Re: [PATCH] grep --no-index: allow use of "git grep" outside a git repository

> Subject: "log --author=me --grep=it" should find intersection, not union
> 
> Historically, any grep filter in "git log" family of commands were taken
> as restricting to commits with any of the words in the commit log message.
> However, the user almost always want to find commits "done by this person
> on that topic".  With "--all-match" option, a series of grep patterns can
> be turned into a requirement that all of them must produce a match, but
> that makes it impossible to ask for "done by me, on either this or that"
> with:
> 
> 	log --author=me --grep=this --grep=that
> 
> because it will require both "this" and "that" to appear.
> 
> Change the "header" parser of grep library to treat the headers specially.
> When parsing the above, behave as if it was specified like this on the
> command line:
> 
> 	--all-match --author=me '(' --grep=this --grep=that ')'
> 
> Even though the "log" command line parser doesn't give direct access to
> the extended grep syntax to group terms with parentheses, this change will
> cover the majority of the case the users would want.