[PATCH v2 1/2] sh-setup: Write a new require_clean_work_tree function

[Ramkumar Ramachandra <artagnon@gmail.com>]

Write a new require_clean_work_tree function to error out when
unstaged changes are present in the working tree and (optionally)
uncommitted changes in the index.

Cc: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 git-sh-setup.sh |   28 ++++++++++++++++++++++++++++
 1 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 6131670..215ec33 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -145,6 +145,34 @@ require_work_tree () {
 	die "fatal: $0 cannot be used without a working tree."
 }
 
+require_clean_work_tree () {
+	# Update the index
+	git update-index -q --ignore-submodules --refresh
+	err=0
+
+	# Disallow unstaged changes in the working tree
+	if ! git diff-files --quiet --ignore-submodules --
+	then
+		echo >&2 "cannot $1: you have unstaged changes."
+		git diff-files --name-status -r --ignore-submodules -- >&2
+		err=1
+	fi
+
+	# Disallow uncommitted changes in the index
+	if ! git diff-index --cached --quiet HEAD --ignore-submodules --
+	then
+		echo >&2 "cannot $1: your index contains uncommitted changes."
+		git diff-index --cached --name-status -r --ignore-submodules HEAD -- >&2
+		err=1
+	fi
+
+	if [ $err = 1 ]
+	then
+	    echo >&2 "Please commit or stash them."
+	    exit 1
+	fi
+}
+
 get_author_ident_from_commit () {
 	pick_author_script='
 	/^author /{
-- 
1.7.2.2.409.gdbb11.dirty