I after with 2+3 but the first part isn't such trivial as it look on the first time. some thoughts to that issue:

Code should not contain debugging code lines except it is explicit made for debugging. This means such code lines should be removed before committing. Code testing should be done by the test suite.

In some cases when code parts of some option or methods or other behaviour is broken than these parts should be commented out during a pre-fix, monkey patch or q&d hack as 1st step, code because the history is accessible in a simple way with blame/annotate the code, otherwise these debugging hints are lost.

If the solution needs a long time the commented code may be remove if and only if that parts are kept track at bugzilla script for script.

I am strictly stains just deleting those comments except the fix could be done with it or the hidden code is trivial.

Regards
xqt

As a discussion we had in Hackathon today, we concluded there is a need for guideline for our codes (something like WP:MoS for codes)

there is already this but it's not for us and we can use it though

Some things I suggest to add to the guideline in the future:

1- Don't use commented out codes

2- use "bot" instead of "robot" in naming and documentation