Re: [PATCH] allow setting GIT_WORK_TREE to "no work tree"

Jeff King schrieb:

In setup_git_directory_gently, we have a special rule
that says "if GIT_DIR is set but GIT_WORK_TREE is not, then
use the current working directory as the work tree." This is
the intended behavior for the user perspective.

However, setup_git_directory_gently sets GIT_DIR itself,
meaning that further setups (either because we are executing
a command via alias, or in a subprocess) will see the
non-existent GIT_WORK_TREE and assume we fall into the
"current working directory is the working tree" codepath.

Instead, we now use a special value of GIT_WORK_TREE to
indicate that we have already checked for a worktree and
that there isn't one, setting it when we set GIT_DIR and
checking for it in the special case path.

The special value is a blank GIT_WORK_TREE; it could be any
value, but this should not conflict with any user values
(and as a bonus, you can now tell git "I don't have a work
tree" with "GIT_WORK_TREE= git", though I suspect the use
case for that is limited).

Hrm. Unfortunately, on Windows there is no such thing as an empty
environment string. setenv(x, "") *removes* the environment variable.

-- Hannes