Re: [docs] [PATCH] dev-manual: add command to force a recipe re-compile

On 6/10/26 10:36 AM, Robert P. J. Day via lists.yoctoproject.org wrote:
> On Wed, 10 Jun 2026, Alexander Kanavin wrote:
> 
>> On Tue, 9 Jun 2026 at 21:20, Robert P. J. Day via
>> lists.yoctoproject.org <[email protected]>
>> wrote:
>>> --- a/documentation/dev-manual/temporary-source-code.rst
>>> +++ b/documentation/dev-manual/temporary-source-code.rst
>>> @@ -65,3 +65,11 @@ build system uses to build the package would be as follows::
>>>
>>>      project/build/tmp/work/qemux86-poky-linux/foo/1.3.0
>>>
>>> +Finally, if you make some changes to a recipe's unpacked source code,
>>> +you can force a re-compile of that recipe with the command::
>>> +
>>> +   $ bitbake -c compile -f recipe-name
>>> +
>>> +The ``-f`` option in the above forces that task to be re-run
>>> +(invalidating any existing stamp file).
>>> +
>>
>> While explaining where to find the unpacked source is okay, taking it
>> further and providing a way to force-build it is not a good advice. If
>> someone needs to modify and build source like this, they should be
>> using 'devtool modify'.
> 
>    i actually thought about adding a link to devtool, along the lines
> of "while this technique works, devtool modify is now the recommended
> way" or something like that, at least as a historical reference for
> people who have been doing it the bitbake way all this time to let
> them know there's a better way.
> 

Do not modify a recipe's unpacked source code, it's the best way to have 
your changes lost. There are non-negligible chances that it'll end up 
being deleted and unpacked again (e.g. because the cache is outdated via 
its dependencies or the recipe parsing resulted in a rebuild of the recipe).

Using -f also taints the build and you need to clean the sstate-cache 
for this recipe to recover from it last time I checked, which is 
something we don't like recommending to people (if you need to clean the 
sstate-cache, either something's wrong with your recipe or there's a bug 
we need to fix), so I don't think documenting this enormous footgun is a 
good thing.

Cheers,
Quentin