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>

1 files changed, 31 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)
 	}
 }