Hi Mike, On Fri, 22 Mar 2019, Mike Hommey wrote: > On Fri, Mar 22, 2019 at 02:39:43PM +0100, Johannes Schindelin wrote: > > Hi Peff & Mike, > > > > On Fri, 22 Mar 2019, Jeff King wrote: > > > > > On Wed, Mar 20, 2019 at 07:19:41PM +0900, Mike Hommey wrote: > > > > > > > I thought of a few options (it's worth noting the helper is invoked in a > > > > way that makes $GIT_EXEC_PATH set, which can help a little): > > > > - spawn `$GIT_EXEC_PATH/git-config -l -z`, parse its output, and set the > > > > internal config from that. That's the barbarian option. > > > > - build the helper with RUNTIME_PREFIX, and modify the RUNTIME_PREFIX > > > > code to use $GIT_EXEC_PATH if it's set, rather than the path the > > > > executable is in. That actually sounds reasonable enough that I'd send > > > > a patch for git itself. But that doesn't quite address the nitpick case > > > > where ETC_GITCONFIG could be either `/etc/gitconfig` or > > > > `etc/gitconfig` depending how git was compiled, and there's no way to > > > > know which is the right one. > > > > > > I'm not entirely sure I understand the problem, but it sounds like you > > > want to know the baked-in ETC_GITCONFIG for a built version of git (that > > > isn't necessarily the one that shares your build of libgit.a). > > > > > > There's no direct way to have Git print that out. It would be reasonable > > > to add one to rev-parse, I think. > > > > > > Barring that, here's a hack: > > > > > > git config --system --show-origin --list -z | > > > perl -lne '/^file:(.*?)\0/ and print $1 and exit 0' > > > > > > If the file is empty, it won't print anything, of course. But then, > > > you'd know that it also has no config in it. :) > > > > How about > > > > GIT_EDITOR=echo git config --system -e 2>/dev/null > > > > It will error out if the directory does not exist, for some reason, e.g. > > when you installed Git in your home directory via `make install` from a > > fresh clone. So you'll have to cope with that contingency. > > Thank you both, I can probably work with this, although I might have to > alter the git init sequence. If you spawn this, you should not need to alter any Git init sequence. Also, I failed to mention that the error message when the directory does not exist is quite helpful, too: it mentions the path to that directory. Oh, and I forgot one really crucial thing: you want to set `LANG=C`, too, to make the output parseable. > I'm not sure my usecase needs git to cater for it more generally, > though. I guess the idea of Git is that the command-line interface is "the API". With that idea, you should indeed not have to know the exact location of the system config, as you can simply consume the output of `git config -l -z`. However, given all those really impressive performance wins we get out of all those conversions from shell/Perl to C, I am inclined to agree with you: any remotely serious application that uses Git either has to access libgit.a directly (even if that is discouraged), or has to have non-trivial code inside Git to support their use cases (all those `for-each-ref` pattern enhancements we had to introduce, for example, to make it remotely feasible for a 3rd-party application to work with the amounts of branches we sometimes have to deal with, for example). > Who else uses libgit.a? I only know of cgit, the fast alternative to gitweb. Ciao, Dscho
