Fix HTTPResponse.read(0) when underlying buffer is empty (#2998)

urllib3 · Apr 29, 2023 · 02ae65a · 02ae65a
1 parent 4fb8da2
commit 02ae65a
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diff --git a/changelog/2998.bugfix.rst b/changelog/2998.bugfix.rst
@@ -0,0 +1 @@
+Fixed ``HTTPResponse.read(0)`` call when underlying buffer is empty.
diff --git a/src/urllib3/response.py b/src/urllib3/response.py
@@ -244,7 +244,9 @@ def put(self, data: bytes) -> None:
         self._size += len(data)
 
     def get(self, n: int) -> bytes:
-        if not self.buffer:
+        if n == 0:
+            return b""
+        elif not self.buffer:
             raise RuntimeError("buffer is empty")
         elif n < 0:
             raise ValueError("n should be > 0")

diff --git a/test/test_response.py b/test/test_response.py
@@ -44,6 +44,8 @@ def test_single_chunk(self) -> None:
         with pytest.raises(RuntimeError, match="buffer is empty"):
             assert buffer.get(10)
 
+        assert buffer.get(0) == b""
+
         buffer.put(b"foo")
         with pytest.raises(ValueError, match="n should be > 0"):
             buffer.get(-1)
@@ -181,6 +183,7 @@ def test_reference_read(self) -> None:
         fp = BytesIO(b"foo")
         r = HTTPResponse(fp, preload_content=False)
 
+        assert r.read(0) == b""
         assert r.read(1) == b"f"
         assert r.read(2) == b"oo"
         assert r.read() == b""