fix

scanner/context.go

@@ -151,6 +151,7 @@ func (c *Context) addDocumentIndent(column int) {
 		}
 		// Since addBuf ignore space character, add to the buffer directly.
 		c.buf = append(c.buf, ' ')
+		c.notSpaceCharPos = len(c.buf)
 	}
 }
 
@@ -295,7 +296,9 @@ func (c *Context) bufferedSrc() []rune {
 		}
 
 		// If the text ends with a space character, remove all of them.
-		src = []rune(strings.TrimRight(string(src), " "))
+		if c.hasTrimAllEndNewlineOpt() {
+			src = []rune(strings.TrimRight(string(src), " "))
+		}
 		if string(src) == "\n" {
 			// If the content consists only of a newline,
 			// it can be considered as the document ending without any specified value,

scanner/scanner.go

@@ -639,13 +639,17 @@ func (s *Scanner) trimCommentFromDocumentOpt(text string, header rune) (string,
 func (s *Scanner) scanDocument(ctx *Context, c rune) error {
 	ctx.addOriginBuf(c)
 	if ctx.isEOS() {
+		if s.isFirstCharAtLine && c == ' ' {
+			ctx.addDocumentIndent(s.column)
+		} else {
+			ctx.addBuf(c)
+		}
 		ctx.updateDocumentLineIndentColumn(s.column)
 		if err := ctx.validateDocumentLineIndentColumn(); err != nil {
 			invalidTk := token.Invalid(err.Error(), string(ctx.obuf), s.pos())
 			s.progressColumn(ctx, 1)
 			return ErrInvalidToken(invalidTk)
 		}
-		ctx.addBuf(c)
 		value := ctx.bufferedSrc()
 		ctx.addToken(token.String(string(value), string(ctx.obuf), s.pos()))
 		ctx.clear()