tools/linters: Add copied golangci-lint lll linter code

In this commit, we copy the implementation of the golangci-lint lll linter which we currently use in our CI flow during the `make lint` check. This commit copies the code mostly as is (the only exception being the line which trims white space before checking if a line starts with "import"), and formats it to fit our codebase guidelines. A test is also added so that we can be sure that the following commits which adjust the implementation have the intended results. The custom linter is put into its own module as this is requied by the `golangci-lint custom` when building the custom linter binary which includes the plugin.
2025-08-29 07:00:55 +02:00 · 2024-11-29 10:39:32 +02:00
parent 506586a37e
commit acbcb771af
4 changed files with 450 additions and 0 deletions
--- a/tools/linters/go.mod
+++ b/tools/linters/go.mod
@@ -0,0 +1,44 @@
+module github.com/lightningnetwork/lnd/tools/linters
+
+go 1.22.6
+
+require (
+	github.com/golangci/golangci-lint v1.62.2
+	github.com/stretchr/testify v1.10.0
+	golang.org/x/tools v0.27.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/fatih/color v1.18.0 // indirect
+	github.com/fsnotify/fsnotify v1.5.4 // indirect
+	github.com/go-viper/mapstructure/v2 v2.2.1 // indirect
+	github.com/hashicorp/go-version v1.7.0 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
+	github.com/ldez/gomoddirectives v0.2.4 // indirect
+	github.com/magiconair/properties v1.8.6 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mitchellh/go-homedir v1.1.0 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
+	github.com/pelletier/go-toml v1.9.5 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.3 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/rogpeppe/go-internal v1.13.1 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	github.com/spf13/afero v1.11.0 // indirect
+	github.com/spf13/cast v1.5.0 // indirect
+	github.com/spf13/jwalterweatherman v1.1.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/spf13/viper v1.12.0 // indirect
+	github.com/stretchr/objx v0.5.2 // indirect
+	github.com/subosito/gotenv v1.4.1 // indirect
+	golang.org/x/exp v0.0.0-20240909161429-701f63a606c0 // indirect
+	golang.org/x/mod v0.22.0 // indirect
+	golang.org/x/sync v0.9.0 // indirect
+	golang.org/x/sys v0.27.0 // indirect
+	golang.org/x/text v0.18.0 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
--- a/tools/linters/go.sum
+++ b/tools/linters/go.sum
@@ -0,0 +1,90 @@
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--- a/tools/linters/ll.go
+++ b/tools/linters/ll.go
@@ -0,0 +1,219 @@
+// The following code is based on code from GolangCI.
+// Source: https://github.com/golangci-lint/pkg/golinters/lll/lll.go
+// License: GNU
+
+package linters
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"go/token"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"unicode/utf8"
+
+	"github.com/golangci/golangci-lint/pkg/config"
+	"github.com/golangci/golangci-lint/pkg/goanalysis"
+	"github.com/golangci/golangci-lint/pkg/lint/linter"
+	"github.com/golangci/golangci-lint/pkg/result"
+	"golang.org/x/tools/go/analysis"
+)
+
+const (
+	linterName               = "lll"
+	goCommentDirectivePrefix = "//go:"
+)
+
+// New creates a new lll linter from the given settings. It satisfies the
+// signature required by the golangci-lint linter for plugins.
+func New(settings *config.LllSettings) *goanalysis.Linter {
+	var (
+		mu        sync.Mutex
+		resIssues []goanalysis.Issue
+	)
+
+	analyzer := &analysis.Analyzer{
+		Name: linterName,
+		Doc:  goanalysis.TheOnlyanalyzerDoc,
+		Run: func(pass *analysis.Pass) (any, error) {
+			issues, err := runLll(pass, settings)
+			if err != nil {
+				return nil, err
+			}
+
+			if len(issues) == 0 {
+				return nil, nil
+			}
+
+			mu.Lock()
+			resIssues = append(resIssues, issues...)
+			mu.Unlock()
+
+			return nil, nil
+		},
+	}
+
+	return goanalysis.NewLinter(
+		linterName, "Reports long lines",
+		[]*analysis.Analyzer{analyzer}, nil,
+	).WithIssuesReporter(func(*linter.Context) []goanalysis.Issue {
+		return resIssues
+	}).WithLoadMode(goanalysis.LoadModeSyntax)
+}
+
+func runLll(pass *analysis.Pass, settings *config.LllSettings) (
+	[]goanalysis.Issue, error) {
+
+	var (
+		fileNames = getFileNames(pass)
+		spaces    = strings.Repeat(" ", settings.TabWidth)
+		issues    []goanalysis.Issue
+	)
+
+	for _, f := range fileNames {
+		lintIssues, err := getLLLIssuesForFile(
+			f, settings.LineLength, spaces,
+		)
+		if err != nil {
+			return nil, err
+		}
+
+		for i := range lintIssues {
+			issues = append(issues, goanalysis.NewIssue(
+				&lintIssues[i], pass,
+			))
+		}
+	}
+
+	return issues, nil
+}
+
+func getLLLIssuesForFile(filename string, maxLineLen int,
+	tabSpaces string) ([]result.Issue, error) {
+
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, fmt.Errorf("can't open file %s: %w", filename, err)
+	}
+	defer f.Close()
+
+	var (
+		res                []result.Issue
+		lineNumber         int
+		multiImportEnabled bool
+	)
+
+	// Scan over each line.
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		lineNumber++
+
+		// Replace all tabs with spaces.
+		line := scanner.Text()
+		line = strings.ReplaceAll(line, "\t", tabSpaces)
+
+		// Ignore any //go: directives since these cant be wrapped onto
+		// a new line.
+		if strings.HasPrefix(line, goCommentDirectivePrefix) {
+			continue
+		}
+
+		// We never want the linter to run on imports since these cannot
+		// be wrapped onto a new line. If this is a single line import
+		// we can skip the line entirely. If this is a multi-line import
+		// skip until the closing bracket.
+		//
+		// NOTE: We trim the line space around the line here purely for
+		// the purpose of being able to test this part of the linter
+		// without the risk of the `gosimports` tool reformatting the
+		// test case and removing the import.
+		if strings.HasPrefix(strings.TrimSpace(line), "import") {
+			multiImportEnabled = strings.HasSuffix(line, "(")
+			continue
+		}
+
+		// If we have marked the start of a multi-line import, we should
+		// skip until the closing bracket of the import block.
+		if multiImportEnabled {
+			if line == ")" {
+				multiImportEnabled = false
+			}
+
+			continue
+		}
+
+		// Otherwise, we can check the length of the line and report if
+		// it exceeds the maximum line length.
+		lineLen := utf8.RuneCountInString(line)
+		if lineLen > maxLineLen {
+			res = append(res, result.Issue{
+				Pos: token.Position{
+					Filename: filename,
+					Line:     lineNumber,
+				},
+				Text: fmt.Sprintf("the line is %d "+
+					"characters long, which exceeds the "+
+					"maximum of %d characters.", lineLen,
+					maxLineLen),
+				FromLinter: linterName,
+			})
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		if errors.Is(err, bufio.ErrTooLong) &&
+			maxLineLen < bufio.MaxScanTokenSize {
+
+			// scanner.Scan() might fail if the line is longer than
+			// bufio.MaxScanTokenSize. In the case where the
+			// specified maxLineLen is smaller than
+			// bufio.MaxScanTokenSize we can return this line as a
+			// long line instead of returning an error. The reason
+			// for this change is that this case might happen with
+			// autogenerated files. The go-bindata tool for instance
+			// might generate a file with a very long line. In this
+			// case, as it's an auto generated file, the warning
+			// returned by lll will be ignored.
+			// But if we return a linter error here, and this error
+			// happens for an autogenerated file the error will be
+			// discarded (fine), but all the subsequent errors for
+			// lll will be discarded for other files, and we'll miss
+			// legit error.
+			res = append(res, result.Issue{
+				Pos: token.Position{
+					Filename: filename,
+					Line:     lineNumber,
+					Column:   1,
+				},
+				Text: fmt.Sprintf("line is more than "+
+					"%d characters",
+					bufio.MaxScanTokenSize),
+				FromLinter: linterName,
+			})
+		} else {
+			return nil, fmt.Errorf("can't scan file %s: %w",
+				filename, err)
+		}
+	}
+
+	return res, nil
+}
+
+func getFileNames(pass *analysis.Pass) []string {
+	var fileNames []string
+	for _, f := range pass.Files {
+		fileName := pass.Fset.PositionFor(f.Pos(), true).Filename
+		ext := filepath.Ext(fileName)
+		if ext != "" && ext != ".go" {
+			// The position has been adjusted to a non-go file,
+			// revert to original file.
+			position := pass.Fset.PositionFor(f.Pos(), false)
+			fileName = position.Filename
+		}
+		fileNames = append(fileNames, fileName)
+	}
+	return fileNames
+}
--- a/tools/linters/ll_test.go
+++ b/tools/linters/ll_test.go
@@ -0,0 +1,97 @@
+package linters
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestGetLLLIssuesForFile tests the line-too-long linter.
+//
+//nolint:ll
+func TestGetLLLIssuesForFile(t *testing.T) {
+	// Test data
+	testCases := []struct {
+		name          string
+		content       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.")`,
+			expectedIssue: []string{
+				"the line is 140 characters long, which " +
+					"exceeds the maximum of 80 characters.",
+			},
+		},
+		{
+			name: "Multiple long lines",
+			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.")`,
+			expectedIssue: []string{
+				"the line is 140 characters long, which " +
+					"exceeds the maximum of 80 characters.",
+				"the line is 148 characters long, which " +
+					"exceeds the maximum of 80 characters.",
+			},
+		},
+		{
+			name: "Short lines",
+			content: `
+				fmt.Println("Short line")`,
+		},
+		{
+			name:    "Directive ignored",
+			content: `//go:generate something very very very very very very very very very long and complex here wowowow`,
+		},
+		{
+			name:    "Long single line import",
+			content: `import "github.com/lightningnetwork/lnd/lnrpc/walletrpc/more/more/more/more/more/more/ok/that/is/enough"`,
+		},
+		{
+			name: "Multi-line import",
+			content: `
+			import (
+				"os"
+				"fmt"
+				"github.com/lightningnetwork/lnd/lnrpc/walletrpc/more/ok/that/is/enough"
+			)`,
+		},
+		{
+			name: "Long single line log",
+			content: `
+		log.Infof("This is a very long log line but since it is a log line, it should be skipped by the linter.")`,
+			expectedIssue: []string{
+				"the line is 121 characters long, which " +
+					"exceeds the maximum of 80 characters.",
+			},
+		},
+	}
+
+	tabSpaces := strings.Repeat(" ", 8)
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Write content to a temporary file.
+			tmpFile := t.TempDir() + "/test.go"
+			err := os.WriteFile(tmpFile, []byte(tc.content), 0644)
+			require.NoError(t, err)
+
+			// Run the linter on the file.
+			issues, err := getLLLIssuesForFile(
+				tmpFile, 80, tabSpaces,
+			)
+			require.NoError(t, err)
+
+			require.Len(t, issues, len(tc.expectedIssue))
+
+			for i, issue := range issues {
+				require.Equal(t, tc.expectedIssue[i], issue.Text)
+			}
+		})
+	}
+}