Variant of patch #1478292. doctest.register_optionflag(name)
shouldn't create a new flag when `name` is already the name of
an option flag.
diff --git a/Lib/doctest.py b/Lib/doctest.py
index 900d871..318b21d 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -129,9 +129,8 @@
OPTIONFLAGS_BY_NAME = {}
def register_optionflag(name):
- flag = 1 << len(OPTIONFLAGS_BY_NAME)
- OPTIONFLAGS_BY_NAME[name] = flag
- return flag
+ # Create a new flag unless `name` is already known.
+ return OPTIONFLAGS_BY_NAME.setdefault(name, 1 << len(OPTIONFLAGS_BY_NAME))
DONT_ACCEPT_TRUE_FOR_1 = register_optionflag('DONT_ACCEPT_TRUE_FOR_1')
DONT_ACCEPT_BLANKLINE = register_optionflag('DONT_ACCEPT_BLANKLINE')
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
index d39aa42..443c962 100644
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -1300,6 +1300,26 @@
ValueError: 2
(3, 5)
+New option flags can also be registered, via register_optionflag(). Here
+we reach into doctest's internals a bit.
+
+ >>> unlikely = "UNLIKELY_OPTION_NAME"
+ >>> unlikely in doctest.OPTIONFLAGS_BY_NAME
+ False
+ >>> new_flag_value = doctest.register_optionflag(unlikely)
+ >>> unlikely in doctest.OPTIONFLAGS_BY_NAME
+ True
+
+Before 2.4.4/2.5, registering a name more than once erroneously created
+more than one flag value. Here we verify that's fixed:
+
+ >>> redundant_flag_value = doctest.register_optionflag(unlikely)
+ >>> redundant_flag_value == new_flag_value
+ True
+
+Clean up.
+ >>> del doctest.OPTIONFLAGS_BY_NAME[unlikely]
+
"""
def option_directives(): r"""