feat: inherit CommandError (also) from subprocess.CalledProcessError

In the DataLad world `CommandError` was traditionally a `RuntimeError`.
Whether or not that makes sense in the general case, one can have
different opinions about.

The rest of the world is using `subprocess.CalledProcessError`. This
exception type is very similar to `CommandError` in the properties
that it can capture. It is only missing the CWD info, and the
context message that comes with `RuntimeError` (see class docs).

This change connects the two worlds, by inheriting from both
`RuntimeError` and `CalledProcessError`, and using the properties
of both, where possible.

The behavior of `CommandError` remains unchanged, but it will now also
work with code that expects a `subprocess` exception.

datasalad/runners/exception.py

@@ -8,10 +8,11 @@
     import os
 
 import signal
+import subprocess
 import sys
 
 
-class CommandError(RuntimeError):
+class CommandError(subprocess.CalledProcessError, RuntimeError):
     """Raised when a subprocess execution fails (non-zero exit)
 
     Key class attributes are aligned with the ``CalledProcessError`` exception
@@ -49,11 +50,14 @@ def __init__(
         cwd: str | os.PathLike | None = None,
     ) -> None:
         RuntimeError.__init__(self, msg)
-        self.cmd = cmd
+        subprocess.CalledProcessError.__init__(
+            self,
+            returncode=returncode,
+            cmd=cmd,
+            output=stdout,
+            stderr=stderr,
+        )
         self.msg = msg
-        self.returncode = returncode
-        self.stdout = stdout
-        self.stderr = stderr
         self.cwd = cwd
 
     def __str__(self) -> str:

datasalad/runners/tests/test_exception.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import subprocess
 import sys
 
 import pytest
@@ -12,6 +13,10 @@ def test_CommandError_minial():
         # we need a command
         CommandError()
 
+def test_CommandError_multiple_inheritence():
+    ce = CommandError('dummy')
+    assert isinstance(ce, RuntimeError)
+    assert isinstance(ce, subprocess.CalledProcessError)
 
 def test_CommandError_str_repr() -> None:
     unicode_out = 'ΔЙקم๗あösdohabcdefdf0j23d2däüߧ!אؠॵΔЙקم๗あöäüߧ!אؠॵℱ⏰︻𐂃𐃍'