# Create a submodule layout used for all tests below.
#
# The following use cases are covered:
# - New submodule (no_submodule => add_sub1)
# - Removed submodule (add_sub1 => remove_sub1)
# - Updated submodule (add_sub1 => modify_sub1)
# - Updated submodule recursively (add_nested_sub => modify_sub1_recursively)
# - Submodule updated to invalid commit (add_sub1 => invalid_sub1)
# - Submodule updated from invalid commit (invalid_sub1 => valid_sub1)
# - Submodule replaced by tracked files in directory (add_sub1 =>
#   replace_sub1_with_directory)
# - Directory containing tracked files replaced by submodule
#   (replace_sub1_with_directory => replace_directory_with_sub1)
# - Submodule replaced by tracked file with the same name (add_sub1 =>
#   replace_sub1_with_file)
# - Tracked file replaced by submodule (replace_sub1_with_file =>
#   replace_file_with_sub1)
#
#                     ----O
#                    /    ^
#                   /     remove_sub1
#                  /
#       add_sub1  /-------O---------O--------O  modify_sub1_recursively
#             |  /        ^         add_nested_sub
#             | /         modify_sub1
#             v/
#      O------O-----------O---------O
#      ^       \          ^         replace_directory_with_sub1
#      |        \         replace_sub1_with_directory
# no_submodule   \
#                 --------O---------O
#                  \      ^         replace_file_with_sub1
#                   \     replace_sub1_with_file
#                    \
#                     ----O---------O
#                         ^         valid_sub1
#                         invalid_sub1
#

create_lib_submodule_repo () {
        git init submodule_update_sub1 &&
        (
                cd submodule_update_sub1 &&
                echo "expect" >>.gitignore &&
                echo "actual" >>.gitignore &&
                echo "x" >file1 &&
                echo "y" >file2 &&
                git add .gitignore file1 file2 &&
                git commit -m "Base inside first submodule" &&
                git branch "no_submodule"
        ) &&
        git init submodule_update_sub2 &&
        (
                cd submodule_update_sub2
                echo "expect" >>.gitignore &&
                echo "actual" >>.gitignore &&
                echo "x" >file1 &&
                echo "y" >file2 &&
                git add .gitignore file1 file2 &&
                git commit -m "nested submodule base" &&
                git branch "no_submodule"
        ) &&
        git init submodule_update_repo &&
        (
                cd submodule_update_repo &&
                echo "expect" >>.gitignore &&
                echo "actual" >>.gitignore &&
                echo "x" >file1 &&
                echo "y" >file2 &&
                git add .gitignore file1 file2 &&
                git commit -m "Base" &&
                git branch "no_submodule" &&

                git checkout -b "add_sub1" &&
                git submodule add ../submodule_update_sub1 sub1 &&
                git submodule add ../submodule_update_sub1 uninitialized_sub &&
                git config -f .gitmodules submodule.sub1.ignore all &&
                git config submodule.sub1.ignore all &&
                git add .gitmodules &&
                git commit -m "Add sub1" &&

                git checkout -b remove_sub1 add_sub1 &&
                git revert HEAD &&

                git checkout -b modify_sub1 add_sub1 &&
                git submodule update &&
                (
                        cd sub1 &&
                        git fetch &&
                        git checkout -b "modifications" &&
                        echo "z" >file2 &&
                        echo "x" >file3 &&
                        git add file2 file3 &&
                        git commit -m "modified file2 and added file3" &&
                        git push origin modifications
                ) &&
                git add sub1 &&
                git commit -m "Modify sub1" &&

                git checkout -b add_nested_sub modify_sub1 &&
                git -C sub1 checkout -b "add_nested_sub" &&
                git -C sub1 submodule add --branch no_submodule ../submodule_update_sub2 sub2 &&
                git -C sub1 commit -a -m "add a nested submodule" &&
                git add sub1 &&
                git commit -a -m "update submodule, that updates a nested submodule" &&
                git checkout -b modify_sub1_recursively &&
                git -C sub1 checkout -b modify_sub1_recursively &&
                git -C sub1/sub2 checkout -b modify_sub1_recursively &&
                echo change >sub1/sub2/file3 &&
                git -C sub1/sub2 add file3 &&
                git -C sub1/sub2 commit -m "make a change in nested sub" &&
                git -C sub1 add sub2 &&
                git -C sub1 commit -m "update nested sub" &&
                git add sub1 &&
                git commit -m "update sub1, that updates nested sub" &&
                git -C sub1 push origin modify_sub1_recursively &&
                git -C sub1/sub2 push origin modify_sub1_recursively &&
                git -C sub1 submodule deinit -f --all &&

                git checkout -b replace_sub1_with_directory add_sub1 &&
                git submodule update &&
                git -C sub1 checkout modifications &&
                git rm --cached sub1 &&
                rm sub1/.git* &&
                git config -f .gitmodules --remove-section "submodule.sub1" &&
                git add .gitmodules sub1/* &&
                git commit -m "Replace sub1 with directory" &&

                git checkout -b replace_directory_with_sub1 &&
                git revert HEAD &&

                git checkout -b replace_sub1_with_file add_sub1 &&
                git rm sub1 &&
                echo "content" >sub1 &&
                git add sub1 &&
                git commit -m "Replace sub1 with file" &&

                git checkout -b replace_file_with_sub1 &&
                git revert HEAD &&

                git checkout -b invalid_sub1 add_sub1 &&
                git update-index --cacheinfo 160000 0123456789012345678901234567890123456789 sub1 &&
                git commit -m "Invalid sub1 commit" &&
                git checkout -b valid_sub1 &&
                git revert HEAD &&

                git checkout master
        )
}

# Helper function to replace gitfile with .git directory
replace_gitfile_with_git_dir () {
        (
                cd "$1" &&
                git_dir="$(git rev-parse --git-dir)" &&
                rm -f .git &&
                cp -R "$git_dir" .git &&
                GIT_WORK_TREE=. git config --unset core.worktree
        )
}

# Test that the .git directory in the submodule is unchanged (except for the
# core.worktree setting, which appears only in $GIT_DIR/modules/$1/config).
# Call this function before test_submodule_content as the latter might
# write the index file leading to false positive index differences.
#
# Note that this only supports submodules at the root level of the
# superproject, with the default name, i.e. same as its path.
test_git_directory_is_unchanged () {
        (
                cd ".git/modules/$1" &&
                # does core.worktree point at the right place?
                test "$(git config core.worktree)" = "../../../$1" &&
                # remove it temporarily before comparing, as
                # "$1/.git/config" lacks it...
                git config --unset core.worktree
        ) &&
        diff -r ".git/modules/$1" "$1/.git" &&
        (
                # ... and then restore.
                cd ".git/modules/$1" &&
                git config core.worktree "../../../$1"
        )
}

test_git_directory_exists() {
        test -e ".git/modules/$1" &&
        if test -f sub1/.git
        then
                # does core.worktree point at the right place?
                test "$(git -C .git/modules/$1 config core.worktree)" = "../../../$1"
        fi
}

# Helper function to be executed at the start of every test below, it sets up
# the submodule repo if it doesn't exist and configures the most problematic
# settings for diff.ignoreSubmodules.
prolog () {
        (test -d submodule_update_repo || create_lib_submodule_repo) &&
        test_config_global diff.ignoreSubmodules all &&
        test_config diff.ignoreSubmodules all
}

# Helper function to bring work tree back into the state given by the
# commit. This includes trying to populate sub1 accordingly if it exists and
# should be updated to an existing commit.
reset_work_tree_to () {
        rm -rf submodule_update &&
        git clone submodule_update_repo submodule_update &&
        (
                cd submodule_update &&
                rm -rf sub1 &&
                git checkout -f "$1" &&
                git status -u -s >actual &&
                test_must_be_empty actual &&
                hash=$(git rev-parse --revs-only HEAD:sub1) &&
                if test -n "$hash" &&
                   test $(cd "../submodule_update_sub1" && git rev-parse --verify "$hash^{commit}")
                then
                        git submodule update --init --recursive "sub1"
                fi
        )
}

reset_work_tree_to_interested () {
        reset_work_tree_to $1 &&
        # make the submodule git dirs available
        if ! test -d submodule_update/.git/modules/sub1
        then
                mkdir -p submodule_update/.git/modules &&
                cp -r submodule_update_repo/.git/modules/sub1 submodule_update/.git/modules/sub1
                GIT_WORK_TREE=. git -C submodule_update/.git/modules/sub1 config --unset core.worktree
        fi &&
        if ! test -d submodule_update/.git/modules/sub1/modules/sub2
        then
                mkdir -p submodule_update/.git/modules/sub1/modules &&
                cp -r submodule_update_repo/.git/modules/sub1/modules/sub2 submodule_update/.git/modules/sub1/modules/sub2
                GIT_WORK_TREE=. git -C submodule_update/.git/modules/sub1/modules/sub2 config --unset core.worktree
        fi &&
        # indicate we are interested in the submodule:
        git -C submodule_update config submodule.sub1.url "bogus" &&
        # sub1 might not be checked out, so use the git dir
        git -C submodule_update/.git/modules/sub1 config submodule.sub2.url "bogus"
}

# Test that the superproject contains the content according to commit "$1"
# (the work tree must match the index for everything but submodules but the
# index must exactly match the given commit including any submodule SHA-1s).
test_superproject_content () {
        git diff-index --cached "$1" >actual &&
        test_must_be_empty actual &&
        git diff-files --ignore-submodules >actual &&
        test_must_be_empty actual
}

# Test that the given submodule at path "$1" contains the content according
# to the submodule commit recorded in the superproject's commit "$2"
test_submodule_content () {
        if test x"$1" = "x-C"
        then
                cd "$2"
                shift; shift;
        fi
        if test $# != 2
        then
                echo "test_submodule_content needs two arguments"
                return 1
        fi &&
        submodule="$1" &&
        commit="$2" &&
        test -d "$submodule"/ &&
        if ! test -f "$submodule"/.git && ! test -d "$submodule"/.git
        then
                echo "Submodule $submodule is not populated"
                return 1
        fi &&
        sha1=$(git rev-parse --verify "$commit:$submodule") &&
        if test -z "$sha1"
        then
                echo "Couldn't retrieve SHA-1 of $submodule for $commit"
                return 1
        fi &&
        (
                cd "$submodule" &&
                git status -u -s >actual &&
                test_must_be_empty actual &&
                git diff "$sha1" >actual &&
                test_must_be_empty actual
        )
}

# Test that the following transitions are correctly handled:
# - Updated submodule
# - New submodule
# - Removed submodule
# - Directory containing tracked files replaced by submodule
# - Submodule replaced by tracked files in directory
# - Submodule replaced by tracked file with the same name
# - tracked file replaced by submodule
#
# The default is that submodule contents aren't changed until "git submodule
# update" is run. And even then that command doesn't delete the work tree of
# a removed submodule.
#
# Removing a submodule containing a .git directory must fail even when forced
# to protect the history!
#

# Internal function; use test_submodule_switch() or
# test_submodule_forced_switch() instead.
test_submodule_switch_common() {
        command="$1"
        ######################### Appearing submodule #########################
        # Switching to a commit letting a submodule appear creates empty dir ...
        if test "$KNOWN_FAILURE_STASH_DOES_IGNORE_SUBMODULE_CHANGES" = 1
        then
                # Restoring stash fails to restore submodule index entry
                RESULT="failure"
        else
                RESULT="success"
        fi
        test_expect_$RESULT "$command: added submodule creates empty directory" '
                prolog &&
                reset_work_tree_to no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_dir_is_empty sub1 &&
                        git submodule update --init --recursive &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... and doesn't care if it already exists.
        test_expect_$RESULT "$command: added submodule leaves existing empty directory alone" '
                prolog &&
                reset_work_tree_to no_submodule &&
                (
                        cd submodule_update &&
                        mkdir sub1 &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_dir_is_empty sub1 &&
                        git submodule update --init --recursive &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # Replacing a tracked file with a submodule produces an empty
        # directory ...
        test_expect_$RESULT "$command: replace tracked file with submodule creates empty directory" '
                prolog &&
                reset_work_tree_to replace_sub1_with_file &&
                (
                        cd submodule_update &&
                        git branch -t replace_file_with_sub1 origin/replace_file_with_sub1 &&
                        $command replace_file_with_sub1 &&
                        test_superproject_content origin/replace_file_with_sub1 &&
                        test_dir_is_empty sub1 &&
                        git submodule update --init --recursive &&
                        test_submodule_content sub1 origin/replace_file_with_sub1
                )
        '
        # ... as does removing a directory with tracked files with a
        # submodule.
        if test "$KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR" = 1
        then
                # Non fast-forward merges fail with "Directory sub1 doesn't
                # exist. sub1" because the empty submodule directory is not
                # created
                RESULT="failure"
        else
                RESULT="success"
        fi
        test_expect_$RESULT "$command: replace directory with submodule" '
                prolog &&
                reset_work_tree_to replace_sub1_with_directory &&
                (
                        cd submodule_update &&
                        git branch -t replace_directory_with_sub1 origin/replace_directory_with_sub1 &&
                        $command replace_directory_with_sub1 &&
                        test_superproject_content origin/replace_directory_with_sub1 &&
                        test_dir_is_empty sub1 &&
                        git submodule update --init --recursive &&
                        test_submodule_content sub1 origin/replace_directory_with_sub1
                )
        '

        ######################## Disappearing submodule #######################
        # Removing a submodule doesn't remove its work tree ...
        if test "$KNOWN_FAILURE_STASH_DOES_IGNORE_SUBMODULE_CHANGES" = 1
        then
                RESULT="failure"
        else
                RESULT="success"
        fi
        test_expect_$RESULT "$command: removed submodule leaves submodule directory and its contents in place" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t remove_sub1 origin/remove_sub1 &&
                        $command remove_sub1 &&
                        test_superproject_content origin/remove_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... especially when it contains a .git directory.
        test_expect_$RESULT "$command: removed submodule leaves submodule containing a .git directory alone" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t remove_sub1 origin/remove_sub1 &&
                        replace_gitfile_with_git_dir sub1 &&
                        $command remove_sub1 &&
                        test_superproject_content origin/remove_sub1 &&
                        test_git_directory_is_unchanged sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # Replacing a submodule with files in a directory must fail as the
        # submodule work tree isn't removed ...
        if test "$KNOWN_FAILURE_NOFF_MERGE_ATTEMPTS_TO_MERGE_REMOVED_SUBMODULE_FILES" = 1
        then
                # Non fast-forward merges attempt to merge the former
                # submodule files with the newly checked out ones in the
                # directory of the same name while it shouldn't.
                RESULT="failure"
        elif test "$KNOWN_FAILURE_FORCED_SWITCH_TESTS" = 1
        then
                # All existing tests that use test_submodule_forced_switch()
                # require this.
                RESULT="failure"
        else
                RESULT="success"
        fi
        test_expect_$RESULT "$command: replace submodule with a directory must fail" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_directory origin/replace_sub1_with_directory &&
                        test_must_fail $command replace_sub1_with_directory &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... especially when it contains a .git directory.
        test_expect_$RESULT "$command: replace submodule containing a .git directory with a directory must fail" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_directory origin/replace_sub1_with_directory &&
                        replace_gitfile_with_git_dir sub1 &&
                        test_must_fail $command replace_sub1_with_directory &&
                        test_superproject_content origin/add_sub1 &&
                        test_git_directory_is_unchanged sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # Replacing it with a file must fail as it could throw away any local
        # work tree changes ...
        test_expect_failure "$command: replace submodule with a file must fail" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        test_must_fail $command replace_sub1_with_file &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... or even destroy unpushed parts of submodule history if that
        # still uses a .git directory.
        test_expect_failure "$command: replace submodule containing a .git directory with a file must fail" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        replace_gitfile_with_git_dir sub1 &&
                        test_must_fail $command replace_sub1_with_file &&
                        test_superproject_content origin/add_sub1 &&
                        test_git_directory_is_unchanged sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '

        ########################## Modified submodule #########################
        # Updating a submodule sha1 doesn't update the submodule's work tree
        if test "$KNOWN_FAILURE_CHERRY_PICK_SEES_EMPTY_COMMIT" = 1
        then
                # When cherry picking a SHA-1 update for an ignored submodule
                # the commit incorrectly fails with "The previous cherry-pick
                # is now empty, possibly due to conflict resolution."
                RESULT="failure"
        else
                RESULT="success"
        fi
        test_expect_$RESULT "$command: modified submodule does not update submodule work tree" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t modify_sub1 origin/modify_sub1 &&
                        $command modify_sub1 &&
                        test_superproject_content origin/modify_sub1 &&
                        test_submodule_content sub1 origin/add_sub1 &&
                        git submodule update &&
                        test_submodule_content sub1 origin/modify_sub1
                )
        '
        # Updating a submodule to an invalid sha1 doesn't update the
        # submodule's work tree, subsequent update will fail
        test_expect_$RESULT "$command: modified submodule does not update submodule work tree to invalid commit" '
                prolog &&
                reset_work_tree_to add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t invalid_sub1 origin/invalid_sub1 &&
                        $command invalid_sub1 &&
                        test_superproject_content origin/invalid_sub1 &&
                        test_submodule_content sub1 origin/add_sub1 &&
                        test_must_fail git submodule update &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # Updating a submodule from an invalid sha1 doesn't update the
        # submodule's work tree, subsequent update will succeed
        test_expect_$RESULT "$command: modified submodule does not update submodule work tree from invalid commit" '
                prolog &&
                reset_work_tree_to invalid_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t valid_sub1 origin/valid_sub1 &&
                        $command valid_sub1 &&
                        test_superproject_content origin/valid_sub1 &&
                        test_dir_is_empty sub1 &&
                        git submodule update --init --recursive &&
                        test_submodule_content sub1 origin/valid_sub1
                )
        '
}

# Declares and invokes several tests that, in various situations, checks that
# the provided transition function:
#  - succeeds in updating the worktree and index of a superproject to a target
#    commit, or fails atomically (depending on the test situation)
#  - if succeeds, the contents of submodule directories are unchanged
#  - if succeeds, once "git submodule update" is invoked, the contents of
#    submodule directories are updated
#
# Use as follows:
#
# my_func () {
#   target=$1
#   # Do something here that updates the worktree and index to match target,
#   # but not any submodule directories.
# }
# test_submodule_switch "my_func"
test_submodule_switch () {
        command="$1"
        test_submodule_switch_common "$command"

        # An empty directory does not prevent the creation of a submodule of
        # the same name, but a file does.
        test_expect_success "$command: added submodule doesn't remove untracked unignored file with same name" '
                prolog &&
                reset_work_tree_to no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        >sub1 &&
                        test_must_fail $command add_sub1 &&
                        test_superproject_content origin/no_submodule &&
                        test_must_be_empty sub1
                )
        '
}

# Same as test_submodule_switch(), except that throwing away local changes in
# the superproject is allowed.
test_submodule_forced_switch () {
        command="$1"
        KNOWN_FAILURE_FORCED_SWITCH_TESTS=1
        test_submodule_switch_common "$command"

        # When forced, a file in the superproject does not prevent creating a
        # submodule of the same name.
        test_expect_success "$command: added submodule does remove untracked unignored file with same name when forced" '
                prolog &&
                reset_work_tree_to no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        >sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_dir_is_empty sub1
                )
        '
}

# Test that submodule contents are correctly updated when switching
# between commits that change a submodule.
# Test that the following transitions are correctly handled:
# (These tests are also above in the case where we expect no change
#  in the submodule)
# - Updated submodule
# - New submodule
# - Removed submodule
# - Directory containing tracked files replaced by submodule
# - Submodule replaced by tracked files in directory
# - Submodule replaced by tracked file with the same name
# - tracked file replaced by submodule
#
# New test cases
# - Removing a submodule with a git directory absorbs the submodules
#   git directory first into the superproject.

test_submodule_switch_recursing_with_args () {
        cmd_args="$1"
        command="git $cmd_args --recurse-submodules"
        RESULTDS=success
        if test "$KNOWN_FAILURE_DIRECTORY_SUBMODULE_CONFLICTS" = 1
        then
                RESULTDS=failure
        fi
        RESULTOI=success
        if test "$KNOWN_FAILURE_SUBMODULE_OVERWRITE_IGNORED_UNTRACKED" = 1
        then
                RESULTOI=failure
        fi
        ######################### Appearing submodule #########################
        # Switching to a commit letting a submodule appear checks it out ...
        test_expect_success "$command: added submodule is checked out" '
                prolog &&
                reset_work_tree_to_interested no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... ignoring an empty existing directory ...
        test_expect_success "$command: added submodule is checked out in empty dir" '
                prolog &&
                reset_work_tree_to_interested no_submodule &&
                (
                        cd submodule_update &&
                        mkdir sub1 &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... unless there is an untracked file in its place.
        test_expect_success "$command: added submodule doesn't remove untracked file with same name" '
                prolog &&
                reset_work_tree_to_interested no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        : >sub1 &&
                        test_must_fail $command add_sub1 &&
                        test_superproject_content origin/no_submodule &&
                        test_must_be_empty sub1
                )
        '
        # ... but an ignored file is fine.
        test_expect_$RESULTOI "$command: added submodule removes an untracked ignored file" '
                test_when_finished "rm submodule_update/.git/info/exclude" &&
                prolog &&
                reset_work_tree_to_interested no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        : >sub1 &&
                        echo sub1 >.git/info/exclude
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        test_expect_success "$command: submodule branch is not changed, detach HEAD instead" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git -C sub1 checkout -b keep_branch &&
                        git -C sub1 rev-parse HEAD >expect &&
                        git branch -t check-keep origin/modify_sub1 &&
                        $command check-keep &&
                        test_superproject_content origin/modify_sub1 &&
                        test_submodule_content sub1 origin/modify_sub1 &&
                        git -C sub1 rev-parse keep_branch >actual &&
                        test_cmp expect actual &&
                        test_must_fail git -C sub1 symbolic-ref HEAD
                )
        '

        # Replacing a tracked file with a submodule produces a checked out submodule
        test_expect_success "$command: replace tracked file with submodule checks out submodule" '
                prolog &&
                reset_work_tree_to_interested replace_sub1_with_file &&
                (
                        cd submodule_update &&
                        git branch -t replace_file_with_sub1 origin/replace_file_with_sub1 &&
                        $command replace_file_with_sub1 &&
                        test_superproject_content origin/replace_file_with_sub1 &&
                        test_submodule_content sub1 origin/replace_file_with_sub1
                )
        '
        # ... as does removing a directory with tracked files with a submodule.
        test_expect_success "$command: replace directory with submodule" '
                prolog &&
                reset_work_tree_to_interested replace_sub1_with_directory &&
                (
                        cd submodule_update &&
                        git branch -t replace_directory_with_sub1 origin/replace_directory_with_sub1 &&
                        $command replace_directory_with_sub1 &&
                        test_superproject_content origin/replace_directory_with_sub1 &&
                        test_submodule_content sub1 origin/replace_directory_with_sub1
                )
        '

        ######################## Disappearing submodule #######################
        # Removing a submodule removes its work tree ...
        test_expect_success "$command: removed submodule removes submodules working tree" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t remove_sub1 origin/remove_sub1 &&
                        $command remove_sub1 &&
                        test_superproject_content origin/remove_sub1 &&
                        ! test -e sub1
                )
        '
        # ... absorbing a .git directory along the way.
        test_expect_success "$command: removed submodule absorbs submodules .git directory" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t remove_sub1 origin/remove_sub1 &&
                        replace_gitfile_with_git_dir sub1 &&
                        rm -rf .git/modules &&
                        $command remove_sub1 &&
                        test_superproject_content origin/remove_sub1 &&
                        ! test -e sub1 &&
                        test_git_directory_exists sub1
                )
        '
        # Replacing a submodule with files in a directory must succeeds
        # when the submodule is clean
        test_expect_$RESULTDS "$command: replace submodule with a directory" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_directory origin/replace_sub1_with_directory &&
                        $command replace_sub1_with_directory &&
                        test_superproject_content origin/replace_sub1_with_directory &&
                        test_submodule_content sub1 origin/replace_sub1_with_directory
                )
        '
        # ... absorbing a .git directory.
        test_expect_$RESULTDS "$command: replace submodule containing a .git directory with a directory must absorb the git dir" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_directory origin/replace_sub1_with_directory &&
                        replace_gitfile_with_git_dir sub1 &&
                        rm -rf .git/modules &&
                        $command replace_sub1_with_directory &&
                        test_superproject_content origin/replace_sub1_with_directory &&
                        test_git_directory_exists sub1
                )
        '

        # Replacing it with a file ...
        test_expect_success "$command: replace submodule with a file" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        $command replace_sub1_with_file &&
                        test_superproject_content origin/replace_sub1_with_file &&
                        test -f sub1
                )
        '

        # ... must check its local work tree for untracked files
        test_expect_$RESULTDS "$command: replace submodule with a file must fail with untracked files" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        : >sub1/untrackedfile &&
                        test_must_fail $command replace_sub1_with_file &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '

        # ... and ignored files are ignored
        test_expect_success "$command: replace submodule with a file works ignores ignored files in submodule" '
                test_when_finished "rm submodule_update/.git/modules/sub1/info/exclude" &&
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        : >sub1/ignored &&
                        $command replace_sub1_with_file &&
                        test_superproject_content origin/replace_sub1_with_file &&
                        test -f sub1
                )
        '

        ########################## Modified submodule #########################
        # Updating a submodule sha1 updates the submodule's work tree
        test_expect_success "$command: modified submodule updates submodule work tree" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t modify_sub1 origin/modify_sub1 &&
                        $command modify_sub1 &&
                        test_superproject_content origin/modify_sub1 &&
                        test_submodule_content sub1 origin/modify_sub1
                )
        '

        test_expect_success "git -c submodule.recurse=true $cmd_args: modified submodule updates submodule work tree" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t modify_sub1 origin/modify_sub1 &&
                        git -c submodule.recurse=true $cmd_args modify_sub1 &&
                        test_superproject_content origin/modify_sub1 &&
                        test_submodule_content sub1 origin/modify_sub1
                )
        '

        # Updating a submodule to an invalid sha1 doesn't update the
        # superproject nor the submodule's work tree.
        test_expect_success "$command: updating to a missing submodule commit fails" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t invalid_sub1 origin/invalid_sub1 &&
                        test_must_fail $command invalid_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '

        # recursing deeper than one level doesn't work yet.
        test_expect_success "$command: modified submodule updates submodule recursively" '
                prolog &&
                reset_work_tree_to_interested add_nested_sub &&
                (
                        cd submodule_update &&
                        git branch -t modify_sub1_recursively origin/modify_sub1_recursively &&
                        $command modify_sub1_recursively &&
                        test_superproject_content origin/modify_sub1_recursively &&
                        test_submodule_content sub1 origin/modify_sub1_recursively &&
                        test_submodule_content -C sub1 sub2 origin/modify_sub1_recursively
                )
        '
}

# Test that submodule contents are updated when switching between commits
# that change a submodule, but throwing away local changes in
# the superproject as well as the submodule is allowed.
test_submodule_forced_switch_recursing_with_args () {
        cmd_args="$1"
        command="git $cmd_args --recurse-submodules"
        RESULT=success
        if test "$KNOWN_FAILURE_DIRECTORY_SUBMODULE_CONFLICTS" = 1
        then
                RESULT=failure
        fi
        ######################### Appearing submodule #########################
        # Switching to a commit letting a submodule appear creates empty dir ...
        test_expect_success "$command: added submodule is checked out" '
                prolog &&
                reset_work_tree_to_interested no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... and doesn't care if it already exists ...
        test_expect_success "$command: added submodule ignores empty directory" '
                prolog &&
                reset_work_tree_to_interested no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        mkdir sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # ... not caring about an untracked file either
        test_expect_success "$command: added submodule does remove untracked unignored file with same name when forced" '
                prolog &&
                reset_work_tree_to_interested no_submodule &&
                (
                        cd submodule_update &&
                        git branch -t add_sub1 origin/add_sub1 &&
                        >sub1 &&
                        $command add_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # Replacing a tracked file with a submodule checks out the submodule
        test_expect_success "$command: replace tracked file with submodule populates the submodule" '
                prolog &&
                reset_work_tree_to_interested replace_sub1_with_file &&
                (
                        cd submodule_update &&
                        git branch -t replace_file_with_sub1 origin/replace_file_with_sub1 &&
                        $command replace_file_with_sub1 &&
                        test_superproject_content origin/replace_file_with_sub1 &&
                        test_submodule_content sub1 origin/replace_file_with_sub1
                )
        '
        # ... as does removing a directory with tracked files with a
        # submodule.
        test_expect_success "$command: replace directory with submodule" '
                prolog &&
                reset_work_tree_to_interested replace_sub1_with_directory &&
                (
                        cd submodule_update &&
                        git branch -t replace_directory_with_sub1 origin/replace_directory_with_sub1 &&
                        $command replace_directory_with_sub1 &&
                        test_superproject_content origin/replace_directory_with_sub1 &&
                        test_submodule_content sub1 origin/replace_directory_with_sub1
                )
        '

        ######################## Disappearing submodule #######################
        # Removing a submodule doesn't remove its work tree ...
        test_expect_success "$command: removed submodule leaves submodule directory and its contents in place" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t remove_sub1 origin/remove_sub1 &&
                        $command remove_sub1 &&
                        test_superproject_content origin/remove_sub1 &&
                        ! test -e sub1
                )
        '
        # ... especially when it contains a .git directory.
        test_expect_success "$command: removed submodule leaves submodule containing a .git directory alone" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t remove_sub1 origin/remove_sub1 &&
                        replace_gitfile_with_git_dir sub1 &&
                        rm -rf .git/modules/sub1 &&
                        $command remove_sub1 &&
                        test_superproject_content origin/remove_sub1 &&
                        test_git_directory_exists sub1 &&
                        ! test -e sub1
                )
        '
        # Replacing a submodule with files in a directory ...
        test_expect_success "$command: replace submodule with a directory" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_directory origin/replace_sub1_with_directory &&
                        $command replace_sub1_with_directory &&
                        test_superproject_content origin/replace_sub1_with_directory
                )
        '
        # ... absorbing a .git directory.
        test_expect_success "$command: replace submodule containing a .git directory with a directory must fail" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_directory origin/replace_sub1_with_directory &&
                        replace_gitfile_with_git_dir sub1 &&
                        rm -rf .git/modules/sub1 &&
                        $command replace_sub1_with_directory &&
                        test_superproject_content origin/replace_sub1_with_directory &&
                        test_submodule_content sub1 origin/modify_sub1
                        test_git_directory_exists sub1
                )
        '
        # Replacing it with a file
        test_expect_success "$command: replace submodule with a file" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        $command replace_sub1_with_file &&
                        test_superproject_content origin/replace_sub1_with_file
                )
        '

        # ... even if the submodule contains ignored files
        test_expect_success "$command: replace submodule with a file ignoring ignored files" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        : >sub1/expect &&
                        $command replace_sub1_with_file &&
                        test_superproject_content origin/replace_sub1_with_file
                )
        '

        # ... but stops for untracked files that would be lost
        test_expect_$RESULT "$command: replace submodule with a file stops for untracked files" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
                        : >sub1/untracked_file &&
                        test_must_fail $command replace_sub1_with_file &&
                        test_superproject_content origin/add_sub1 &&
                        test -f sub1/untracked_file
                )
        '

        ########################## Modified submodule #########################
        # Updating a submodule sha1 updates the submodule's work tree
        test_expect_success "$command: modified submodule updates submodule work tree" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t modify_sub1 origin/modify_sub1 &&
                        $command modify_sub1 &&
                        test_superproject_content origin/modify_sub1 &&
                        test_submodule_content sub1 origin/modify_sub1
                )
        '
        # Updating a submodule to an invalid sha1 doesn't update the
        # submodule's work tree, subsequent update will fail
        test_expect_success "$command: modified submodule does not update submodule work tree to invalid commit" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t invalid_sub1 origin/invalid_sub1 &&
                        test_must_fail $command invalid_sub1 &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )
        '
        # Updating a submodule from an invalid sha1 updates
        test_expect_success "$command: modified submodule does update submodule work tree from invalid commit" '
                prolog &&
                reset_work_tree_to_interested invalid_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t valid_sub1 origin/valid_sub1 &&
                        $command valid_sub1 &&
                        test_superproject_content origin/valid_sub1 &&
                        test_submodule_content sub1 origin/valid_sub1
                )
        '

        # Old versions of Git were buggy writing the .git link file
        # (e.g. before f8eaa0ba98b and then moving the superproject repo
        # whose submodules contained absolute paths)
        test_expect_success "$command: updating submodules fixes .git links" '
                prolog &&
                reset_work_tree_to_interested add_sub1 &&
                (
                        cd submodule_update &&
                        git branch -t modify_sub1 origin/modify_sub1 &&
                        echo "gitdir: bogus/path" >sub1/.git &&
                        $command modify_sub1 &&
                        test_superproject_content origin/modify_sub1 &&
                        test_submodule_content sub1 origin/modify_sub1
                )
        '
}