activate mise under MSYS2 bash/zsh, in particular Git Bash

mise.sh

# To make Mise work in MSYS2/Cygwin, see
# https://github.com/jdx/mise/discussions/3961#discussioncomment-16024383

# -- 1. Locate the mise binary ------------------------------------------
local mise_bin=""

if [[ -n "$MSYSTEM" ]]; then
  # MSYS2 / Cygwin: prefer the Windows-native exe resolved through cygpath
  local scoop_shim_dir="$(/usr/bin/cygpath -u "$USERPROFILE")/scoop/shims"
  local scoop_mise="${scoop_shim_dir}/mise"

  if command -v mise.exe >/dev/null 2>&1; then
    mise_bin="$(/usr/bin/cygpath -u "$(command -v mise.exe)")"
  elif [[ -x "$scoop_mise" ]]; then
    mise_bin="$scoop_mise"
  fi
elif command -v mise >/dev/null 2>&1; then
  mise_bin="$(command -v mise)"
fi

[[ -n "$mise_bin" && -x "$mise_bin" ]] || return 0

# -- 2. Shell name ------------------------------------------------------
local shell_name="${SHELL:-bash}"

# -- 3. MSYS2-specific path fixup & activation -------------------------
if [[ -n "$MSYSTEM" ]]; then
  # Guard: only run once per session
  [[ -z "${__MISE_ORIG_PATH+X}" ]] || return 0

  # Expose a wrapper so bare `mise` invocations work in MSYS2
  _MISE_EXE_UNIX="$mise_bin"
  mise() { command "$_MISE_EXE_UNIX" "$@"; }
  export MISE_EXE="$_MISE_EXE_UNIX"
  export MISE_SHELL=bash   # mise itself always expects "bash" compat here

  # Generate the activation script
  local activate_script
  activate_script="$("$mise_bin" activate "$shell_name")"

  # Convert the first PATH= export from Windows-style to Unix-style
  local win_path_line
  win_path_line="$(printf '%s\n' "$activate_script" \
    | sed -n 's/^export PATH="\([^"]*\)".*$/\1/p')"
  if [[ -n "$win_path_line" ]]; then
    local unix_path_line
    unix_path_line="$(/usr/bin/cygpath -u -p "$win_path_line")"
    activate_script="$(printf '%s\n' "$activate_script" \
      | awk -v newpath="$unix_path_line" \
        'BEGIN{done=0} {
          if (!done && $0 ~ /^export PATH=/) {
            print "export PATH=\"" newpath "\""; done=1
          } else { print $0 }
        }')"
  fi

  # Replace any remaining Windows-style mise.exe references
  activate_script="$(printf '%s\n' "$activate_script" \
    | sed -E "s@[A-Za-z]:\\\\[^\"']*\\\\mise\.exe@$_MISE_EXE_UNIX@g")"

  eval "$activate_script"
  eval "$("$mise_bin" hook-env -s "$shell_name")"

  # Install a hook that converts PATH back to Unix form after mise touches it
  __mise_fix_path() {
    export PATH="$(/usr/bin/cygpath -u -p "$PATH")"
  }

  if [[ "$shell_name" == "zsh" ]]; then
    autoload -Uz add-zsh-hook
    add-zsh-hook precmd __mise_fix_path
  else
    PROMPT_COMMAND="__mise_fix_path${PROMPT_COMMAND:+;$PROMPT_COMMAND}"
  fi
  __mise_fix_path

# -- 4. Native (Linux / macOS / plain WSL) activation -------------------
else
  eval "$("$mise_bin" activate "$shell_name")"
fi