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[3.14] gh-132775: Fix Interpreter.call() __main__ Visibility (gh-135638)
As noted in the new tests, there are a few situations we must carefully accommodate for functions that get pickled during interp.call(). We do so by running the script from the main interpreter's __main__ module in a hidden module in the other interpreter. That hidden module is used as the function __globals__. (cherry picked from commit 269e19e, AKA gh-135595) Co-authored-by: Eric Snow <[email protected]>
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‎Lib/test/test_interpreters/test_api.py

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@@ -1356,6 +1356,187 @@ def {funcname}():
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with self.assertRaises(interpreters.NotShareableError):
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interp.call(defs.spam_returns_arg, arg)
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def test_func_in___main___hidden(self):
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# When a top-level function that uses global variables is called
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# through Interpreter.call(), it will be pickled, sent over,
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# and unpickled. That requires that it be found in the other
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# interpreter's __main__ module. However, the original script
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# that defined the function is only run in the main interpreter,
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# so pickle.loads() would normally fail.
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#
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# We work around this by running the script in the other
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# interpreter. However, this is a one-off solution for the sake
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# of unpickling, so we avoid modifying that interpreter's
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# __main__ module by running the script in a hidden module.
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#
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# In this test we verify that the function runs with the hidden
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# module as its __globals__ when called in the other interpreter,
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# and that the interpreter's __main__ module is unaffected.
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text = dedent("""
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eggs = True
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def spam(*, explicit=False):
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if explicit:
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import __main__
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ns = __main__.__dict__
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else:
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# For now we have to have a LOAD_GLOBAL in the
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# function in order for globals() to actually return
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# spam.__globals__. Maybe it doesn't go through pickle?
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# XXX We will fix this later.
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spam
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ns = globals()
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func = ns.get('spam')
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return [
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id(ns),
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ns.get('__name__'),
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ns.get('__file__'),
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id(func),
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None if func is None else repr(func),
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ns.get('eggs'),
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ns.get('ham'),
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]
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if __name__ == "__main__":
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from concurrent import interpreters
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interp = interpreters.create()
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ham = True
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print([
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[
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spam(explicit=True),
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spam(),
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],
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[
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interp.call(spam, explicit=True),
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interp.call(spam),
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],
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])
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""")
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with os_helper.temp_dir() as tempdir:
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filename = script_helper.make_script(tempdir, 'my-script', text)
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res = script_helper.assert_python_ok(filename)
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stdout = res.out.decode('utf-8').strip()
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local, remote = eval(stdout)
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# In the main interpreter.
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main, unpickled = local
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nsid, _, _, funcid, func, _, _ = main
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self.assertEqual(main, [
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nsid,
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'__main__',
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filename,
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funcid,
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func,
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True,
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True,
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])
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self.assertIsNot(func, None)
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self.assertRegex(func, '^<function spam at 0x.*>$')
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self.assertEqual(unpickled, main)
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# In the subinterpreter.
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main, unpickled = remote
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nsid1, _, _, funcid1, _, _, _ = main
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self.assertEqual(main, [
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nsid1,
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'__main__',
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None,
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funcid1,
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None,
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None,
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None,
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])
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nsid2, _, _, funcid2, func, _, _ = unpickled
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self.assertEqual(unpickled, [
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nsid2,
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'<fake __main__>',
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filename,
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funcid2,
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func,
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True,
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None,
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])
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self.assertIsNot(func, None)
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self.assertRegex(func, '^<function spam at 0x.*>$')
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self.assertNotEqual(nsid2, nsid1)
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self.assertNotEqual(funcid2, funcid1)
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def test_func_in___main___uses_globals(self):
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# See the note in test_func_in___main___hidden about pickle
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# and the __main__ module.
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#
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# Additionally, the solution to that problem must provide
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# for global variables on which a pickled function might rely.
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#
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# To check that, we run a script that has two global functions
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# and a global variable in the __main__ module. One of the
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# functions sets the global variable and the other returns
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# the value.
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#
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# The script calls those functions multiple times in another
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# interpreter, to verify the following:
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#
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# * the global variable is properly initialized
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# * the global variable retains state between calls
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# * the setter modifies that persistent variable
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# * the getter uses the variable
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# * the calls in the other interpreter do not modify
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# the main interpreter
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# * those calls don't modify the interpreter's __main__ module
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# * the functions and variable do not actually show up in the
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# other interpreter's __main__ module
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text = dedent("""
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count = 0
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def inc(x=1):
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global count
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count += x
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def get_count():
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return count
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if __name__ == "__main__":
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counts = []
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results = [count, counts]
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from concurrent import interpreters
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interp = interpreters.create()
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val = interp.call(get_count)
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counts.append(val)
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interp.call(inc)
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val = interp.call(get_count)
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counts.append(val)
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interp.call(inc, 3)
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val = interp.call(get_count)
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counts.append(val)
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results.append(count)
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modified = {name: interp.call(eval, f'{name!r} in vars()')
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for name in ('count', 'inc', 'get_count')}
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results.append(modified)
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print(results)
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""")
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with os_helper.temp_dir() as tempdir:
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filename = script_helper.make_script(tempdir, 'my-script', text)
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res = script_helper.assert_python_ok(filename)
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stdout = res.out.decode('utf-8').strip()
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before, counts, after, modified = eval(stdout)
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self.assertEqual(modified, {
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'count': False,
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'inc': False,
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'get_count': False,
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})
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self.assertEqual(before, 0)
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self.assertEqual(after, 0)
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self.assertEqual(counts, [0, 1, 4])
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def test_raises(self):
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interp = interpreters.create()
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with self.assertRaises(ExecutionFailed):

‎Modules/_interpretersmodule.c

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Original file line numberDiff line numberDiff line change
@@ -601,6 +601,7 @@ _make_call(struct interp_call *call,
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unwrap_not_shareable(tstate, failure);
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return -1;
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}
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assert(!_PyErr_Occurred(tstate));
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// Make the call.
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PyObject *resobj = PyObject_Call(func, args, kwargs);

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