dap: pass exit code through exited event

commands/build.go

@@ -398,10 +398,6 @@ func runBuild(ctx context.Context, dockerCli command.Cli, debugOpts debuggerOpti
 	done := timeBuildCommand(mp, attributes)
 	resp, inputs, retErr := runBuildWithOptions(ctx, dockerCli, opts, dbg, printer)
 
-	if err := printer.Wait(); retErr == nil {
-		retErr = err
-	}
-
 	done(retErr)
 	if retErr != nil {
 		return retErr
@@ -462,12 +458,21 @@ func runBuildWithOptions(ctx context.Context, dockerCli command.Cli, opts *Build
 		if err := dbg.Start(printer, opts); err != nil {
 			return nil, nil, err
 		}
-		defer dbg.Stop()
+		defer func() { dbg.Stop(retErr) }()
 
 		bh = dbg.Handler()
 		dockerCli.SetIn(nil)
 	}
 
+	// Ensure messages sent to the printer are flushed before the debugger completes.
+	// This prevents late messages from not being sent because the connection was
+	// terminated before completion of the debugger.
+	defer func() {
+		if err := printer.Wait(); retErr == nil {
+			retErr = err
+		}
+	}()
+
 	in := dockerCli.In()
 	for {
 		resp, inputs, err := RunBuild(ctx, dockerCli, opts, in, printer, &bh)

commands/dap.go

@@ -91,9 +91,9 @@ func (d *adapterProtocolDebugger) Start(printer *progress.Printer, opts *BuildOp
 	return nil
 }
 
-func (d *adapterProtocolDebugger) Stop() error {
+func (d *adapterProtocolDebugger) Stop(retErr error) error {
 	defer d.conn.Close()
-	return d.Adapter.Stop()
+	return d.Adapter.Stop(retErr)
 }
 
 func dapAttachCmd() *cobra.Command {

commands/debug.go

@@ -41,7 +41,7 @@ type debuggerOptions interface {
 type debuggerInstance interface {
 	Start(printer *progress.Printer, opts *BuildOptions) error
 	Handler() build.Handler
-	Stop() error
+	Stop(retErr error) error
 	Out() io.Writer
 }
 
@@ -98,7 +98,7 @@ func (d *monitorDebuggerInstance) Handler() build.Handler {
 	return d.m.Handler()
 }
 
-func (d *monitorDebuggerInstance) Stop() error {
+func (d *monitorDebuggerInstance) Stop(_ error) error {
 	return d.m.Close()
 }
 

dap/adapter.go

@@ -83,7 +83,7 @@ func (d *Adapter[C]) Start(conn Conn) (C, error) {
 	return resp.Config, resp.Error
 }
 
-func (d *Adapter[C]) Stop() error {
+func (d *Adapter[C]) Stop(retErr error) error {
 	if d.eg == nil {
 		return nil
 	}
@@ -94,15 +94,19 @@ func (d *Adapter[C]) Stop() error {
 				Event: "terminated",
 			},
 		}
-		// TODO: detect exit code from threads
-		// c.C() <- &dap.ExitedEvent{
-		// 	Event: dap.Event{
-		// 		Event: "exited",
-		// 	},
-		// 	Body: dap.ExitedEventBody{
-		// 		ExitCode: exitCode,
-		// 	},
-		// }
+
+		exitCode := 0
+		if retErr != nil {
+			exitCode = 1
+		}
+		c.C() <- &dap.ExitedEvent{
+			Event: dap.Event{
+				Event: "exited",
+			},
+			Body: dap.ExitedEventBody{
+				ExitCode: exitCode,
+			},
+		}
 	})
 	d.srv.Stop()
 

dap/adapter_test.go

@@ -253,7 +253,7 @@ func NewTestAdapter[C LaunchConfig](t *testing.T) (*Adapter[C], Conn, *daptest.C
 	client := daptest.NewClient(clientConn)
 	t.Cleanup(func() { client.Close() })
 
-	t.Cleanup(func() { adapter.Stop() })
+	t.Cleanup(func() { adapter.Stop(nil) })
 	return adapter, srvConn, client
 }
 

tests/dap_build.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"path/filepath"
 	"runtime"
 	"slices"
 	"syscall"
@@ -85,6 +86,7 @@ var dapBuildTests = []func(t *testing.T, sb integration.Sandbox){
 	testDapBuildStepNext,
 	testDapBuildStepOut,
 	testDapBuildVariables,
+	testDapBuildExitedEvent,
 }
 
 func testDapBuild(t *testing.T, sb integration.Sandbox) {
@@ -857,6 +859,73 @@ func testDapBuildVariables(t *testing.T, sb integration.Sandbox) {
 	}
 }
 
+func testDapBuildExitedEvent(t *testing.T, sb integration.Sandbox) {
+	t.Run("success", func(t *testing.T) {
+		dir := createTestProject(t)
+		client, done, err := dapBuildCmd(t, sb)
+		require.NoError(t, err)
+
+		ch := make(chan *dap.ExitedEvent, 1)
+		client.RegisterEvent("exited", func(em dap.EventMessage) {
+			ch <- em.(*dap.ExitedEvent)
+			close(ch)
+		})
+
+		// Project should just build normally.
+		doLaunch(t, client, commands.LaunchConfig{
+			Dockerfile:  path.Join(dir, "Dockerfile"),
+			ContextPath: dir,
+		})
+
+		select {
+		case exited := <-ch:
+			require.Equal(t, 0, exited.Body.ExitCode)
+		case <-time.After(5 * time.Second):
+			require.Fail(t, "timeout reached")
+		}
+
+		require.NoError(t, done(true))
+	})
+
+	t.Run("failure", func(t *testing.T) {
+		dir := createTestProject(t)
+		client, done, err := dapBuildCmd(t, sb)
+		require.NoError(t, err)
+
+		ch := make(chan *dap.ExitedEvent, 1)
+		client.RegisterEvent("exited", func(em dap.EventMessage) {
+			ch <- em.(*dap.ExitedEvent)
+			close(ch)
+		})
+
+		// Delete foo from the test project so this will fail.
+		err = os.Remove(filepath.Join(dir, "foo"))
+		require.NoError(t, err)
+
+		interruptCh := pollInterruptEvents(client)
+		doLaunch(t, client, commands.LaunchConfig{
+			Dockerfile:  path.Join(dir, "Dockerfile"),
+			ContextPath: dir,
+		})
+
+		// We will hit an interrupt because of the failure.
+		stopped := waitForInterrupt[*dap.StoppedEvent](t, interruptCh)
+		require.Equal(t, "exception", stopped.Body.Reason)
+
+		// Continue execution which should trigger the exited event.
+		doNext(t, client, stopped.Body.ThreadId)
+		select {
+		case exited := <-ch:
+			require.NotEqual(t, 0, exited.Body.ExitCode)
+		case <-time.After(time.Second):
+			require.Fail(t, "timeout reached")
+		}
+
+		var exitErr *exec.ExitError
+		require.ErrorAs(t, done(false), &exitErr)
+	})
+}
+
 func doLaunch(t *testing.T, client *daptest.Client, config commands.LaunchConfig, bps ...dap.SourceBreakpoint) {
 	t.Helper()