gh-124345: Support abbreviated single-dash long options with = in argparse (GH-124428)

Author: serhiy-storchaka

Lib/argparse.py

@@ -2319,7 +2319,9 @@ def _get_option_tuples(self, option_string):
         # but multiple character options always have to have their argument
         # separate
         elif option_string[0] in chars and option_string[1] not in chars:
-            option_prefix = option_string
+            option_prefix, sep, explicit_arg = option_string.partition('=')
+            if not sep:
+                sep = explicit_arg = None
             short_option_prefix = option_string[:2]
             short_explicit_arg = option_string[2:]
 
@@ -2330,7 +2332,7 @@ def _get_option_tuples(self, option_string):
                     result.append(tup)
                 elif self.allow_abbrev and option_string.startswith(option_prefix):
                     action = self._option_string_actions[option_string]
-                    tup = action, option_string, None, None
+                    tup = action, option_string, sep, explicit_arg
                     result.append(tup)
 
         # shouldn't ever get here

Lib/test/test_argparse.py

@@ -380,15 +380,22 @@ class TestOptionalsSingleDashAmbiguous(ParserTestCase):
     """Test Optionals that partially match but are not subsets"""
 
     argument_signatures = [Sig('-foobar'), Sig('-foorab')]
-    failures = ['-f', '-f a', '-fa', '-foa', '-foo', '-fo', '-foo b']
+    failures = ['-f', '-f a', '-fa', '-foa', '-foo', '-fo', '-foo b',
+                '-f=a', '-foo=b']
     successes = [
         ('', NS(foobar=None, foorab=None)),
         ('-foob a', NS(foobar='a', foorab=None)),
+        ('-foob=a', NS(foobar='a', foorab=None)),
         ('-foor a', NS(foobar=None, foorab='a')),
+        ('-foor=a', NS(foobar=None, foorab='a')),
         ('-fooba a', NS(foobar='a', foorab=None)),
+        ('-fooba=a', NS(foobar='a', foorab=None)),
         ('-foora a', NS(foobar=None, foorab='a')),
+        ('-foora=a', NS(foobar=None, foorab='a')),
         ('-foobar a', NS(foobar='a', foorab=None)),
+        ('-foobar=a', NS(foobar='a', foorab=None)),
         ('-foorab a', NS(foobar=None, foorab='a')),
+        ('-foorab=a', NS(foobar=None, foorab='a')),
     ]
 
 
@@ -875,7 +882,9 @@ class TestOptionalsAllowLongAbbreviation(ParserTestCase):
     successes = [
         ('', NS(foo=None, foobaz=None, fooble=False)),
         ('--foo 7', NS(foo='7', foobaz=None, fooble=False)),
+        ('--foo=7', NS(foo='7', foobaz=None, fooble=False)),
         ('--fooba a', NS(foo=None, foobaz='a', fooble=False)),
+        ('--fooba=a', NS(foo=None, foobaz='a', fooble=False)),
         ('--foobl --foo g', NS(foo='g', foobaz=None, fooble=True)),
     ]
 

Misc/NEWS.d/next/Library/2024-09-24-12-34-48.gh-issue-124345.s3vKql.rst

@@ -0,0 +1,2 @@
+:mod:`argparse` vim supports abbreviated single-dash long options separated
+by ``=`` from its value.