kickstart.nvim/lua/kickstart/plugins/debug_python.lua

-- debug.lua
--
-- Shows how to use the DAP plugin to debug your code.
--
-- Configured for Python debugging with debugpy.
-- Can be extended to other languages as well.

return {
  -- NOTE: Yes, you can install new plugins here!
  'mfussenegger/nvim-dap',
  -- NOTE: And you can specify dependencies as well
  dependencies = {
    -- Creates a beautiful debugger UI
    'rcarriga/nvim-dap-ui',

    -- Required dependency for nvim-dap-ui
    'nvim-neotest/nvim-nio',

    -- Installs the debug adapters for you
    'mason-org/mason.nvim',
    'jay-babu/mason-nvim-dap.nvim',

    -- Python debugging support
    'mfussenegger/nvim-dap-python',
  },
  keys = {
    -- Keymaps aligned with debug_scala.lua
    { '<leader>dc', function() require('dap').continue() end, desc = 'Debug: Start/Continue' },
    { '<leader>dr', function() require('dap').repl.toggle() end, desc = 'Debug: Toggle REPL' },
    { '<leader>dK', function() require('dap.ui.widgets').hover() end, desc = 'Debug: Hover Widget' },
    { '<leader>dt', function() require('dap').toggle_breakpoint() end, desc = 'Debug: Toggle Breakpoint' },
    { '<leader>dso', function() require('dap').step_over() end, desc = 'Debug: Step Over' },
    { '<leader>dsi', function() require('dap').step_into() end, desc = 'Debug: Step Into' },
    { '<leader>dl', function() require('dap').run_last() end, desc = 'Debug: Run Last' },
    { '<leader>du', function() require('dapui').toggle() end, desc = 'Debug: Toggle DAP UI' },
    { '<leader>dB', function() require('dap').set_breakpoint(vim.fn.input 'Breakpoint condition: ') end, desc = 'Debug: Set Conditional Breakpoint' },
  },
  config = function()
    local dap = require 'dap'
    local dapui = require 'dapui'

    require('mason-nvim-dap').setup {
      -- Makes a best effort to setup the various debuggers with
      -- reasonable debug configurations
      automatic_installation = true,

      -- You can provide additional configuration to the handlers,
      -- see mason-nvim-dap README for more information
      handlers = {},

      -- You'll need to check that you have the required things installed
      -- online, please don't ask me how to install them :)
      ensure_installed = {
        -- Update this to ensure that you have the debuggers for the langs you want
        'debugpy',
      },
    }

    -- Dap UI setup
    -- For more information, see |:help nvim-dap-ui|
    dapui.setup {
      -- Set icons to characters that are more likely to work in every terminal.
      --    Feel free to remove or use ones that you like more! :)
      --    Don't feel like these are good choices.
      icons = { expanded = '▾', collapsed = '▸', current_frame = '*' },
      controls = {
        icons = {
          pause = '⏸',
          play = '▶',
          step_into = '⏎',
          step_over = '⏭',
          step_out = '⏮',
          step_back = 'b',
          run_last = '▶▶',
          terminate = '⏹',
          disconnect = '⏏',
        },
      },
    }

    -- Change breakpoint icons
    -- vim.api.nvim_set_hl(0, 'DapBreak', { fg = '#e51400' })
    -- vim.api.nvim_set_hl(0, 'DapStop', { fg = '#ffcc00' })
    -- local breakpoint_icons = vim.g.have_nerd_font
    --     and { Breakpoint = '', BreakpointCondition = '', BreakpointRejected = '', LogPoint = '', Stopped = '' }
    --   or { Breakpoint = '●', BreakpointCondition = '⊜', BreakpointRejected = '⊘', LogPoint = '◆', Stopped = '⭔' }
    -- for type, icon in pairs(breakpoint_icons) do
    --   local tp = 'Dap' .. type
    --   local hl = (type == 'Stopped') and 'DapStop' or 'DapBreak'
    --   vim.fn.sign_define(tp, { text = icon, texthl = hl, numhl = hl })
    -- end

    dap.listeners.after.event_initialized['dapui_config'] = dapui.open
    dap.listeners.before.event_terminated['dapui_config'] = dapui.close
    dap.listeners.before.event_exited['dapui_config'] = dapui.close

    -- Install Python specific config
    -- Function to find the best Python executable with debugpy
    local function find_python_with_debugpy()
      local python_candidates = {
        '~/.config/nvim/.venv/bin/python', -- nvim config venv
        vim.fn.exepath('python3'), -- system python3
        vim.fn.exepath('python'), -- system python
      }
      
      for _, python_path in ipairs(python_candidates) do
        if python_path and python_path ~= '' and vim.fn.executable(python_path) == 1 then
          -- Test if this python has debugpy
          local handle = io.popen(python_path .. ' -c "import debugpy; print(debugpy.__file__)" 2>/dev/null')
          if handle then
            local result = handle:read('*a')
            handle:close()
            if result and result:match('debugpy') then
              return python_path
            end
          end
        end
      end
      
      -- Fallback to the nvim config venv (we just installed debugpy there)
      return '~/.config/nvim/.venv/bin/python'
    end
    
    require('dap-python').setup(find_python_with_debugpy())
    
    -- Add Python debugging configurations
    table.insert(dap.configurations.python, {
      type = 'python',
      request = 'launch',
      name = 'Launch file',
      program = '${file}',
      pythonPath = function()
        -- debugpy supports launching an application with a different interpreter
        -- The code below looks for a `venv` or `.venv` folder in the current directly and uses the python within.
        -- You could adapt this - to for example use the `VIRTUAL_ENV` environment variable.
        local cwd = vim.fn.getcwd()
        if vim.fn.executable(cwd .. '/venv/bin/python') == 1 then
          return cwd .. '/venv/bin/python'
        elseif vim.fn.executable(cwd .. '/.venv/bin/python') == 1 then
          return cwd .. '/.venv/bin/python'
        else
          return '/usr/bin/python'
        end
      end,
    })
  end,
}