#!/bin/sh

test_description='test aborting in-progress merges

Set up repo with conflicting and non-conflicting branches:

There are three files foo/bar/baz, and the following graph illustrates the
content of these files in each commit:

# foo/bar/baz --- foo/bar/bazz     <-- master
#             \
#              --- foo/barf/bazf   <-- conflict_branch
#               \
#                --- foo/bart/baz  <-- clean_branch

Next, test git merge --abort with the following variables:
- before/after successful merge (should fail when not in merge context)
- with/without conflicts
- clean/dirty index before merge
- clean/dirty worktree before merge
- dirty index before merge matches contents on remote branch
- changed/unchanged worktree after merge
- changed/unchanged index after merge
'
. ./test-lib.sh

test_expect_success 'setup' '
	# Create the above repo
	echo foo > foo &&
	echo bar > bar &&
	echo baz > baz &&
	git add foo bar baz &&
	git commit -m initial &&
	echo bazz > baz &&
	git commit -a -m "second" &&
	git checkout -b conflict_branch HEAD^ &&
	echo barf > bar &&
	echo bazf > baz &&
	git commit -a -m "conflict" &&
	git checkout -b clean_branch HEAD^ &&
	echo bart > bar &&
	git commit -a -m "clean" &&
	git checkout master
'

pre_merge_head="$(git rev-parse HEAD)"

test_expect_success 'fails without MERGE_HEAD (unstarted merge)' '
	test_must_fail git merge --abort 2>output &&
	grep -q MERGE_HEAD output &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)"
'

test_expect_success 'fails without MERGE_HEAD (completed merge)' '
	git merge clean_branch &&
	test ! -f .git/MERGE_HEAD &&
	# Merge successfully completed
	post_merge_head="$(git rev-parse HEAD)" &&
	test_must_fail git merge --abort 2>output &&
	grep -q MERGE_HEAD output &&
	test ! -f .git/MERGE_HEAD &&
	test "$post_merge_head" = "$(git rev-parse HEAD)"
'

test_expect_success 'Forget previous merge' '
	git reset --hard "$pre_merge_head"
'

test_expect_success 'Abort after --no-commit' '
	# Redo merge, but stop before creating merge commit
	git merge --no-commit clean_branch &&
	test -f .git/MERGE_HEAD &&
	# Abort non-conflicting merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff)" &&
	test -z "$(git diff --staged)"
'

test_expect_success 'Abort after conflicts' '
	# Create conflicting merge
	test_must_fail git merge conflict_branch &&
	test -f .git/MERGE_HEAD &&
	# Abort conflicting merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff)" &&
	test -z "$(git diff --staged)"
'

test_expect_success 'Clean merge with dirty index fails' '
	echo xyzzy >> foo &&
	git add foo &&
	git diff --staged > expect &&
	test_must_fail git merge clean_branch &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff)" &&
	git diff --staged > actual &&
	test_cmp expect actual
'

test_expect_success 'Conflicting merge with dirty index fails' '
	test_must_fail git merge conflict_branch &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff)" &&
	git diff --staged > actual &&
	test_cmp expect actual
'

test_expect_success 'Reset index (but preserve worktree changes)' '
	git reset "$pre_merge_head" &&
	git diff > actual &&
	test_cmp expect actual
'

test_expect_success 'Abort clean merge with non-conflicting dirty worktree' '
	git merge --no-commit clean_branch &&
	test -f .git/MERGE_HEAD &&
	# Abort merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff --staged)" &&
	git diff > actual &&
	test_cmp expect actual
'

test_expect_success 'Abort conflicting merge with non-conflicting dirty worktree' '
	test_must_fail git merge conflict_branch &&
	test -f .git/MERGE_HEAD &&
	# Abort merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff --staged)" &&
	git diff > actual &&
	test_cmp expect actual
'

test_expect_success 'Reset worktree changes' '
	git reset --hard "$pre_merge_head"
'

test_expect_success 'Fail clean merge with conflicting dirty worktree' '
	echo xyzzy >> bar &&
	git diff > expect &&
	test_must_fail git merge --no-commit clean_branch &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff --staged)" &&
	git diff > actual &&
	test_cmp expect actual
'

test_expect_success 'Fail conflicting merge with conflicting dirty worktree' '
	test_must_fail git merge conflict_branch &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff --staged)" &&
	git diff > actual &&
	test_cmp expect actual
'

test_expect_success 'Reset worktree changes' '
	git reset --hard "$pre_merge_head"
'

test_expect_success 'Fail clean merge with matching dirty worktree' '
	echo bart > bar &&
	git diff > expect &&
	test_must_fail git merge --no-commit clean_branch &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff --staged)" &&
	git diff > actual &&
	test_cmp expect actual
'

test_expect_success 'Abort clean merge with matching dirty index' '
	git add bar &&
	git diff --staged > expect &&
	git merge --no-commit clean_branch &&
	test -f .git/MERGE_HEAD &&
	### When aborting the merge, git will discard all staged changes,
	### including those that were staged pre-merge. In other words,
	### --abort will LOSE any staged changes (the staged changes that
	### are lost must match the merge result, or the merge would not
	### have been allowed to start). Change expectations accordingly:
	rm expect &&
	touch expect &&
	# Abort merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	git diff --staged > actual &&
	test_cmp expect actual &&
	test -z "$(git diff)"
'

test_expect_success 'Reset worktree changes' '
	git reset --hard "$pre_merge_head"
'

test_expect_success 'Fail conflicting merge with matching dirty worktree' '
	echo barf > bar &&
	git diff > expect &&
	test_must_fail git merge conflict_branch &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	test -z "$(git diff --staged)" &&
	git diff > actual &&
	test_cmp expect actual
'

test_expect_success 'Abort conflicting merge with matching dirty index' '
	git add bar &&
	git diff --staged > expect &&
	test_must_fail git merge conflict_branch &&
	test -f .git/MERGE_HEAD &&
	### When aborting the merge, git will discard all staged changes,
	### including those that were staged pre-merge. In other words,
	### --abort will LOSE any staged changes (the staged changes that
	### are lost must match the merge result, or the merge would not
	### have been allowed to start). Change expectations accordingly:
	rm expect &&
	touch expect &&
	# Abort merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	git diff --staged > actual &&
	test_cmp expect actual &&
	test -z "$(git diff)"
'

test_expect_success 'Reset worktree changes' '
	git reset --hard "$pre_merge_head"
'

test_expect_success 'Abort merge with pre- and post-merge worktree changes' '
	# Pre-merge worktree changes
	echo xyzzy > foo &&
	echo barf > bar &&
	git add bar &&
	git diff > expect &&
	git diff --staged > expect-staged &&
	# Perform merge
	test_must_fail git merge conflict_branch &&
	test -f .git/MERGE_HEAD &&
	# Post-merge worktree changes
	echo yzxxz > foo &&
	echo blech > baz &&
	### When aborting the merge, git will discard staged changes (bar)
	### and unmerged changes (baz). Other changes that are neither
	### staged nor marked as unmerged (foo), will be preserved. For
	### these changed, git cannot tell pre-merge changes apart from
	### post-merge changes, so the post-merge changes will be
	### preserved. Change expectations accordingly:
	git diff -- foo > expect &&
	rm expect-staged &&
	touch expect-staged &&
	# Abort merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	git diff > actual &&
	test_cmp expect actual &&
	git diff --staged > actual-staged &&
	test_cmp expect-staged actual-staged
'

test_expect_success 'Reset worktree changes' '
	git reset --hard "$pre_merge_head"
'

test_expect_success 'Abort merge with pre- and post-merge index changes' '
	# Pre-merge worktree changes
	echo xyzzy > foo &&
	echo barf > bar &&
	git add bar &&
	git diff > expect &&
	git diff --staged > expect-staged &&
	# Perform merge
	test_must_fail git merge conflict_branch &&
	test -f .git/MERGE_HEAD &&
	# Post-merge worktree changes
	echo yzxxz > foo &&
	echo blech > baz &&
	git add foo bar &&
	### When aborting the merge, git will discard all staged changes
	### (foo, bar and baz), and no changes will be preserved. Whether
	### the changes were staged pre- or post-merge does not matter
	### (except for not preventing starting the merge).
	### Change expectations accordingly:
	rm expect expect-staged &&
	touch expect &&
	touch expect-staged &&
	# Abort merge
	git merge --abort &&
	test ! -f .git/MERGE_HEAD &&
	test "$pre_merge_head" = "$(git rev-parse HEAD)" &&
	git diff > actual &&
	test_cmp expect actual &&
	git diff --staged > actual-staged &&
	test_cmp expect-staged actual-staged
'

test_done