From 69cf9843d4c27994a7b8e10d4a16ecfd1f0bf075 Mon Sep 17 00:00:00 2001
From: breken-ai <312387581+breken-ai@users.noreply.github.com>
Date: Tue, 29 Sep 2026 17:52:08 -0700
Subject: [PATCH 1/2] fix: report a mismatch for undecodable bodies in
 json_params_matcher

A request body that is neither UTF-8 nor gzip (for example a binary upload) made json_params_matcher raise UnicodeDecodeError or BadGzipFile from the gzip fallback, aborting the request instead of returning a mismatch so another registered response could match.
---
 CHANGES                          |  3 +++
 responses/matchers.py            |  7 +++++++
 responses/tests/test_matchers.py | 22 ++++++++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/CHANGES b/CHANGES
index fcab1798..9fab64a4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -11,6 +11,9 @@ Unreleased
   include the ``params`` and ``req_kwargs`` attributes added by ``responses``.
 * Fixed non-strict `json_params_matcher` raising `TypeError` when an actual
   nested object is compared with an expected scalar value.
+* Fixed `json_params_matcher` raising `UnicodeDecodeError` or `BadGzipFile`
+  for a request body that is neither UTF-8 nor gzip (e.g. a binary upload)
+  instead of reporting a mismatch and letting other responses match.
 
 0.26.3
 ------
diff --git a/responses/matchers.py b/responses/matchers.py
index 15df1884..506192e6 100644
--- a/responses/matchers.py
+++ b/responses/matchers.py
@@ -167,6 +167,13 @@ def match(request: PreparedRequest) -> Tuple[bool, str]:
             reason = (
                 "request.body doesn't match: JSONDecodeError: Cannot parse request.body"
             )
+        except (UnicodeDecodeError, OSError, EOFError):
+            # body is neither UTF-8 text nor gzip-compressed UTF-8 text
+            valid = False
+            reason = (
+                "request.body doesn't match: Cannot decode request.body "
+                "as UTF-8 or gzip-compressed UTF-8"
+            )
 
         return valid, reason
 
diff --git a/responses/tests/test_matchers.py b/responses/tests/test_matchers.py
index 4f67810c..4ae2ed91 100644
--- a/responses/tests/test_matchers.py
+++ b/responses/tests/test_matchers.py
@@ -272,6 +272,28 @@ def test_json_params_matcher_body_is_gzipped():
     assert result == (True, "")
 
 
+def test_json_params_matcher_body_not_utf8_or_gzip():
+    @responses.activate
+    def run():
+        url = "http://example.com/upload"
+        responses.post(url, match=[matchers.json_params_matcher({"name": "a.png"})])
+        responses.post(url, body="uploaded")
+
+        # a binary body that is neither UTF-8 nor gzip must be reported as a
+        # mismatch so the next registered response can match
+        resp = requests.post(url, data=b"\x89PNG\r\n\x1a\n\xff\x00")
+        assert_response(resp, "uploaded")
+
+    run()
+    assert_reset()
+
+    # gzip-compressed body whose content is not UTF-8
+    mock_request = Mock(body=gzip.compress(b"\xff\xfe\x00"))
+    valid, reason = matchers.json_params_matcher({"foo": 42})(mock_request)
+    assert not valid
+    assert "Cannot decode request.body" in reason
+
+
 def test_urlencoded_params_matcher_blank():
     @responses.activate
     def run():

From 01cf4d0b3bc1e4d8829ce54d067f0e3d72f016b2 Mon Sep 17 00:00:00 2001
From: breken-ai <312387581+breken-ai@users.noreply.github.com>
Date: Tue, 29 Sep 2026 18:02:41 -0700
Subject: [PATCH 2/2] fix: also treat zlib.error from corrupt gzip bodies as a
 mismatch

A body with a valid gzip header but corrupt deflate data makes gzip.decompress raise zlib.error, which is not an OSError subclass.
---
 responses/matchers.py            | 3 ++-
 responses/tests/test_matchers.py | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/responses/matchers.py b/responses/matchers.py
index 506192e6..1a1641e9 100644
--- a/responses/matchers.py
+++ b/responses/matchers.py
@@ -1,6 +1,7 @@
 import gzip
 import json as json_module
 import re
+import zlib
 from json.decoder import JSONDecodeError
 from typing import Any
 from typing import Callable
@@ -167,7 +168,7 @@ def match(request: PreparedRequest) -> Tuple[bool, str]:
             reason = (
                 "request.body doesn't match: JSONDecodeError: Cannot parse request.body"
             )
-        except (UnicodeDecodeError, OSError, EOFError):
+        except (UnicodeDecodeError, OSError, EOFError, zlib.error):
             # body is neither UTF-8 text nor gzip-compressed UTF-8 text
             valid = False
             reason = (
diff --git a/responses/tests/test_matchers.py b/responses/tests/test_matchers.py
index 4ae2ed91..8a3cad4a 100644
--- a/responses/tests/test_matchers.py
+++ b/responses/tests/test_matchers.py
@@ -293,6 +293,12 @@ def run():
     assert not valid
     assert "Cannot decode request.body" in reason
 
+    # gzip header followed by corrupt deflate data raises zlib.error
+    mock_request = Mock(body=b"\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\xff\xff\xff\xff")
+    valid, reason = matchers.json_params_matcher({"foo": 42})(mock_request)
+    assert not valid
+    assert "Cannot decode request.body" in reason
+
 
 def test_urlencoded_params_matcher_blank():
     @responses.activate