#!/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 switch-example
cd switch-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'
git branch same-point

printf 'unfinished work\n' > note.txt
before=$(git hash-object note.txt)
git switch -q same-point
test "$(git branch --show-current)" = same-point
test "$(git hash-object note.txt)" = "$before"
printf 'Existing branch at the same commit: edits carried across\n'
git status --short

git switch -qc new-work
test "$(git branch --show-current)" = new-work
test "$(git hash-object note.txt)" = "$before"
printf 'New branch: edits remain available for its next commit\n'
git add note.txt
git commit -qm 'Keep unfinished work'
git switch -q main
printf 'different local edit\n' > note.txt
before=$(git hash-object note.txt)
head_before=$(git rev-parse HEAD)
if git switch -q new-work 2>switch-refusal.txt; then
  printf 'Unexpected switch success\n' >&2
  exit 1
fi
test "$(git branch --show-current)" = main
test "$(git rev-parse HEAD)" = "$head_before"
test "$(git hash-object note.txt)" = "$before"
printf 'Conflicting target: switch refused; branch and edits retained\n'
cat switch-refusal.txt
rm switch-refusal.txt
git status --short