On 11/19/2021 3:05 PM, Johannes Sixt wrote: > Am 19.11.21 um 15:51 schrieb Derrick Stolee: >> What is unclear to me is what exactly "match a directory" means. >> If we ignore a directory, then we ignore everything inside it (until >> another pattern says we should care about it), but the converse >> should also hold: if we have a pattern like "!data/**/", then that >> should mean "include everything inside data/<A>/ where <A> is any >> directory name". >> >> My inability to form a mental model where the existing behavior >> matches the documented specification is an indicator that this was >> changed erroneously. A revert patch is included at the end of this >> message. >> >> If anyone could help clarify my understanding here, then maybe >> there is room for improving the documentation. > > You form a wrong mental model when you start with the grand picture of a > working tree. That is, when you say > > - here I have theeeeeese many files and directories, > - and I want to ignore some: foo/**/, > - but I don't want to ignore others: !bar/**/. > > This forms the wrong mental model because that is not how Git sees the > working tree: it never has a grand picture of all of its contents. > > Git only ever sees the contents of one directory. When Git determines > that a sub-directory is ignored, then that one's contents are never > inspected, and there is no opportunity to un-ignore some of the > sub-directory's contents. So the problem is this: I want to know "I have a file named <X>, and a certain pattern set, does <X> match the patterns or not?" but in fact it's not just "check <X> against the patterns in order" but actually "check every parent directory of <X> in order to see if any directory is unmatched, which would preclude any later matches to other parents of <X>" So really, to check a path, we really want to first iterate on the parent directories. If we get a match on a positive pattern on level i, then we check level (i+1) for a match on a negative pattern. If we find that negative pattern match, then continue. If we do not see a negative match, then we terminate by matching the entire path <X>. I'm still not seeing a clear way of describing the matching procedure here for a single path, and that's fine. Me understanding is not a necessary condition for fixing this bug. Thanks, -Stolee
