fix: forgit add shows dir view for submodules

bin/git-forgit

@@ -166,6 +166,10 @@ _forgit_list_files() {
     git ls-files -z "$@" "$rootdir" | tr '\0' '\n' | uniq
 }
 
+_forgit_is_submodule() {
+    git submodule --quiet status "$1"
+}
+
 _forgit_log_preview() {
     local sha
     sha=$(echo "$1" | _forgit_extract_sha)
@@ -418,10 +422,12 @@ _forgit_show() {
 
 _forgit_add_preview() {
     file=$(echo "$1" | _forgit_get_single_file_from_add_line)
-    # $file can be a directory when status.showUntrackedFiles is explicitly set to 'normal'
-    # In this case, show the content of the directory and return
-    [ -d "$file" ] && eval "$_forgit_dir_view \"$file\"" && return 0
-
+    # $file can be a directory when status.showUntrackedFiles is set to 'normal'
+    # When this is the case and the directory is not a submodule show the content of the directory and return
+    if [[ -d "$file"  ]] && ! _forgit_is_submodule "$file"; then
+        eval "$_forgit_dir_view \"$file\""
+        return 0
+    fi
     if (git status -s -- "$file" | grep '^??') &>/dev/null; then  # diff with /dev/null for untracked files
         git diff --color=always --no-index -- /dev/null "$file" | _forgit_pager diff | sed '2 s/added:/untracked:/'
     else

tests/is-submodule.test.sh

@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+
+function set_up_before_script() {
+    local submod submod1
+    source bin/git-forgit
+
+    # Ignore global git config files
+    export GIT_CONFIG_SYSTEM=/dev/null
+    export GIT_CONFIG_GLOBAL=/dev/null
+
+    # create repositories for submodule usage
+    submod=$(create_submodule)
+    submod1=$(create_submodule)
+
+    # create a new git repository in a temp directory
+    create_repo
+
+    # create submodules to test against
+    git -c protocol.file.allow=always submodule add "$submod" submodule
+    git -c protocol.file.allow=always submodule add "$submod1" 'submodule with spaces'
+
+    # create regular directories
+    mkdir regular-directory
+    mkdir 'directory with spaces'
+}
+
+function create_submodule() {
+    create_repo
+    touch file
+    git add file
+    git commit -q -m "initial commit"
+}
+
+function create_repo() {
+    cd "$(bashunit::temp_dir)" || return 1
+    git init --quiet
+    git config user.email "test@example.com"
+    git config user.name "Test User"
+    pwd
+}
+
+# @data_provider provider_is_submodule
+function test_forgit_is_submodule() {
+    _forgit_is_submodule "$1"
+    assert_exit_code "0"
+}
+
+function provider_is_submodule() {
+    bashunit::data_set submodule
+    bashunit::data_set 'submodule with spaces'
+}
+
+# @data_provider provider_is_no_submodule
+function test_forgit_is_no_submodule() {
+    _forgit_is_submodule "$1"
+    assert_exit_code "1"
+}
+
+function provider_is_no_submodule() {
+    bashunit::data_set regular-directory
+    bashunit::data_set 'directory with spaces'
+    bashunit::data_set unknown
+}