fix(asm): change ipaddress backport library (backport #4221) (#4223)

This is an automatic backport of pull request #4221 done by [Mergify](https://mergify.com).


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Author: mergify[bot]

docs/spelling_wordlist.txt

@@ -33,6 +33,7 @@ autodetected
 autopatching
 backend
 backends
+backport
 bdd
 bikeshedding
 booleans

releasenotes/notes/asm-fix-ipaddress-backport-lib-4684ce71e63459e7.yaml

@@ -0,0 +1,3 @@
+fixes:
+  - |
+    ASM: fix a conflict with another backport of ipaddress by using the same lib. Add a test.

setup.py

@@ -258,7 +258,7 @@ def get_exts_for(name):
         "pathlib2; python_version<'3.5'",
         "jsonschema",
         "xmltodict>=0.12",
-        "backport_ipaddress; python_version=='2.7'",
+        "ipaddress",
         "envier",
     ]
     + bytecode,

tests/tracer/test_trace_utils.py

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from ipaddress import ip_network
 import sys
 
 from hypothesis import given
@@ -21,6 +22,7 @@
 from ddtrace.contrib import trace_utils
 from ddtrace.ext import http
 from ddtrace.internal import _context
+from ddtrace.internal.compat import six
 from ddtrace.internal.compat import stringify
 from ddtrace.propagation.http import HTTP_HEADER_PARENT_ID
 from ddtrace.propagation.http import HTTP_HEADER_TRACE_ID
@@ -570,6 +572,16 @@ def test_set_http_meta_headers_ip(
             mock_store_headers.assert_called()
 
 
+def test_ip_subnet_regression():
+    del_ip = "1.2.3.4/32"
+    req_ip = "10.2.3.4"
+
+    del_ip = six.ensure_text(del_ip)
+    req_ip = six.ensure_text(req_ip)
+
+    assert not ip_network(req_ip).subnet_of(ip_network(del_ip))
+
+
 @pytest.mark.skipif(sys.version_info < (3, 0, 0), reason="Python2 tests")
 @mock.patch("ddtrace.contrib.trace_utils._store_headers")
 @pytest.mark.parametrize(