Python 3.10: required field "lineno" missing from alias

[tianon]

Python 3.10 has introduced a change that breaks Hy (feeling like a case of "This Is The Way" with Python pre-releases ).

It seems to be related to https://bugs.python.org/issue43798 (some potentially useful discussion in pytest-dev/pytest#8539).

Here's the full backtrace (on latest master; specifically e1150cf):

$ python --version
Python 3.10.0b1
$ hy
Traceback (most recent call last):
  File "/opt/hylang/hy/hy/compiler.py", line 1648, in compile_eval_and_compile
    hy_eval(new_expr + body,
  File "/opt/hylang/hy/hy/compiler.py", line 1977, in hy_eval
    eval(ast_compile(_ast, filename, "exec"),
  File "/opt/hylang/hy/hy/compiler.py", line 62, in ast_compile
    return compile(a, filename, mode, hy_ast_compile_flags)
TypeError: required field "lineno" missing from alias

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/bin/hy", line 8, in <module>
    from hy.cmdline import hy_main
  File "/opt/hylang/hy/hy/__init__.py", line 14, in <module>
    hy.importer._inject_builtins()
  File "/opt/hylang/hy/hy/importer.py", line 178, in _inject_builtins
    core = importlib.import_module('hy.core')
  File "/usr/local/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/opt/hylang/hy/hy/core/__init__.py", line 1, in <module>
    from .shadow import *
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 879, in exec_module
  File "<frozen importlib._bootstrap_external>", line 1017, in get_code
  File "/opt/hylang/hy/hy/importer.py", line 130, in _hy_source_to_code
    data = hy_compile(hy_tree, module)
  File "/opt/hylang/hy/hy/compiler.py", line 2066, in hy_compile
    stdlib_ast = compiler.compile(mkexpr("eval-and-compile", mkexpr("import", "hy")))
  File "/opt/hylang/hy/hy/compiler.py", line 379, in compile
    raise e
  File "/opt/hylang/hy/hy/compiler.py", line 370, in compile
    ret = self.compile_atom(tree)
  File "/opt/hylang/hy/hy/compiler.py", line 364, in compile_atom
    return Result() + _model_compilers[type(atom)](self, atom)
  File "/opt/hylang/hy/hy/compiler.py", line 1730, in compile_expression
    return Result() + build_method(
  File "/opt/hylang/hy/hy/compiler.py", line 1665, in compile_eval_and_compile
    raise HyEvalError(str(e), self.filename, body, self.source)
hy.errors.HyEvalError: 
  File "[hy.models.Expression([
  hy.models.Symbol('import'),
  hy.models.Symbol('hy')])]", line 1
    ;; Copyright 2021 the authors.
    ^----------------------------^
required field "lineno" missing from alias

(I'm testing with the Dockerfile here in the repo by changing python:3 to python:3.10-rc, but any way of getting a recent Python 3.10 pre-release should reproduce similarly.)

[Kodiologist]

Unfortunately, Travis is still using 3.10.0a5 for 3.10, so it will be a while before we'll be able to test this regularly. Thanks for the heads-up.

[tianon]

Yeah, I figured that was the case, but wanted to make sure it was filed and on the radar (with a central place to track it). 👍 ❤️

(Any appetite for switching to GitHub Actions? 😅)

[Kodiologist]

If you mean that GitHub Actions can be used for testing, in place of Travis, then I'm not aware of that.