Error when trying to install with Python 2 pip is really bad

[rwbarton]

I accidentally ran pip install typed_ast using Python 2 and got these errors:

[many more errors from gcc skipped]

ast27/Parser/tokenizer.c:512:45: error: ‘PyId_readline’ undeclared (first use in this function)

     readline = _PyObject_GetAttrId(stream, &PyId_readline);

                                             ^

error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

----------------------------------------
Cleaning up...
Command /usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-uAt4J4/typed-ast/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-oRixWl-record/install-record.txt --single-version-externally-managed --compile failed with error code 1 in /tmp/pip-build-uAt4J4/typed-ast
Traceback (most recent call last):
  File "/usr/bin/pip", line 9, in <module>
    load_entry_point('pip==1.5.6', 'console_scripts', 'pip')()
  File "/usr/lib/python2.7/dist-packages/pip/__init__.py", line 248, in main
    return command.main(cmd_args)
  File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 161, in main
    text = '\n'.join(complete_log)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 41: ordinal not in range(128)

Surely the terrible final error message is not typed_ast's fault, but can the package just be marked as Python 3-only on PyPI somehow?

[ddfisher]

It doesn't look like that's possible as far as I can tell, but I can check the Python version at the top of setup.py and give a better error, at least.