On Thu, May 10, 2018 at 09:04:34AM +0900, Junio C Hamano wrote: > Taylor Blau <me@xxxxxxxxxxxx> writes: > > > This check we should retain and change the wording to mention '--and', > > '--or', and '--not' specifically. > > Why are these problematic in the first place? If I said > > $ git grep -e first --and -e these > $ git grep -e first --and --not -e those > $ git grep -e first --or -e those > > I'd expect that the first line of this paragraph will hit, and the > first hit for these three are "these", "first" and "first", > respectively. Most importantly, in the last one, "--or" can be > omitted and the whole thing stops being "extended", so rejecting > extended as a whole does not make much sense. Agreed that this is what I would expect, too. The trouble is that we never do a compilation step from containing --and, --or, --not to a POSIX regexp. So, if we're extended, we have to assume that there might not be an answer. Given this, I don't think we should categorically die() when we encounter this (more below in the next hunk of this mail). I think this thread has established that there are certainly cases where we cannot provide a meaningful answer, (--not at the top-level, for instance) but there are cases where we can (as you indicate above). One day, I would like to support --column with --and, --or, or --not in cases where there _is_ a definite answer. That said, omitting this information for now and at least not die()-ing I think is worth taking this patch earlier, and leaving some #leftoverbits. > $ git grep -v second > $ git grep --not -e second > > may hit all lines in this message (except for the obvious two > lines), but we cannot say which column we found a hit. I am > wondering if it is too grave a sin to report "the whole line is what > satisfied the criteria given" and say the match lies at column #1. I think that is sensible. I previously was opposed to this because I thought that it would be too difficult to script around the 'sometimes we have columns but other times not' and 'I gave --column' but have to check whether or not they are really there. I no longer believe that my above argument is sound. It simplifies the matter greatly to simply not share columns when we don't have a good answer, and do when we do. In other terms: * not giving '--column' will _never_ give a column, * '--column --invert' will _always_ die(), and * '--column --[and | or | not]' will _never_ give a column. Thanks, Taylor
