ipython · zhangli091011 · Jul 20, 2026 · Jul 20, 2026 · Jul 24, 2026
diff --git a/IPython/core/magic_arguments.py b/IPython/core/magic_arguments.py
@@ -84,6 +84,7 @@ def my_cell_magic(line, cell):
 #-----------------------------------------------------------------------------
 import argparse
 import re
+import shlex
 
 # Our own imports
 from IPython.core.error import UsageError
@@ -92,6 +93,10 @@ def my_cell_magic(line, cell):
 from IPython.utils.text import dedent
 
 NAME_RE = re.compile(r"[a-zA-Z][a-zA-Z0-9_-]*$")
+QUOTED_ARG_VALUE_RE = re.compile(
+    r"""(?<!\S)(?P<option>[^\s=]+)=(?P<value>"(?:\\.|[^"\\])*"|'[^']*')(?=\s|$)"""
+)
+
 
 @undoc
 class MagicHelpFormatter(argparse.RawDescriptionHelpFormatter):
@@ -164,7 +169,26 @@ def error(self, message):
     def parse_argstring(self, argstring, *, partial=False):
         """ Split a string into an argument list and parse that argument list.
         """
-        argv = arg_split(argstring, strict=not partial)
+        replacements: dict[str, str] = {}
+
+        def replace_quoted_value(match):
+            action = self._option_string_actions.get(match.group("option"))
+            if action is None or action.nargs == 0:
+                return match.group()
+            # Keep the platform splitter from breaking an attached quoted value.
+            marker = f"__IPYTHON_MAGIC_ARG_{len(replacements)}__"
+            while marker in argstring:
+                marker += "_"
+            replacements[marker] = shlex.split(match.group("value"), posix=True)[0]
+            return f"{match.group('option')}={marker}"
+
+        masked = QUOTED_ARG_VALUE_RE.sub(replace_quoted_value, argstring)
+        argv = arg_split(masked, strict=not partial)
+        for index, token in enumerate(argv):
+            for marker, value in replacements.items():
+                if marker in token:
+                    argv[index] = token.replace(marker, value)
+                    break
         if partial:
             return self.parse_known_args(argv)
         return self.parse_args(argv)

diff --git a/tests/test_magic_arguments.py b/tests/test_magic_arguments.py
@@ -83,6 +83,13 @@ def foo(self, args):
     return parse_argstring(foo, args)
 
 
+@magic_arguments()
+@argument("--path", action="append", default=[])
+@argument("remainder", nargs="*")
+def magic_paths(self, args):
+    return parse_argstring(magic_paths, args)
+
+
 def test_magic_arguments():
     assert (
         magic_foo1.__doc__
@@ -143,3 +150,57 @@ def test_magic_arguments():
     assert real_name(foo) == "foo"
     assert foo(None, "") == argparse.Namespace(foo=None)
     assert hasattr(foo, "has_arguments")
+
+
+def test_quoted_option_values_with_spaces(monkeypatch):
+    assert magic_paths(
+        None, '--path="-L/Users/carlos/Desktop/Test LGBM API"'
+    ) == argparse.Namespace(
+        path=["-L/Users/carlos/Desktop/Test LGBM API"], remainder=[]
+    )
+
+    # Exercise the quote-preserving splitter used on POSIX on every platform.
+    from IPython.utils._process_common import arg_split
+
+    monkeypatch.setattr("IPython.core.magic_arguments.arg_split", arg_split)
+
+    assert magic_paths(
+        None,
+        '--path="-L/Users/carlos/Desktop/Test LGBM API" '
+        "--path='single quoted path' "
+        '--path="say \\"hello\\" here" '
+        '--path="C:\\Program Files\\project" '
+        '--path="héllo 世界" tail',
+    ) == argparse.Namespace(
+        path=[
+            "-L/Users/carlos/Desktop/Test LGBM API",
+            "single quoted path",
+            'say "hello" here',
+            "C:\\Program Files\\project",
+            "héllo 世界",
+        ],
+        remainder=["tail"],
+    )
+
+
+def test_magic_argument_existing_quote_behavior(monkeypatch):
+    from IPython.utils._process_common import arg_split
+
+    monkeypatch.setattr("IPython.core.magic_arguments.arg_split", arg_split)
+
+    assert magic_paths(
+        None, '--path plain --path "separate quoted value" "quoted positional"'
+    ) == argparse.Namespace(
+        path=["plain", '"separate quoted value"'],
+        remainder=['"quoted positional"'],
+    )
+
+
+def test_non_option_equals_quote_behavior(monkeypatch):
+    from IPython.utils._process_common import arg_split
+
+    monkeypatch.setattr("IPython.core.magic_arguments.arg_split", arg_split)
+
+    assert magic_paths(None, 'expression="still split apart"') == argparse.Namespace(
+        path=[], remainder=['expression="still', "split", 'apart"']
+    )