feat(gnovm): enable debugger for gno test

This change brings interactive debugging to gno tests, using -debug
flag.

gnovm/cmd/gno/lint.go

@@ -148,7 +148,7 @@ func execLint(cfg *lintCfg, args []string, io commands.IO) error {
 
 		// Handle runtime errors
 		hasRuntimeErr := catchRuntimeError(pkgPath, io.Err(), func() {
-			tm := test.Machine(testStore, stdout, memPkg.Path)
+			tm := test.Machine(testStore, stdout, memPkg.Path, false)
 			defer tm.Release()
 
 			// Check package

gnovm/cmd/gno/test.go

@@ -26,6 +26,8 @@ type testCfg struct {
 	updateGoldenTests   bool
 	printRuntimeMetrics bool
 	printEvents         bool
+	debug               bool
+	debugAddr           string
 }
 
 func newTestCmd(io commands.IO) *commands.Command {
@@ -143,6 +145,20 @@ func (c *testCfg) RegisterFlags(fs *flag.FlagSet) {
 		false,
 		"print emitted events",
 	)
+
+	fs.BoolVar(
+		&c.debug,
+		"debug",
+		false,
+		"enable interactive debugger using stdin and stdout",
+	)
+
+	fs.StringVar(
+		&c.debugAddr,
+		"debug-addr",
+		"",
+		"enable interactive debugger using tcp address in the form [host]:port",
+	)
 }
 
 func execTest(cfg *testCfg, args []string, io commands.IO) error {
@@ -187,6 +203,7 @@ func execTest(cfg *testCfg, args []string, io commands.IO) error {
 	opts.Verbose = cfg.verbose
 	opts.Metrics = cfg.printRuntimeMetrics
 	opts.Events = cfg.printEvents
+	opts.Debug = cfg.debug
 
 	buildErrCount := 0
 	testErrCount := 0

gnovm/pkg/gnolang/debugger.go

@@ -43,19 +43,19 @@ type Debugger struct {
 	out     io.Writer      // debugger output, defaults to Stdout
 	scanner *bufio.Scanner // to parse input per line
 
-	state       DebugState          // current state of debugger
-	lastCmd     string              // last debugger command
-	lastArg     string              // last debugger command arguments
-	loc         Location            // source location of the current machine instruction
-	prevLoc     Location            // source location of the previous machine instruction
-	breakpoints []Location          // list of breakpoints set by user, as source locations
-	call        []Location          // for function tracking, ideally should be provided by machine frame
-	frameLevel  int                 // frame level of the current machine instruction
-	getSrc      func(string) string // helper to access source from repl or others
+	state       DebugState                  // current state of debugger
+	lastCmd     string                      // last debugger command
+	lastArg     string                      // last debugger command arguments
+	loc         Location                    // source location of the current machine instruction
+	prevLoc     Location                    // source location of the previous machine instruction
+	breakpoints []Location                  // list of breakpoints set by user, as source locations
+	call        []Location                  // for function tracking, ideally should be provided by machine frame
+	frameLevel  int                         // frame level of the current machine instruction
+	getSrc      func(string, string) string // helper to access source from repl or others
 }
 
 // Enable makes the debugger d active, using in as input reader, out as output writer and f as a source helper.
-func (d *Debugger) Enable(in io.Reader, out io.Writer, f func(string) string) {
+func (d *Debugger) Enable(in io.Reader, out io.Writer, f func(string, string) string) {
 	d.in = in
 	d.out = out
 	d.enabled = true
@@ -505,7 +505,7 @@ func debugList(m *Machine, arg string) (err error) {
 	if err != nil {
 		// Use optional getSrc helper as fallback to get source.
 		if m.Debugger.getSrc != nil {
-			src = m.Debugger.getSrc(loc.File)
+			src = m.Debugger.getSrc(loc.PkgPath, loc.File)
 		}
 		if src == "" {
 			return err

gnovm/pkg/repl/repl.go

@@ -156,7 +156,7 @@ func (r *Repl) Process(input string) (out string, err error) {
 	r.state.id++
 
 	if r.debug {
-		r.state.machine.Debugger.Enable(os.Stdin, os.Stdout, func(file string) string {
+		r.state.machine.Debugger.Enable(os.Stdin, os.Stdout, func(ppath, file string) string {
 			return r.state.files[file]
 		})
 		r.debug = false

gnovm/pkg/test/filetest.go

@@ -63,6 +63,7 @@ func (opts *TestOptions) runFiletest(filename string, source []byte) (string, er
 		Store:         opts.TestStore.BeginTransaction(cw, cw),
 		Context:       ctx,
 		MaxAllocBytes: maxAlloc,
+		Debug:         opts.Debug,
 	})
 	defer m.Release()
 	result := opts.runTest(m, pkgPath, filename, source)

gnovm/pkg/test/test.go

@@ -71,11 +71,12 @@ func Context(pkgPath string, send std.Coins) *teststd.TestExecContext {
 }
 
 // Machine is a minimal machine, set up with just the Store, Output and Context.
-func Machine(testStore gno.Store, output io.Writer, pkgPath string) *gno.Machine {
+func Machine(testStore gno.Store, output io.Writer, pkgPath string, debug bool) *gno.Machine {
 	return gno.NewMachineWithOptions(gno.MachineOptions{
 		Store:   testStore,
 		Output:  output,
 		Context: Context(pkgPath, nil),
+		Debug:   debug,
 	})
 }
 
@@ -108,6 +109,8 @@ type TestOptions struct {
 	Output io.Writer
 	// Used for os.Stderr, and for printing errors.
 	Error io.Writer
+	// Debug enables the interactive debugger on gno tests.
+	Debug bool
 
 	// Not set by NewTestOptions:
 
@@ -288,9 +291,8 @@ func (opts *TestOptions) runTestFiles(
 	// reset store ops, if any - we only need them for some filetests.
 	opts.TestStore.SetLogStoreOps(false)
 
-	// Check if we already have the package - it may have been eagerly
-	// loaded.
-	m = Machine(gs, opts.WriterForStore(), memPkg.Path)
+	// Check if we already have the package - it may have been eagerly loaded.
+	m = Machine(gs, opts.WriterForStore(), memPkg.Path, opts.Debug)
 	m.Alloc = alloc
 	if opts.TestStore.GetMemPackage(memPkg.Path) == nil {
 		m.RunMemPackage(memPkg, true)
@@ -310,14 +312,31 @@ func (opts *TestOptions) runTestFiles(
 		// - Run the test files before this for loop (but persist it to store;
 		//   RunFiles doesn't do that currently)
 		// - Wrap here.
-		m = Machine(gs, opts.Output, memPkg.Path)
+		m = Machine(gs, opts.Output, memPkg.Path, opts.Debug)
 		m.Alloc = alloc
 		m.SetActivePackage(pv)
 
 		testingpv := m.Store.GetPackage("testing", false)
 		testingtv := gno.TypedValue{T: &gno.PackageType{}, V: testingpv}
 		testingcx := &gno.ConstExpr{TypedValue: testingtv}
 
+		if opts.Debug {
+			fileContent := func(ppath, name string) string {
+				p := filepath.Join(opts.RootDir, ppath, name)
+				b, err := os.ReadFile(p)
+				if err != nil {
+					p = filepath.Join(opts.RootDir, "gnovm", "stdlibs", ppath, name)
+					b, err = os.ReadFile(p)
+				}
+				if err != nil {
+					p = filepath.Join(opts.RootDir, "examples", ppath, name)
+					b, err = os.ReadFile(p)
+				}
+				return string(b)
+			}
+			m.Debugger.Enable(os.Stdin, os.Stdout, fileContent)
+		}
+
 		eval := m.Eval(gno.Call(
 			gno.Sel(testingcx, "RunTest"),            // Call testing.RunTest
 			gno.Str(opts.RunFlag),                    // run flag