)
+        generic_tokenizer = Tokenizer(
+            open(generic_file, "rt", encoding="utf-8"), filename=generic_file
+        )
 
         while True:
             while True:
diff --git a/tests/test_zone.py b/tests/test_zone.py
index 2e590e70..1d7cde35 100644
--- a/tests/test_zone.py
+++ b/tests/test_zone.py
@@ -320,8 +320,8 @@ def make_xfr(zone):
 
 
 def compare_files(test_name, a_name, b_name):
-    with open(a_name, "r") as a:
-        with open(b_name, "r") as b:
+    with open(a_name, "rt", encoding="utf-8") as a:
+        with open(b_name, "rt", encoding="utf-8") as b:
             differences = list(difflib.unified_diff(a.readlines(), b.readlines()))
             if len(differences) == 0:
                 return True
@@ -377,7 +377,7 @@ class ZoneTestCase(unittest.TestCase):
     def testToFileTextual(self):
         z = dns.zone.from_file(here("example"), "example")
         try:
-            f = open(here("example3-textual.out"), "w")
+            f = open(here("example3-textual.out"), "wt", encoding="utf-8")
             z.to_file(f)
             f.close()
             ok = compare_files(
@@ -421,7 +421,7 @@ class ZoneTestCase(unittest.TestCase):
         ok = False
         try:
             text_zone = z.to_text(nl="\x0a")
-            f = open(here("example3.out"), "w")
+            f = open(here("example3.out"), "wt", encoding="utf-8")
             f.write(text_zone)
             f.close()
             ok = compare_files(
@@ -435,7 +435,7 @@ class ZoneTestCase(unittest.TestCase):
     def testToFileTextualWithOrigin(self):
         z = dns.zone.from_file(here("example"), "example")
         try:
-            f = open(here("example4-textual.out"), "w")
+            f = open(here("example4-textual.out"), "wt", encoding="utf-8")
             z.to_file(f, want_origin=True)
             f.close()
             ok = compare_files(
-- 
2.47.3