Support lazy files with pyjson5

In order for pyjson5 to be satisfied, it must be passed the real file
descriptor (or something satisfying `io.IOBase`). For simplicity, pass
it the underlying open() result.

Also improve the file close behavior using a `finally` block.

Author: sirosen

src/check_jsonschema/cli/param_types.py

@@ -109,7 +109,7 @@ def convert(
         return t.cast(t.Type[jsonschema.protocols.Validator], result)
 
 
-class _CustomLazyFile(click.utils.LazyFile):
+class CustomLazyFile(click.utils.LazyFile):
     def __init__(
         self,
         filename: str | os.PathLike[str],
@@ -150,7 +150,7 @@ def convert(
 
         value_: str | os.PathLike[str] = t.cast("str | os.PathLike[str]", value)
 
-        lf = _CustomLazyFile(value_, mode="rb")
+        lf = CustomLazyFile(value_, mode="rb")
         if ctx is not None:
             ctx.call_on_close(lf.close_intelligently)
         return t.cast(t.IO[bytes], lf)

src/check_jsonschema/instance_loader.py

@@ -3,14 +3,16 @@
 import io
 import typing as t
 
+from check_jsonschema.cli.param_types import CustomLazyFile
+
 from .parsers import ParseError, ParserSet
 from .transforms import Transform
 
 
 class InstanceLoader:
     def __init__(
         self,
-        files: t.Sequence[t.BinaryIO],
+        files: t.Sequence[t.BinaryIO | CustomLazyFile],
         default_filetype: str = "json",
         data_transform: Transform | None = None,
     ) -> None:
@@ -35,14 +37,21 @@ def iter_files(self) -> t.Iterator[tuple[str, ParseError | t.Any]]:
                 name = "<stdin>"
             else:
                 raise ValueError(f"File {file} has no name attribute")
+
             try:
-                data: t.Any = self._parsers.parse_data_with_path(
-                    file, name, self._default_filetype
-                )
-            except ParseError as err:
-                data = err
-            else:
-                data = self._data_transform(data)
+                if isinstance(file, CustomLazyFile):
+                    stream: t.BinaryIO = t.cast(t.BinaryIO, file.open())
+                else:
+                    stream = file
 
-            file.close()
+                try:
+                    data: t.Any = self._parsers.parse_data_with_path(
+                        stream, name, self._default_filetype
+                    )
+                except ParseError as err:
+                    data = err
+                else:
+                    data = self._data_transform(data)
+            finally:
+                file.close()
             yield (name, data)