Issue #14910: Add allow_abbrev parameter to argparse.ArgumentParser.

Patch by Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.

2 files changed, 39 insertions, 4 deletions

diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 8b3d9fc..1f75cd9 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -135,7 +135,7 @@ ArgumentParser objects
                           formatter_class=argparse.HelpFormatter, \
                           prefix_chars='-', fromfile_prefix_chars=None, \
                           argument_default=None, conflict_handler='error', \
-                          add_help=True)
+                          add_help=True, allow_abbrev=True)
 
    Create a new :class:`ArgumentParser` object. All parameters should be passed
    as keyword arguments. Each parameter has its own more detailed description
@@ -169,6 +169,12 @@ ArgumentParser objects
 
    * add_help_ - Add a -h/--help option to the parser (default: ``True``)
 
+   * allow_abbrev_ - Allows long options to be abbreviated if the
+     abbreviation is unambiguous. (default: ``True``)
+
+   .. versionchanged:: 3.5
+      *allow_abbrev* parameter was added.
+
 The following sections describe how each of these are used.
 
 
@@ -518,6 +524,26 @@ calls, we supply ``argument_default=SUPPRESS``::
    >>> parser.parse_args([])
    Namespace()
 
+.. _allow_abbrev:
+
+allow_abbrev
+^^^^^^^^^^^^
+
+Normally, when you pass an argument list to the
+:meth:`~ArgumentParser.parse_args` method of a :class:`ArgumentParser`,
+it :ref:`recognizes abbreviations <prefix-matching>` of long options.
+
+This feature can be disabled by setting ``allow_abbrev`` to ``False``::
+
+   >>> parser = argparse.ArgumentParser(prog='PROG', allow_abbrev=False)
+   >>> parser.add_argument('--foobar', action='store_true')
+   >>> parser.add_argument('--foonley', action='store_false')
+   >>> parser.parse_args([--foon])
+   usage: PROG [-h] [--foobar] [--foonley]
+   PROG: error: unrecognized arguments: --foon
+
+.. versionadded:: 3.5
+
 
 conflict_handler
 ^^^^^^^^^^^^^^^^
@@ -1410,9 +1436,9 @@ argument::
 Argument abbreviations (prefix matching)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-The :meth:`~ArgumentParser.parse_args` method allows long options to be
-abbreviated to a prefix, if the abbreviation is unambiguous (the prefix matches
-a unique option)::
+The :meth:`~ArgumentParser.parse_args` method :ref:`by default <allow_abbrev>`
+allows long options to be abbreviated to a prefix, if the abbreviation is
+unambiguous (the prefix matches a unique option)::
 
    >>> parser = argparse.ArgumentParser(prog='PROG')
    >>> parser.add_argument('-bacon')
@@ -1426,6 +1452,7 @@ a unique option)::
    PROG: error: ambiguous option: -ba could match -badger, -bacon
 
 An error is produced for arguments that could produce more than one options.
+This feature can be disabled by setting :ref:`allow_abbrev` to ``False``.
 
 
 Beyond ``sys.argv``
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
index 1de9e8f..c8be694 100644
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -146,6 +146,14 @@ New Modules
 Improved Modules
 ================
 
+argparse
+--------
+
+* :class:`~argparse.ArgumentParser` now allows to disable
+  :ref:`abbreviated usage <prefix-matching>` of long options by setting
+  :ref:`allow_abbrev` to ``False``.
+  (Contributed by Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.)
+
 cgi
 ---