PythonCharmers/python-future

ParseError when trying to translate a module

Open

#353 opened on Aug 13, 2018

View on GitHub
 (0 comments) (0 reactions) (0 assignees)Python (1,172 stars) (327 forks)batch import
0.22bughelp wanted

Description

Using past to load a Python2 library, as:

from past import autotranslate
autotranslate(['chrono'])
import chrono

After installing it:

pip install git+git://github.com/wanasit/chrono-python.git

Throws this error:

Traceback (most recent call last): File "/Users/admin/dev/deep-grammar/utils/delex.py", line 5, in import chrono File "", line 971, in _find_and_load File "", line 955, in _find_and_load_unlocked File "", line 656, in _load_unlocked File "", line 626, in _load_backward_compatible File "/anaconda3/envs/deep-grammar/lib/python3.6/site-packages/past/translation/init.py", line 413, in load_module exec(code, mod.dict) File "/anaconda3/envs/deep-grammar/lib/python3.6/lib2to3/fixes/fix_itertools.py", line 1, in """ Fixer for itertools.(imap|ifilter|izip) --> (map|filter|zip) and File "", line 971, in _find_and_load File "", line 955, in _find_and_load_unlocked File "", line 656, in _load_unlocked File "", line 626, in _load_backward_compatible File "/anaconda3/envs/deep-grammar/lib/python3.6/site-packages/past/translation/init.py", line 413, in load_module exec(code, mod.dict) File "/anaconda3/envs/deep-grammar/lib/python3.6/site-packages/chrono/Chrono.py", line 8, in from parsed_result import ParsedResult File "", line 971, in _find_and_load File "", line 955, in _find_and_load_unlocked File "", line 656, in _load_unlocked File "", line 626, in _load_backward_compatible File "/anaconda3/envs/deep-grammar/lib/python3.6/site-packages/past/translation/init.py", line 413, in load_module exec(code, mod.dict) File "/anaconda3/envs/deep-grammar/lib/python3.6/site-packages/chrono/options.py", line 7, in from parsers.en import ENMonthNameMiddleEndianParser File "", line 971, in _find_and_load File "", line 955, in _find_and_load_unlocked File "", line 656, in _load_unlocked File "", line 626, in _load_backward_compatible File "/anaconda3/envs/deep-grammar/lib/python3.6/site-packages/past/translation/init.py", line 396, in load_module if detect_python2(source, self.pathname): File "/anaconda3/envs/deep-grammar/lib/python3.6/site-packages/past/translation/init.py", line 213, in detect_python2 tree = RTs._rt_py2_detect.refactor_string(source, pathname) File "/anaconda3/envs/deep-grammar/lib/python3.6/lib2to3/refactor.py", line 377, in refactor_string name, err.class.name, err) File "/anaconda3/envs/deep-grammar/lib/python3.6/lib2to3/refactor.py", line 374, in refactor_string tree = self.driver.parse_string(data) File "/anaconda3/envs/deep-grammar/lib/python3.6/lib2to3/pgen2/driver.py", line 107, in parse_string return self.parse_tokens(tokens, debug) File "/anaconda3/envs/deep-grammar/lib/python3.6/lib2to3/pgen2/driver.py", line 72, in parse_tokens if p.addtoken(type, value, (prefix, start)): File "/anaconda3/envs/deep-grammar/lib/python3.6/lib2to3/pgen2/parse.py", line 159, in addtoken raise ParseError("bad input", type, value, context) lib2to3.pgen2.parse.ParseError: bad input: type=0, value='', context=('\n', (7, 0))

Contributor guide

Tech stack
python
Domain
backenddeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
understanding of lib2to3familiarity with python future
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
The issue is a ParseError in lib2to3 when using past.translation. The error occurs in fix itertools.py. The root cause may be a parsing issue with empty lines or syntax that lib2to3 cannot handle. To investigate, look at the translation code in past/translation/ init .py around line 213 and 396. Also examine the chrono python library's source to understand what triggers the error. Possibly a fix could involve handling the ParseError or adjusting the fixer.