On Tue, Mar 14, 2023 at 01:44:11PM -0700, Junio C Hamano wrote: > John Cai <johncai86@xxxxxxxxx> writes: > > > I wasn't aware of those config options. Indeed that's a good option! My only > > concern with that is that there is already some precedence for passing a > > <tree-ish> as a source for attributes in [1], so I thought adding a command line > > option would be somewhat consistent. > > > > But I can also see the benefit of using a config value since there is also > > precedence because of mailmap.file and mailmap.blob. Not sure what others think, > > but this may be the less invasive way to go. > > I actually hate these one-off variables, and I wish we didn't do > mailmap.file or mailmap.blob at all. Instead we could have taught > the machinery to read from $GIT_DIR/info/mailmap just like the > exclude and the attribute machinery already knows to read excludea > and attributes files in the directory. I don't think $GIT_DIR/info/mailmap is a good substitute for mailmap.blob. The point there is to pull it from the repository, and you'd have to do: git cat-file HEAD:.mailmap >.git/info/mailmap before each command to get the equivalent. It is even worse for attributes, because the in-tree representation is not even a single file that is compatible with $GIT_DIR/ (there can be many attributes spread throughout the tree). It's true that mailmap.file, when specified in the local config, is redundant with a repo-level info/mailmap file. I always assumed that people put it in their ~/.gitconfig, though, to cover multiple projects (just like we have core.attributesFile in addition to the in-repo meta-file). > As your "per filetype (determined by the attribute) diff algorithm > in a bare repository" feature already depends on being able to use > config (as the look-up is "attributes determines the diff filetype > name, and then diff.<filetype>.algo is looked up in the config") to > configure, it does not sound too bad to add the attribute info in > the $GIT_DIR/info/attributes file in your bare repository (and you'd > set the algorithm in $GIT_DIR/config file there), and it would just > work without any new "read from HEAD" feature, I would presume? I don't think that's quite a substitute. If you have a static list of attributes, that is OK (though you are presumably better off with /etc/gitattributes or similar that covers all repos). But if you want to respect in-repo ones, you need to look at the whole tree (and can't even just dump them out). It does seem at first glance that you are limited to a static list of attributes, because any diff "type" you mention has to have a corresponding entry in the config to do anything useful. But these lists are only loosely coupled. For example, you could have static entries like this: # in config [diff "json"] algorithm = patience # in attributes *.json diff=json but still tell users that "json" is a well-known name, and if they want to get the same treatment for an arbitrary file "foo" that they would get for "foo.json", they have to add attributes mapping it, like: foo diff=json inside their repo. -Peff
