python can delete - Automatically deleting pyc files when corresponding py is moved (Mercurial)

4 Answers

  1. Do not store .pyc files in the repository.
  2. Automatize .pyc delete with: find . -name '*.pyc' -delete
  3. While develop use -B argument in Python.
windows remove

(I foresaw this problem might happen 3 months ago, and was told to be diligent to avoid it. Yesterday, I was bitten by it, hard, and now that it has cost me real money, I am keen to fix it.)

If I move one of my Python source files into another directory, I need to remember to tell Mercurial that it moved (hg move).

When I deploy the new software to my server with Mercurial, it carefully deletes the old Python file and creates it in the new directory.

However, Mercurial is unaware of the pyc file in the same directory, and leaves it behind. The old pyc is used preferentially over new python file by other modules in the same directory.

What ensues is NOT hilarity.

How can I persuade Mercurial to automatically delete my old pyc file when I move the python file? Is there another better practice? Trying to remember to delete the pyc file from all the Mercurial repositories isn't working.

You need:

1) A real deployment infrastructure, even if it's just a shell script, which does everything. Cloning/checking out an updated copy from source control is not a deployment strategy.

2) Any deployment system should completely clean the directory structure. My usual preference is that each deployment happens to a new directory named with a date+timestamp, and a symlink (with a name like "current") is updated to point to the new directory. This gives you breadcrumbs on each server should something go wrong.

3) To fix whatever is running the Python code. New .py source files should always take precedence over cached .pyc files. If that is not the behavior you are seeing, it is a bug, and you need to figure out why it is happening.

Here's a unix one-liner that will delete .pyc files each time you run hg update.

Add this to your hgrc file:

preupdate.cleanpyc = hg status --no-status --removed --deleted --include "**.py" --rev .:$HG_PARENT1 --print0 | xargs -0 -I '{}' rm -f '{}c'

This runs just prior to update, and gets all .py files which will be removed or deleted when the update is performed, and then deletes corresponding .pyc files.

Here's a quick breakdown of how it works:

hg status --no-status --removed --deleted --include "**.py" --rev .:$HG_PARENT1

This gets all files removed (e.g. hg forget) or deleted (hg rm, hg mv, etc) between the current revision . and the destination ($HG_PARENT). You could add --subrepos to get all changes in sub-repositories as well if you use that feature.

xargs -0 -I '{}' rm -f '{}c'

This simply adds a 'c' to the end of each file name returned from hg status and tries to delete it. The -f flag for rm ensures that it doesn't error if the .pyc file does not exist.

Note that mercurial automatically deletes empty directories after an update, but orphaned .pyc files often cause directories to be left around. Since this runs before update, it ensure that empty directories are properly deleted.

i use this script to delete the .pyc files in the current folder, this script could be used alone or include it in the exit function to delete the .pyc files when u exit.

import os
files = [f for f in os.listdir('.') if os.path.isfile(f) and '.pyc' in str(f)]
for f in files : os.unlink(os.getcwd()+'/'+f)