refactor(SubprocessCommand): Skip defaults in __repr__ of dataclass

In dataclass, skip printing of attributes that are defaults.

Credit to Pietro Oldrati
- https://stackoverflow.com/a/72161437/1396928
- License is unilicense:
  - https://stats.stackexchange.com/users/357193/user2246849
  - https://unlicense.org/

Author: tony

libvcs/utils/subprocess.py

@@ -41,6 +41,7 @@
 import dataclasses
 import subprocess
 import sys
+from operator import attrgetter
 from typing import (
     IO,
     Any,
@@ -351,6 +352,22 @@ def run(
             check=check,
         )
 
+    def __repr__(self):
+        """Skip defaults.
+
+        Credit: Pietro Oldrati, 2022-05-08, Unlicense
+
+        See also: https://stackoverflow.com/a/72161437/1396928
+        """
+        nodef_f_vals = (
+            (f.name, attrgetter(f.name)(self))
+            for f in dataclasses.fields(self)
+            if attrgetter(f.name)(self) != f.default
+        )
+
+        nodef_f_repr = ",".join(f"{name}={value}" for name, value in nodef_f_vals)
+        return f"{self.__class__.__name__}({nodef_f_repr})"
+
 
 #
 # Composable mixins