segfault with empty query file in blastn mode

[f-heeger]

I get a segfault when I run blastn mode with a empty query file. In default mode I get a correct error message.

To reproduce (with attached input files):

lambda-1.9.2-Linux-x86_64_sse4/bin/lambda_indexer -d testd.fasta -p blastn
lambda-1.9.2-Linux-x86_64_sse4/bin/lambda -q >testq.fasta -i testd.fasta.lambda -p blastn

I get this output:

LAMBDA - the Local Aligner for Massive Biological DatA
======================================================
Version 1.9.2

Loading Subj Sequences... done.
Loading Subj Ids... done.
Loading Database Index... done.
Loading Query Sequences and Ids... generating reverse complements...Segmentation fault (core >dumped)

test.zip

[h-2]

This is actually a SeqAn bug, but I will provide a workaround in Lambda!

[h-2]

@f-heeger the fix is quite easy, do you want to do a pull request? 😄

[f-heeger]

Absolutely not.

[h-2]

@f-heeger Look at it, it's a really tiny diff :)
Can you verify that it fixes your problem? [note that indexes from lambda-next branch are incompatible to 1.9.2's]

[f-heeger]

Yes it's fixed.