`:` in region strings passed to `--chrom`

[julibeg]

Region strings passed to --chrom can be of the format ref_id:start-end to only consider part of a reference sequence. However, reference sequences sometimes have : in their sequence name (e.g. if they were created with samtools faidx. In this case, mosdepth fails with chromosome name ... not found if the whole reference name is provided (see example below).

Example:

$ samtools view -h example.bam
@HD     VN:1.6  SO:unsorted     GO:query
@SQ     SN:seq:1-100    LN:100
@PG     ID:samtools     PN:samtools     VN:1.19 CL:samtools view -h example.bam
read    0       seq:1-100       1       4       100M    *       0       0       AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA *       NM:i:0  ms:i:200        AS:i:200        nn:i:0  tp:A:P  cm:i:85 s1:i:100        s2:i:98 de:f:0  rl:i:0

$ mosdepth test example.bam --chrom seq:1-100
[mosdepth] chromosome seq not found

In contrast, samtools commands work with sequence IDs that contain colons (see example below).
samtools example:

$ cat ref.fa
>seq:1-100
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

$ samtools faidx ref.fa seq:1-100
>seq:1-100
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

$ samtools faidx ref.fa seq:1-100:50-60
>seq:1-100:50-60
AAAAAAAAAAA

Could mosdepth be adapted to do the same?

Many thanks!