gh-148740: Allow setting namespace from command line usage of uuid module by sumpygump · Pull Request #148741 · python/cpython

sumpygump · 2026-04-18T22:48:46Z

This applies to generating version 3 and 5 UUIDs
Will correctly bail when invalid UUID is supplied as namespace

Example usage with correction:

./python -m uuid --uuid uuid5 --namespace '0d6a16cc-34a7-47d8-b660-214d0ae184d2' --name some.user
a32f4562-2058-5b20-8055-5f38b28285b6

Example error if invalid UUID is supplied as --namespace argument:

./python -m uuid --uuid uuid5 --namespace 'invalid uuid' --name some.user
usage: python -m uuid [-h] [-u {uuid1,uuid3,uuid4,uuid5,uuid6,uuid7,uuid8}] [-n {any UUID,@dns,@url,@oid,@x500}] [-N NAME] [-C NUM]
python -m uuid: error: badly formed hexadecimal UUID string: 'invalid uuid'.

My solution was to update the argparse options to use metavar instead of choices for the namespace
argument. This allows to supply suggestions of options that can be supplied for the --namespace arguments instead of requiring ONLY the ones in the list.

My intent was to keep the help message consistent with how it looked before. Note that it still displays the possible values in the help text for the namespace: -n, --namespace {any UUID,@dns,@url,@oid,@x500}:

./python -m uuid --help
usage: python -m uuid [-h] [-u {uuid1,uuid3,uuid4,uuid5,uuid6,uuid7,uuid8}] [-n {any UUID,@dns,@url,@oid,@x500}] [-N NAME] [-C NUM]

Generate a UUID using the selected UUID function.

options:
  -h, --help            show this help message and exit
  -u, --uuid {uuid1,uuid3,uuid4,uuid5,uuid6,uuid7,uuid8}
                        function to generate the UUID (default: uuid4)
  -n, --namespace {any UUID,@dns,@url,@oid,@x500}
                        uuid3/uuid5 only: a UUID, or a well-known predefined UUID addressed by namespace name (default: None)
  -N, --name NAME       uuid3/uuid5 only: name used as part of generating the UUID (default: None)
  -C, --count NUM       generate NUM fresh UUIDs (default: 1)

Issue: Fix UUID's CLI for custom namespaces for v3/v5 #148740

- This applies to generating version 3 and 5 UUIDs - Will correctly bail when invalid UUID is supplied as namespace

python-cla-bot · 2026-04-18T22:48:52Z

All commit authors signed the Contributor License Agreement.

picnixz · 2026-04-20T11:50:03Z

Please update the docs for this.

picnixz · 2026-04-20T11:51:28Z

                        default="uuid4",
                        help="function to generate the UUID")
    parser.add_argument("-n", "--namespace",
-                        choices=["any UUID", *namespaces.keys()],


I see that it was actually a real bug here.

picnixz · 2026-04-20T16:04:57Z

Please avoid updating your branch if the CI is green. See our devguide. It wastes CI resources

picnixz · 2026-04-20T16:06:35Z

+            self.uuid.main()
+        # Check that exception code is the same as argparse.ArgumentParser.error
+        self.assertEqual(cm.exception.code, 2)
+        self.assertIn("error: badly formed hexadecimal UUID string", mock_err.getvalue())


Make sure that your line does not exceed 80 chars otherwise wrap the call.

picnixz · 2026-04-20T16:09:21Z

+
+    @mock.patch.object(sys, "argv",
+                       ["", "-u", "uuid3", "-n", "0d6a16cc-34a7-47d8-b660-214d0ae184d2", "-N", "some.user"])
+    def test_cli_uuid3_ouputted_with_user_provided_namespace_and_name(self):


Change "user_provided" to "custom" to make it a bit shorter.

picnixz · 2026-04-20T16:10:54Z

+        output = stdout.getvalue().strip()
+        uuid_output = self.uuid.UUID(output)
+
+        # Output should be in the form of uuid5


picnixz · 2026-04-20T16:11:46Z

                        help="function to generate the UUID")
    parser.add_argument("-n", "--namespace",
-                        choices=["any UUID", *namespaces.keys()],
+                        metavar=f"{{any UUID,{','.join(namespaces.keys())}}}",


Suggested change

metavar=f"{{any UUID,{','.join(namespaces.keys())}}}",

metavar=f"{{any UUID,{','.join(namespaces)}}}",

picnixz · 2026-04-20T16:13:02Z

@@ -0,0 +1,2 @@
+Fix usage for :mod:`uuid` command line interface to support a custom namespace be


Suggested change

Fix usage for :mod:`uuid` command line interface to support a custom namespace be

Fix usage for :mod:`uuid` command-line interface to support a custom namespace be

Allow setting namespace from command line usage of uuid module

69566ee

- This applies to generating version 3 and 5 UUIDs - Will correctly bail when invalid UUID is supplied as namespace

bedevere-app bot added the awaiting review label Apr 18, 2026

bedevere-app bot mentioned this pull request Apr 18, 2026

Fix UUID's CLI for custom namespaces for v3/v5 #148740

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sumpygump added 2 commits April 19, 2026 07:18

Merge branch 'main' into fix/148740-uuid-cli-usage

8e798db

Merge branch 'main' into fix/148740-uuid-cli-usage

7ddf95a

picnixz reviewed Apr 20, 2026

View reviewed changes

Merge branch 'main' into fix/148740-uuid-cli-usage

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picnixz reviewed Apr 20, 2026

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gh-148740: Allow setting namespace from command line usage of uuid module#148741

gh-148740: Allow setting namespace from command line usage of uuid module#148741
sumpygump wants to merge 4 commits intopython:mainfrom
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	metavar=f"{{any UUID,{','.join(namespaces.keys())}}}",
	metavar=f"{{any UUID,{','.join(namespaces)}}}",

		@@ -0,0 +1,2 @@
		Fix usage for :mod:`uuid` command line interface to support a custom namespace be

	Fix usage for :mod:`uuid` command line interface to support a custom namespace be
	Fix usage for :mod:`uuid` command-line interface to support a custom namespace be

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sumpygump commented Apr 18, 2026 •

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