mbuild read request loops infinitely if same file listed twice in .mb build script

[Gary Dixon]

The build script shown below lists the info_seg_.pl1 file twice. The mbuild read request goes into an infinite loop when parsing this file, because it continually adds that same file to the scan_Tb thread (in the end_Seg internal procedure of mbuild_script_parse_.rd).

Installation_directory:  >udd>m>gd>w>vi_07;

 Build_script:             vi_07.mb;

 Bound_obj:                bound_info_rtns_                  IN: sss  UPDATE;
     bindfile:             bound_info_rtns_.bind              REPLACE;
     source:               help.pl1                           REPLACE            compiler: pl1 -ot;
     source:               help_.pl1                          REPLACE            compiler: pl1 -ot;
     source:               help_request_tables_.alm           ADD                compiler: alm;
     source:               info_seg_.pl1                      ADD                compiler: pl1 -ot;
     source:               info_seg_.pl1                      ADD                compiler: pl1 -ot;
     source:               info_seg_allocate_.pl1             ADD                compiler: pl1 -ot;
     source:               info_seg_error_.pl1                ADD                compiler: pl1 -ot;
     source:               info_seg_parse_.pl1                ADD                compiler: pl1 -ot;
     source:               info_seg_specifications_.cds       ADD                compiler: cds;
     source:               info_seg_util_.pl1                 ADD                compiler: pl1 -ot;
     source:               info_seg_verify_.pl1               ADD                compiler: pl1 -ot;
     source:               info_seg_verify_iFile_.pl1         ADD                compiler: pl1 -ot;
     source:               verify_info.pl1                    ADD                compiler: pl1 -ot;

 Include:                  _help_shared_data_.incl.pl1       IN: sss.include  ADD;
 Include:                  help_args_.incl.pl1               IN: sss.include  REPLACE;
 Include:                  help_cis_args_.incl.pl1           IN: sss.include  REPLACE;
 Include:                  info_seg_dcls_.incl.pl1           IN: sss.include  ADD;
 Include:                  ssu_invoker_dcls_.incl.pl1        IN: sss.include  ADD;
 Include:                  verify_info_data.incl.pl1         IN: sss.include  ADD;

 Info:                     info_seg_.info                    IN: sss.info  ADD;
 Info:                     info_seg_verify_.info             IN: sss.info  ADD;
 Info:                     verify_info.info                  IN: sss.info  ADD;
                             add_name:  vi.info;

[Eric Swenson]

​https://s3.amazonaws.com/eswenson-multics/public/mcrs/MCR10086.pdf