bpo-46080: fix argparse help generation exception in edge case (GH-30111)
Fix an uncaught exception during help text generation when
argparse.BooleanOptionalAction is used with default=argparse.SUPPRESS
and help is specified.
(cherry picked from commit 9e87c0e03fa501fb90008547983ce4c1dcaaf90c)
Co-authored-by: Felix Fontein <felix@fontein.de>
diff --git a/Lib/argparse.py b/Lib/argparse.py
index e177e4f..b71a670 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -878,7 +878,7 @@ def __init__(self,
option_string = '--no-' + option_string[2:]
_option_strings.append(option_string)
- if help is not None and default is not None:
+ if help is not None and default is not None and default is not SUPPRESS:
help += " (default: %(default)s)"
super().__init__(
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 37a73e0..9d66ace 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -3597,6 +3597,8 @@ class TestHelpUsage(HelpTestCase):
Sig('--bar', help='Whether to bar', default=True,
action=argparse.BooleanOptionalAction),
Sig('-f', '--foobar', '--barfoo', action=argparse.BooleanOptionalAction),
+ Sig('--bazz', action=argparse.BooleanOptionalAction,
+ default=argparse.SUPPRESS, help='Bazz!'),
]
argument_group_signatures = [
(Sig('group'), [
@@ -3609,8 +3611,8 @@ class TestHelpUsage(HelpTestCase):
usage = '''\
usage: PROG [-h] [-w W [W ...]] [-x [X ...]] [--foo | --no-foo]
[--bar | --no-bar]
- [-f | --foobar | --no-foobar | --barfoo | --no-barfoo] [-y [Y]]
- [-z Z Z Z]
+ [-f | --foobar | --no-foobar | --barfoo | --no-barfoo]
+ [--bazz | --no-bazz] [-y [Y]] [-z Z Z Z]
a b b [c] [d ...] e [e ...]
'''
help = usage + '''\
@@ -3627,6 +3629,7 @@ class TestHelpUsage(HelpTestCase):
--foo, --no-foo Whether to foo
--bar, --no-bar Whether to bar (default: True)
-f, --foobar, --no-foobar, --barfoo, --no-barfoo
+ --bazz, --no-bazz Bazz!
group:
-y [Y] y
diff --git a/Misc/NEWS.d/next/Library/2021-12-15-06-29-00.bpo-46080.AuQpLt.rst b/Misc/NEWS.d/next/Library/2021-12-15-06-29-00.bpo-46080.AuQpLt.rst
new file mode 100644
index 0000000..e42d84e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-12-15-06-29-00.bpo-46080.AuQpLt.rst
@@ -0,0 +1,3 @@
+Fix exception in argparse help text generation if a
+:class:`argparse.BooleanOptionalAction` argument's default is
+``argparse.SUPPRESS`` and it has ``help`` specified. Patch by Felix Fontein.
\ No newline at end of file
