Proposal: Exclude generated files from code repository

[iperdomo]

Context

The project used Xtend to generate Java source code. Those files under *xtend-gen* folders are almost always modified.
After fresh clone and compilation you get 68 modified files without any other intervention:

git status | grep -E '.*modified:.*xtend-gen*.*\.java$' | wc -l
68

The modifications are a full rewrite of the files, e.g.

git diff kim/org.integratedmodelling.kim/xtend-gen/org/integratedmodelling/kim/validation/KimValidator.java | diffstat
 KimValidator.java | 6180 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----------------------------------------------------------------------------------
 1 file changed, 3090 insertions(+), 3090 deletions(-)

Proposal

Since those are generated files, they shouldn't be tracked and part of the code repository.

• Remove those files from source code
• Include xtend-gen folders to .gitignore

[iperdomo]

@fvilla feedback, more than welcome.

[fvilla]

We have intentionally left these - it's clearly bad practice, but we have several users who work from a code installation so that they can pick up updates, do some limited debugging and check out the logs from a closer perspective, report exception stack traces and the like. Unfortunately regenerating the languages whenever the grammar has changed is much above their understanding. Not sure what we should do, but so far it's worked out well this way. When we had the "proper" repository structure it was a constant nightmare telling people how to do that.