+ $line =~ s{
+ \b
+ (
+ # The output of "git describe", e.g. v2.10.0-297-gf6727b0
+ # or hadoop-20160921-113441-20-g094fb7d
+ (?<!-) # see strbuf_check_tag_ref(). Tags can't start with -
+ [A-Za-z0-9.-]+
+ (?!\.) # refs can't end with ".", see check_refname_format()
+ -g[0-9a-fA-F]{7,40}
+ |
+ # Just a normal looking Git SHA1
+ [0-9a-fA-F]{7,40}
+ )
+ \b
+ }{