TextArea should handle missing tree-sitter-languages binaries

[tconbeer]

I'm upstreaming tconbeer/harlequin#420 (ultimately from a Harlequin user).

When installed with the syntax extra, the TextArea assumes that all of the binaries for the "built-in" languages for tree-sitter will be present. However, this may not be the case; for example (in the lijnked issue), Conda (micromamba) seems to struggle with installing the language binaries, and they may be missing on some platforms.

In that case, initializing a TextArea with a built-in language name will raise an OSError, which is not handled by the widget. I think it would be better to handle this error and re-raise as a SyntaxAwareDocumentError, so the TextArea degrades instead of crashes.

I'll be opening a PR with a simple fix for this shortly.

Full trace from the linked issue:

╭─────────────────────────────── Traceback (most recent call last) ────────────────────────────────╮
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/textual/widget.py:3386 │
│ in _on_compose                                                                                   │
│                                                                                                  │
│   3383 │                                                                                         │
│   3384 │   async def _on_compose(self) -> None:                                                  │
│   3385 │   │   try:                                                                              │
│ ❱ 3386 │   │   │   widgets = [*self._nodes, *compose(self)]                                      │
│   3387 │   │   except TypeError as error:                                                        │
│   3388 │   │   │   raise TypeError(                                                              │
│   3389 │   │   │   │   f"{self!r} compose() method returned an invalid result; {error}"          │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/textual_textarea/texta │
│ rea.py:950 in compose                                                                            │
│                                                                                                  │
│    947 │                                                                                         │
│    948 │   def compose(self) -> ComposeResult:                                                   │
│    949 │   │   with TextContainer():                                                             │
│ ❱  950 │   │   │   yield TextInput(language=self._language)                                      │
│    951 │   │   │   yield CompletionList()                                                        │
│    952 │   │   with FooterContainer():                                                           │
│    953 │   │   │   yield Label("", id="validation_label")                                        │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/textual_textarea/texta │
│ rea.py:191 in __init__                                                                           │
│                                                                                                  │
│    188 │   │   classes: str | None = None,                                                       │
│    189 │   │   disabled: bool = False,                                                           │
│    190 │   ) -> None:                                                                            │
│ ❱  191 │   │   super().__init__(                                                                 │
│    192 │   │   │   text,                                                                         │
│    193 │   │   │   language=language,                                                            │
│    194 │   │   │   theme=theme,                                                                  │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/textual/widgets/_text_ │
│ area.py:339 in __init__                                                                          │
│                                                                                                  │
│    336 │   │   reactive is set as a string, the watcher will update this attribute to the        │
│    337 │   │   corresponding `TextAreaTheme` object."""                                          │
│    338 │   │                                                                                     │
│ ❱  339 │   │   self.language = language                                                          │
│    340 │   │                                                                                     │
│    341 │   │   self.theme = theme                                                                │
│    342                                                                                           │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/textual/widgets/_text_ │
│ area.py:479 in _watch_language                                                                   │
│                                                                                                  │
│    476 │   │   │   │   f"then switch to it by setting the `TextArea.language` attribute."        │
│    477 │   │   │   )                                                                             │
│    478 │   │                                                                                     │
│ ❱  479 │   │   self._set_document(                                                               │
│    480 │   │   │   self.document.text if self.document is not None else self._initial_text,      │
│    481 │   │   │   language,                                                                     │
│    482 │   │   )                                                                                 │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/textual/widgets/_text_ │
│ area.py:637 in _set_document                                                                     │
│                                                                                                  │
│    634 │   │   │   │   highlight_query = self._get_builtin_highlight_query(language)             │
│    635 │   │   │   document: DocumentBase                                                        │
│    636 │   │   │   try:                                                                          │
│ ❱  637 │   │   │   │   document = SyntaxAwareDocument(text, document_language)                   │
│    638 │   │   │   except SyntaxAwareDocumentError:                                              │
│    639 │   │   │   │   document = Document(text)                                                 │
│    640 │   │   │   │   log.warning(                                                              │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/textual/document/_synt │
│ ax_aware_document.py:61 in __init__                                                              │
│                                                                                                  │
│    58 │   │   if isinstance(language, str):                                                      │
│    59 │   │   │   if language not in BUILTIN_LANGUAGES:                                          │
│    60 │   │   │   │   raise SyntaxAwareDocumentError(f"Invalid language {language!r}")           │
│ ❱  61 │   │   │   self.language = get_language(language)                                         │
│    62 │   │   │   self._parser = get_parser(language)                                            │
│    63 │   │   else:                                                                              │
│    64 │   │   │   self.language = language                                                       │
│                                                                                                  │
│ in tree_sitter_languages.core.get_language:14                                                    │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/site-packages/tree_sitter/__init__.p │
│ y:131 in __init__                                                                                │
│                                                                                                  │
│   128 │   │   at the given path.                                                                 │
│   129 │   │   """                                                                                │
│   130 │   │   self.name = name                                                                   │
│ ❱ 131 │   │   self.lib = cdll.LoadLibrary(library_path)                                          │
│   132 │   │   language_function: Callable[[], c_void_p] = getattr(self.lib, "tree_sitter_%s" %   │
│   133 │   │   language_function.restype = c_void_p                                               │
│   134 │   │   self.language_id: c_void_p = language_function()                                   │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/ctypes/__init__.py:454 in            │
│ LoadLibrary                                                                                      │
│                                                                                                  │
│   451 │   │   return getattr(self, name)                                                         │
│   452 │                                                                                          │
│   453 │   def LoadLibrary(self, name):                                                           │
│ ❱ 454 │   │   return self._dlltype(name)                                                         │
│   455 │                                                                                          │
│   456 │   __class_getitem__ = classmethod(_types.GenericAlias)                                   │
│   457                                                                                            │
│                                                                                                  │
│ /home/moritz/micromamba/envs/harlequin-issue/lib/python3.11/ctypes/__init__.py:376 in __init__   │
│                                                                                                  │
│   373 │   │   self._FuncPtr = _FuncPtr                                                           │
│   374 │   │                                                                                      │
│   375 │   │   if handle is None:                                                                 │
│ ❱ 376 │   │   │   self._handle = _dlopen(self._name, mode)                                       │
│   377 │   │   else:                                                                              │
│   378 │   │   │   self._handle = handle                                                          │
│   379                                                                                            │
╰──────────────────────────────────────────────────────────────────────────────────────────────────╯

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