simulate_experiment() fails when idfield (default: "transcript_id") is not present in the first line of the gtf file

[alorchhota]

simulate_experiment() fails when idfield (dafault = "transcript_id") is not present in the first row (did not check later rows) of the gtf file. The error is, I believe, in the 2nd line of the following code, because getAttributeField() returns NA.

names(these_seqs) = getAttributeField(dftmp$attributes, idfield, attrsep = attrsep)
if (substr(names(these_seqs)[1], 1, 1) == "\"") {
        x = names(these_seqs)
        names(these_seqs) = substr(x, 2, nchar(x) - 1)
}