vcs-python
diff --git a/‎src/libvcs/_internal/run.py
Copy file name to clipboardExpand all lines: src/libvcs/_internal/run.py
+22-6Lines changed: 22 additions & 6 deletions b/‎src/libvcs/_internal/run.py
Copy file name to clipboardExpand all lines: src/libvcs/_internal/run.py
+22-6Lines changed: 22 additions & 6 deletions
@@ -16,6 +16,7 @@
 import sys
 import typing as t
 from collections.abc import Iterable, Mapping, MutableMapping, Sequence
+from typing import IO, Any
 
 from libvcs import exc
 from libvcs._internal.types import StrOrBytesPath
@@ -24,6 +25,10 @@
 
 console_encoding = sys.stdout.encoding
 
+PIPE_NOT_SET_ERR = (
+    "File descriptor is None, which should not happen as we set PIPE as default"
+)
+
 
 def console_to_str(s: bytes) -> str:
     """From pypa/pip project, pip.backwardwardcompat. License MIT."""
@@ -104,7 +109,7 @@ def __call__(self, output: t.AnyStr, timestamp: datetime.datetime) -> None:
     ]
 
 _CMD = t.Union[StrOrBytesPath, Sequence[StrOrBytesPath]]
-_FILE: TypeAlias = t.Optional[t.Union[int, t.IO[t.Any]]]
+_FILE: TypeAlias = t.Optional[t.Union[int, IO[Any]]]
 
 
 def run(
@@ -226,12 +231,23 @@ def progress_cb(output: t.AnyStr, timestamp: datetime.datetime) -> None:
     if callback and callable(callback):
         callback(output="\r", timestamp=datetime.datetime.now())
 
-    lines = filter(None, (line.strip() for line in proc.stdout.readlines()))
-    all_output = console_to_str(b"\n".join(lines))
+    if proc.stdout is None:
+        raise RuntimeError(PIPE_NOT_SET_ERR)
+
+    stdout_lines: list[bytes] = [
+        line.strip() for line in proc.stdout.readlines() if line
+    ]
+    all_output = [console_to_str(b"\n".join(stdout_lines))]
+
     if code:
-        stderr_lines = filter(None, (line.strip() for line in proc.stderr.readlines()))
-        all_output = console_to_str(b"".join(stderr_lines))
+        if proc.stderr is None:
+            raise RuntimeError(PIPE_NOT_SET_ERR)
+        stderr_lines: list[bytes] = [
+            line.strip() for line in proc.stderr.readlines() if line
+        ]
+        all_output = [console_to_str(b"".join(stderr_lines))]
+
     output = "".join(all_output)
     if code != 0 and check_returncode:
-        raise exc.CommandError(output=output, returncode=code, cmd=args)
+        raise exc.CommandError(output=output, returncode=code, cmd=str(args))
     return output