[Bug 1476614] New: RFE: Modify the Erlang VM to search in /usr/share/ erlang/lib for noarch libs

https://bugzilla.redhat.com/show_bug.cgi?id=1476614

Bug ID: 1476614
           Summary: RFE: Modify the Erlang VM to search in
                    /usr/share/erlang/lib for noarch libs
           Product: Fedora
           Version: rawhide
         Component: erlang
          Severity: medium
          Assignee: [e-mail]
          Reporter: [e-mail]
        QA Contact: [e-mail]
                CC: [e-mail], [e-mail],
                    [e-mail], [e-mail], [e-mail]

Created attachment 1306684
  --> https://bugzilla.redhat.com/attachment.cgi?id=1306684&action=edit
noarch_libs.patch

Description of problem:
As part of a change for Fedora 27, I have written a patch for the erlang spec
file that will modify the Erlang VM to also search in /usr/share/erlang/lib for
noarch libs. I am attaching a patch I wrote that uses sed in the spec file to
append this new path just before the archful libs in the search path.

I have tested this patch with ejabberd by moving one of its dependencies
(p1_utils) into the new /usr/share/erlang/lib. Without this patch ejabberd
fails to start, but with the patch it starts up successfully.

Once we have this patch applied, we just need to modify the RPM macros to use
the new path for noarch packages and we'll have the change completed.

[Bug 1476614] RFE: Modify the Erlang VM to search in /usr/share/erlang/ lib for noarch libs

https://bugzilla.redhat.com/show_bug.cgi?id=1476614

Randy Barlow  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |1434311

Referenced Bugs:

https://bugzilla.redhat.com/show_bug.cgi?id=1434311
[Bug 1434311] True Noarch Erlang Packages

[Bug 1476614] RFE: Modify the Erlang VM to search in /usr/share/erlang/ lib for noarch libs

https://bugzilla.redhat.com/show_bug.cgi?id=1476614

Randy Barlow  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |needinfo?([e-mail]
                   |                            |m)

--- Comment #1 from Randy Barlow  ---
I tried to build erlang-cache_tab with this patch applied on my system, and it
looks like rebar does not find p1_utils:

+ /usr/bin/rebar eunit skip_deps=true -vv                                       
DEBUG: Evaluating config script
"/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/rebar.config.script"              
DEBUG: Consult config file
"/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/rebar.config"                     
DEBUG: Rebar location: "/usr/bin/rebar"                                         
DEBUG: Consult config file
"/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/src/cache_tab.app.src"            
DEBUG: is_app_available, looking for App p1_utils with Path
"/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/deps/p1_utils"                    
DEBUG: Directory expected to be an app dir, but it doesn't exist (yet?):        
/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/deps/p1_utils                      
DEBUG: Available deps: []                                  
DEBUG: Missing deps  : [{dep,bad_name,p1_utils,".*",       
                             {git,"https://github.com/processone/p1_utils",     
                                  {tag,"1.0.9"}},                               
                             false}]

Does rebar not use Erlang's code_server.erl to find its libs? If not, I think
we might need to either patch rebar, or patch the macros to add the new path to
the search path for rebar.

What do you think?

[Bug 1476614] RFE: Modify the Erlang VM to search in /usr/share/erlang/ lib for noarch libs

https://bugzilla.redhat.com/show_bug.cgi?id=1476614

--- Comment #2 from Randy Barlow  ---
https://github.com/lemenkov/erlang-rpm-macros/pull/4/ will modify the RPM
macros to build into the new location. Now we just need to figure out how to
get Rebar to look in the right place for dependencies.

[Bug 1476614] RFE: Modify the Erlang VM to search in /usr/share/erlang/ lib for noarch libs

https://bugzilla.redhat.com/show_bug.cgi?id=1476614

Peter Lemenkov  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]

--- Comment #3 from Peter Lemenkov  ---
(In reply to Randy Barlow from comment #1)
> I tried to build erlang-cache_tab with this patch applied on my system, and
> it looks like rebar does not find p1_utils:
> /usr/bin/rebar eunit skip_deps=true -vv
>
> DEBUG: Evaluating config script
> "/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/rebar.config.script"
>
> DEBUG: Consult config file
> "/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/rebar.config"
>
> DEBUG: Rebar location: "/usr/bin/rebar"
>
> DEBUG: Consult config file
> "/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/src/cache_tab.app.src"
>
> DEBUG: is_app_available, looking for App p1_utils with Path
> "/home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/deps/p1_utils"
>
> DEBUG: Directory expected to be an app dir, but it doesn't exist (yet?):
>
> /home/rbarlow/rpmbuild/BUILD/cache_tab-1.0.9/deps/p1_utils
>
> DEBUG: Available deps: []                                  
> DEBUG: Missing deps  : [{dep,bad_name,p1_utils,".*",       
>                              {git,"https://github.com/processone/p1_utils",
>                               {tag,"1.0.9"}},                           
>
>                          false}]
>
> Does rebar not use Erlang's code_server.erl to find its libs? If not, I
> think we might need to either patch rebar, or patch the macros to add the
> new path to the search path for rebar.
>
> What do you think?

I believe rebar redefines paths in some different way (to include ./deps/*/ebin
and some other paths) so I think it's not a blocker at this point.

What I'd consider a successful Feature completion is running some code from
/usr/share without providing any extra command line switches.

[Bug 1476614] RFE: Modify the Erlang VM to search in /usr/share/erlang/ lib for noarch libs

https://bugzilla.redhat.com/show_bug.cgi?id=1476614

Peter Lemenkov  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |CLOSED
   Fixed In Version|                            |erlang-19.3.6.2-2.fc27
         Resolution|---                         |RAWHIDE
              Flags|needinfo?([e-mail] |
                   |m)                          |
        Last Closed|                            |2017-08-11 10:38:11

--- Comment #4 from Peter Lemenkov  ---
Initial implementation in erlang-19.3.6.2-2.fc27. Let's test it!

[Bug 1476614] RFE: Modify the Erlang VM to search in /usr/share/erlang/ lib for noarch libs

https://bugzilla.redhat.com/show_bug.cgi?id=1476614

--- Comment #5 from Randy Barlow  ---
Fantastic, thanks Peter!

Just to give you a heads up, it was decided in today's FESCo meeting that I
didn't get all of the changes needed for the Erlang noarch change done in time
(since Rebar still doesn't work). Thus, they have decided to delay the change
until Fedora 28.

That's OK though, we can just make the rebar and rpm macro changes on Rawhide
after Fedora 27 branches. This change shouldn't harm anything on Fedora 27
since it won't fail if there aren't libs in /usr/share.