Error when calculating irreducible representations of PcGroup using Baum-Clausen

[stertooy]

On GAP 4.16.0:

gap> G := SmallGroup( 1440, 74 );;
gap> Irr( G );
Error, not all relative orders given
Stack trace:
*[1] Error( "not all relative orders given" );
   @ /opt/gap/4.16.0/lib/pcgspcg.gi:95
 [2] PcgsByPcSequenceNC( efam, pcs )
   @ /opt/gap/4.16.0/lib/pcgspcg.gi:244
 [3] PcgsByPcSequence( ElementsFamily( FamilyObj( G ) ), pcgs )
   @ /opt/gap/4.16.0/lib/ctblsolv.gi:1076
 [4] BaumClausenInfo( G )
   @ /opt/gap/4.16.0/lib/ctblsolv.gi:2099
 [5] IrrBaumClausen( G )
   @ /opt/gap/4.16.0/lib/ctblgrp.gi:2312
...  at *stdin*:2
you can 'quit;' to quit to outer loop, or
you can 'return;' to continue

It does work if we first convert G to a permutation group:

gap> H := Image( IsomorphismPermGroup( G ) );;
gap> Irr( H );
[ Character( CharacterTable( Group(  [...]

A bit of digging shows the problem happens here:

gap/lib/ctblsolv.gi

Lines 1073 to 1076 in 3b1e5bc

	G:= ImagesSource( hom );
	pcgs:= List( pcgs, x -> ImagesRepresentative( hom, x ) );
	pcgs:= Filtered( pcgs, x -> Order( x ) <> 1 );
	pcgs:= PcgsByPcSequence( ElementsFamily( FamilyObj( G ) ), pcgs );

In the PcGroup case, this happens:

gap> G:= ImagesSource( hom );
Group([ f1, f2, f3, f4, f5, f6, f6, f7 ])
gap> pcgs:= List( pcgs, x -> ImagesRepresentative( hom, x ) );
[ f1, f2, f3, f4, f5, f6, f6, f7 ]
gap> pcgs:= Filtered( pcgs, x -> Order( x ) <> 1 );
[ f1, f2, f3, f4, f5, f6, f6, f7 ]
gap> pcgs:= PcgsByPcSequence( ElementsFamily( FamilyObj( G ) ), pcgs );
Error, not all relative orders given

In the PermGroup case, this happens:

gap> G := ImagesSource( hom );
Group([ f1, f2, f3, f4, f5, f6, f7 ])
gap> pcgs:= List( pcgs, x -> ImagesRepresentative( hom, x ) );
[ f1*f3, f3, f2, f5*f7, f4*f5*f6, f7, <identity> of ..., f6*f7 ]
gap> pcgs:= Filtered( pcgs, x -> Order( x ) <> 1 );
[ f1*f3, f3, f2, f5*f7, f4*f5*f6, f7, f6*f7 ]
gap> pcgs:= PcgsByPcSequence( ElementsFamily( FamilyObj( G ) ), pcgs );
Pcgs([ f1*f3, f3, f2, f5*f7, f4*f5*f6, f7, f6*f7 ])

[ThomasBreuer]

Thanks for the report. I am going to provide a fix for this problem.
The error did not happen in GAP up to version 4.14 because in the Baum-Clausen method was not tried for the given group.