mpbb fails parsing command line options if disk is full

[ryandesign (Ryan Carsten Schmidt)]

If the disk is full, mpbb ​fails while parsing command line options:

/opt/bblocal/var/buildworker/ports/build/mpbb/functions: line 46: cannot create temp file for here document: No space left on device
/opt/bblocal/var/buildworker/ports/build/mpbb/functions: line 20: validopts[@]: unbound variable

Would be great if mpbb cleanup at least could work even if the disk is full, since this failure leaves the builder in a wedged state with no disk space available, causing subsequent builds to fail, requiring some manual cleanup and rescheduling of the failed builds.

Lines 46-47 of ​functions are:

    IFS=, read -ra validopts <<<"$1"
    readonly validopts=("${validopts[@]/#/--}")

Apparently a here document (<<<) requires a temporary file. Could the options be parsed successfully without a heredoc?

[ryandesign (Ryan Carsten Schmidt)]

Or maybe it is unreasonable to accommodate a full disk, and we should instead focus on preventing that from occurring; #57869 is an idea for that.