On Thu, Jun 20, 2019 at 07:29:36PM +0000, Pugh, Logan wrote: > Thanks for the explanation. It sounds like I was under the incorrect > assumption that I could use the difftool command the same way as the > diff command. Part of my confusion could be blamed on the git-difftool > documentation (https://git-scm.com/docs/git-difftool) which near the top > states: Well, it _is_ true that you can use it the same way. It's just that you need to configure it to use whatever 3rd-party tool you want (and if you do not want to configure a tool, then you are better off just using git-diff directly). It was only due to a bug/historical accident that it behaved just like git-diff in the no-index case (but not in the regular case -- AFAICT, that would have been broken for your script always). > My use case is a CLI program I've written that processes and then > compares two arbitrary files using the git difftool apparatus as > configured by the end user, leaving the choice to them whether to use > the internal diff tool or an external tool. > > Now, if I'm understanding correctly, I should not rely on the behavior > of git difftool --no-index passing through to git diff. I could add > another CLI switch and code path to my program that calls git diff > directly instead of git difftool but the passthrough behavior seemed > more elegant at the time. > > Ideally, in my mind, git difftool should work as it says on the tin, as > a straight up passthrough to git diff *unless* explicitly configured to > use external tools (e.g. diff.tool and diff.guitool). That does make some sense to me for your use case. But I'm worried it would be a worse experience for people new to difftool (they run it and scratch their heads why it does not do anything different, whereas now they get walked through an interactive configuration). I dunno. I do not use difftool myself, so I don't have strong opinions. In the meantime, I think you can probably switch behavior in your script by checking if the diff.tool config is set. It might be nice if difftool had a better way to query that without you having to know if it's configured. Or in your case I suppose even better would just be an option like "--if-not-configured-just-use-regular-diff". Then it would do what you want, without impacting users who do want the interactive setup. -Peff
