Handle EINTR retry in os.write() (PEP 475)

youknowone · youknowone · commit 00129ea3fa9a · 2026-03-23T14:39:49.000+09:00
Add EINTR retry loop to os.write(), matching the existing
pattern in os.read() and os.readinto(). Remove the
expectedFailure marker from test_write in _test_eintr.py.
diff --git a/Lib/test/_test_eintr.py b/Lib/test/_test_eintr.py
@@ -163,7 +163,6 @@ def test_readinto(self):
             self.assertEqual(os.readinto(fd, buffer), len(expected))
             self.assertEqual(buffer, expected)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; InterruptedError: [Errno 4] Interrupted system call
     def test_write(self):
         rd, wr = os.pipe()
         self.addCleanup(os.close, wr)
diff --git a/crates/vm/src/stdlib/os.rs b/crates/vm/src/stdlib/os.rs
@@ -321,12 +321,19 @@ pub(super) mod _os {
     }
 
     #[pyfunction]
-    fn write(
-        fd: crt_fd::Borrowed<'_>,
-        data: ArgBytesLike,
-        vm: &VirtualMachine,
-    ) -> io::Result<usize> {
-        data.with_ref(|b| vm.allow_threads(|| crt_fd::write(fd, b)))
+    fn write(fd: crt_fd::Borrowed<'_>, data: ArgBytesLike, vm: &VirtualMachine) -> PyResult<usize> {
+        data.with_ref(|b| {
+            loop {
+                match vm.allow_threads(|| crt_fd::write(fd, b)) {
+                    Ok(n) => return Ok(n),
+                    Err(e) if e.raw_os_error() == Some(libc::EINTR) => {
+                        vm.check_signals()?;
+                        continue;
+                    }
+                    Err(e) => return Err(e.into_pyexception(vm)),
+                }
+            }
+        })
     }
 
     #[cfg(not(windows))]
