Re: [PATCH] pager: do not leak "GIT_PAGER_IN_USE" to the pager

On Fri, Jul 03, 2015 at 10:18:45AM -0700, Junio C Hamano wrote:

Since 2e6c01e2, we export GIT_PAGER_IN_USE so that a process that

I imagine you mean 2e6c012e here.

becomes the upstream of the spawned pager can still tell that we
have spawned the pager and decide to do colored output even when
its output no longer goes to a terminal (i.e. isatty(1)).

But we forgot to clear it from the enviornment of the spawned pager.
This is not a problem in a sane world, but if you have a handful of
thousands Git users in your organization, somebody is bound to do
strange things, e.g. typing "!<ENTER>" instead of 'q' to get control
back from $LESS.  GIT_PAGER_IN_USE is still set in that subshell
spawned by "less", and all sorts of interesting things starts
happening, e.g. "git diff | cat" starts coloring its output.

We can clear the environment variable in the half of the fork that
runs the pager to avoid the confusion.

I think this is a reasonable fix. I guess it would be possible that some
pager would want to react differently depending on the variable, but I
could not think of a useful case. And certainly your pager, being the
pager itself, can assume that the pager is in use. ;) At the very worst,
somebody can set GIT_PAGER="GIT_PAGER_IN_USE=1 my-pager" if they truly
want to do something bizarre.

So,

Acked-by: Jeff King <redacted>

-Peff