From 66a0cc567797d3aaf79fd89430dd8bed2a80e4ab Mon Sep 17 00:00:00 2001
From: Ruben Vorderman <r.h.p.vorderman@lumc.nl>
Date: Tue, 3 Nov 2026 12:48:56 +0100
Subject: [PATCH 1/3] Add test for broken pipe

---
 tests/test_igzip.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/test_igzip.py b/tests/test_igzip.py
index 6d9cbf5d..f9e28b2d 100644
--- a/tests/test_igzip.py
+++ b/tests/test_igzip.py
@@ -769,3 +769,11 @@ def test_small_writes_tell_and_flush():
         assert decompressor.decompress(output.getvalue()) == b"abcdef"
         gzip_file.write(b"gh")
     assert gzip.decompress(output.getvalue()) == b"abcdefgh"
+
+
+@pytest.mark.skipif(sys.platform != "linux", reason="bash required")
+def test_no_broken_pipe():
+      subprocess.run([
+          "bash", "-c", "-e", "-o", "pipefail",
+          f"{sys.executable} -m isal.igzip -cd {TEST_FILE} | head -n 10"] ,
+          check=True)

From 305bc592fd4a35508854faa9f80c76a06e67ec12 Mon Sep 17 00:00:00 2001
From: Ruben Vorderman <r.h.p.vorderman@lumc.nl>
Date: Tue, 3 Nov 2026 12:51:10 +0100
Subject: [PATCH 2/3] Fix BrokenPipeError

---
 CHANGELOG.rst     | 5 +++++
 src/isal/igzip.py | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 307b330b..7de0e76d 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -7,6 +7,11 @@ Changelog
 .. This document is user facing. Please word the changes in such a way
 .. that users understand how the changes affect the new version.
 
+develop
+-----------------
++ Fix BrokenPipeError when piping ``python -m isal.igzip`` into ``head``,
+  ``less`` or similar programs.
+
 
 version 1.9.0
 -----------------
diff --git a/src/isal/igzip.py b/src/isal/igzip.py
index eb9b8042..b18af11c 100644
--- a/src/isal/igzip.py
+++ b/src/isal/igzip.py
@@ -386,6 +386,9 @@ def main():
 
     try:
         shutil.copyfileobj(in_file, out_file, args.buffer_size)
+    except BrokenPipeError:
+        # Do not throw errors when a pipe to head or less closes.
+        pass
     finally:
         if in_file is not sys.stdin.buffer:
             in_file.close()

From a3f07e32c386bb9da2a4c6b79735a3aa176fb75a Mon Sep 17 00:00:00 2001
From: Ruben Vorderman <r.h.p.vorderman@lumc.nl>
Date: Tue, 3 Nov 2026 12:55:38 +0100
Subject: [PATCH 3/3] Fix linting

---
 tests/test_igzip.py | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/tests/test_igzip.py b/tests/test_igzip.py
index f9e28b2d..457f13f6 100644
--- a/tests/test_igzip.py
+++ b/tests/test_igzip.py
@@ -773,7 +773,10 @@ def test_small_writes_tell_and_flush():
 
 @pytest.mark.skipif(sys.platform != "linux", reason="bash required")
 def test_no_broken_pipe():
-      subprocess.run([
-          "bash", "-c", "-e", "-o", "pipefail",
-          f"{sys.executable} -m isal.igzip -cd {TEST_FILE} | head -n 10"] ,
-          check=True)
+    subprocess.run(
+        [
+            "bash", "-c", "-e", "-o", "pipefail",
+            f"{sys.executable} -m isal.igzip -cd {TEST_FILE} | head -n 10"
+        ],
+        check=True
+    )