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Merge pull request #13213 from Kojoley/fix-bunch-of-doctests...
Merge pull request #13213 from Kojoley/fix-bunch-of-doctests Fix bunch of doctests

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Async helper function that are invalid syntax on Python 3.5 and below.
This code is best effort, and may have edge cases not behaving as expected. In
particular it contain a number of heuristics to detect whether code is
effectively async and need to run in an event loop or not.
Some constructs (like top-level `return`, or `yield`) are taken care of
explicitly to actually raise a SyntaxError and stay as close as possible to
Python semantics.
import ast
import sys
import inspect
from textwrap import dedent, indent
class _AsyncIORunner:
def __call__(self, coro):
Handler for asyncio autoawait
import asyncio
return asyncio.get_event_loop().run_until_complete(coro)
def __str__(self):
return 'asyncio'
_asyncio_runner = _AsyncIORunner()
def _curio_runner(coroutine):
handler for curio autoawait
import curio
return curio.run(coroutine)
def _trio_runner(async_fn):
import trio
async def loc(coro):
We need the dummy no-op async def to protect from
trio's internal. See https://github.com/python-trio/trio/issues/89
return await coro
return trio.run(loc, async_fn)
def _pseudo_sync_runner(coro):
A runner that does not really allow async execution, and just advance the coroutine.
See discussion in https://github.com/python-trio/trio/issues/608,
Credit to Nathaniel Smith
except StopIteration as exc:
return exc.value
# TODO: do not raise but return an execution result with the right info.
raise RuntimeError(
"{coro_name!r} needs a real async loop".format(coro_name=coro.__name__)
def _asyncify(code: str) -> str:
"""wrap code in async def definition.
And setup a bit of context to run it later.
res = dedent(
async def __wrapper__():
).format(usercode=indent(code, " " * 8))
return res
class _AsyncSyntaxErrorVisitor(ast.NodeVisitor):
Find syntax errors that would be an error in an async repl, but because
the implementation involves wrapping the repl in an async function, it
is erroneously allowed (e.g. yield or return at the top level)
def __init__(self):
if sys.version_info >= (3,8):
raise ValueError('DEPRECATED in Python 3.8+')
self.depth = 0
def generic_visit(self, node):
func_types = (ast.FunctionDef, ast.AsyncFunctionDef)
invalid_types_by_depth = {
0: (ast.Return, ast.Yield, ast.YieldFrom),
1: (ast.Nonlocal,)
should_traverse = self.depth < max(invalid_types_by_depth.keys())
if isinstance(node, func_types) and should_traverse:
self.depth += 1
self.depth -= 1
elif isinstance(node, invalid_types_by_depth[self.depth]):
raise SyntaxError()
def _async_parse_cell(cell: str) -> ast.AST:
This is a compatibility shim for pre-3.7 when async outside of a function
is a syntax error at the parse stage.
It will return an abstract syntax tree parsed as if async and await outside
of a function were not a syntax error.
if sys.version_info < (3, 7):
# Prior to 3.7 you need to asyncify before parse
wrapped_parse_tree = ast.parse(_asyncify(cell))
return wrapped_parse_tree.body[0].body[0]
return ast.parse(cell)
def _should_be_async(cell: str) -> bool:
"""Detect if a block of code need to be wrapped in an `async def`
Attempt to parse the block of code, it it compile we're fine.
Otherwise we wrap if and try to compile.
If it works, assume it should be async. Otherwise Return False.
Not handled yet: If the block of code has a return statement as the top
level, it will be seen as async. This is a know limitation.
if sys.version_info > (3, 8):
code = compile(cell, "<>", "exec", flags=getattr(ast,'PyCF_ALLOW_TOP_LEVEL_AWAIT', 0x0))
return inspect.CO_COROUTINE & code.co_flags == inspect.CO_COROUTINE
except (SyntaxError, MemoryError):
return False
# we can't limit ourself to ast.parse, as it __accepts__ to parse on
# 3.7+, but just does not _compile_
code = compile(cell, "<>", "exec")
except (SyntaxError, MemoryError):
parse_tree = _async_parse_cell(cell)
# Raise a SyntaxError if there are top-level return or yields
v = _AsyncSyntaxErrorVisitor()
except (SyntaxError, MemoryError):
return False
return True
return False