Reason for code overlays

I have some issues with the code overlay mechanism. We run a slightly
modified version of RT3 with just a few added/changed/deleted lines. I
don’t think it’s a good idea to copy the surrounding subroutines to an
overlay file and change it there. If the original changed during an RT
upgrade, we’d override these changes.

Am I missing something, or is the overlay mechanism mainly for those who
haven’t yet discovered version control software? :sunglasses:

Code overlays are to minimize the diffing you have to do with
each upgrade. It allows you to only worry about changes in
the areas that you customized. It’s easier than maintaining
your own branch and doing merges with every new release. But
you don’t have to use them if you don’t want to…

-ToddOn Thu, Feb 05, 2004 at 07:01:25PM +0100, Florian Weimer wrote:

I have some issues with the code overlay mechanism. We run a slightly
modified version of RT3 with just a few added/changed/deleted lines. I
don’t think it’s a good idea to copy the surrounding subroutines to an
overlay file and change it there. If the original changed during an RT
upgrade, we’d override these changes.

Am I missing something, or is the overlay mechanism mainly for those who
haven’t yet discovered version control software? :sunglasses:


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Todd Chapman wrote:

Code overlays are to minimize the diffing you have to do with
each upgrade. It allows you to only worry about changes in
the areas that you customized. It’s easier than maintaining
your own branch and doing merges with every new release.

I don’t think so. Diffing my overlay file to the original file in a new
upstream release is more difficult than comparing in-place modifications
(and can hardly be automated). AFAICT, you have to do some merging
anyway, and it’s easier if you can use the usual tools.

It helps somewhat for completely new subroutines, but I don’t see the
point for tweaks to existing ones.