tools/linters: ignore log lines

This commit adds a feature to our custom lll linter which will ignore
log lines (both single and multi-lined log lines) for the lll linter.

tools/linters/ll.go

@@ -12,6 +12,7 @@ import (
 	"go/token"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"unicode/utf8"
 
@@ -25,12 +26,14 @@ const (
 
 	defaultMaxLineLen       = 80
 	defaultTabWidthInSpaces = 8
+	defaultLogRegex         = `^\s*.*(L|l)og\.`
 )
 
 // LLConfig is the configuration for the ll linter.
 type LLConfig struct {
 	LineLength int    `json:"line-length"`
 	TabWidth   int    `json:"tab-width"`
+	LogRegex   string `json:"log-regex"`
 }
 
 // New creates a new LLPlugin from the given settings. It satisfies the
@@ -48,6 +51,9 @@ func New(settings any) (register.LinterPlugin, error) {
 	if cfg.TabWidth == 0 {
 		cfg.TabWidth = defaultTabWidthInSpaces
 	}
+	if cfg.LogRegex == "" {
+		cfg.LogRegex = defaultLogRegex
+	}
 
 	return &LLPlugin{cfg: cfg}, nil
 }
@@ -79,13 +85,16 @@ func (l *LLPlugin) GetLoadMode() string {
 }
 
 func (l *LLPlugin) run(pass *analysis.Pass) (any, error) {
-	var spaces = strings.Repeat(" ", l.cfg.TabWidth)
+	var (
+		spaces   = strings.Repeat(" ", l.cfg.TabWidth)
+		logRegex = regexp.MustCompile(l.cfg.LogRegex)
+	)
 
 	for _, f := range pass.Files {
 		fileName := getFileName(pass, f)
 
 		issues, err := getLLLIssuesForFile(
-			fileName, l.cfg.LineLength, spaces,
+			fileName, l.cfg.LineLength, spaces, logRegex,
 		)
 		if err != nil {
 			return nil, err
@@ -114,7 +123,7 @@ type issue struct {
 }
 
 func getLLLIssuesForFile(filename string, maxLineLen int,
-	tabSpaces string) ([]*issue, error) {
+	tabSpaces string, logRegex *regexp.Regexp) ([]*issue, error) {
 
 	f, err := os.Open(filename)
 	if err != nil {
@@ -126,6 +135,7 @@ func getLLLIssuesForFile(filename string, maxLineLen int,
 		res                []*issue
 		lineNumber         int
 		multiImportEnabled bool
+		multiLinedLog      bool
 	)
 
 	// Scan over each line.
@@ -167,6 +177,21 @@ func getLLLIssuesForFile(filename string, maxLineLen int,
 			continue
 		}
 
+		// Check if the line matches the log pattern.
+		if logRegex.MatchString(line) {
+			multiLinedLog = !strings.HasSuffix(line, ")")
+			continue
+		}
+
+		if multiLinedLog {
+			// Check for the end of a multiline log call.
+			if strings.HasSuffix(line, ")") {
+				multiLinedLog = false
+			}
+
+			continue
+		}
+
 		// Otherwise, we can check the length of the line and report if
 		// it exceeds the maximum line length.
 		lineLen := utf8.RuneCountInString(line)

tools/linters/ll_test.go

@@ -2,6 +2,7 @@ package linters
 
 import (
 	"os"
+	"regexp"
 	"strings"
 	"testing"
 
@@ -16,12 +17,14 @@ func TestGetLLLIssuesForFile(t *testing.T) {
 	testCases := []struct {
 		name          string
 		content       string
+		logRegex      string
 		expectedIssue []string
 	}{
 		{
 			name: "Single long line",
 			content: `
 				fmt.Println("This is a very long line that exceeds the maximum length and should be flagged by the linter.")`,
+			logRegex: defaultLogRegex,
 			expectedIssue: []string{
 				"the line is 140 characters long, which " +
 					"exceeds the maximum of 80 characters.",
@@ -32,6 +35,7 @@ func TestGetLLLIssuesForFile(t *testing.T) {
 			content: `
 				fmt.Println("This is a very long line that exceeds the maximum length and should be flagged by the linter.")
 				fmt.Println("This is a another very long line that exceeds the maximum length and should be flagged by the linter.")`,
+			logRegex: defaultLogRegex,
 			expectedIssue: []string{
 				"the line is 140 characters long, which " +
 					"exceeds the maximum of 80 characters.",
@@ -41,19 +45,23 @@ func TestGetLLLIssuesForFile(t *testing.T) {
 		},
 		{
 			name:     "Short lines",
+			logRegex: defaultLogRegex,
 			content: `
 				fmt.Println("Short line")`,
 		},
 		{
 			name:     "Directive ignored",
+			logRegex: defaultLogRegex,
 			content:  `//go:generate something very very very very very very very very very long and complex here wowowow`,
 		},
 		{
 			name:     "Long single line import",
+			logRegex: defaultLogRegex,
 			content:  `import "github.com/lightningnetwork/lnd/lnrpc/walletrpc/more/more/more/more/more/more/ok/that/is/enough"`,
 		},
 		{
 			name:     "Multi-line import",
+			logRegex: defaultLogRegex,
 			content: `
 			import (
 				"os"
@@ -63,19 +71,67 @@ func TestGetLLLIssuesForFile(t *testing.T) {
 		},
 		{
 			name:     "Long single line log",
+			logRegex: defaultLogRegex,
 			content: `
-		log.Infof("This is a very long log line but since it is a log line, it should be skipped by the linter.")`,
+			log.Infof("This is a very long log line but since it is a log line, it should be skipped by the linter."),
+			rpcLog.Info("Another long log line with a slightly different name and should still be skipped")`,
+		},
+		{
+			name:     "Long single line log followed by a non-log line",
+			logRegex: defaultLogRegex,
+			content: `
+				log.Infof("This is a very long log line but since it is a log line, it should be skipped by the linter.")
+				fmt.Println("This is a very long line that exceeds the maximum length and should be flagged by the linter.")`,
 			expectedIssue: []string{
-				"the line is 121 characters long, which " +
+				"the line is 140 characters long, which " +
+					"exceeds the maximum of 80 characters.",
+			},
+		},
+		{
+			name:     "Multi-line log",
+			logRegex: defaultLogRegex,
+			content: `
+				log.Infof("This is a very long log line but 
+						since it is a log line, it 
+						should be skipped by the linter.")`,
+		},
+		{
+			name:     "Multi-line log followed by a non-log line",
+			logRegex: defaultLogRegex,
+			content: `
+				log.Infof("This is a very long log line but 
+						since it is a log line, it 
+						should be skipped by the linter.")
+				fmt.Println("This is a very long line that 
+						exceeds the maximum length and 
+						should be flagged by the linter.")`,
+			expectedIssue: []string{
+				"the line is 82 characters long, which " +
+					"exceeds the maximum of 80 characters.",
+			},
+		},
+		{
+			name:     "Only skip 'S' logs",
+			logRegex: `^\s*.*(L|l)og\.(Info|Debug|Trace|Warn|Error|Critical)S\(`,
+			content: `
+				log.Infof("A long log line but it is not an S log and so should be caught")
+				log.InfoS("This is a very long log line but 
+						since it is an 'S' log line, it 
+						should be skipped by the linter.")
+				log.TraceS("Another S log that should be skipped by the linter")`,
+			expectedIssue: []string{
+				"the line is 107 characters long, which " +
 					"exceeds the maximum of 80 characters.",
 			},
 		},
 	}
 
-	tabSpaces := strings.Repeat(" ", 8)
+	tabSpaces := strings.Repeat(" ", defaultTabWidthInSpaces)
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
+			logRegex := regexp.MustCompile(tc.logRegex)
+
 			// Write content to a temporary file.
 			tmpFile := t.TempDir() + "/test.go"
 			err := os.WriteFile(tmpFile, []byte(tc.content), 0644)
@@ -83,7 +139,7 @@ func TestGetLLLIssuesForFile(t *testing.T) {
 
 			// Run the linter on the file.
 			issues, err := getLLLIssuesForFile(
-				tmpFile, 80, tabSpaces,
+				tmpFile, defaultMaxLineLen, tabSpaces, logRegex,
 			)
 			require.NoError(t, err)