Issue 35202: Remove unused imports in standard library

Please find the modules where we need to remove.


codecs.py:1105:5: F401 'encodings' imported but unused
code.py:298:13: F401 'readline' imported but unused
platform.py:118:1: F401 'warnings' imported but unused
platform.py:509:9: F401 'java.lang' imported but unused
pstats.py:562:9: F401 'readline' imported but unused
shutil.py:13:1: F401 'io' imported but unused
site.py:409:13: F401 'rlcompleter' imported but unused
site.py:511:13: F401 'sitecustomize' imported but unused
site.py:531:13: F401 'usercustomize' imported but unused
trace.py:54:1: F401 're' imported but unused
typing.py:21:1: F401 'abc' imported but unused


I was just wondering that as a community, do we recommend this practice of cleaning up Or just we keep as is inorder to NOT to break accidental imports?

I have raised a partial PR  here  - https://github.com/python/cpython/pull/10438;  if it is merged please take up the rest of the changes mentioned in the issue description.

I think we can remove these in 3.8. My understanding of the policy (which I cannot find: the search terms are too generic) is that if a module defines __all__, and the symbol we want to remove isn't in it, then we can remove the symbol in the next feature release without requiring a deprecation period.

If a module doesn't define __all__, then we need a deprecation period in order to remove a symbol, unless the symbol is a module, and then we can just remove it in the next feature release.

Let me restate that: I think we can remove these in 3.8 if they're not in the module's __all__. I haven't checked that, although it would surprise me if any of them were in __all__.

There's a few that should be discussed with the module maintainers first.  A patch for IDLE should go through Terry Reedy.  The "java.lang" in platform isn't a normal import and may have something to do with Jython.  The "abc" in typing.py might be there for a reason, so ask Guido before zapping it.  It's also possible that "encodings" might be in codecs for a reason as well, but I'm not sure who you should check with. 

I'm not sure about readline, rlcompleter, sitecustomize, and usercustomize. I think think those imports may be there for their side-effects.  Just importing them may suffice to enable some behavior, so be careful with these.

New changeset 43a74abb3a87092a7fd6c71042eafb977d70d8e0 by Terry Jan Reedy (Srinivas  Thatiparthy (శ్రీనివాస్  తాటిపర్తి)) in branch 'master':
bpo-35202: Remove unused imports in idlelib (GH-10438)
https://github.com/python/cpython/commit/43a74abb3a87092a7fd6c71042eafb977d70d8e0

New changeset 2847ccae4687cb43334d87d86fb6c11cb14218f5 by Miss Islington (bot) in branch '3.7':
bpo-35202: Remove unused imports in idlelib (GH-10438)
https://github.com/python/cpython/commit/2847ccae4687cb43334d87d86fb6c11cb14218f5

New changeset 2903b0fd38a65e16ddafae7754ed5d605fea68ff by Miss Islington (bot) in branch '3.6':
bpo-35202: Remove unused imports in idlelib (GH-10438)
https://github.com/python/cpython/commit/2903b0fd38a65e16ddafae7754ed5d605fea68ff

Srinivas, if you thing the issue is finished, please close it.  Otherwise say something about what is left to do.

I have raised one more PR; I think i am done with this issue. People who are interested can take up from here. ,

For the record, following are some filters to search;

Query to find unused imports
----------------------------------

find . -type f -name \*.py -print  | xargs flake8 | grep F401
----------------------------------

Search query 
------------------------------------
grep -v warnings | grep -v "\.\*" | grep -v tkinter | grep -v sysconfig | grep -v readline | grep -v py3_test_grammar.py  | grep -v java | grep -v rlcompleter | grep -v sitecustomize | grep -v __all__ | grep -v test_importlib | grep -v async | grep -v test_future | grep -v circular_import | grep -v dataclasses
------------------------------------

With the current PR, i think i removed all unused imports in Lib folder.

New changeset 3a600d224c1e1106756cc71639232ae1acae45bd by Miss Islington (bot) in branch '3.7':
bpo-35202: Remove more unused imports in idlelib (GH-10573)
https://github.com/python/cpython/commit/3a600d224c1e1106756cc71639232ae1acae45bd

New changeset 8d816f74d7673c836b16e4423fed0ec6ee510290 by Miss Islington (bot) in branch '3.6':
bpo-35202: Remove more unused imports in idlelib (GH-10573)
https://github.com/python/cpython/commit/8d816f74d7673c836b16e4423fed0ec6ee510290

Thank you for the cleanup.

stage: patch review -> resolved

messages: + msg329563
versions: + Python 3.8