[development] Getting rid of core hacks for drupal upgrade to happen. Need tips on the process.

[marcel partap]

> 1> Apart from svn history, diffing files one by one, does any one have
> suggestions to find out changes between hacked and clean file? Maybe at
> a folder level? Like diff the whole include folder or diff the whole
> modules folder. (I know about beyond compare, anything else?)
Beyond Compare is not bad but not quite the tool to compare trees of 
source files with comfort..
Kdiff3 is your friend - i use it all the time to update core and my 
contrib modules locally, review the changes and merge customizations 
respectively fixes that need to go upstream. A real time saver, with 
windows version available, too!

> 2> Any tips, experiences, suggestions on the process of removing core
> hacks and implementing them outside of core.
Instead of reverting them, figure out what each change functionally 
intends to accomplish, make a list, check D6 and contrib for same 
functionality, install D6 and go wild testing this functionality.
The idea of first encapsulating all core hacks into a custom module, 
then upgrading D5, then possibly to D6 might be the cleanest path but 
also the most cumbersome, and you may be able to cut it short if the 
specific functionality already has a D6 module available.
In any case, a good first step might be to single out security relevant 
patches that have been applied between your hacked D5 version and the 
latest, possibly applying them manually. Kdiff3 has a nice 
three-way-diff-merge mode for tasks like this by the way ;)

regards,
marcel.