Use errno.EISDIR instead of hardcoding values

core/results.py

@@ -10,6 +10,7 @@ import logging
 import re
 import os
 import os.path as op
+from errno import EISDIR
 from xml.etree import ElementTree as ET
 
 from hscommon.jobprogress.job import nulljob
@@ -375,9 +376,8 @@ class Results(Markable):
         try:
             do_write(outfile)
         except OSError as e:
-            # If our OSError is because dest is already a directory, we want to handle that. 21 is
-            # the code we get on OS X and Linux, 13 is what we get on Windows.
-            if e.errno in {21, 13}:
+            # If our OSError is because dest is already a directory, we want to handle that.
+            if e.errno == EISDIR:
                 p = str(outfile)
                 dirname, basename = op.split(p)
                 otherfiles = os.listdir(dirname)

hscommon/conflict.py

@@ -14,6 +14,7 @@ import re
 import os
 import shutil
 
+from errno import EISDIR
 from pathlib import Path
 from typing import Callable, List
 
@@ -75,10 +76,7 @@ def smart_copy(source_path: Path, dest_path: Path) -> None:
     try:
         _smart_move_or_copy(shutil.copy, source_path, dest_path)
     except OSError as e:
-        if e.errno in {
-            21,
-            13,
-        }:  # it's a directory, code is 21 on OS X / Linux and 13 on Windows
+        if e.errno == EISDIR:  # it's a directory
             _smart_move_or_copy(shutil.copytree, source_path, dest_path)
         else:
             raise