On Mon, Sep 07, 2020 at 04:17:39AM -0400, Jeff King wrote: > Our color tests of "git add -p" do something a bit different from how a > normal user would behave: we pretend there's a pager in use, so that Git > thinks it's OK to write color to a non-tty stdout. This comes from > 8539b46534 (t3701: avoid depending on the TTY prerequisite, 2019-12-06), > which allows us to avoid a lot of complicated mock-tty code. > > However, those environment variables also make their way down to > sub-processes of add--interactive, including the "diff-files" we run to > generate the patches. As a result, it thinks it should output color, > too. So in t3701.50, for example, the machine-readable version of the > diff we get unexpectedly has color in it. We fail to parse it as a diff > and think there are zero hunks. By the way, this is an instance of a more generic bug, which is that: git -p my-script will cause any sub-programs of git-my-script to think their stdout is going to a pager, even if my-script redirects them to a file or another pipe. I had a solution long ago in: https://lore.kernel.org/git/20150810052353.GB15441@xxxxxxxxxxxxxxxxxxxxx/ but it raises a bunch of interesting portability questions. Since this comes up so rarely, I never really pursued it further. -Peff
