Jeff King <peff@xxxxxxxx> writes: >> (3) when set to any other string, it is taken as a filename that >> has the global configuration. Unlike $HOME/.gitconfig or >> $XDG_HOME/git/config, it is an error if the named file does not >> exist (this is to catch misconfiguration). >> >> And once this is accepted by users and established as a pattern, we >> could migrate GIT_CONFIG_NOSYSTEM to GIT_CONFIG_SYSTEM=/dev/null > > That seems pretty reasonable. I'm on the fence on your (3). Conceivably > somebody could want to override the baked-in defaults without being sure > the file is present. But I'm not sure how useful that would be in > practice. I was also on the fence. If your plan is to create $HOME/.alternate-config and point at it by setting GIT_CONFIG_GLOBAL=$HOME/.alternate-config, there are two places you can make typo. You may write a file with a wrong name. You may export a variable with a wrong name. > Some other things to consider: > > - does setting GIT_CONFIG_GLOBAL override both the $HOME and > $XDG_CONFIG_HOME? If the plan is to override them, that makes sense. > But we do usually read from both of them, so conceivably you might > want to override just one? That's probably over-engineering, though. I viewed this to be working at the more conceptual "here is the file to read 'system' (or 'per-user') stuff from" level, and not at the level of the individual file, as I consider that it is a mere implementation detail that 'per-user' may read from multiple files. > - if we have config for "read from this file instead of the system > config" and "read from this instead of the user-level config", then > I wonder if people will want "read this instead of the repo config". > We have resisted having GIT_CONFIG mean that for many years, because > I think it gets awkward in some cases (e.g., we'd still want to read > it for core.repositoryformatversion, etc). I'm OK with drawing the > line there and saying it's not a support feature, but we should be > prepared to explain it to users (in the docs or at least in the > commit message adding the system/global override variables). We may have to bite the bullet and make an official catalog of really "structurely fundamental" configuration variables that must appear in the per-repository file, and a mechanism to enforce that by always reading these variables from "$GIT_DIR/config" and always ignoring appearances of them in any other places. That alone would probably be a good thing to do regardless of the GIT_CONFIG_NOGLOBAL issue, as I suspect you may be able to wreak havoc by adding random configuration like [extension] in $HOME/.gitconfig ;-) With that, it would make sense to allow overriding the per-repo configuration in a similar way, only as a mechanism to override configuration variables that are about "preferences" (as opposed to the structurally fundamental ones).
