gh-76785: Fixes for test.support.interpreters (gh-112982)

This involves a number of changes for PEP 734.

1 files changed, 189 insertions, 0 deletions

diff --git a/Lib/test/test_interpreters/test_lifecycle.py b/Lib/test/test_interpreters/test_lifecycle.py
new file mode 100644
index 0000000..c2917d8
--- /dev/null
+++ b/Lib/test/test_interpreters/test_lifecycle.py
@@ -0,0 +1,189 @@
+import contextlib
+import json
+import os
+import os.path
+import sys
+from textwrap import dedent
+import unittest
+
+from test import support
+from test.support import import_helper
+from test.support import os_helper
+# Raise SkipTest if subinterpreters not supported.
+import_helper.import_module('_xxsubinterpreters')
+from .utils import TestBase
+
+
+class StartupTests(TestBase):
+
+    # We want to ensure the initial state of subinterpreters
+    # matches expectations.
+
+    _subtest_count = 0
+
+    @contextlib.contextmanager
+    def subTest(self, *args):
+        with super().subTest(*args) as ctx:
+            self._subtest_count += 1
+            try:
+                yield ctx
+            finally:
+                if self._debugged_in_subtest:
+                    if self._subtest_count == 1:
+                        # The first subtest adds a leading newline, so we
+                        # compensate here by not printing a trailing newline.
+                        print('### end subtest debug ###', end='')
+                    else:
+                        print('### end subtest debug ###')
+                self._debugged_in_subtest = False
+
+    def debug(self, msg, *, header=None):
+        if header:
+            self._debug(f'--- {header} ---')
+            if msg:
+                if msg.endswith(os.linesep):
+                    self._debug(msg[:-len(os.linesep)])
+                else:
+                    self._debug(msg)
+                    self._debug('<no newline>')
+            self._debug('------')
+        else:
+            self._debug(msg)
+
+    _debugged = False
+    _debugged_in_subtest = False
+    def _debug(self, msg):
+        if not self._debugged:
+            print()
+            self._debugged = True
+        if self._subtest is not None:
+            if True:
+                if not self._debugged_in_subtest:
+                    self._debugged_in_subtest = True
+                    print('### start subtest debug ###')
+                print(msg)
+        else:
+            print(msg)
+
+    def create_temp_dir(self):
+        import tempfile
+        tmp = tempfile.mkdtemp(prefix='test_interpreters_')
+        tmp = os.path.realpath(tmp)
+        self.addCleanup(os_helper.rmtree, tmp)
+        return tmp
+
+    def write_script(self, *path, text):
+        filename = os.path.join(*path)
+        dirname = os.path.dirname(filename)
+        if dirname:
+            os.makedirs(dirname, exist_ok=True)
+        with open(filename, 'w', encoding='utf-8') as outfile:
+            outfile.write(dedent(text))
+        return filename
+
+    @support.requires_subprocess()
+    def run_python(self, argv, *, cwd=None):
+        # This method is inspired by
+        # EmbeddingTestsMixin.run_embedded_interpreter() in test_embed.py.
+        import shlex
+        import subprocess
+        if isinstance(argv, str):
+            argv = shlex.split(argv)
+        argv = [sys.executable, *argv]
+        try:
+            proc = subprocess.run(
+                argv,
+                cwd=cwd,
+                capture_output=True,
+                text=True,
+            )
+        except Exception as exc:
+            self.debug(f'# cmd: {shlex.join(argv)}')
+            if isinstance(exc, FileNotFoundError) and not exc.filename:
+                if os.path.exists(argv[0]):
+                    exists = 'exists'
+                else:
+                    exists = 'does not exist'
+                self.debug(f'{argv[0]} {exists}')
+            raise  # re-raise
+        assert proc.stderr == '' or proc.returncode != 0, proc.stderr
+        if proc.returncode != 0 and support.verbose:
+            self.debug(f'# python3 {shlex.join(argv[1:])} failed:')
+            self.debug(proc.stdout, header='stdout')
+            self.debug(proc.stderr, header='stderr')
+        self.assertEqual(proc.returncode, 0)
+        self.assertEqual(proc.stderr, '')
+        return proc.stdout
+
+    def test_sys_path_0(self):
+        # The main interpreter's sys.path[0] should be used by subinterpreters.
+        script = '''
+            import sys
+            from test.support import interpreters
+
+            orig = sys.path[0]
+
+            interp = interpreters.create()
+            interp.exec_sync(f"""if True:
+                import json
+                import sys
+                print(json.dumps({{
+                    'main': {orig!r},
+                    'sub': sys.path[0],
+                }}, indent=4), flush=True)
+                """)
+            '''
+        # <tmp>/
+        #   pkg/
+        #     __init__.py
+        #     __main__.py
+        #     script.py
+        #   script.py
+        cwd = self.create_temp_dir()
+        self.write_script(cwd, 'pkg', '__init__.py', text='')
+        self.write_script(cwd, 'pkg', '__main__.py', text=script)
+        self.write_script(cwd, 'pkg', 'script.py', text=script)
+        self.write_script(cwd, 'script.py', text=script)
+
+        cases = [
+            ('script.py', cwd),
+            ('-m script', cwd),
+            ('-m pkg', cwd),
+            ('-m pkg.script', cwd),
+            ('-c "import script"', ''),
+        ]
+        for argv, expected in cases:
+            with self.subTest(f'python3 {argv}'):
+                out = self.run_python(argv, cwd=cwd)
+                data = json.loads(out)
+                sp0_main, sp0_sub = data['main'], data['sub']
+                self.assertEqual(sp0_sub, sp0_main)
+                self.assertEqual(sp0_sub, expected)
+        # XXX Also check them all with the -P cmdline flag?
+
+
+class FinalizationTests(TestBase):
+
+    def test_gh_109793(self):
+        # Make sure finalization finishes and the correct error code
+        # is reported, even when subinterpreters get cleaned up at the end.
+        import subprocess
+        argv = [sys.executable, '-c', '''if True:
+            from test.support import interpreters
+            interp = interpreters.create()
+            raise Exception
+            ''']
+        proc = subprocess.run(argv, capture_output=True, text=True)
+        self.assertIn('Traceback', proc.stderr)
+        if proc.returncode == 0 and support.verbose:
+            print()
+            print("--- cmd unexpected succeeded ---")
+            print(f"stdout:\n{proc.stdout}")
+            print(f"stderr:\n{proc.stderr}")
+            print("------")
+        self.assertEqual(proc.returncode, 1)
+
+
+if __name__ == '__main__':
+    # Test needs to be a package, so we can do relative imports.
+    unittest.main()