StageStatsIsBroken.md

Eep! How did this happen?

Stage start      :   0.000

    precomp lib/Goo/Polyline.pm6
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
    --stagestats
Stage parse      :   8.196
Stage syntaxcheck:   0.000
Stage ast        :   0.000
Stage optimize   :   0.001
Stage mast       :   0.003
Stage mbc        :   0.000
Stage moar       :   0.000

This looks to be the problematic piece of code:

            if $stagestats {
                whenever $proc.stderr.lines {
                    note("    $stagestats");
                    $*ERR.flush;
                }
            }

This will output "--stagestats" for every line of $proc.stderr

This appears to be the offending commit: rakudo/rakudo@c9d9a096e8

What I don't understand how that could have made a difference ?

Well, the original commit used $_ instead of $stagestats.

Minor mixup?

Aah... duh...! The with was used for the defined test, not for setting the topic! Indeed, a minor mixup.

Fixed with rakudo/rakudo@d66068c189

Seems we don't have tests for this case, would you care to add some?