Add dcargs.conf.OmitSubcommandPrefixes, version bump

dcargs/_arguments.py

@@ -36,25 +36,12 @@
     from backports.cached_property import cached_property  # type: ignore
 
 
-class _PatchedList(list):
-    """Custom tuple type, for avoiding "default not in choices" errors when the default
-    is set to MISSING_NONPROP.
-
-    This solves a choices error raised by argparse in a very specific edge case:
-    literals in containers as positional arguments."""
-
-    def __init__(self, li):
-        super(_PatchedList, self).__init__(li)
-
-    def __contains__(self, x: Any) -> bool:
-        return list.__contains__(self, x) or x is _fields.MISSING_NONPROP
-
-
 @dataclasses.dataclass(frozen=True)
 class ArgumentDefinition:
     """Structure containing everything needed to define an argument."""
 
     prefix: str  # Prefix for nesting.
+    subcommand_prefix: str  # Prefix for nesting.
     field: _fields.FieldDefinition
     type_from_typevar: Dict[TypeVar, Type]
 
@@ -77,10 +64,7 @@ def add_argument(
         # the field default to a string format, then back to the desired type.
         kwargs["default"] = _fields.MISSING_NONPROP
 
-        if "choices" in kwargs:
-            kwargs["choices"] = _PatchedList(kwargs["choices"])
-
-        # Note that the name must be passed in as a position argument.
+        # Add argument! Note that the name must be passed in as a position argument.
         arg = parser.add_argument(name_or_flag, **kwargs)
 
         # Do our best to tab complete paths.
@@ -119,8 +103,9 @@ def lowered(self) -> LoweredArgumentDefinition:
             _rule_recursive_instantiator_from_type,
             _rule_convert_defaults_to_strings,
             _rule_generate_helptext,
-            _rule_set_name_or_flag,
+            _rule_set_name_or_flag_and_dest,
             _rule_positional_special_handling,
+            _rule_static_cast_choices_to_patched_list,
         )
         return functools.reduce(
             lambda lowered, rule: rule(self, lowered),
@@ -362,19 +347,30 @@ def _rule_generate_helptext(
     return dataclasses.replace(lowered, help=" ".join(help_parts))
 
 
-def _rule_set_name_or_flag(
+def _rule_set_name_or_flag_and_dest(
     arg: ArgumentDefinition,
     lowered: LoweredArgumentDefinition,
 ) -> LoweredArgumentDefinition:
+    # Positional arguments: no -- prefix.
     if arg.field.is_positional():
         name_or_flag = _strings.make_field_name([arg.prefix, arg.field.name])
+    # Negated booleans.
     elif lowered.action == "store_false":
         name_or_flag = "--" + _strings.make_field_name(
             [arg.prefix, "no-" + arg.field.name]
         )
+    # Prefix keyword arguments with --.
     else:
         name_or_flag = "--" + _strings.make_field_name([arg.prefix, arg.field.name])
 
+    # Strip.
+    if name_or_flag.startswith("--") and arg.subcommand_prefix != "":
+        # This will run even when unused because we want the assert.
+        strip_prefix = "--" + arg.subcommand_prefix + "."
+        assert name_or_flag.startswith(strip_prefix)
+        if _markers.OMIT_SUBCOMMAND_PREFIXES in arg.field.markers:
+            name_or_flag = "--" + name_or_flag[len(strip_prefix) :]
+
     return dataclasses.replace(
         lowered,
         name_or_flag=name_or_flag,
@@ -410,3 +406,27 @@ def _rule_positional_special_handling(
         metavar=metavar,
         nargs=nargs,
     )
+
+
+class _PatchedList(list):
+    """Custom list type, for avoiding "default not in choices" errors when the default
+    is set to MISSING_NONPROP.
+
+    This solves a choices error raised by argparse in a very specific edge case:
+    literals in containers as positional arguments."""
+
+    def __init__(self, li):
+        super(_PatchedList, self).__init__(li)
+
+    def __contains__(self, x: Any) -> bool:
+        return list.__contains__(self, x) or x is _fields.MISSING_NONPROP
+
+
+def _rule_static_cast_choices_to_patched_list(
+    arg: ArgumentDefinition,
+    lowered: LoweredArgumentDefinition,
+) -> LoweredArgumentDefinition:
+    return dataclasses.replace(
+        lowered,
+        choices=_PatchedList(lowered.choices) if lowered.choices is not None else None,
+    )

dcargs/_parsers.py

@@ -6,7 +6,7 @@
 import itertools
 from typing import Any, Callable, Dict, List, Optional, Set, Type, TypeVar, Union, cast
 
-from typing_extensions import get_args, get_origin
+from typing_extensions import Annotated, get_args, get_origin
 
 from . import (
     _argparse_formatter,
@@ -44,6 +44,7 @@ def from_callable_or_type(
             T, _fields.PropagatingMissingType, _fields.NonpropagatingMissingType
         ],
         prefix: str,
+        subcommand_prefix: str = "",
     ) -> ParserSpecification:
         """Create a parser definition from a callable or type."""
 
@@ -131,6 +132,7 @@ def from_callable_or_type(
                         parent_type_from_typevar=type_from_typevar,
                         default_instance=field.default,
                         prefix=_strings.make_field_name([prefix, field.name]),
+                        subcommand_prefix=subcommand_prefix,
                     )
                     args.extend(nested_parser.args)
 
@@ -159,6 +161,7 @@ def from_callable_or_type(
             # (3) Handle primitive or fixed types. These produce a single argument!
             arg = _arguments.ArgumentDefinition(
                 prefix=prefix,
+                subcommand_prefix=subcommand_prefix,
                 field=field,
                 type_from_typevar=type_from_typevar,
             )
@@ -305,12 +308,16 @@ def from_field(
                 )
 
             subparser = ParserSpecification.from_callable_or_type(
-                option,
+                # Recursively apply markers.
+                Annotated.__class_getitem__((option,) + tuple(field.markers))  # type: ignore
+                if len(field.markers) > 0
+                else option,
                 description=found_subcommand_configs[0].description,
                 parent_classes=parent_classes,
                 parent_type_from_typevar=type_from_typevar,
                 default_instance=found_subcommand_configs[0].default,
                 prefix=prefix,
+                subcommand_prefix=prefix,
             )
 
             # Apply prefix to helptext in nested classes in subparsers.

dcargs/conf/__init__.py

@@ -5,13 +5,21 @@
 Features here are supported, but generally unnecessary and should be used sparingly.
 """
 
-from ._markers import AvoidSubcommands, Fixed, FlagConversionOff, Positional, Suppress
+from ._markers import (
+    AvoidSubcommands,
+    Fixed,
+    FlagConversionOff,
+    OmitSubcommandPrefixes,
+    Positional,
+    Suppress,
+)
 from ._subcommands import subcommand
 
 __all__ = [
     "AvoidSubcommands",
     "Fixed",
     "FlagConversionOff",
+    "OmitSubcommandPrefixes",
     "Positional",
     "Suppress",
     "subcommand",

dcargs/conf/_markers.py

@@ -54,3 +54,15 @@ def __repr__(self):
 
 Can be used directly on union types, `AvoidSubcommands[Union[...]]`, or recursively
 applied to nested types."""
+
+OMIT_SUBCOMMAND_PREFIXES = _make_marker("OmitSubcommandPrefixes")
+OmitSubcommandPrefixes = Annotated[T, OMIT_SUBCOMMAND_PREFIXES]
+"""Make flags used for keyword arguments in subcommands shorter by omitting prefixes.
+
+If we have a structure with the field:
+
+    cmd: Union[Commit, Checkout]
+
+By default, --cmd.branch may be generated as a flag for each dataclass in the union.
+If subcommand prefixes are omitted, we would instead simply have --branch.
+"""

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "dcargs"
-version = "0.3.14"
+version = "0.3.15"
 description = "Strongly typed, zero-effort CLI interfaces"
 authors = ["brentyi <[email protected]>"]
 include = ["./dcargs/**/*"]

tests/test_metadata.py

@@ -7,6 +7,49 @@
 import dcargs
 
 
+def test_omit_subcommand_prefix():
+    @dataclasses.dataclass
+    class DefaultInstanceHTTPServer:
+        y: int = 0
+
+    @dataclasses.dataclass
+    class DefaultInstanceSMTPServer:
+        z: int = 0
+
+    @dataclasses.dataclass
+    class DefaultInstanceSubparser:
+        x: int
+        # bc: Union[DefaultInstanceHTTPServer, DefaultInstanceSMTPServer]
+        bc: dcargs.conf.OmitSubcommandPrefixes[
+            Union[DefaultInstanceHTTPServer, DefaultInstanceSMTPServer]
+        ]
+
+    assert (
+        dcargs.cli(
+            DefaultInstanceSubparser,
+            args=["--x", "1", "bc:default-instance-http-server", "--y", "5"],
+        )
+        == dcargs.cli(
+            DefaultInstanceSubparser,
+            args=["--x", "1", "bc:default-instance-http-server", "--y", "5"],
+            default=DefaultInstanceSubparser(x=1, bc=DefaultInstanceHTTPServer(y=3)),
+        )
+        == DefaultInstanceSubparser(x=1, bc=DefaultInstanceHTTPServer(y=5))
+    )
+    assert (
+        dcargs.cli(
+            DefaultInstanceSubparser,
+            args=["--x", "1", "bc:default-instance-http-server", "--y", "8"],
+        )
+        == dcargs.cli(
+            DefaultInstanceSubparser,
+            args=["--x", "1", "bc:default-instance-http-server", "--y", "8"],
+            default=DefaultInstanceSubparser(x=1, bc=DefaultInstanceHTTPServer(y=7)),
+        )
+        == DefaultInstanceSubparser(x=1, bc=DefaultInstanceHTTPServer(y=8))
+    )
+
+
 def test_avoid_subparser_with_default():
     @dataclasses.dataclass
     class DefaultInstanceHTTPServer: