On Thu, Jan 18, 2018 at 11:18 PM, brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx> wrote: > There are various git subcommands (among them, clone) which don't set up > the repository (that is, they lack RUN_SETUP or RUN_SETUP_GENTLY) but > end up needing to have information about the hash algorithm in use. > Because the hash algorithm is part of struct repository and it's only > initialized in repository setup, we can end up dereferencing a NULL > pointer in some cases if we call one of these subcommands and look up > the empty blob or empty tree values. > > In the future, we can add a command line option for this or read it from > the configuration, but until we're ready to expose that functionality to > the user, simply initialize the repository structure to use the current > hash algorithm, SHA-1. > > Signed-off-by: brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx> > --- > I'm still quite mystified as to why this is working on Linux and not > macOS, but I can only guess that compilers are just very advanced and > have somehow concluded that we would clearly never dereference a NULL > pointer, so they picked the only non-NULL value. Now that we know (due to Duy's excellent detective work[1]) that the trigger is files with names differing only in case on case-insensitive filesystems, the commit message can be updated appropriately. > I haven't included a test because I have no way to reproduce the issue. > This patch is the first from a series I'm working on where I do expand > the use of the hash struct and therefore caused a segfault on clone, so > I can imagine what's going on without having a way to prove it affects > this particular case. > > If someone with access to macOS can provide a test, I'd be very > grateful. Done. Find the test here[2]. It fails without your fix on MacOS and (presumably) Windows, and succeeds with the fix. > My apologies for the error and inconvenience. [1]: https://public-inbox.org/git/CACsJy8BTFm_0sv=roL1OKKW=1DyU3vqD50NKyHg3KQ7G+mAepQ@xxxxxxxxxxxxxx/ [2]: https://public-inbox.org/git/20180119074001.GA55929@flurp.local/
