refactor: extract branch helpers and ANSI strip utility

- Add _forgit_strip_ansi for removing ANSI escape codes
- Add _forgit_branch_list to list branches with current branch first
- Add _forgit_extract_branch_name to parse branch names from git output
- Update checkout_branch, switch_branch, branch_delete, cherry_pick_from_branch,
  and branch_preview to use the new helpers
- Fix _forgit_inside_work_tree to suppress stderr

bin/git-forgit

@@ -31,9 +31,10 @@ $FORGIT_FZF_DEFAULT_OPTS
 
 _forgit_warn() { printf "%b[Warn]%b %s\n" '\e[0;33m' '\e[0m' "$@" >&2; }
 _forgit_info() { printf "%b[Info]%b %s\n" '\e[0;32m' '\e[0m' "$@" >&2; }
-_forgit_inside_work_tree() { git rev-parse --is-inside-work-tree >/dev/null; }
+_forgit_inside_work_tree() { git rev-parse --is-inside-work-tree >/dev/null 2>&1; }
 # tac is not available on OSX, tail -r is not available on Linux, so we use either of them
 _forgit_reverse_lines() { tac 2> /dev/null || tail -r; }
+_forgit_strip_ansi() { local ESC=$'\033'; sed "s/${ESC}\[[0-9;]*m//g"; }
 
 _forgit_previous_commit() {
     # "SHA~" is invalid when the commit is the first commit, but we can use "--root" instead
@@ -151,6 +152,33 @@ _forgit_is_file_tracked() {
     git ls-files "$1" --error-unmatch &> /dev/null
 }
 
+# List branches with current branch first (for use as fzf header)
+# Usage: _forgit_branch_list [git-branch-options...]
+#
+# Note: We explicitly print the current branch first rather than using
+# `LC_ALL=C sort -k1.1,1.1 -rs` because git branch output has three possible
+# prefixes: '*' (current), '+' (checked out in a worktree), and ' ' (other).
+# Sorting by the first character doesn't reliably place '*' first when '+'
+# is present, since their ASCII order (* < +) conflicts with the desired order.
+_forgit_branch_list() {
+    local current
+    current=$(git branch --show-current)
+    if [[ -n "$current" ]]; then
+        printf '\e[90m%s\e[0m\n' "* $current"
+    else
+        printf '\e[90m%s\e[0m\n' "* (HEAD detached at $(git rev-parse --short HEAD))"
+    fi
+    git branch --color=always "$@" | grep -v '^\*' | grep -v ' -> '
+}
+
+# Extract branch name from git branch output
+# Handles ANSI escape codes, prefix characters (* + ' '), and symbolic refs (->)
+_forgit_extract_branch_name() {
+    _forgit_strip_ansi |
+        sed -E 's/^[*+ ] //; s/ -> .*//' |
+        awk '{print $1}'
+}
+
 _forgit_list_files() {
     local rootdir
     rootdir=$(git rev-parse --show-toplevel)
@@ -686,7 +714,9 @@ _forgit_cherry_pick() {
 }
 
 _forgit_cherry_pick_from_branch_preview() {
-    git log --right-only --color=always --cherry-pick --oneline "$1"..."$2"
+    local branch
+    branch=$(echo "$2" | _forgit_extract_branch_name)
+    git log --right-only --color=always --cherry-pick --oneline "$1"..."$branch"
 }
 
 _forgit_cherry_pick_from_branch() {
@@ -703,7 +733,7 @@ _forgit_cherry_pick_from_branch() {
     opts="
         $FORGIT_FZF_DEFAULT_OPTS
         +s +m --tiebreak=index --header-lines=1
-        --preview=\"$FORGIT cherry_pick_from_branch_preview '$base' {1}\"
+        --preview=\"$FORGIT cherry_pick_from_branch_preview '$base' {}\"
         $FORGIT_CHERRY_PICK_FROM_BRANCH_FZF_OPTS
         "
     # loop until either the branch selector is closed or a commit to be cherry
@@ -711,10 +741,7 @@ _forgit_cherry_pick_from_branch() {
     while true
     do
         if [[ -z $input_branch ]]; then
-            branch="$(git branch --color=always --all |
-            LC_ALL=C sort -k1.1,1.1 -rs |
-            FZF_DEFAULT_OPTS="$opts" fzf |
-            awk '{print $1}')"
+            branch="$(_forgit_branch_list --all | FZF_DEFAULT_OPTS="$opts" fzf | _forgit_extract_branch_name)"
         else
             branch=$input_branch
         fi
@@ -888,13 +915,13 @@ _forgit_checkout_branch() {
     opts="
         $FORGIT_FZF_DEFAULT_OPTS
         +s +m --tiebreak=index --header-lines=1
-        --preview=\"$FORGIT branch_preview {1}\"
+        --preview=\"$FORGIT branch_preview {}\"
         $FORGIT_CHECKOUT_BRANCH_FZF_OPTS
         "
     _forgit_checkout_branch_branch_git_opts=()
     _forgit_parse_array _forgit_checkout_branch_branch_git_opts "$FORGIT_CHECKOUT_BRANCH_BRANCH_GIT_OPTS"
-    branch="$(git branch --color=always "${_forgit_checkout_branch_branch_git_opts[@]:---all}" | LC_ALL=C sort -k1.1,1.1 -rs |
-              FZF_DEFAULT_OPTS="$opts" fzf | awk '{print $1}')"
+    branch="$(_forgit_branch_list "${_forgit_checkout_branch_branch_git_opts[@]:---all}" |
+        FZF_DEFAULT_OPTS="$opts" fzf | _forgit_extract_branch_name)"
     [[ -z "$branch" ]] && return 1
 
     # track the remote branch if possible
@@ -934,13 +961,13 @@ _forgit_switch_branch() {
     opts="
         $FORGIT_FZF_DEFAULT_OPTS
         +s +m --tiebreak=index --header-lines=1
-        --preview=\"$FORGIT branch_preview {1}\"
+        --preview=\"$FORGIT branch_preview {}\"
         $FORGIT_SWITCH_BRANCH_FZF_OPTS
         "
     _forgit_switch_branch_branch_git_opts=()
     _forgit_parse_array _forgit_switch_branch_branch_git_opts "$FORGIT_SWITCH_BRANCH_BRANCH_GIT_OPTS"
-    branch="$(git branch --color=always "${_forgit_switch_branch_branch_git_opts[@]:---all}" | LC_ALL=C sort -k1.1,1.1 -rs |
-              FZF_DEFAULT_OPTS="$opts" fzf | awk '{print $1}')"
+    branch="$(_forgit_branch_list "${_forgit_switch_branch_branch_git_opts[@]:---all}" |
+        FZF_DEFAULT_OPTS="$opts" fzf | _forgit_extract_branch_name)"
     [[ -z "$branch" ]] && return 1
 
     # track the remote branch if possible
@@ -1012,9 +1039,11 @@ _forgit_checkout_commit() {
 }
 
 _forgit_branch_preview() {
+    local branch
+    branch=$(echo "$1" | _forgit_extract_branch_name)
     # the trailing '--' ensures that this works for branches that have a name
     # that is identical to a file
-    git log "$1" "${_forgit_log_preview_options[@]}" --
+    git log "$branch" "${_forgit_log_preview_options[@]}" --
 }
 
 _forgit_git_branch_delete() {
@@ -1031,14 +1060,10 @@ _forgit_branch_delete() {
     opts="
         $FORGIT_FZF_DEFAULT_OPTS
         +s --multi --tiebreak=index --header-lines=1
-        --preview=\"$FORGIT branch_preview {1}\"
+        --preview=\"$FORGIT branch_preview {}\"
         $FORGIT_BRANCH_DELETE_FZF_OPTS
     "
-
-    for branch in $(git branch --color=always |
-        LC_ALL=C sort -k1.1,1.1 -rs |
-        FZF_DEFAULT_OPTS="$opts" fzf |
-        awk '{print $1}')
+    for branch in $(_forgit_branch_list | FZF_DEFAULT_OPTS="$opts" fzf | _forgit_extract_branch_name)
     do
         _forgit_git_branch_delete "$branch"
     done

tests/branch-helpers.test.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+function set_up_before_script() {
+    source bin/git-forgit
+}
+
+# --- _forgit_extract_branch_name ---
+
+# @data_provider provider_extract_branch_name
+function test_forgit_extract_branch_name() {
+    local -r input="$1"
+    local -r expected="$2"
+    local actual
+    actual=$(echo "$input" | _forgit_extract_branch_name)
+    assert_same "$expected" "$actual"
+}
+
+function provider_extract_branch_name() {
+    bashunit::data_set "  main" "main"
+    bashunit::data_set "* main" "main"
+    bashunit::data_set "+ feature" "feature"
+    bashunit::data_set "  remotes/origin/HEAD -> origin/main" "remotes/origin/HEAD"
+    bashunit::data_set "  remotes/origin/feature/foo" "remotes/origin/feature/foo"
+}
+
+# --- _forgit_strip_ansi ---
+
+# @data_provider provider_strip_ansi
+function test_forgit_strip_ansi() {
+    local -r input="$1"
+    local -r expected="$2"
+    local actual
+    actual=$(printf '%b' "$input" | _forgit_strip_ansi)
+    assert_same "$expected" "$actual"
+}
+
+function provider_strip_ansi() {
+    bashunit::data_set '\e[32mfoo\e[0m' "foo"
+    bashunit::data_set '\e[1;31mbar\e[0m' "bar"
+    bashunit::data_set 'no-ansi' "no-ansi"
+}