On Tue, Jul 24, 2018 at 7:11 PM, Junio C Hamano <gitster@xxxxxxxxx> wrote: > > Another thing I noticed from 2/5 is that you can have up to 7 such > capture groups. I do not have any opinion if 7 is too few or too > many, but we would want the number to be documented, and end-user > input diagnosed when it requires more captures than we support (if > we are not already checking, that is). This is the new documentation: -> Refs are grouped into islands based on their "names", and two regexes -> that produce the same name are considered to be in the same -> island. The names are computed from the regexes by concatenating any -> capture groups from the regex, with a '-' dash in between. (And if -> there are no capture groups, then the name is the empty string, as in -> the above example.) This allows you to create arbitrary numbers of -> islands. Only up to 7 such capture groups are supported though. I added the last sentence above, but I wonder if it is 7 or 8. The code is the following: -> static int find_island_for_ref(const char *refname, const struct object_id *oid, -> int flags, void *data) -> { -> int i, m; -> regmatch_t matches[8]; -> struct strbuf island_name = STRBUF_INIT; -> -> /* walk backwards to get last-one-wins ordering */ -> for (i = island_regexes_nr - 1; i >= 0; i--) { -> if (!regexec(&island_regexes[i], refname, -> ARRAY_SIZE(matches), matches, 0)) -> break; -> } I also wonder if the above is enough to diagnose end-user input when it requires more captures than we support. A quick look at the man page of the regex functions wasn't enough to enlighten me. Any input on these issues is very welcome!