Why are these derivations different?

Why are these derivations different?

[Jack Hill]

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Hi Guix,

I'm trying to copy the store items for ungoogled-chromium from one of my 
hosts that has many computational resources to another one that does not, 
so that I do not have to build ungoogled-chromium on the less powerful 
host.

However, even after copying the store items using guix archive --export | 
guix archive --import, the less powerful host wants to build 
ungoogled-chromium because the derivations differ (see attachments).

How can I go about seeing why the derivations differ?

Both hosts are using the same version of guix:

$ guix describe
Generation 35	Jun 07 2019 21:49:47	(current)
   guix 07023eb
     repository URL: https://git.savannah.gnu.org/git/guix.git
     commit: 07023ebc1892a559cad1f80235a4afb0955b29ab

and

$ guix describe
Generation 3    Jun 06 2019 16:39:40    (current)
   guix 07023eb
     repository URL: https://git.savannah.gnu.org/git/guix.git
     branch: master
     commit: 07023ebc1892a559cad1f80235a4afb0955b29ab

Best,
Jack

[-- Attachment #2: more powerful derivation --]
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Derive([("out","/gnu/store/kpbfydvf16vvva7gy56p1d85b2ry9dgn-ungoogled-chromium-74.0.3729.169-0.d2beaef","","")],[("/gnu/store/05g7z2cndn7snvwmhb0ghjxd7bscdzr5-cups-2.2.11.drv",["out"]),("/gnu/store/0hg04ci30k9f46lycq3a38k5jnd6pkpv-cairo-1.16.0.drv",["out"]),("/gnu/store/0pqbf0jy7h29p7hm02a8lya8c6wgwrya-ffmpeg-4.1.3.drv",["out"]),("/gnu/store/0pswzqisl4frkahc8n25v0khzm5qwk9q-libjpeg-turbo-2.0.1.drv",["out"]),("/gnu/store/13lni3376l0asaryf5v7yx1pkclg724c-pango-1.42.4.drv",["out"]),("/gnu/store/14zh54fjfnrjm108mj857l4ckgn3w0wa-fontconfig-2.13.1.drv",["out"]),("/gnu/store/16i2br91zcamkq08jazhy0lxa0dxmlwg-openjpeg-2.3.1.drv",["out"]),("/gnu/store/1ywcgh6rwvjhs6qqj1h8izcg22idl2x3-module-import-compiled.drv",["out"]),("/gnu/store/2yzhaf13j1nrcag78y683z6kdnnnpmr0-cairo-1.16.0.drv",["out"]),("/gnu/store/37qkp6861qnmx2ixy7jg51jg1dywd9m2-harfbuzz-2.2.0.drv",["out"]),("/gnu/store/3r8d3h2l1dwbvad4p20bchk3ljlwqh6i-gtk+-3.24.7.drv",["out"]),("/gnu/store/5dl6856mpvqv1qwdp5vmri76ab8x4acz-nss-3.43.drv",["out"]),("/gnu/store/5q3kdzj1hq85i9a5nr6z8yl54xigjcc2-openjpeg-2.3.0.drv",["out"]),("/gnu/store/6343p3yq191mc8cxrz1y8jrm840v2whj-fontconfig-2.13.1.drv",["out"]),("/gnu/store/8ha35c10aghpwwd2v0c8xk46vlppbz19-lcms-2.9.drv",["out"]),("/gnu/store/9i3iz56a403km3b97mwvdavyi488yhpf-ffmpeg-4.1.3.drv",["out"]),("/gnu/store/bmgyx3il9i3qvwr2wyi4ak7my59dl5nk-libwebp-1.0.2.drv",["out"]),("/gnu/store/bp7hq2bwcy9d8937814c5gr15ylgp5k6-harfbuzz-2.2.0.drv",["out"]),("/gnu/store/c83y8vza2x19w03cav577a3mq4h80w81-gtk+-3.24.7.drv",["out"]),("/gnu/store/f1ajr6s8gy4ldmiaqr5s9i9m724r5a5r-freetype-2.9.1.drv",["out"]),("/gnu/store/fqg9n41z2ca66r9m6dcy2b1kmz2gpx7i-guile-2.0.14.drv",["out"]),("/gnu/store/ivighhym2js9xpj77c27qg4gfw16xxwr-freetype-2.9.1.drv",["out"]),("/gnu/store/js4ix1yhhhk2j184bc19ynq3cap1f3a5-gdk-pixbuf-2.38.1.drv",["out"]),("/gnu/store/kwnn6x7z45g8j1iha1087mpiv48pwz3j-cups-2.2.11.drv",["out"]),("/gnu/store/lkhd8g814l0c9wy9h4dii9gw44vi964f-libva-2.4.0.drv",["out"]),("/gnu/store/n07vg2agjv9m7yg6dyi59ys65aaqxjkv-lcms-2.9.drv",["out"]),("/gnu/store/nr087v1hy3x2byjvvvmbqk6nhrzcxrmg-libpng-1.6.34.drv",["out"]),("/gnu/store/qk80f8arfbsmsxrx0f7645ph5y3nrwnr-mesa-18.3.5.drv",["out"]),("/gnu/store/qr4vv4br4sspi1sllzzaqn7fiilbxg9f-pango-1.42.4.drv",["out"]),("/gnu/store/qz49ik2lvbff7xrl5685kvng6iv6qa7x-libpng-1.6.37.drv",["out"]),("/gnu/store/s9w71hlp4xaw65hn027gnbir6rl2pp3x-ungoogled-chromium-74.0.3729.169-0.d2beaef.drv",["out"]),("/gnu/store/shmm2wml357xpwyzl42hkl6wzjsw7jws-libwebp-1.0.2.drv",["out"]),("/gnu/store/svylcniwjvpv1hm12pbf0zrxp224pshz-libva-2.4.0.drv",["out"]),("/gnu/store/v9chjkf5fgqdm7igikszxm9y5zc6chdx-gdk-pixbuf-2.38.1.drv",["out"]),("/gnu/store/vhkrlh8g2jjrjpcr53w455297z8fqzn7-libevent-2.1.10.drv",["out"]),("/gnu/store/vq1alsi8yh55h4y4ggjqp1w8vp3prswf-nss-3.43.drv",["out"]),("/gnu/store/wq0v31rj2lbs63hvi9gg1dm27rck3mx8-libevent-2.1.10.drv",["out"]),("/gnu/store/x0v5hll1sw6sqf9wjclkw526hflaar1x-module-import.drv",["out"]),("/gnu/store/y7z4g1gf9knrjb44yspvsfab0ksfvjwy-libjpeg-turbo-2.0.2.drv",["out"]),("/gnu/store/ziyqnilzi6is9g79blw8q820liddfjf5-mesa-18.3.5.drv",["out"])],["/gnu/store/41wxjzb4yhwdqbn4bwjqprb8l5di34dc-ungoogled-chromium-74.0.3729.169-0.d2beaef-guile-builder"],"x86_64-linux","/gnu/store/1fl9vk8fpafkws4qyy25vcdfpybxyh1k-guile-2.0.14/bin/guile",["--no-auto-compile","-L","/gnu/store/d84nbv6r94i8ixvz7f6g22pwdyvnnx6g-module-import","/gnu/store/41wxjzb4yhwdqbn4bwjqprb8l5di34dc-ungoogled-chromium-74.0.3729.169-0.d2beaef-guile-builder"],[("GUILE_LOAD_COMPILED_PATH","/gnu/store/gza8djv7fmxh60pdh8jkkjj7shy3mnsz-module-import-compiled"),("allowSubstitutes","0"),("guix properties","((type . graft) (graft (count . 18)))"),("out","/gnu/store/kpbfydvf16vvva7gy56p1d85b2ry9dgn-ungoogled-chromium-74.0.3729.169-0.d2beaef"),("preferLocalBuild","1")])

[-- Attachment #3: less powerful derivation --]
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Re: Why are these derivations different?

[Marius Bakke]

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Jack Hill <jackhill@jackhill.us> writes:

> Hi Guix,
>
> I'm trying to copy the store items for ungoogled-chromium from one of my 
> hosts that has many computational resources to another one that does not, 
> so that I do not have to build ungoogled-chromium on the less powerful 
> host.
>
> However, even after copying the store items using guix archive --export | 
> guix archive --import, the less powerful host wants to build 
> ungoogled-chromium because the derivations differ (see attachments).

I suspect this has to do with grafts.  Guix is missing a substitute for
the 'ungrafted' package and fails to realize the grafted derivation.

Exporting with --no-grafts should do the trick.

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Re: Why are these derivations different?

[Jack Hill]

On Sat, 8 Jun 2019, Marius Bakke wrote:

> Jack Hill <jackhill@jackhill.us> writes:
>
>> Hi Guix,
>>
>> I'm trying to copy the store items for ungoogled-chromium from one of my
>> hosts that has many computational resources to another one that does not,
>> so that I do not have to build ungoogled-chromium on the less powerful
>> host.
>>
>> However, even after copying the store items using guix archive --export |
>> guix archive --import, the less powerful host wants to build
>> ungoogled-chromium because the derivations differ (see attachments).
>
> I suspect this has to do with grafts.  Guix is missing a substitute for
> the 'ungrafted' package and fails to realize the grafted derivation.
>
> Exporting with --no-grafts should do the trick.

Marius,

Thanks! That was it.

If you don't mind, I have a few follow up question to help me understand 
how everything works:

How is guix archive --no-grafts different from guix build --no-grafts? Oh, 
or after reading the manual for --no-grafts again, maybe I used the wrong 
incantation (guix build --no-grafts package-name instead of guix build 
package-name --no-grafts)?

What's really going on with --no-grafts. Is it that guix on my less 
powerful host has never seen the the ungoogled-chromium version build 
against the older dependencies, so doesn't accept the older version that 
could be grafted? I guess, I'm not sure exactly what you mean by "fails to 
realize the grafted derivation". Is that a bug?

Sorry, I don't think that question was very clear. It probably means that 
while I think I know what grafts are, I don't know enough about what's 
going on to ask the question properly. I think this all could be summarized 
as, "please explain more."

Many thanks,
Jack

Re: Why are these derivations different?

[Marius Bakke]

[-- Attachment #1: Type: text/plain, Size: 2425 bytes --]

Jack Hill <jackhill@jackhill.us> writes:

> On Sat, 8 Jun 2019, Marius Bakke wrote:
>
>> Jack Hill <jackhill@jackhill.us> writes:
>>
>>> Hi Guix,
>>>
>>> I'm trying to copy the store items for ungoogled-chromium from one of my
>>> hosts that has many computational resources to another one that does not,
>>> so that I do not have to build ungoogled-chromium on the less powerful
>>> host.
>>>
>>> However, even after copying the store items using guix archive --export |
>>> guix archive --import, the less powerful host wants to build
>>> ungoogled-chromium because the derivations differ (see attachments).
>>
>> I suspect this has to do with grafts.  Guix is missing a substitute for
>> the 'ungrafted' package and fails to realize the grafted derivation.
>>
>> Exporting with --no-grafts should do the trick.
>
> Marius,
>
> Thanks! That was it.
>
> If you don't mind, I have a few follow up question to help me understand 
> how everything works:
>
> How is guix archive --no-grafts different from guix build --no-grafts? Oh, 
> or after reading the manual for --no-grafts again, maybe I used the wrong 
> incantation (guix build --no-grafts package-name instead of guix build 
> package-name --no-grafts)?
>
> What's really going on with --no-grafts. Is it that guix on my less 
> powerful host has never seen the the ungoogled-chromium version build 
> against the older dependencies, so doesn't accept the older version that 
> could be grafted? I guess, I'm not sure exactly what you mean by "fails to 
> realize the grafted derivation". Is that a bug?

Sorry, just a lazy and poor attempt at explaining what's going on...  :-)

> Sorry, I don't think that question was very clear. It probably means that 
> while I think I know what grafts are, I don't know enough about what's 
> going on to ask the question properly. I think this all could be summarized 
> as, "please explain more."

Grafts are are ignored in some parts of Guix.  In this case, if you
inspect the profile derivation when doing 'guix install -n
ungoogled-chromium', you can see that the computed profile.drv needs to
produce the ungrafted ungoogled-chromium-x.y.z.drv, because the
profile-builder references the _ungrafted_ package. 

I'm not sure of the exact mechanics that follow, but I guess grafts are
only computed afterwards, recursively, for the generated profile.

HTH,
Marius

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Re: Why are these derivations different?

[Jack Hill]

On Mon, 10 Jun 2019, Marius Bakke wrote:

>> What's really going on with --no-grafts. Is it that guix on my less
>> powerful host has never seen the the ungoogled-chromium version build
>> against the older dependencies, so doesn't accept the older version that
>> could be grafted? I guess, I'm not sure exactly what you mean by "fails to
>> realize the grafted derivation". Is that a bug?
>
> Sorry, just a lazy and poor attempt at explaining what's going on...  :-)

No worries, I appreciate you taking the time to help me understand.

>> Sorry, I don't think that question was very clear. It probably means that
>> while I think I know what grafts are, I don't know enough about what's
>> going on to ask the question properly. I think this all could be summarized
>> as, "please explain more."
>
> Grafts are are ignored in some parts of Guix.  In this case, if you
> inspect the profile derivation when doing 'guix install -n
> ungoogled-chromium', you can see that the computed profile.drv needs to
> produce the ungrafted ungoogled-chromium-x.y.z.drv, because the
> profile-builder references the _ungrafted_ package.
>
> I'm not sure of the exact mechanics that follow, but I guess grafts are
> only computed afterwards, recursively, for the generated profile.

Ok, thank help. Thank you.

Jack