#!/bin/sh

test_description="merges with unrelated index changes"

. ./test-lib.sh

# Testcase for some simple merges
#   A
#   o-------o B
#    \
#     \-----o C
#      \
#       \---o D
#        \
#         \-o E
#          \
#           o F
#   Commit A: some file a
#   Commit B: adds file b, modifies end of a
#   Commit C: adds file c
#   Commit D: adds file d, modifies beginning of a
#   Commit E: renames a->subdir/a, adds subdir/e
#   Commit F: empty commit

test_expect_success 'setup trivial merges' '
        test_seq 1 10 >a &&
        git add a &&
        test_tick && git commit -m A &&

        git branch A &&
        git branch B &&
        git branch C &&
        git branch D &&
        git branch E &&
        git branch F &&

        git checkout B &&
        echo b >b &&
        echo 11 >>a &&
        git add a b &&
        test_tick && git commit -m B &&

        git checkout C &&
        echo c >c &&
        git add c &&
        test_tick && git commit -m C &&

        git checkout D &&
        test_seq 2 10 >a &&
        echo d >d &&
        git add a d &&
        test_tick && git commit -m D &&

        git checkout E &&
        mkdir subdir &&
        git mv a subdir/a &&
        echo e >subdir/e &&
        git add subdir &&
        test_tick && git commit -m E &&

        git checkout F &&
        test_tick && git commit --allow-empty -m F
'

test_expect_success 'ff update' '
        git reset --hard &&
        git checkout A^0 &&

        touch random_file && git add random_file &&

        git merge E^0 &&

        test_must_fail git rev-parse HEAD:random_file &&
        test "$(git diff --name-only --cached E)" = "random_file"
'

test_expect_success 'ff update, important file modified' '
        git reset --hard &&
        git checkout A^0 &&

        mkdir subdir &&
        touch subdir/e &&
        git add subdir/e &&

        test_must_fail git merge E^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'resolve, trivial' '
        git reset --hard &&
        git checkout B^0 &&

        touch random_file && git add random_file &&

        test_must_fail git merge -s resolve C^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'resolve, non-trivial' '
        git reset --hard &&
        git checkout B^0 &&

        touch random_file && git add random_file &&

        test_must_fail git merge -s resolve D^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'recursive' '
        git reset --hard &&
        git checkout B^0 &&

        touch random_file && git add random_file &&

        test_must_fail git merge -s recursive C^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'recursive, when merge branch matches merge base' '
        git reset --hard &&
        git checkout B^0 &&

        touch random_file && git add random_file &&

        test_must_fail git merge -s recursive F^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'merge-recursive, when index==head but head!=HEAD' '
        git reset --hard &&
        git checkout C^0 &&

        # Make index match B
        git diff C B -- | git apply --cached &&
        # Merge B & F, with B as "head"
        git merge-recursive A -- B F > out &&
        test_i18ngrep "Already up to date" out
'

test_expect_failure 'recursive, when file has staged changes not matching HEAD nor what a merge would give' '
        git reset --hard &&
        git checkout B^0 &&

        mkdir subdir &&
        test_seq 1 10 >subdir/a &&
        git add subdir/a &&

        # HEAD has no subdir/a; merge would write 1..11 to subdir/a;
        # Since subdir/a matches neither HEAD nor what the merge would write
        # to that file, the merge should fail to avoid overwriting what is
        # currently found in subdir/a
        test_must_fail git merge -s recursive E^0
'

test_expect_failure 'recursive, when file has staged changes matching what a merge would give' '
        git reset --hard &&
        git checkout B^0 &&

        mkdir subdir &&
        test_seq 1 11 >subdir/a &&
        git add subdir/a &&

        # HEAD has no subdir/a; merge would write 1..11 to subdir/a;
        # Since subdir/a matches what the merge would write to that file,
        # the merge should be safe to proceed
        git merge -s recursive E^0
'

test_expect_success 'octopus, unrelated file touched' '
        git reset --hard &&
        git checkout B^0 &&

        touch random_file && git add random_file &&

        test_must_fail git merge C^0 D^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'octopus, related file removed' '
        git reset --hard &&
        git checkout B^0 &&

        git rm b &&

        test_must_fail git merge C^0 D^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'octopus, related file modified' '
        git reset --hard &&
        git checkout B^0 &&

        echo 12 >>a && git add a &&

        test_must_fail git merge C^0 D^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'ours' '
        git reset --hard &&
        git checkout B^0 &&

        touch random_file && git add random_file &&

        test_must_fail git merge -s ours C^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_expect_success 'subtree' '
        git reset --hard &&
        git checkout B^0 &&

        touch random_file && git add random_file &&

        test_must_fail git merge -s subtree E^0 &&
        test_path_is_missing .git/MERGE_HEAD
'

test_done