Invert major version check

src/requests/compat.py

@@ -17,10 +17,10 @@
 
 # Detect which major version of urllib3 is being used.
 try:
-    is_urllib3_2 = int(urllib3_version.split(".")[0]) == 2
+    is_urllib3_1 = int(urllib3_version.split(".")[0]) == 1
 except (TypeError, AttributeError):
     # If we can't discern a version, prefer old functionality.
-    is_urllib3_2 = False
+    is_urllib3_1 = True
 
 # -------------------
 # Character Detection

src/requests/utils.py

@@ -38,7 +38,7 @@
     getproxies,
     getproxies_environment,
     integer_types,
-    is_urllib3_2,
+    is_urllib3_1,
 )
 from .compat import parse_http_list as _parse_list_header
 from .compat import (
@@ -137,8 +137,8 @@ def super_len(o):
     total_length = None
     current_position = 0
 
-    if is_urllib3_2 and isinstance(o, str):
-        # urllib3 2.x treats all strings as utf-8 instead
+    if not is_urllib3_1 and isinstance(o, str):
+        # urllib3 2.x+ treats all strings as utf-8 instead
         # of latin-1 (iso-8859-1) like http.client.
         o = o.encode("utf-8")
 

tests/test_requests.py

@@ -25,7 +25,7 @@
     builtin_str,
     cookielib,
     getproxies,
-    is_urllib3_2,
+    is_urllib3_1,
     urlparse,
 )
 from requests.cookies import cookiejar_from_dict, morsel_to_cookie
@@ -2961,7 +2961,7 @@ def test_content_length_for_bytes_data(httpbin):
 
 
 @pytest.mark.skipif(
-    not is_urllib3_2,
+    is_urllib3_1,
     reason="urllib3 2.x encodes all strings to utf-8, urllib3 1.x uses latin-1",
 )
 def test_content_length_for_string_data_counts_bytes(httpbin):