fix: strip script headers and footers in saved output

cmd/root_test.go

@@ -299,7 +299,7 @@ func addFakeRecordDependencies(t *testing.T, names ...string) {
 		path := filepath.Join(binDir, name)
 		body := "#!/bin/sh\nexit 0\n"
 		if name == "script" {
-			body = "#!/bin/sh\nin=''\nout=''\nwhile [ \"$#\" -gt 0 ]; do\n  case \"$1\" in\n    -I)\n      in=\"$2\"\n      shift 2\n      ;;\n    -O)\n      out=\"$2\"\n      shift 2\n      ;;\n    *)\n      shift\n      ;;\n  esac\ndone\nprintf 'fake recorded input\\n' > \"$in\"\nprintf 'fake recorded output\\n' > \"$out\"\nexit 0\n"
+			body = "#!/bin/sh\nin=''\nout=''\nwhile [ \"$#\" -gt 0 ]; do\n  case \"$1\" in\n    -I)\n      in=\"$2\"\n      shift 2\n      ;;\n    -O)\n      out=\"$2\"\n      shift 2\n      ;;\n    *)\n      shift\n      ;;\n  esac\ndone\ncat <<'EOF' > \"$in\"\nfake recorded input\nEOF\ncat <<'EOF' > \"$out\"\nScript started on 2026-03-18 11:13:38+00:00 [TERM=\"xterm-256color\"]\nfake recorded output\nScript done on 2026-03-18 11:13:44+00:00 [COMMAND_EXIT_CODE=\"0\"]\nEOF\nexit 0\n"
 		}
 		if err := os.WriteFile(path, []byte(body), 0o755); err != nil {
 			t.Fatalf("WriteFile(%q) error = %v", path, err)

internal/miro/post_process.go

@@ -0,0 +1,82 @@
+package miro
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+)
+
+var (
+	scriptStartPrefix = []byte("Script started on ")
+	scriptDonePrefix  = []byte("Script done on ")
+)
+
+func loadRecordedOutput(path string) ([]byte, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	return stripScriptWrapper(data)
+}
+
+func stripScriptWrapper(data []byte) ([]byte, error) {
+	hasHeader := bytes.HasPrefix(data, scriptStartPrefix)
+
+	headerEnd := bytes.IndexByte(data, '\n')
+	if hasHeader && headerEnd == -1 {
+		return nil, fmt.Errorf("could not parse script wrapper from recorded output: incomplete header line")
+	}
+
+	body := data
+	if hasHeader {
+		body = data[headerEnd+1:]
+	}
+
+	footerStart, footerState := findScriptFooter(body)
+	switch {
+	case hasHeader && footerState == footerMissing:
+		return nil, fmt.Errorf("could not parse script wrapper from recorded output: missing footer line")
+	case !hasHeader && footerState == footerFound:
+		return nil, fmt.Errorf("could not parse script wrapper from recorded output: missing header line")
+	case !hasHeader && footerState == footerMissing:
+		return nil, fmt.Errorf("could not parse script wrapper from recorded output: missing header and footer lines")
+	case footerState == footerMalformed:
+		return nil, fmt.Errorf("could not parse script wrapper from recorded output: incomplete footer line")
+	}
+
+	return body[:footerStart], nil
+}
+
+type footerMatchState int
+
+const (
+	footerMissing footerMatchState = iota
+	footerMalformed
+	footerFound
+)
+
+func findScriptFooter(data []byte) (int, footerMatchState) {
+	candidate := -1
+	switch {
+	case bytes.HasPrefix(data, scriptDonePrefix):
+		candidate = 0
+	default:
+		idx := bytes.LastIndex(data, append([]byte{'\n'}, scriptDonePrefix...))
+		if idx != -1 {
+			candidate = idx + 1
+		}
+	}
+
+	if candidate == -1 {
+		return 0, footerMissing
+	}
+
+	footer := data[candidate:]
+	newline := bytes.IndexByte(footer, '\n')
+	if newline == -1 || candidate+newline+1 != len(data) {
+		return 0, footerMalformed
+	}
+
+	return candidate, footerFound
+}

internal/miro/record_session.go

@@ -48,10 +48,15 @@ func recordScenario(target string, rio recordIO) error {
 		return ErrRecordingDiscarded
 	}
 
-	if err := copyRecordFile(rawIn, filepath.Join(target, "in")); err != nil {
+	recordedIn, recordedOut, err := loadRecordedFixtures(rawIn, rawOut)
+	if err != nil {
 		return err
 	}
-	if err := copyRecordFile(rawOut, filepath.Join(target, "out")); err != nil {
+
+	if err := os.WriteFile(filepath.Join(target, "in"), recordedIn, 0o644); err != nil {
+		return err
+	}
+	if err := os.WriteFile(filepath.Join(target, "out"), recordedOut, 0o644); err != nil {
 		return err
 	}
 
@@ -131,11 +136,16 @@ func recordFixturesExist(target string) (bool, error) {
 	return false, nil
 }
 
-func copyRecordFile(src, dst string) error {
+func loadRecordedFixtures(rawIn, rawOut string) ([]byte, []byte, error) {
-	data, err := os.ReadFile(src)
+	recordedIn, err := os.ReadFile(rawIn)
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
-	return os.WriteFile(dst, data, 0o644)
+	recordedOut, err := loadRecordedOutput(rawOut)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return recordedIn, recordedOut, nil
 }

internal/miro/record_test.go

@@ -33,6 +33,13 @@ func TestRecordCreatesRelativePath(t *testing.T) {
 			t.Fatalf("Stat(%q) error = %v", filepath.Join(want, name), err)
 		}
 	}
+
+	if got := readFile(t, filepath.Join(want, "in")); got != "fake recorded input\n" {
+		t.Fatalf("saved in = %q, want %q", got, "fake recorded input\n")
+	}
+	if got := readFile(t, filepath.Join(want, "out")); got != "fake recorded output\n" {
+		t.Fatalf("saved out = %q, want %q", got, "fake recorded output\n")
+	}
 }
 
 func TestRecordStripsExplicitTestDirPrefix(t *testing.T) {
@@ -60,6 +67,10 @@ func TestRecordStripsExplicitTestDirPrefix(t *testing.T) {
 			t.Fatalf("Stat(%q) error = %v", filepath.Join(want, name), err)
 		}
 	}
+
+	if got := readFile(t, filepath.Join(want, "out")); got != "fake recorded output\n" {
+		t.Fatalf("saved out = %q, want %q", got, "fake recorded output\n")
+	}
 }
 
 func TestRecordRejectsAbsolutePathOutsideTestDir(t *testing.T) {
@@ -193,6 +204,17 @@ func withStdin(t *testing.T, input string, fn func()) {
 	fn()
 }
 
+func readFile(t *testing.T, path string) string {
+	t.Helper()
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("ReadFile(%q) error = %v", path, err)
+	}
+
+	return string(data)
+}
+
 type ioDiscard struct{}
 
 func (ioDiscard) Write(p []byte) (int, error) {
@@ -207,7 +229,7 @@ func addFakeRecordDependencies(t *testing.T, names ...string) {
 		path := filepath.Join(binDir, name)
 		body := "#!/bin/sh\nexit 0\n"
 		if name == "script" {
-			body = "#!/bin/sh\nin=''\nout=''\nwhile [ \"$#\" -gt 0 ]; do\n  case \"$1\" in\n    -I)\n      in=\"$2\"\n      shift 2\n      ;;\n    -O)\n      out=\"$2\"\n      shift 2\n      ;;\n    *)\n      shift\n      ;;\n  esac\ndone\nprintf 'fake recorded input\\n' > \"$in\"\nprintf 'fake recorded output\\n' > \"$out\"\nexit 0\n"
+			body = "#!/bin/sh\nin=''\nout=''\nwhile [ \"$#\" -gt 0 ]; do\n  case \"$1\" in\n    -I)\n      in=\"$2\"\n      shift 2\n      ;;\n    -O)\n      out=\"$2\"\n      shift 2\n      ;;\n    *)\n      shift\n      ;;\n  esac\ndone\nif [ -n \"${FAKE_SCRIPT_LOG_IN+x}\" ]; then\n  printf '%s' \"$FAKE_SCRIPT_LOG_IN\" > \"$in\"\nelse\n  cat <<'EOF' > \"$in\"\nfake recorded input\nEOF\nfi\nif [ -n \"${FAKE_SCRIPT_LOG_OUT+x}\" ]; then\n  printf '%s' \"$FAKE_SCRIPT_LOG_OUT\" > \"$out\"\nelse\n  cat <<'EOF' > \"$out\"\nScript started on 2026-03-18 11:13:38+00:00 [TERM=\"xterm-256color\"]\nfake recorded output\nScript done on 2026-03-18 11:13:44+00:00 [COMMAND_EXIT_CODE=\"0\"]\nEOF\nfi\nexit 0\n"
 		}
 		if err := os.WriteFile(path, []byte(body), 0o755); err != nil {
 			t.Fatalf("WriteFile(%q) error = %v", path, err)