writer/init.py: Fix UnboundLocalError
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Authored by anlambert on Jan 6 2020, 3:39 PM.

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olasd

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rDJNLace4bacb5d63: writer/__init__.py: Fix UnboundLocalError

Summary

I noticed docker tests were failing since a couple of days
(see https://jenkins.softwareheritage.org/view/all/job/swh-docker-dev/286/ for instance).

This is due to the following error being raised since a9fb7c733a4f:

;1mswh-storage_1                   | Traceback (most recent call last):
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/flask/app.py", line 1949, in full_dispatch_request
;1mswh-storage_1                   |     rv = self.dispatch_request()
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/flask/app.py", line 1935, in dispatch_request
;1mswh-storage_1                   |     return self.view_functions[rule.endpoint](**req.view_args)
;1mswh-storage_1                   |   File "</srv/softwareheritage/venv/lib/python3.7/site-packages/decorator.py:decorator-gen-100>", line 2, in origin_add_one
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/core/api/negotiation.py", line 144, in _negotiate
;1mswh-storage_1                   |     return f.negotiator(*args, **kwargs)
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/core/api/negotiation.py", line 79, in __call__
;1mswh-storage_1                   |     result = self.func(*args, **kwargs)
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/core/api/__init__.py", line 374, in _f
;1mswh-storage_1                   |     obj_meth = getattr(backend_factory(), meth_name)
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/storage/api/server.py", line 22, in get_storage
;1mswh-storage_1                   |     storage = get_swhstorage(**app.config['storage'])
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/storage/__init__.py", line 62, in get_storage
;1mswh-storage_1                   |     return Storage(**kwargs)
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/storage/storage.py", line 76, in __init__
;1mswh-storage_1                   |     self.journal_writer = get_journal_writer(**journal_writer)
;1mswh-storage_1                   |   File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/journal/writer/__init__.py", line 11, in get_journal_writer
;1mswh-storage_1                   |     warnings.warn(
;1mswh-storage_1                   | UnboundLocalError: local variable 'warnings' referenced before assignment

This simple diff fixes the issue but I do not really understand why we get such an error though.

Diff Detail

Repository

rDJNL Journal infrastructure

Branch

fix-unboundlocalerror

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Unit

No Unit Test Coverage

Build Status

Buildable 9972
Build 14739: tox-on-jenkins	Jenkins
Build 14738: arc lint + arc unit

Event Timeline

anlambert created this revision.Jan 6 2020, 3:39 PM

Herald added a reviewer: Reviewers. · View Herald TranscriptJan 6 2020, 3:39 PM

Build is green
See https://jenkins.softwareheritage.org/job/DJNL/job/tox/318/ for more details.

Harbormaster completed remote builds in B9968: Diff 8872.Jan 6 2020, 3:42 PM

This is plain Python AST stupid^Wbehavior:

when the code is parsed by the compiler, the compiler notices that the warnings variable is created by the import statement on line 17; warnings is therefore set as a local variable to the get_journal_writer function
when the code is run, line 10 accesses the warnings variable, which hasn't been bound yet within the function, even though it exists globally. This raises an UnboundLocalError.

Removing the extra import should fix the issue.