fix: field index out of bounds

Author: Akkadius

godump.go

@@ -216,11 +216,11 @@ func printValue(tw *tabwriter.Writer, v reflect.Value, indent int, visited map[u
 		t := v.Type()
 		fmt.Fprintf(tw, "%s ", colorize(colorGray, "#"+t.String()))
 		fmt.Fprintln(tw)
-		for i, _ := range reflect.VisibleFields(t) {
-			field := t.Field(i)
-			fieldVal := v.Field(i)
+		visibleFields := reflect.VisibleFields(t)
+		for _, field := range visibleFields {
+			fieldVal := v.FieldByIndex(field.Index)
 			symbol := "+"
-			if field.PkgPath != "" { // private
+			if field.PkgPath != "" {
 				symbol = "-"
 				fieldVal = forceExported(fieldVal)
 			}

godump_test.go

@@ -487,3 +487,88 @@ func timePtrsEqual(a, b *time.Time) bool {
 	}
 	return a.Equal(*b)
 }
+
+func TestPanicOnVisibleFieldsIndexMismatch(t *testing.T) {
+	type Embedded struct {
+		Secret string
+	}
+	type Outer struct {
+		Embedded // Promoted field
+		Age      int
+	}
+
+	// This will panic with:
+	// panic: reflect: Field index out of bounds
+	_ = DumpStr(Outer{
+		Embedded: Embedded{Secret: "classified"},
+		Age:      42,
+	})
+}
+
+type FriendlyDuration time.Duration
+
+func (fd FriendlyDuration) String() string {
+	td := time.Duration(fd)
+	return fmt.Sprintf("%02d:%02d:%02d", int(td.Hours()), int(td.Minutes())%60, int(td.Seconds())%60)
+}
+
+func TestTheKitchenSink(t *testing.T) {
+
+	type Inner struct {
+		ID    int
+		Notes []string
+	}
+
+	type Ref struct {
+		Self *Ref
+	}
+
+	type Everything struct {
+		String        string
+		Bool          bool
+		Int           int
+		Float         float64
+		Time          time.Time
+		Duration      time.Duration
+		Friendly      FriendlyDuration
+		PtrString     *string
+		PtrDuration   *time.Duration
+		SliceInts     []int
+		ArrayStrings  [2]string
+		MapValues     map[string]int
+		Nested        Inner
+		NestedPtr     *Inner
+		Interface     any
+		Recursive     *Ref
+		privateField  string
+		privateStruct Inner
+	}
+
+	now := time.Now()
+	ptrStr := "Hello"
+	dur := time.Minute * 20
+
+	val := Everything{
+		String:        "test",
+		Bool:          true,
+		Int:           42,
+		Float:         3.1415,
+		Time:          now,
+		Duration:      dur,
+		Friendly:      FriendlyDuration(dur),
+		PtrString:     &ptrStr,
+		PtrDuration:   &dur,
+		SliceInts:     []int{1, 2, 3},
+		ArrayStrings:  [2]string{"foo", "bar"},
+		MapValues:     map[string]int{"a": 1, "b": 2},
+		Nested:        Inner{ID: 10, Notes: []string{"alpha", "beta"}},
+		NestedPtr:     &Inner{ID: 99, Notes: []string{"x", "y"}},
+		Interface:     map[string]bool{"ok": true},
+		Recursive:     &Ref{},
+		privateField:  "should show",
+		privateStruct: Inner{ID: 5, Notes: []string{"private"}},
+	}
+	val.Recursive.Self = val.Recursive // cycle
+
+	Dump(val)
+}