Change type annotation of _add_ws (#67)

CHANGELOG.md

@@ -6,6 +6,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+## [UNRELEASED]
+
+* Changed the type annotation of `_add_ws` from `bool` to `TagAttrValue`. This makes it easier to write functions which call `Tag` functions and pass along `**kwargs`. (#67)
+
+
 ## [0.4.1] 2023-10-30
 
 * Fixed deserialization of JSON HTML dependencies when they contained newline characters. (#65)

htmltools/__init__.py

@@ -1,4 +1,4 @@
-__version__ = "0.4.1"
+__version__ = "0.4.1.9000"
 
 from . import svg, tags
 from ._core import TagAttrArg  # pyright: ignore[reportUnusedImport]  # noqa: F401

htmltools/_core.py

@@ -472,7 +472,8 @@ class Tag:
     *args
         Children for the tag.
     _add_ws
-        Whether to add whitespace surrounding the tag (see Note for details).
+        A ``bool`` indicating whether to add whitespace surrounding the tag (see Note
+        for details).
     **kwargs
         Attributes for the tag.
 
@@ -522,10 +523,18 @@ def __init__(
         self,
         _name: str,
         *args: TagChild | TagAttrs,
-        _add_ws: bool = True,
+        _add_ws: TagAttrValue = True,
         **kwargs: TagAttrValue,
     ) -> None:
         self.name = _name
+
+        # Note that _add_ws is marked as a TagAttrValue for the sake of static type
+        # checking, but it must in fact be a bool. This is due to limitations in
+        # Python's type system when passing along **kwargs.
+        # https://github.com/posit-dev/py-htmltools/pull/67
+        if not isinstance(_add_ws, bool):
+            raise TypeError("`_add_ws` must be `True` or `False`")
+
         self.add_ws = _add_ws
 
         attrs = [x for x in args if isinstance(x, dict)]