pack_install - requires(prolog:c_cxx) in pack.pl causes crash

[kamahen]

I get the following when doing a local install. The problem goes away when I remove the line

requires(prolog:c_cxx).

Note that pack.pl also contains the line requires(prolog >= "9.3.8").
SWI-Prolog version 9.3.10-12-g9614a9b3a-DIRTY

[debug]  ?- pack_install(.).
Installation plan:
  Install space as symlink to /home/peter/src/space/
Activate pack? Y/n? y
% Found new dependencies after downloading ([prolog:c_cxx]).
% Contacting server at https://www.swi-prolog.org/pack/query ... ok
ERROR: pack `space' does not exist
ERROR: In:
ERROR:   [22] throw(error(existence_error(pack,space),_49458))
ERROR:   [21] error:existence_error(pack,space) at /home/peter/.local/lib/swipl/library/error.pl:115
ERROR:   [20] prolog_pack:select_version([space- ...],[... - [],...],[plan(_49574),...|...],_49532,[]) at /home/peter/.local/lib/swipl/library/prolog_pack.pl:1127
ERROR:   [19] call_dcg(prolog_pack:select_version(...,...,...),_49606,[]) at /home/peter/.local/lib/swipl/boot/dcg.pl:359
ERROR:   [18] phrase(prolog_pack:select_version(...,...,...),_49648,[]) at /home/peter/.local/lib/swipl/boot/dcg.pl:350
ERROR:   [17] phrase(prolog_pack:select_version(...,...,...),_49690) at /home/peter/.local/lib/swipl/boot/dcg.pl:346
ERROR:   [16] prolog_pack:pack_resolve([space- ...],[#{all_downloads:0,conflicts:[],downloaded:'file:///home/peter/src/space/',git:true,hash:a2978d68eb22ab9563b88b4fa6661896ac93d94d,installed:'/home/peter/.local/share/swi-prolog/pack/space',link:true,pack:space,provides:[],requires: ...,title:'Space package',url:'https://github.com/JanWielemaker/space/archive/V*.zip',version:'0.3.5'}],[... - []],_49740,[pack_directory('/home/peter/.local/share/swi-prolog/pack'),...|...]) at /home/peter/.local/lib/swipl/library/prolog_pack.pl:1017
ERROR:   [15] prolog_pack:download_plan([space- ...],[#{all_downloads:0,link:true,pack:space,url:'file:///home/peter/src/space/',version:'0.3.5'}],_49878,[pack_directory('/home/peter/.local/share/swi-prolog/pack'),...|...]) at /home/peter/.local/lib/swipl/library/prolog_pack.pl:1372
ERROR:   [14] prolog_pack:pack_install_set([space- ...],'/home/peter/.local/share/swi-prolog/pack',[pack(space),...|...]) at /home/peter/.local/lib/swipl/library/prolog_pack.pl:982
ERROR:   [13] prolog_pack:pack_install(space,[pack(space),...|...]) at /home/peter/.local/lib/swipl/library/prolog_pack.pl:709
ERROR:   [12] prolog_pack:pack_install('.') at /home/peter/.local/lib/swipl/library/prolog_pack.pl:695
ERROR:   [11] toplevel_call(user:user: ...) at /home/peter/.local/lib/swipl/boot/toplevel.pl:1318
   Exception: (21) error:existence_error(pack, space) ? a

[kamahen]

You can assign this bug to me -- I intend to look into it as part of my review of the pack documentation and code.
(The problem showed up when I updated the packages hdt and space.)

[kamahen]

This should have been requires(prolog:c_cxx(_)).
TODO: documentation change to make this clear.