Revert "[3.11] pythongh-101634: regrtest reports decoding error as fa…

…iled test (python#106169) (python#106175)"

This reverts commit d5418e9.

Lib/test/libregrtest/runtest_mp.py

@@ -269,7 +269,6 @@ def _runtest(self, test_name: str) -> MultiprocessResult:
             encoding = locale.getencoding()
         else:
             encoding = sys.stdout.encoding
-
         # gh-94026: Write stdout+stderr to a tempfile as workaround for
         # non-blocking pipes on Emscripten with NodeJS.
         with tempfile.TemporaryFile('w+', encoding=encoding) as stdout_fh:
@@ -278,14 +277,7 @@ def _runtest(self, test_name: str) -> MultiprocessResult:
             # Python finalization: too late for libregrtest.
             retcode = self._run_process(test_name, stdout_fh)
             stdout_fh.seek(0)
-
-            try:
-                stdout = stdout_fh.read().strip()
-            except Exception as exc:
-                # gh-101634: Catch UnicodeDecodeError if stdout cannot be
-                # decoded from encoding
-                err_msg = f"Cannot read process stdout: {exc}"
-                return self.mp_result_error(ChildError(test_name), '', err_msg)
+            stdout = stdout_fh.read().strip()
 
         if retcode is None:
             return self.mp_result_error(Timeout(test_name), stdout)
@@ -460,8 +452,6 @@ def _process_result(self, item: QueueOutput) -> bool:
             # Thread got an exception
             format_exc = item[1]
             print_warning(f"regrtest worker thread failed: {format_exc}")
-            result = ChildError("<regrtest worker>")
-            self.regrtest.accumulate_result(result)
             return True
 
         self.test_index += 1

Lib/test/test_regrtest.py

@@ -7,7 +7,6 @@
 import contextlib
 import glob
 import io
-import locale
 import os.path
 import platform
 import re
@@ -1519,41 +1518,6 @@ def test_cleanup(self):
         for name in names:
             self.assertFalse(os.path.exists(name), name)
 
-    def test_mp_decode_error(self):
-        # gh-101634: If a worker stdout cannot be decoded, report a failed test
-        # and a non-zero exit code.
-        if sys.platform == 'win32':
-            encoding = locale.getencoding()
-        else:
-            encoding = sys.stdout.encoding
-            if encoding is None:
-                encoding = sys.__stdout__.encoding
-                if encoding is None:
-                    self.skipTest(f"cannot get regrtest worker encoding")
-
-        nonascii = b"byte:\xa0\xa9\xff\n"
-        try:
-            nonascii.decode(encoding)
-        except UnicodeDecodeError:
-            pass
-        else:
-            self.skipTest(f"{encoding} can decode non-ASCII bytes {nonascii!a}")
-
-        code = textwrap.dedent(fr"""
-            import sys
-            # bytes which cannot be decoded from UTF-8
-            nonascii = {nonascii!a}
-            sys.stdout.buffer.write(nonascii)
-            sys.stdout.buffer.flush()
-        """)
-        testname = self.create_test(code=code)
-
-        output = self.run_tests("--fail-env-changed", "-v", "-j1", testname,
-                                exitcode=EXITCODE_BAD_TEST)
-        self.check_executed_tests(output, [testname],
-                                  failed=[testname],
-                                  randomize=True)
-
 
 class TestUtils(unittest.TestCase):
     def test_format_duration(self):