Tab complete for paths in bash

dcargs/_arguments.py

@@ -8,6 +8,7 @@
 import functools
 import itertools
 import shlex
+from pathlib import Path
 from typing import (
     Any,
     Dict,
@@ -21,7 +22,9 @@
     Union,
 )
 
-from . import _fields, _instantiators, _resolver, _strings
+from . import _fields, _instantiators, _resolver
+from . import _shtab as shtab
+from . import _strings
 from .conf import _markers
 
 try:
@@ -77,7 +80,21 @@ def add_argument(
             kwargs["choices"] = _PatchedList(kwargs["choices"])
 
         # Note that the name must be passed in as a position argument.
-        parser.add_argument(name_or_flag, **kwargs)
+        arg = parser.add_argument(name_or_flag, **kwargs)
+
+        # Do our best to tab complete paths.
+        # There will be false positives here, but if choices is unset they should be
+        # harmless.
+        if "choices" not in kwargs:
+            if "dir" in self.field.name:
+                arg.complete = shtab.DIRECTORY  # type: ignore
+            elif (
+                # Catch types like Path, List[Path], Tuple[Path, ...] etc.
+                "Path" in str(self.field.typ)
+                or "path" in self.field.name
+                or "file" in self.field.name
+            ):
+                arg.complete = shtab.FILE  # type: ignore
 
     @cached_property
     def lowered(self) -> LoweredArgumentDefinition:

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "dcargs"
-version = "0.3.8"
+version = "0.3.9"
 description = "Strongly typed, zero-effort CLI interfaces"
 authors = ["brentyi <[email protected]>"]
 include = ["./dcargs/**/*"]

tests/test_dcargs.py

@@ -99,7 +99,7 @@ class InitFalseDataclass:
         i: int
         s: str
         f: float
-        p: pathlib.Path
+        dir: pathlib.Path
         ignored: str = dataclasses.field(default="hello", init=False)
 
     assert dcargs.cli(
@@ -111,15 +111,26 @@ class InitFalseDataclass:
             "5",
             "--f",
             "5",
-            "--p",
+            "--dir",
             "~",
         ],
-    ) == InitFalseDataclass(i=5, s="5", f=5.0, p=pathlib.Path("~"))
+    ) == InitFalseDataclass(i=5, s="5", f=5.0, dir=pathlib.Path("~"))
 
     with pytest.raises(SystemExit):
         dcargs.cli(
             InitFalseDataclass,
-            args=["--i", "5", "--s", "5", "--f", "5", "--p", "~", "--ignored", "blah"],
+            args=[
+                "--i",
+                "5",
+                "--s",
+                "5",
+                "--f",
+                "5",
+                "--dir",
+                "~",
+                "--ignored",
+                "blah",
+            ],
         )