Fixing handling of CRLF #2352

pkg/yqlib/decoder_yaml.go

@@ -11,6 +11,13 @@ import (
 	yaml "go.yaml.in/yaml/v4"
 )
 
+var (
+	commentLineRe       = regexp.MustCompile(`^\s*#`)
+	yamlDirectiveLineRe = regexp.MustCompile(`^\s*%YAML`)
+	separatorLineRe     = regexp.MustCompile(`^\s*---\s*$`)
+	separatorPrefixRe   = regexp.MustCompile(`^\s*---\s+`)
+)
+
 type yamlDecoder struct {
 	decoder yaml.Decoder
 
@@ -33,51 +40,72 @@ func NewYamlDecoder(prefs YamlPreferences) Decoder {
 }
 
 func (dec *yamlDecoder) processReadStream(reader *bufio.Reader) (io.Reader, string, error) {
-	var commentLineRegEx = regexp.MustCompile(`^\s*#`)
-	var yamlDirectiveLineRegEx = regexp.MustCompile(`^\s*%YA`)
 	var sb strings.Builder
+
 	for {
-		peekBytes, err := reader.Peek(4)
-		if errors.Is(err, io.EOF) {
-			// EOF are handled else where..
-			return reader, sb.String(), nil
-		} else if err != nil {
-			return reader, sb.String(), err
-		} else if string(peekBytes[0]) == "\n" {
-			_, err := reader.ReadString('\n')
-			sb.WriteString("\n")
-			if errors.Is(err, io.EOF) {
-				return reader, sb.String(), nil
-			} else if err != nil {
-				return reader, sb.String(), err
-			}
-		} else if string(peekBytes) == "--- " {
-			_, err := reader.ReadString(' ')
-			sb.WriteString("$yqDocSeparator$\n")
-			if errors.Is(err, io.EOF) {
-				return reader, sb.String(), nil
-			} else if err != nil {
-				return reader, sb.String(), err
-			}
-		} else if string(peekBytes) == "---\n" {
-			_, err := reader.ReadString('\n')
-			sb.WriteString("$yqDocSeparator$\n")
-			if errors.Is(err, io.EOF) {
-				return reader, sb.String(), nil
-			} else if err != nil {
-				return reader, sb.String(), err
-			}
-		} else if commentLineRegEx.MatchString(string(peekBytes)) || yamlDirectiveLineRegEx.MatchString(string(peekBytes)) {
-			line, err := reader.ReadString('\n')
-			sb.WriteString(line)
-			if errors.Is(err, io.EOF) {
-				return reader, sb.String(), nil
-			} else if err != nil {
-				return reader, sb.String(), err
-			}
-		} else {
+		line, err := reader.ReadString('\n')
+		if errors.Is(err, io.EOF) && line == "" {
+			// no more data
 			return reader, sb.String(), nil
 		}
+		if err != nil && !errors.Is(err, io.EOF) {
+			return reader, sb.String(), err
+		}
+
+		// Determine newline style and strip it for inspection
+		newline := ""
+		if strings.HasSuffix(line, "\r\n") {
+			newline = "\r\n"
+			line = strings.TrimSuffix(line, "\r\n")
+		} else if strings.HasSuffix(line, "\n") {
+			newline = "\n"
+			line = strings.TrimSuffix(line, "\n")
+		}
+
+		trimmed := strings.TrimSpace(line)
+
+		// Document separator: exact line '---' or a '--- ' prefix followed by content
+		if separatorLineRe.MatchString(trimmed) {
+			sb.WriteString("$yqDocSeparator$")
+			sb.WriteString(newline)
+			if errors.Is(err, io.EOF) {
+				return reader, sb.String(), nil
+			}
+			continue
+		}
+
+		// Handle lines that start with '--- ' followed by more content (e.g. '--- cat')
+		if separatorPrefixRe.MatchString(line) {
+			match := separatorPrefixRe.FindString(line)
+			remainder := line[len(match):]
+			// normalize separator newline: if original had none, default to LF
+			sepNewline := newline
+			if sepNewline == "" {
+				sepNewline = "\n"
+			}
+			sb.WriteString("$yqDocSeparator$")
+			sb.WriteString(sepNewline)
+			// push the remainder back onto the reader and continue processing
+			reader = bufio.NewReader(io.MultiReader(strings.NewReader(remainder), reader))
+			if errors.Is(err, io.EOF) && remainder == "" {
+				return reader, sb.String(), nil
+			}
+			continue
+		}
+
+		// Comments, YAML directives, and blank lines are leading content
+		if commentLineRe.MatchString(line) || yamlDirectiveLineRe.MatchString(line) || trimmed == "" {
+			sb.WriteString(line)
+			sb.WriteString(newline)
+			if errors.Is(err, io.EOF) {
+				return reader, sb.String(), nil
+			}
+			continue
+		}
+
+		// First non-leading line: push it back onto a reader and return
+		originalLine := line + newline
+		return io.MultiReader(strings.NewReader(originalLine), reader), sb.String(), nil
 	}
 }