[lit] Make lit stop writing .pyc files

[zturner]

Summary

This seems to be causing endless SVN tree conflicts on certain buildbots. I guess what's happening is that we run the test suite, and the test suite does import lit.llvm and that creates a .pyc file in the source tree. Then, svn gets confused when doing an update and refuses to update it because it thinks there's a conflict.

I don't know why this isn't happening for other lit folders (e.g. lit/formats), but it definitely seems to be the problem. I don't know of a better way to fix this then just disabling pyc generation, which I think this does the trick.

[zturner]

Sorry, ignore the inode changes, they are part of a different patch.

[zturner]

Removed code that belonged in another patch

[smeenai]

This seems fine as a workaround, though I'm curious about the root cause. Shouldn't there only be conflicts during an update if the update is bringing in pyc files of its own (i.e. if pyc files got committed to svn)?

[dlj]

Would it make more sense to set this as an SVN property?

http://svnbook.red-bean.com/nightly/en/svn.advanced.props.special.ignore.html

svn propset svn:global-ignores . '*.pyc'

(Or as svn:ignore on the lit directories)

[zturner]

In D38016#874699, @dlj wrote:

Would it make more sense to set this as an SVN property?

http://svnbook.red-bean.com/nightly/en/svn.advanced.props.special.ignore.html

svn propset svn:global-ignores . '*.pyc'

(Or as svn:ignore on the lit directories)

I actually did set svn:ignore on the lit directory and it didn't work. It's kind of hard diagnosing this kind of thing because I can't physically see it reproducing so all I can do is hit it with as big of a hammer as possible. I guess I can wait and see if it happens again on another bot the next time I check something in, and if so I can try to get one of the bot owners to help me investigate.

[dlj]

In D38016#874719, @zturner wrote:

In D38016#874699, @dlj wrote:

Would it make more sense to set this as an SVN property?

http://svnbook.red-bean.com/nightly/en/svn.advanced.props.special.ignore.html

svn propset svn:global-ignores . '*.pyc'

(Or as svn:ignore on the lit directories)

I actually did set svn:ignore on the lit directory and it didn't work. It's kind of hard diagnosing this kind of thing because I can't physically see it reproducing so all I can do is hit it with as big of a hammer as possible. I guess I can wait and see if it happens again on another bot the next time I check something in, and if so I can try to get one of the bot owners to help me investigate.

Yeah, that sounds pretty strange. Although it could be because svn:ignore doesn't inherit (as opposed to svn:global-ignores).

Either way, this seems OK.

[rnk]

Are you sure you can't reproduce this behavior by checking out the lit subtree with SVN before you deleted that directory, importing some .py files from that tree to create .pycs, and then doing svn up and checking if it creates a conflict? I'd really prefer to have an explanatory comment in here that says why we're setting this mysterious configuration.

I hate it when I trip over configuration tweaks that exist to work around problems that have been completely forgotten.

llvm/utils/lit/lit.py

 #!/usr/bin/env python
+import sys
+
+sys.dont_write_bytecode = True
 
 from lit.main import main
 
 if __name__=='__main__':
     main()

llvm/utils/llvm-lit/llvm-lit.in

 #!/usr/bin/env python
 
 import os
 import sys
 
+sys.dont_write_bytecode = True
+
 config_map = {}
 
 def map_config(source_dir, site_config):
     global config_map
     source_inode = os.stat(source_dir).st_ino
     site_config = os.path.normpath(site_config)
     config_map[source_inode] = site_config