#!/bin/sh
# SPDX-License-Identifier: MIT
set -eu
export TZ=UTC LC_ALL=C
export GIT_CONFIG_NOSYSTEM=1 GIT_CONFIG_GLOBAL=/dev/null
export GIT_AUTHOR_NAME='Example Author'
export GIT_AUTHOR_EMAIL='author@example.invalid'
export GIT_COMMITTER_NAME='Example Author'
export GIT_COMMITTER_EMAIL='author@example.invalid'
export GIT_AUTHOR_DATE='2026-10-25T12:00:00+00:00'
export GIT_COMMITTER_DATE='2026-10-25T12:00:00+00:00'
test "$(git version)" = 'git version 2.56.0'

mkdir unstage-example
cd unstage-example
git init -q --template= --initial-branch=main --object-format=sha1
git config commit.gpgsign false
git config core.autocrlf false
printf 'base\n' > note.txt
git add note.txt
git commit -qm 'Base note'
head_before=$(git rev-parse HEAD)

printf 'base\nstaged line\n' > note.txt
git add note.txt
printf 'later edit\n' >> note.txt
printf 'new file\n' > draft.txt
git add draft.txt
file_before=$(git hash-object note.txt)
new_before=$(git hash-object draft.txt)
printf 'Before: one staged addition and one twice-edited file\n'
git status --short
git diff --cached -- note.txt
git diff -- note.txt

git diff --cached -- note.txt > staged.patch
test -s staged.patch
git restore --staged -- note.txt
test "$(git rev-parse HEAD)" = "$head_before"
test "$(git hash-object note.txt)" = "$file_before"
test "$(git show :note.txt)" = base
test "$(git status --porcelain=v1 -- note.txt)" = ' M note.txt'
printf 'Tracked file: all local lines remain; none are staged\n'
git diff --cached -- note.txt
git diff -- note.txt

git restore --staged -- draft.txt
test "$(git hash-object draft.txt)" = "$new_before"
test "$(git status --porcelain=v1 -- draft.txt)" = '?? draft.txt'
printf 'New file: still present, now untracked\n'
git status --short
git diff --cached --exit-code
git add note.txt
test "$(git show :note.txt)" = "$(cat note.txt)"
printf 'Restaging takes the current complete note.txt content\n'
git diff --cached -- note.txt