check-ref-format --branch: strip refs/heads/ using skip_prefix
The expansion returned from strbuf_check_branch_ref always starts with
"refs/heads/" by construction, but there is nothing about its name or
advertised API making that obvious. This command is used to process
human-supplied input from the command line and is usually not the
inner loop, so we can spare some cycles to be more defensive. Instead
of hard-coding the offset strlen("refs/heads/") to skip, verify that
the expansion actually starts with refs/heads/.
[jn: split out from a larger patch, added explanation]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>