it is created/modified by PLY, the library that is used internally
for language parsing.
flanker is likewise using PLY:
> grep -r 'ply'
> addresslib/_parser/parser.py: import ply.yacc as yacc
> addresslib/_parser/lexer.py: import ply.lex as lex
> addresslib/address.py: from ply.lex import LexError
> addresslib/address.py: from ply.yacc import YaccError
This file is updated automatically if you're using a different
version of the library than the one with which the file was created
originally.
This seems to confirm that for each version of the package, these files
should be generated from debian/rules at build time.
Another possible approach (not ideal) would be to save the generated
files under /var/lib/python3-flanker. However, that approach would
require maintaining a patch to save/load the generated files from that
location. Also, most sysadmins would not expect Python files (or
executable files in general) to be under /var. On my system, the only
Python or executable files under /var are for dpkg, docker, and snap.
However, as long as a particular version of flanker generates a
consistent set of files, there is no need to generate at run time, and
much better to generate at build time and package.
However, even if it fails to update it, it should still be working.
In the case of python3-flanker, the package does not work until the file
is generated. Generating the files (correctly) fails due to lack of
permissions.
