Exclude .venv from Time Machine backups

pyproject.toml

@@ -66,6 +66,7 @@ shellingham = "^1.1"
 tomlkit = ">=0.7.0,<1.0.0"
 # exclude 20.4.5 - 20.4.6 due to https://github.com/pypa/pip/issues/9953
 virtualenv = "(>=20.4.3,<20.4.5 || >=20.4.7)"
+xattr = { version = "^0.9.7", markers = "sys_platform == 'darwin'" }
 urllib3 = "^1.26.0"
 dulwich = "^0.20.35"
 
@@ -157,6 +158,7 @@ module = [
   'requests_toolbelt.*',
   'shellingham.*',
   'virtualenv.*',
+  'xattr.*',
 ]
 ignore_missing_imports = true
 

src/poetry/utils/env.py

@@ -6,6 +6,7 @@
 import json
 import os
 import platform
+import plistlib
 import re
 import subprocess
 import sys
@@ -1087,7 +1088,20 @@ def build_venv(
 
         args.append(str(path))
 
-        return virtualenv.cli_run(args)
+        cli_result = virtualenv.cli_run(args)
+
+        # Exclude the venv folder from from macOS Time Machine backups
+        # TODO: Add backup-ignore markers for other platforms too
+        if sys.platform == "darwin":
+            import xattr
+
+            xattr.setxattr(
+                str(path),
+                "com.apple.metadata:com_apple_backup_excludeItem",
+                plistlib.dumps("com.apple.backupd", fmt=plistlib.FMT_BINARY),
+            )
+
+        return cli_result
 
     @classmethod
     def remove_venv(cls, path: Path | str) -> None:

tests/utils/test_env.py

@@ -96,6 +96,27 @@ def test_virtualenvs_with_spaces_in_their_path_work_as_expected(
     assert venv.run("python", "-V", shell=True).startswith("Python")
 
 
+@pytest.mark.skipif(sys.platform != "darwin", reason="requires darwin")
+def test_venv_backup_exclusion(tmp_dir: str, manager: EnvManager):
+    import xattr
+
+    venv_path = Path(tmp_dir) / "Virtual Env"
+
+    manager.build_venv(str(venv_path))
+
+    value = (
+        b"bplist00_\x10\x11com.apple.backupd"
+        b"\x08\x00\x00\x00\x00\x00\x00\x01\x01\x00\x00\x00\x00\x00\x00\x00"
+        b"\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x1c"
+    )
+    assert (
+        xattr.getxattr(
+            str(venv_path), "com.apple.metadata:com_apple_backup_excludeItem"
+        )
+        == value
+    )
+
+
 def test_env_commands_with_spaces_in_their_arg_work_as_expected(
     tmp_dir: str, manager: EnvManager
 ):