[rant] Code duplication

[klenze]

For a fun exercise, run
find . -iname \*.cxx | xargs cat | grep -v include | gcc -E - | sed 's/^[ \t]*//' | sort | uniq -cd | sort -h | less

Pick a nontrivial line with a high duplication count, such as

gGeoManager->SetCurrentDirection(newdirection);

(which appears 36 times in the code), then run an appropriate grep pipe like in

grep -C 10 -F "gGeoManager->SetCurrentDirection(newdirection);" -r * | less

Notice how virtually the same block of code appears 36 times in our project. (kudos to xball/R3BXBall.cxx, for being the only ones to remove the //TGeoNode *bla comment line.)

I am not a software designer, but from my perspective, this does not seem like code which can be maintained easily. If you copy a file, chances are that both versions will slowly diverge, resulting in twice as much legacy code.

For a perhaps more recent example, take the fibers. At the moment, we have 17 directories matching "fi[0-9]+[ab]?". At the top level, no less. Each contains a different Mapped2Cal.h class. In my opinion, this raises the question: "what is unique about the calibration process of fiber detector 7?" I am not a fiber person, so I don't know. If fi7 channels are calibrated using a pol2, while all the other fibers use pol1, then that might be a good reason to have separate calibration code for fi7. If it is just "it uses different collection names from fi6", that is not a good reason, IMHO.

OOP (and C++ in particular with TMP) offers powerful tools for abstraction.
If handling all the fiber detectors in one task/collection is not an option, why not use

template <int N, char suffix='\0' >
class R3BFiber
{ ...
};

That way, one still has the power to specialize when needed (if fi7 needs a pol2 calibration or whatever) without creating 17x as much legacy code.

Backup copies in the repository are another pet peeve of mine. Take califa/unpack/oldCode. We have git. At the most, a comment in the new version "rewrite, see bf5282e for old version" should be enough.

TL;DR: commit code like you had to pay per line added.

Just my 2 cents. Sorry for the rant and apologies to the detectors I singled out.

[kresan]

Looking forward for not only creating "ranting" issues, but for a reasonable technical solution of code duplication problem and a corresponding PR.

[hapol]

Perfectly agree with the removal of backup copies. Please, proceed to remove califa/unpack/oldCode

[jose-luis-rs]

I think that currently this problem is already solved.