[TopGit PATCH] Ensure we are inside a Git worktree

["martin f. krafft" <madduck@debian.org>]

Bert Wesarg suggests to check that we are not inside the .git directory before
setting up topgit. Because git rev-parse --git-dir only works in the top .git
dir, not deeper (i.e. inside .git/refs) and will always return "."

This patch thus causes topgit to die early on when it's called from outside of
a Git repository, or from underneath .git and outputs error messages
accordingly.

This temporarily makes it even more impossible to call tg --help, but I expect
to have that fixed soon too.

Signed-off-by: martin f. krafft <madduck@debian.org>

---
 tg.sh |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/tg.sh b/tg.sh
index 8c23d26..f8c8de4 100644
--- a/tg.sh
+++ b/tg.sh
@@ -17,6 +17,20 @@ die()
 	exit 1
 }
 
+# Make sure we are in the worktree, not under .git; die otherwise
+ensure_git_repo_or_die()
+{
+	local is_inside_repo is_inside_git_dir
+	is_inside_repo=1
+	is_inside_git_dir=$(git rev-parse --is-inside-git-dir 2>/dev/null) ||
+		is_inside_repo=0
+
+	case "$is_inside_repo/$is_inside_git_dir" in
+	0*) die "Cannot run outside of a Git repository.";;
+	1/true) die "Cannot run from inside \`.git\` hierarchy, please switch to work-tree.";;
+	esac
+}
+
 # setup_hook NAME
 setup_hook()
 {
@@ -249,6 +263,8 @@ do_help()
 [ -d "@cmddir@" ] ||
 	die "No command directory: '@cmddir@'"
 
+ensure_git_repo_or_die
+
 ## Initial setup
 
 set -e
-- 
tg: (2ea19b6..) fixes/ensure-worktree (depends on: upstream)