[BUG] FlutterToolsAppStarted never fires when running with the debugger (DAP event name mismatch) #563

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

When the app runs through the debugger runner (debugger.enabled = true), the FlutterToolsAppStarted User event is never emitted. Autocmds listening for it never run, and the statusline decorations in decorations.lua are not refreshed on app start.

debugger_runner.lua listens for a DAP event named app.started (lines 187 and 238):

{ "before", "event_app.started" },
dap.listeners.before["event_app.started"][plugin_identifier] = function(_, _)

Flutter's debug adapter never sends a DAP event with that name. app.started is the event flutter run --machine emits. The adapter receives it internally (handleJsonEvent in flutter_adapter.dart) and forwards it to the DAP client as flutter.appStarted:

// packages/flutter_tools/lib/src/debug_adapters/flutter_adapter.dart
sendEvent(RawEventBody(<String, Object?>{}), eventType: 'flutter.appStarted');

Expected Behavior

FlutterToolsAppStarted fires once the app is running, the same as with the job runner.

Steps To Reproduce

1. Save this as repro.lua:

vim.env.LAZY_STDPATH = ".repro"
load(vim.fn.system("curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua"))()

require("lazy.minit").repro({
  spec = {
    {
      "nvim-flutter/flutter-tools.nvim",
      dependencies = { "nvim-lua/plenary.nvim", "mfussenegger/nvim-dap" },
      config = function()
        require("flutter-tools").setup({ debugger = { enabled = true } })
        vim.api.nvim_create_autocmd("User", {
          pattern = "FlutterToolsAppStarted",
          callback = function() print("FlutterToolsAppStarted fired") end,
        })
        require("dap").listeners.before["event_flutter.appStarted"]["repro"] = function()
          print("DAP event flutter.appStarted received")
        end
      end,
    },
  },
})

2. In a Flutter project, run nvim -u repro.lua lib/main.dart.
3. Run :FlutterRun and wait until the app is running on the device.
4. Check :messages. DAP event flutter.appStarted received is printed, but FlutterToolsAppStarted fired is not.

Environment

- OS: macOS 26.7.2
- Device: macOS desktop (-d macos), fresh flutter create app
- Flutter version: 3.41.9
- Is flutter in $PATH: yes
- neovim version: 0.13.0-dev
- flutter-tools.nvim: latest `main` (8b139a8)

Anything else?

Suggested fix: change event_app.started to event_flutter.appStarted in both places in lua/flutter-tools/runners/debugger_runner.lua. With that change applied, the repro above prints FlutterToolsAppStarted fired right after the DAP event.
I can open a PR.