Attached are the patches that make the --with-source option recursive, 
add documentation, add a test, adjust a test, and update the news.

As expected, the changes I made are incompatible with the test 
"options->transformation, with-source, no matches". Since 
options->transformation, with-source does a recursive replacement, it 
returns a clone of the package in question. I have tried changing the 
comparison to eq?, eqv? and equal?, each returning false, so I settled 
on a (limited) comparison of the packages' attributes.

On 9/13/20 6:55 AM, Ludovic Courtès wrote:
> Hi,
>
> Jesse Gibbons <jgibbons2357@gmail.com> skribis:
>
>> On 9/11/20 9:43 AM, Ludovic Courtès wrote:
> [...]
>
>>> So maybe drop the second clause for non-recursive replacement, and drop
>>> ‘transform-package-source’ as well.
>> I included a fallback to transform-package-source because the
>> following happens:
>>
>> $ ./pre-inst-env guix build --with-source=$(guix build --source hello) hello
>> guix build: error: invalid source replacement specification:
>> "/gnu/store/hbdalsf5lpf01x4dcknwx6xbn6n5km6k-hello-2.10.tar.gz"
>>
>> This does not fail when I fall back to the non-recursive logic.
>>
>> I can drop transform-package-source, but I will need to do some more
>> hacking to figure out how the package name and version are parsed from
>> the file name as described in the manual, and move it to the logic in
>> transform-package-inputs/source.
> Yes, that’d be nice.  Namely, if you do:
>
>    guix build hello --source=hello-1.2.3.tar.gz
>
> it should work just as now (from the source file name, we assume that
> the source applies to package “hello”).
>
> Conversely, doing:
>
>    guix build hello --source=xyz-hello-1.2.3.tar.gz
>
> would have no effect.  It would not even emit a warning, unlike now.
>
>> I'm not going to have as much free time starting next week, so I might
>> not be able to do that for a while, but I will try to get it done
>> ASAP.
> Sure, let’s stay in touch, I think we’re almost done!
>
> Thank you,
> Ludo’.