Golangci-lint v2 part two (#498)

errors.go

@@ -50,7 +50,7 @@ func (e *DecodeError) String() string {
 	return e.human
 }
 
-/// Position returns the (line, column) pair indicating where the error
+// Position returns the (line, column) pair indicating where the error
 // occurred in the document. Positions are 1-indexed.
 func (e *DecodeError) Position() (row int, column int) {
 	return e.line, e.column
@@ -63,110 +63,147 @@ func (e *DecodeError) Position() (row int, column int) {
 //
 // The function copies all bytes used in DecodeError, so that document and
 // highlight can be freely deallocated.
+//nolint:funlen
 func wrapDecodeError(document []byte, de *decodeError) error {
 	if de == nil {
 		return nil
 	}
-	err := &DecodeError{
-		message: de.message,
-	}
 
 	offset := unsafe.SubsliceOffset(document, de.highlight)
 
-	err.line, err.column = positionAtEnd(document[:offset])
+	errMessage := de.message
+	errLine, errColumn := positionAtEnd(document[:offset])
 	before, after := linesOfContext(document, de.highlight, offset, 3)
 
 	var buf strings.Builder
 
-	maxLine := err.line + len(after) - 1
+	maxLine := errLine + len(after) - 1
 	lineColumnWidth := len(strconv.Itoa(maxLine))
 
 	for i := len(before) - 1; i > 0; i-- {
-		line := err.line - i
+		line := errLine - i
 		buf.WriteString(formatLineNumber(line, lineColumnWidth))
-		buf.WriteString("| ")
-		buf.Write(before[i])
+		buf.WriteString("|")
+
+		if len(before[i]) > 0 {
+			buf.WriteString(" ")
+			buf.Write(before[i])
+		}
+
 		buf.WriteRune('\n')
 	}
 
-	buf.WriteString(formatLineNumber(err.line, lineColumnWidth))
+	buf.WriteString(formatLineNumber(errLine, lineColumnWidth))
 	buf.WriteString("| ")
 
 	if len(before) > 0 {
 		buf.Write(before[0])
 	}
+
 	buf.Write(de.highlight)
+
 	if len(after) > 0 {
 		buf.Write(after[0])
 	}
+
 	buf.WriteRune('\n')
 	buf.WriteString(strings.Repeat(" ", lineColumnWidth))
 	buf.WriteString("| ")
+
 	if len(before) > 0 {
 		buf.WriteString(strings.Repeat(" ", len(before[0])))
 	}
+
 	buf.WriteString(strings.Repeat("~", len(de.highlight)))
-	buf.WriteString(" ")
-	buf.WriteString(err.message)
+
+	if len(errMessage) > 0 {
+		buf.WriteString(" ")
+		buf.WriteString(errMessage)
+	}
 
 	for i := 1; i < len(after); i++ {
 		buf.WriteRune('\n')
-		line := err.line + i
+		line := errLine + i
 		buf.WriteString(formatLineNumber(line, lineColumnWidth))
-		buf.WriteString("| ")
-		buf.Write(after[i])
+		buf.WriteString("|")
+
+		if len(after[i]) > 0 {
+			buf.WriteString(" ")
+			buf.Write(after[i])
+		}
 	}
 
-	err.human = buf.String()
-	return err
+	return &DecodeError{
+		message: errMessage,
+		line:    errLine,
+		column:  errColumn,
+		human:   buf.String(),
+	}
 }
 
 func formatLineNumber(line int, width int) string {
 	format := "%" + strconv.Itoa(width) + "d"
+
 	return fmt.Sprintf(format, line)
 }
 
 func linesOfContext(document []byte, highlight []byte, offset int, linesAround int) ([][]byte, [][]byte) {
+	return beforeLines(document, offset, linesAround), afterLines(document, highlight, offset, linesAround)
+}
+
+func beforeLines(document []byte, offset int, linesAround int) [][]byte {
 	var beforeLines [][]byte
 
-	// Walk the document in reverse from the highlight to find previous lines
+	// Walk the document backward from the highlight to find previous lines
 	// of context.
 	rest := document[:offset]
+backward:
 	for o := len(rest) - 1; o >= 0 && len(beforeLines) <= linesAround && len(rest) > 0; {
-		if rest[o] == '\n' {
+		switch {
+		case rest[o] == '\n':
 			// handle individual lines
 			beforeLines = append(beforeLines, rest[o+1:])
 			rest = rest[:o]
 			o = len(rest) - 1
-		} else if o == 0 {
+		case o == 0:
 			// add the first line only if it's non-empty
 			beforeLines = append(beforeLines, rest)
-			break
-		} else {
+
+			break backward
+		default:
 			o--
 		}
 	}
 
+	return beforeLines
+}
+
+func afterLines(document []byte, highlight []byte, offset int, linesAround int) [][]byte {
 	var afterLines [][]byte
 
 	// Walk the document forward from the highlight to find the following
 	// lines of context.
-	rest = document[offset+len(highlight):]
+	rest := document[offset+len(highlight):]
+forward:
 	for o := 0; o < len(rest) && len(afterLines) <= linesAround; {
-		if rest[o] == '\n' {
+		switch {
+		case rest[o] == '\n':
 			// handle individual lines
 			afterLines = append(afterLines, rest[:o])
 			rest = rest[o+1:]
 			o = 0
-		} else if o == len(rest)-1 && o > 0 {
+
+		case o == len(rest)-1 && o > 0:
 			// add last line only if it's non-empty
 			afterLines = append(afterLines, rest)
-			break
-		} else {
+
+			break forward
+		default:
 			o++
 		}
 	}
-	return beforeLines, afterLines
+
+	return afterLines
 }
 
 func positionAtEnd(b []byte) (row int, column int) {
@@ -181,5 +218,6 @@ func positionAtEnd(b []byte) (row int, column int) {
 			column++
 		}
 	}
+
 	return
 }