Qt-based build broke after merging #23, rpath is not set

[gabm]

Issue: A build that depends on qt and worked before merging #23 broke on linux-64 for me. The recipe looks like this:

requirements:
  build:
    - {{ compiler("c") }}
    - {{ compiler("cxx") }}
    - {{ cdt('mesa-libgl-devel') }} # [linux]
    - {{ cdt('mesa-dri-drivers') }} # [linux]
    - {{ cdt('libselinux') }} # [linux]
    - {{ cdt('libxdamage') }} # [linux]
    - {{ cdt('libxfixes') }} # [linux]
    - {{ cdt('libxxf86vm') }} # [linux]
    - libxcb # [linux]
    - xorg-libxext # [linux]
    - cmake
    - make # [unix]

  host:
    - qt

  run:
    - qt

The build fails with:

/builds/test-gui/builds/test-gui_1595492796512/_build_env/bin/../lib/gcc/x86_64-conda_cos6-linux-gnu/7.5.0/../../../../x86_64-conda_cos6-linux-gnu/bin/ld: warning: libXext.so.6, needed by /builds/test-gui/builds/test-gui_1595492796512/_build_env/bin/../x86_64-conda_cos6-linux-gnu/sysroot/usr/lib64/libGL.so.1, not found (try using -rpath or -rpath-link)

The resolved envrionment between yesterday (when it worked) and today (that it failed) differes in

<     libdrm-cos6-x86_64:            2.4.65-hdf0574f_102     conda-forge
---
>     libdrm-cos6-x86_64:            2.4.65-ha826a6f_103     conda-forge
21,22c21,22
<     libselinux-cos6-x86_64:        2.0.94-hdf0574f_102     conda-forge
<     libsepol-cos6-x86_64:          2.0.41-hdf0574f_102     conda-forge
---
>     libselinux-cos6-x86_64:        2.0.94-ha826a6f_103     conda-forge
>     libsepol-cos6-x86_64:          2.0.41-ha826a6f_103     conda-forge
26,27c26,27
<     libx11-common-cos6-x86_64:     1.6.4-hdf0574f_102      conda-forge
<     libx11-cos6-x86_64:            1.6.4-hdf0574f_102      conda-forge
---
>     libx11-common-cos6-x86_64:     1.6.4-ha826a6f_103      conda-forge
>     libx11-cos6-x86_64:            1.6.4-ha826a6f_103      conda-forge
29,31c29,31
<     libxdamage-cos6-x86_64:        1.1.3-hdf0574f_102      conda-forge
<     libxfixes-cos6-x86_64:         5.0.3-hdf0574f_102      conda-forge
<     libxxf86vm-cos6-x86_64:        1.1.3-hdf0574f_102      conda-forge
---
>     libxdamage-cos6-x86_64:        1.1.3-ha826a6f_103      conda-forge
>     libxfixes-cos6-x86_64:         5.0.3-ha826a6f_103      conda-forge
>     libxxf86vm-cos6-x86_64:        1.1.3-ha826a6f_103      conda-forge
33,36c33,36
<     mesa-dri-drivers-cos6-x86_64:  11.0.7-hdf0574f_102     conda-forge
<     mesa-dri1-drivers-cos6-x86_64: 7.11-hdf0574f_102       conda-forge
<     mesa-libgl-cos6-x86_64:        11.0.7-hdf0574f_102     conda-forge
<     mesa-libgl-devel-cos6-x86_64:  11.0.7-hdf0574f_102     conda-forge
---
>     mesa-dri-drivers-cos6-x86_64:  11.0.7-ha826a6f_103     conda-forge
>     mesa-dri1-drivers-cos6-x86_64: 7.11-ha826a6f_103       conda-forge
>     mesa-libgl-cos6-x86_64:        11.0.7-ha826a6f_103     conda-forge
>     mesa-libgl-devel-cos6-x86_64:  11.0.7-ha826a6f_103     conda-forge

Environment (conda list):

``` $ conda list ```

Details about conda and system ( conda info ):

``` $ conda info ```

[gabm]

Basically the rpath is not set for libGL.so and others

on build 102:

objdump -x libGL.so | grep RPATH
  RPATH                $ORIGIN/../../../../lib

but on build 103 its empty

objdump -x libGL.so | grep RPATH

[beckermr]

@isuruf Should we turn binary relocation back on?

[isuruf]

No. the recipe is wrong. - xorg-libxext # [linux] should be turned in to a CDT.

[beckermr]

Ok. We have that one already built so should be an easy fix.

Can you explain why here or what is going on or how that fixes it?

[beckermr]

I guess the general rule is to not link stuff in the sysroot to builds outside of the sysroot?

[gabm]

Yeah, a bit of clarification might be useful here.

I suppose @beckermr is right, link nothing from sysroot to outside, it should be self-contained...

So the rule would be:

• build your recipe as normal, list your dependencies
• when you get linker errors, check whether the packages exist as cdt packages. If yes -> add them to the build as CDT dependencies

Is that so? @isuruf

[isuruf]

CDT packages should link with CDT packages. Qt was relying on CDT packages linking with conda packages which is not guaranteed to work.

[gabm]

Meanwhile I confirmed your fix: with the following recipe it works:

requirements:
  build:
    - {{ compiler("c") }}
    - {{ compiler("cxx") }}
    - {{ cdt('mesa-libgl-devel') }} # [linux]
    - {{ cdt('mesa-dri-drivers') }} # [linux]
    - {{ cdt('libselinux') }} # [linux]
    - {{ cdt('libxdamage') }} # [linux]
    - {{ cdt('libxfixes') }} # [linux]
    - {{ cdt('libxxf86vm') }} # [linux]
    - {{ cdt('libxext') }} # [linux]
    - cmake
    - make # [unix]

  host:
    - qt

  run:
    - qt

[gabm]

Okay, thank you for clarification!

[beckermr]

I just remembered this docs page exists too: https://conda-forge.org/docs/maintainer/knowledge_base.html#libgl

looks like we have converged on the correct solution