Make anyio.run_process() accept stdin argument

docs/versionhistory.rst

@@ -3,6 +3,13 @@ Version history
 
 This library adheres to `Semantic Versioning 2.0 <http://semver.org/>`_.
 
+**UNRELEASED**
+
+- Added ``stdin`` argument to ``anyio.run_process()`` akin to what
+  ``anyio.open_process()``, ``asyncio.create_subprocess_…()``, ``trio.run_process()``,
+  and ``subprocess.run()`` already accept.
+  (`#859 <https://github.com/agronholm/anyio/pull/859>`_; PR by @jmehnle)
+
 **4.8.0**
 
 - Added **experimental** support for running functions in subinterpreters on Python

src/anyio/_core/_subprocesses.py

@@ -23,6 +23,7 @@ async def run_process(
     command: StrOrBytesPath | Sequence[StrOrBytesPath],
     *,
     input: bytes | None = None,
+    stdin: int | IO[Any] | None = None,
     stdout: int | IO[Any] | None = PIPE,
     stderr: int | IO[Any] | None = PIPE,
     check: bool = True,
@@ -45,6 +46,8 @@ async def run_process(
     :param command: either a string to pass to the shell, or an iterable of strings
         containing the executable name or path and its arguments
     :param input: bytes passed to the standard input of the subprocess
+    :param stdin: one of :data:`subprocess.PIPE`, :data:`subprocess.DEVNULL`,
+        a file-like object, or `None`; ``input`` overrides this
     :param stdout: one of :data:`subprocess.PIPE`, :data:`subprocess.DEVNULL`,
         a file-like object, or `None`
     :param stderr: one of :data:`subprocess.PIPE`, :data:`subprocess.DEVNULL`,
@@ -84,7 +87,7 @@ async def drain_stream(stream: AsyncIterable[bytes], index: int) -> None:
 
     async with await open_process(
         command,
-        stdin=PIPE if input else DEVNULL,
+        stdin=(input and PIPE) or stdin or DEVNULL,
         stdout=stdout,
         stderr=stderr,
         cwd=cwd,

tests/test_subprocesses.py

@@ -129,7 +129,7 @@ async def test_process_new_session_sid() -> None:
     assert result.stdout.decode().strip() != str(sid)
 
 
-async def test_run_process_connect_to_file(tmp_path: Path) -> None:
+async def test_open_process_connect_to_file(tmp_path: Path) -> None:
     stdinfile = tmp_path / "stdin"
     stdinfile.write_text("Hello, process!\n")
     stdoutfile = tmp_path / "stdout"
@@ -162,6 +162,38 @@ async def test_run_process_connect_to_file(tmp_path: Path) -> None:
     )
 
 
+async def test_run_process_connect_to_file(tmp_path: Path) -> None:
+    stdinfile = tmp_path / "stdin"
+    stdinfile.write_text("Hello, process!\n")
+    stdoutfile = tmp_path / "stdout"
+    stderrfile = tmp_path / "stderr"
+    with (
+        stdinfile.open("rb") as fin,
+        stdoutfile.open("wb") as fout,
+        stderrfile.open("wb") as ferr,
+    ):
+        await run_process(
+            [
+                sys.executable,
+                "-c",
+                "import sys; txt = sys.stdin.read().strip(); "
+                'print("stdin says", repr(txt), "but stderr says NO!", '
+                "file=sys.stderr); "
+                'print("stdin says", repr(txt), "and stdout says YES!")',
+            ],
+            stdin=fin,
+            stdout=fout,
+            stderr=ferr,
+        )
+
+    assert (
+        stdoutfile.read_text() == "stdin says 'Hello, process!' and stdout says YES!\n"
+    )
+    assert (
+        stderrfile.read_text() == "stdin says 'Hello, process!' but stderr says NO!\n"
+    )
+
+
 async def test_run_process_inherit_stdout(capfd: pytest.CaptureFixture[str]) -> None:
     await run_process(
         [