Add filesystem path autocompletion for click.Path parameters

pyproject.toml

@@ -30,6 +30,7 @@ classifiers = [
 python = "^3.9.1"
 textual = ">=2.1.2"
 click = ">=8.0.0"
+textual-autocomplete = ">=4.0.0"
 typer = {version = ">=0.9.0", optional = true}
 
 [tool.poetry.extras]
@@ -39,8 +40,12 @@ typer = ["typer"]
 mypy = "^1.2.0"
 black = "^24.3.0"
 pytest = ">=8.0.0"
+pytest-asyncio = ">=0.23.0"
 textual-dev = ">=1.0"
 
 [build-system]
 requires = ["poetry-core"]
 build-backend = "poetry.core.masonry.api"
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"

tests/test_introspect.py

@@ -0,0 +1,39 @@
+import click
+
+from trogon.introspect import MultiValueParamData, introspect_click_app
+
+
+def test_option_with_no_default_does_not_leak_click_sentinel():
+    @click.command()
+    @click.option("--path", type=click.Path())
+    def cli(path):
+        pass
+
+    data = introspect_click_app(cli)
+    option = data["cli"].options[0]
+
+    assert option.default == MultiValueParamData([])
+
+
+def test_argument_with_no_default_does_not_leak_click_sentinel():
+    @click.command()
+    @click.argument("path", type=click.Path(), required=False)
+    def cli(path):
+        pass
+
+    data = introspect_click_app(cli)
+    argument = data["cli"].arguments[0]
+
+    assert argument.default == MultiValueParamData([])
+
+
+def test_option_with_explicit_default_is_preserved():
+    @click.command()
+    @click.option("--name", type=click.STRING, default="trogon")
+    def cli(name):
+        pass
+
+    data = introspect_click_app(cli)
+    option = data["cli"].options[0]
+
+    assert option.default == MultiValueParamData([("trogon",)])

tests/test_parameter_controls.py

@@ -0,0 +1,59 @@
+import click
+from textual.widgets import Input
+from textual_autocomplete import PathAutoComplete
+
+from trogon.trogon import Trogon
+from trogon.widgets.parameter_controls import ControlGroup, ParameterControls
+
+
+@click.group()
+@click.option("--in-path", type=click.Path(), help="An input path")
+@click.option("--name", type=str, help="A plain string")
+def path_cli(in_path, name):
+    pass
+
+
+@path_cli.command()
+def sub():
+    pass
+
+
+async def test_path_option_gets_autocomplete_targeting_its_input():
+    """A click.Path option's Input is targeted by exactly one PathAutoComplete."""
+    app = Trogon(path_cli, app_name="path_cli", command_name="tui")
+    async with app.run_test() as pilot:
+        app.query_one("CommandTree").focus()
+        await pilot.pause()
+
+        autocompletes = list(app.query(PathAutoComplete))
+        assert len(autocompletes) == 1
+
+        path_controls = next(
+            pc
+            for pc in app.query(ParameterControls)
+            if pc.schema.name == ["--in-path"]
+        )
+        path_input = path_controls.query_one(f".{path_controls.schema.key}", Input)
+        assert autocompletes[0].target is path_input
+
+
+async def test_non_path_option_has_no_autocomplete():
+    """A plain string option gets no PathAutoComplete, and single-item styling
+    still counts only the real control widgets."""
+    app = Trogon(path_cli, app_name="path_cli", command_name="tui")
+    async with app.run_test() as pilot:
+        app.query_one("CommandTree").focus()
+        await pilot.pause()
+
+        name_controls = next(
+            pc for pc in app.query(ParameterControls) if pc.schema.name == ["--name"]
+        )
+        assert not list(name_controls.query(PathAutoComplete))
+
+        for control_group in app.query(ControlGroup):
+            children = list(control_group.children)
+            real_controls = [
+                c for c in children if not isinstance(c, PathAutoComplete)
+            ]
+            if "single-item" in control_group.classes:
+                assert len(real_controls) == 1

trogon/introspect.py

@@ -7,6 +7,14 @@
 import click
 from click import BaseCommand, ParamType
 
+try:
+    # Click 8.3+ uses a dedicated sentinel to distinguish "no default was
+    # supplied" from a default value of `None`. Older versions of Click
+    # don't have this sentinel, and just use `None` for both cases.
+    from click.core import UNSET as CLICK_UNSET
+except ImportError:
+    CLICK_UNSET = None
+
 
 def generate_unique_id():
     return f"id_{str(uuid.uuid4())[:8]}"
@@ -18,7 +26,7 @@ class MultiValueParamData:
 
     @staticmethod
     def process_cli_option(value) -> "MultiValueParamData":
-        if value is None:
+        if value is None or value is CLICK_UNSET:
             value = MultiValueParamData([])
         elif isinstance(value, tuple):
             value = MultiValueParamData([value])

trogon/widgets/parameter_controls.py

@@ -19,6 +19,7 @@
     Static,
     Button,
 )
+from textual_autocomplete import PathAutoComplete
 
 from trogon.introspect import ArgumentSchema, OptionSchema, MultiValueParamData
 from trogon.widgets.multiple_choice import MultipleChoice
@@ -163,6 +164,10 @@ def compose(self) -> ComposeResult:
                             if first_focus_control is None:
                                 first_focus_control = control_widget
 
+                        yield from self._make_path_autocompletes(
+                            widget_group, argument_type
+                        )
+
                 # We always need to display the original group of controls,
                 # regardless of whether there are defaults
                 if multiple or not default.values:
@@ -177,6 +182,10 @@ def compose(self) -> ComposeResult:
                             if first_focus_control is None:
                                 first_focus_control = control_widget
 
+                        yield from self._make_path_autocompletes(
+                            widget_group, argument_type
+                        )
+
         # Take note of the first form control, so we can easily focus it
         if self.first_control is None:
             self.first_control = first_focus_control
@@ -221,6 +230,20 @@ def make_widget_group(self) -> Iterable[ControlWidgetType]:
             )
             yield from control_widgets
 
+    @staticmethod
+    def _make_path_autocompletes(
+        widget_group: list[ControlWidgetType], parameter_type: click.ParamType
+    ) -> Iterable[PathAutoComplete]:
+        """Pair each Input backed by a click.Path type with a PathAutoComplete."""
+        parameter_types = (
+            parameter_type.types
+            if isinstance(parameter_type, click.Tuple)
+            else [parameter_type]
+        )
+        for control_widget, _type in zip(widget_group, parameter_types):
+            if isinstance(_type, click.Path) and isinstance(control_widget, Input):
+                yield PathAutoComplete(target=control_widget)
+
     @on(Button.Pressed, ".add-another-button")
     def add_another_widget_group(self, event: Button.Pressed) -> None:
         widget_group = list(self.make_widget_group())