[New-bugs-announce] [issue38735] PYTHONPYCACHEPREFIX fails when importing a module from the root ("/")

[Ned Batchelder]

New submission from Ned Batchelder <ned at nedbatchelder.com>:

On the manylinux docker images, the current directory is "/".

If I create a file there and try to import it with PYTHONPYCACHEPREFIX set, I get a stack trace:

$ docker run -it --init --rm -v `pwd`:/io quay.io/pypa/manylinux1_x86_64 bash
[root at 29d75403d7d1 /]# cat > foo.py
a = 1
[root at 29d75403d7d1 /]# /opt/python/cp38-cp38/bin/python
Python 3.8.0 (default, Oct 30 2019, 22:13:22)
[GCC 4.8.2 20140120 (Red Hat 4.8.2-15)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import foo
>>> foo.a
1
>>>
[root at 29d75403d7d1 /]# PYTHONPYCACHEPREFIX=/opt/pyc /opt/python/cp38-cp38/bin/python
Python 3.8.0 (default, Oct 30 2019, 22:13:22)
[GCC 4.8.2 20140120 (Red Hat 4.8.2-15)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import foo
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 657, in _load_unlocked
  File "<frozen importlib._bootstrap>", line 562, in module_from_spec
  File "<frozen importlib._bootstrap>", line 541, in _init_module_attrs
  File "<frozen importlib._bootstrap>", line 382, in cached
  File "<frozen importlib._bootstrap_external>", line 427, in _get_cached
  File "<frozen importlib._bootstrap_external>", line 352, in cache_from_source
IndexError: string index out of range
>>>

----------
messages: 356188
nosy: nedbat
priority: normal
severity: normal
status: open
title: PYTHONPYCACHEPREFIX fails when importing a module from the root ("/")

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38735>
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