# What are the best practices to handle local gem modification

**URL:** <https://www.ruby-forum.com/t/what-are-the-best-practices-to-handle-local-gem-modification/194416>\
**Category:** Ruby\
**Created:** [September 4, 2010, 5:59pm UTC](https://www.ruby-forum.com/t/what-are-the-best-practices-to-handle-local-gem-modification/194416 "2010-09-04T17:59:21Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![fourchette](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/ac91a4/32.png) [@fourchette](https://www.ruby-forum.com/u/fourchette)\
**Post date:** [September 4, 2010, 5:59pm UTC](https://www.ruby-forum.com/t/what-are-the-best-practices-to-handle-local-gem-modification/194416/1 "2010-09-04T17:59:21Z")

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hi there,

i hope i’m posting at the right place. i have the feeling that what i’m  
asking is a very frequent issue, but somewhat i have not been ale to ask  
it to google in the right way so i’m posting it here instead

basically, there’s this classifier gem that i want to use.  
it depends on fast-stemmer  
it works, i like it.

however, fast-stemmer may be fast, but it stems english words only. and  
basically i am trying to stem french text. So it is not really stemming  
it in the right way.

instead there’s this stemmer4r gem that actually supports french. The  
gem is aging, but it’s source code is clean, the author seems to be  
french and it support a large variety of european languages, so i  
figured i could maybe modify the classifier gem so that it uses  
stemmer4r instead of fast-stemmer.

after one hour or so, i got it up and running. My new hacked version of  
the classifier gem uses stemmer4r and works nicely with french text.

however, i know i am bound to face some issues in the near future if i  
do nothing else:

1. my hacked classifier gem resides in the gem directory, not in my  
working copy. so basically my modifications are NOT commited in my svn  
repository. it makes me feel very uncomfortable because if i checkout  
the repo on another machine, i will just have to make it all over again.  
a waste.

2. i had to hack stemmer4r gem too because it wouldn’t install on cygwin  
(i had to modify a ruby file and a Makefile too ==\>  
[How to install the stemmer4r gem on Mac OS X and Linux](http://snippets.aktagon.com/snippets/165-How-to-install-the-stemmer4r-gem-on-Mac-OS-X-and-Linux)  
those modifications are not commited in my svn repo either. (besides if  
they were, it would be easier to submit to patch to the author anyway)

3. what happens if classifier gem gets updated and i make a gem update?  
i guess either the classifier gem won’t be updated or my hacked version  
of the gem will break, or both. besides, i may want to integrate such  
modification in my own version of classifier

4. i know svn has the concept of a vendor branch, i read this in the svn  
red book a few years ago but never really encountered a situation where  
i would have to tweak a third party lib before so i’m not really used to  
this feature…  
Also, i know any rails app have a vendor directory that is somewhat  
dedicated to such things (put some third party libs there that you can  
later tweak or update if you want). but i am working on some pure ruby  
command line scripts for the moment, rails is off topic for now. besides  
i am not rails expert yet anyway.

i have the feeling that situation is probably classic for a lot of  
people. So i do not want to reinvent the wheel here. instead, i would  
rather apply best practices tested by other people and save the  
trial&error process.

what are the best practices to handle local gem modifications in this  
with-svn / without-rails context?

thanks

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<div class="post-metadata">

**Author:** ![fourchette](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/ac91a4/32.png) [@fourchette](https://www.ruby-forum.com/u/fourchette)\
**Post date:** [September 6, 2010, 4:39pm UTC](https://www.ruby-forum.com/t/what-are-the-best-practices-to-handle-local-gem-modification/194416/2 "2010-09-06T16:39:52Z")

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On Saturday, September 04, 2010 10:59:23 am Fourchette Fourchette wrote:

> after one hour or so, i got it up and running. My new hacked version of  
> the classifier gem uses stemmer4r and works nicely with french text.

Find the author of the classifier gem, or better yet, find a Github repo  
or  
something, and send a patch.

> 1. my hacked classifier gem resides in the gem directory, not in my  
> working copy.

You can always put a copy of the gem in some ‘lib’ directory of your  
working  
copy, and prepend that to $:.

> 1. what happens if classifier gem gets updated and i make a gem update?  
> i guess either the classifier gem won’t be updated or my hacked version  
> of the gem will break, or both. besides, i may want to integrate such  
> modification in my own version of classifier

The new version would be installed in a new directory. You can force a  
specific version with Kernel#gem, but that doesn’t help you integrate  
those  
changes.

But this is exactly what version control is for. In the future, do NOT  
make  
changes to an installed gem. Instead, find the source repository for  
that gem,  
make your changes to a local branch, and build from that branch to  
install a  
gem – or add that branch to your project’s path temporarily, for  
testing.  
That way, when you’re done, you can send a patch back to the gem, or you  
can  
fork the project and maintain your own version.

> 1. i know svn has the concept of a vendor branch, i read this in the svn  
> red book a few years ago but never really encountered a situation where  
> i would have to tweak a third party lib before so i’m not really used to  
> this feature…

Most Ruby people aren’t using SVN. They’re using Git, and you should be,  
too.  
Git does have a concept of a submodule, but this probably isn’t what you  
want,  
since it’s not that you want to track a specific revision of upstream –  
and  
if you did, Gem would be enough. Rather, it’s that you want to fork it.

Now, Rails has a concept of a vendor branch, where you can simply unpack  
a gem  
to a “vendor” folder under your project, but I’m pretty sure this  
doesn’t use  
any scm features, and you’re responsible for keeping it in sync. Seems  
pretty  
inconvenient compared to using the native features of something like Git  
to  
handle tracking new changes.

> what are the best practices to handle local gem modifications in this  
> with-svn / without-rails context?

Best practices are:

1: Use Git, not SVN.  
2: Don’t modify the installed gem. Instead, go find its source  
repository and  
work from there.