Re: What is the recommended method to patch a recipe?

Philip Balister

On 4/13/20 10:31 AM, Nicolas Dechesne wrote:
On Mon, Apr 13, 2020 at 12:55 PM Alexander Kanavin <alex.kanavin@...>

On Mon, 13 Apr 2020 at 12:46, Nicolas Dechesne <
nicolas.dechesne@...> wrote:

A good rule of thumb is to never modify a metadata that is not yours.
That applies to everything:
* if you need to modify a bb file from a 3rd party library, create a
bbappend file in your layer
* if you need to modify a bbappend from a 3rd party, then create another
bbappend in your layer

And by 3rd party i mean any layer/tree which is not yours (OE-core, or
any other layer your are using).
I beg to differ! Bbappends are making it difficult to reason about what
the recipe with all its appends is doing (because they destroy spatial
locality and aren't easily visible), and I would actually discourage using
them if the modification can go to the original recipe.
Ok.. you're right. Well at least my answer is not complete ;)

Is it fixing a problem? Is it adding a build option absent from the
original recipe? Then please take the trouble to submit the change to the
owners of the recipe.
This is correct. We should encourage everyone to report, and even better
propose a fix, to the relevant layer, when the 'problem' is applicable. I
didn't want to discourage that, for sure!
When developing against master, it's a no brainer. When developing against
a stable branch (like probably many users), it's not as obvious. In that
case I think trying to avoid 'touching' somebody else layer remains a good
advice, since it makes upgrades and maintenance trickier.

Similarly, if a bbappend is re-setting the component version to something
else (yes, people do that despite my best efforts to prohibit the
practice), then a much cleaner approach is to actually make a fully copy of
the recipe, or go and fix the original.
I just ran across a bbappend that change configure options, but looking
at the original recipe, there is a PACKAGECONFIG option to do the same
thing. So they could have used that mechanism instram of the bbappend.


Recipes version upgrades (or downgrade) should be done in a dedicated layer
owned by the 'developer', and in that case, I agree that bbappend should be
prohibited, and the entire recipe should be copied.


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