internal/pkg: treat bare carriage return as end-of-line marker

This avoids having progress indicators mess up logging.

Signed-off-by: Ophestra <cat@gensokyo.uk>

2 files changed, 124 insertions, 1 deletions

diff --git a/internal/pkg/exec.go b/internal/pkg/exec.go
index 7c4133eb..e499ecf1 100644
--- a/internal/pkg/exec.go
+++ b/internal/pkg/exec.go
@@ -2,6 +2,7 @@ package pkg
 
 import (
 	"bufio"
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -439,6 +440,34 @@ const (
 	execWaitDelay = time.Nanosecond
 )
 
+// scanLinesCR is like [bufio.ScanLines], but also treats a bare \r as an
+// end-of-line marker.
+func scanLinesCR(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if atEOF && len(data) == 0 {
+		return 0, nil, nil
+	}
+	ri, ni := bytes.IndexByte(data, '\r'), bytes.IndexByte(data, '\n')
+
+	if ri >= 0 && (ni < 0 || ri < ni) {
+		if ri+1 == ni {
+			// We have a full \r\n-terminated line.
+			return ri + 2, data[:ri], nil
+		}
+		// We have a bare \r, probably some kind of progress indicator.
+		return ri + 1, data[:ri], nil
+	}
+	if ni >= 0 && (ri < 0 || ni < ri) {
+		// We have a full newline-terminated line.
+		return ni + 1, data[:ni], nil
+	}
+	// If we're at EOF, we have a final, non-terminated line. Return it.
+	if atEOF {
+		return len(data), data, nil
+	}
+	// Request more data.
+	return 0, nil, nil
+}
+
 // scanVerbose prefixes program output for a verbose [message.Msg].
 func scanVerbose(
 	msg message.Msg,
@@ -449,6 +478,7 @@ func scanVerbose(
 ) {
 	defer close(done)
 	s := bufio.NewScanner(r)
+	s.Split(scanLinesCR)
 	s.Buffer(
 		make([]byte, bufio.MaxScanTokenSize),
 		bufio.MaxScanTokenSize<<12,
@@ -458,7 +488,7 @@ func scanVerbose(
 	}
 	if err := s.Err(); err != nil && !errors.Is(err, os.ErrClosed) {
 		cancel()
-		msg.Verbose("*"+prefix, err)
+		msg.Verbose("*"+prefix, err.Error()+suffix)
 	}
 }
 
diff --git a/internal/pkg/exec_test.go b/internal/pkg/exec_test.go
index 222ab790..408d6257 100644
--- a/internal/pkg/exec_test.go
+++ b/internal/pkg/exec_test.go
@@ -1,6 +1,7 @@
 package pkg_test
 
 import (
+	"bufio"
 	"bytes"
 	_ "embed"
 	"encoding/gob"
@@ -11,7 +12,9 @@ import (
 	"os/exec"
 	"path/filepath"
 	"slices"
+	"strings"
 	"testing"
+	_ "unsafe" // for go:linkname
 
 	"hakurei.app/check"
 	"hakurei.app/container"
@@ -41,6 +44,96 @@ func init() {
 	})
 }
 
+// scanLinesCR is like [bufio.ScanLines], but also treats a bare \r as an
+// end-of-line marker.
+//
+//go:linkname scanLinesCR hakurei.app/internal/pkg.scanLinesCR
+func scanLinesCR(data []byte, atEOF bool) (advance int, token []byte, err error)
+
+func TestScan(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		data string
+		want []string
+	}{
+		{"progress indicator", "Updating files:  76% (8655/11256)\r" +
+			"Updating files:  77% (8668/11256)\r" +
+			"Updating files:  78% (8780/11256)\r" +
+			"Updating files:  79% (8893/11256)\r" +
+			"Updating files:  80% (9005/11256)\r" +
+			"Updating files:  81% (9118/11256)\r" +
+			"Updating files:  82% (9230/11256)\r" +
+			"Updating files:  83% (9343/11256)\r" +
+			"Updating files:  84% (9456/11256)\r" +
+			"Updating files:  85% (9568/11256)\r" +
+			"Updating files:  86% (9681/11256)\r" +
+			"Updating files:  87% (9793/11256)\r" +
+			"Updating files:  88% (9906/11256)\r" +
+			"Updating files:  89% (10018/11256)\r" +
+			"Updating files:  90% (10131/11256)\r" +
+			"Updating files:  91% (10243/11256)\r" +
+			"Updating files:  92% (10356/11256)\r" +
+			"Updating files:  93% (10469/11256)\r" +
+			"Updating files:  94% (10581/11256)\r" +
+			"Updating files:  95% (10694/11256)\r" +
+			"Updating files:  96% (10806/11256)\r" +
+			"Updating files:  97% (10919/11256)\r" +
+			"Updating files:  98% (11031/11256)\r" +
+			"Updating files:  99% (11144/11256)\r" +
+			"Updating files: 100% (11256/11256)\r" +
+			"Updating files: 100% (11256/11256), done.\n", []string{
+			"Updating files:  76% (8655/11256)",
+			"Updating files:  77% (8668/11256)",
+			"Updating files:  78% (8780/11256)",
+			"Updating files:  79% (8893/11256)",
+			"Updating files:  80% (9005/11256)",
+			"Updating files:  81% (9118/11256)",
+			"Updating files:  82% (9230/11256)",
+			"Updating files:  83% (9343/11256)",
+			"Updating files:  84% (9456/11256)",
+			"Updating files:  85% (9568/11256)",
+			"Updating files:  86% (9681/11256)",
+			"Updating files:  87% (9793/11256)",
+			"Updating files:  88% (9906/11256)",
+			"Updating files:  89% (10018/11256)",
+			"Updating files:  90% (10131/11256)",
+			"Updating files:  91% (10243/11256)",
+			"Updating files:  92% (10356/11256)",
+			"Updating files:  93% (10469/11256)",
+			"Updating files:  94% (10581/11256)",
+			"Updating files:  95% (10694/11256)",
+			"Updating files:  96% (10806/11256)",
+			"Updating files:  97% (10919/11256)",
+			"Updating files:  98% (11031/11256)",
+			"Updating files:  99% (11144/11256)",
+			"Updating files: 100% (11256/11256)",
+			"Updating files: 100% (11256/11256), done.",
+		}},
+
+		{"crlf", "0\r1\n2\n3\r\n4\n5\r6\r\n7\n", []string{
+			"0", "1", "2", "3", "4", "5", "6", "7",
+		}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			s := bufio.NewScanner(strings.NewReader(tc.data))
+			s.Split(scanLinesCR)
+			got := make([]string, 0, len(tc.want))
+			for s.Scan() {
+				got = append(got, s.Text())
+			}
+			if err := s.Err(); err != nil {
+				t.Fatal(err)
+			}
+			if !slices.Equal(got, tc.want) {
+				t.Fatalf("Scan: %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
 func TestExec(t *testing.T) {
 	t.Parallel()