feat: use problem matchers for GitHub Action format

Author: ldez

pkg/printers/github.go

@@ -1,28 +1,102 @@
 package printers
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
+	"os"
 	"path/filepath"
 
 	"github.com/golangci/golangci-lint/pkg/result"
 )
 
+const defaultGitHubSeverity = "error"
+
+const filenameGitHubActionProblemMatchers = "golangci-lint-action-problem-matchers.json"
+
+// GitHubProblemMatchers defines the root of problem matchers.
+// - https://github.com/actions/toolkit/blob/main/docs/problem-matchers.md
+// - https://github.com/actions/toolkit/blob/main/docs/commands.md#problem-matchers
+type GitHubProblemMatchers struct {
+	Matchers []GitHubMatcher `json:"problemMatcher,omitempty"`
+}
+
+// GitHubMatcher defines a problem matcher.
+type GitHubMatcher struct {
+	// Owner an ID field that can be used to remove or replace the problem matcher.
+	// **required**
+	Owner string `json:"owner,omitempty"`
+	// Severity indicates the default severity, either 'warning' or 'error' case-insensitive.
+	// Defaults to 'error'.
+	Severity string          `json:"severity,omitempty"`
+	Pattern  []GitHubPattern `json:"pattern,omitempty"`
+}
+
+// GitHubPattern defines a pattern for a problem matcher.
+type GitHubPattern struct {
+	// Regexp the regexp pattern that provides the groups to match against.
+	// **required**
+	Regexp string `json:"regexp,omitempty"`
+	// File a group number containing the file name.
+	File int `json:"file,omitempty"`
+	// FromPath a group number containing a filepath used to root the file (e.g. a project file).
+	FromPath int `json:"fromPath,omitempty"`
+	// Line a group number containing the line number.
+	Line int `json:"line,omitempty"`
+	// Column a group number containing the column information.
+	Column int `json:"column,omitempty"`
+	// Severity a group number containing either 'warning' or 'error' case-insensitive.
+	// Defaults to `error`.
+	Severity int `json:"severity,omitempty"`
+	// Code a group number containing the error code.
+	Code int `json:"code,omitempty"`
+	// Message a group number containing the error message.
+	// **required** at least one pattern must set the message.
+	Message int `json:"message,omitempty"`
+	// Loop whether to loop until a match is not found,
+	// only valid on the last pattern of a multi-pattern matcher.
+	Loop bool `json:"loop,omitempty"`
+}
+
 type GitHub struct {
 	w io.Writer
 }
 
-const defaultGithubSeverity = "error"
-
-// NewGitHub output format outputs issues according to GitHub actions format:
-// https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-error-message
+// NewGitHub output format outputs issues according to GitHub actions the problem matcher regexp.
 func NewGitHub(w io.Writer) *GitHub {
 	return &GitHub{w: w}
 }
 
-// print each line as: ::error file=app.js,line=10,col=15::Something went wrong
-func formatIssueAsGithub(issue *result.Issue) string {
-	severity := defaultGithubSeverity
+func (p *GitHub) Print(issues []result.Issue) error {
+	// Note: the file with the problem matcher definition should not be removed.
+	// A sleep can mitigate this problem but this will be flaky.
+	//
+	// Error: Unable to process command '::add-matcher::/tmp/golangci-lint-action-problem-matchers.json' successfully.
+	// Error: Could not find file '/tmp/golangci-lint-action-problem-matchers.json'.
+	//
+	filename, err := storeProblemMatcher()
+	if err != nil {
+		return err
+	}
+
+	_, _ = fmt.Fprintln(p.w, "::debug::problem matcher definition file: "+filename)
+
+	_, _ = fmt.Fprintln(p.w, "::add-matcher::"+filename)
+
+	for ind := range issues {
+		_, err := fmt.Fprintln(p.w, formatIssueAsGitHub(&issues[ind]))
+		if err != nil {
+			return err
+		}
+	}
+
+	_, _ = fmt.Fprintln(p.w, "::remove-matcher owner=golangci-lint-action::")
+
+	return nil
+}
+
+func formatIssueAsGitHub(issue *result.Issue) string {
+	severity := defaultGitHubSeverity
 	if issue.Severity != "" {
 		severity = issue.Severity
 	}
@@ -32,21 +106,49 @@ func formatIssueAsGithub(issue *result.Issue) string {
 	// Otherwise, GitHub won't be able to show the annotations pointing to the file path with backslashes.
 	file := filepath.ToSlash(issue.FilePath())
 
-	ret := fmt.Sprintf("::%s file=%s,line=%d", severity, file, issue.Line())
+	ret := fmt.Sprintf("%s\t%s:%d:", severity, file, issue.Line())
 	if issue.Pos.Column != 0 {
-		ret += fmt.Sprintf(",col=%d", issue.Pos.Column)
+		ret += fmt.Sprintf("%d:", issue.Pos.Column)
 	}
 
-	ret += fmt.Sprintf("::%s (%s)", issue.Text, issue.FromLinter)
+	ret += fmt.Sprintf("\t%s (%s)", issue.Text, issue.FromLinter)
 	return ret
 }
 
-func (p *GitHub) Print(issues []result.Issue) error {
-	for ind := range issues {
-		_, err := fmt.Fprintln(p.w, formatIssueAsGithub(&issues[ind]))
-		if err != nil {
-			return err
-		}
+func storeProblemMatcher() (string, error) {
+	//nolint:gosec // To be able to clean the file during tests, we need a deterministic filepath.
+	file, err := os.Create(filepath.Join(os.TempDir(), filenameGitHubActionProblemMatchers))
+	if err != nil {
+		return "", err
+	}
+
+	defer file.Close()
+
+	err = json.NewEncoder(file).Encode(generateProblemMatcher())
+	if err != nil {
+		return "", err
+	}
+
+	return file.Name(), nil
+}
+
+func generateProblemMatcher() GitHubProblemMatchers {
+	return GitHubProblemMatchers{
+		Matchers: []GitHubMatcher{
+			{
+				Owner:    "golangci-lint-action",
+				Severity: "error",
+				Pattern: []GitHubPattern{
+					{
+						Regexp:   `^([^\s]+)\s+([^:]+):(\d+):(?:(\d+):)?\s+(.+)$`,
+						Severity: 1,
+						File:     2,
+						Line:     3,
+						Column:   4,
+						Message:  5,
+					},
+				},
+			},
+		},
 	}
-	return nil
 }

pkg/printers/github_test.go

@@ -2,8 +2,13 @@ package printers
 
 import (
 	"bytes"
+	"fmt"
 	"go/token"
+	"os"
+	"path/filepath"
+	"regexp"
 	"runtime"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -13,6 +18,10 @@ import (
 )
 
 func TestGitHub_Print(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skip("Skipping tests because temp folder depends on OS")
+	}
+
 	issues := []result.Issue{
 		{
 			FromLinter: "linter-a",
@@ -43,20 +52,27 @@ func TestGitHub_Print(t *testing.T) {
 		},
 	}
 
+	t.Cleanup(func() {
+		_ = os.RemoveAll(filepath.Join(t.TempDir(), filenameGitHubActionProblemMatchers))
+	})
+
 	buf := new(bytes.Buffer)
 	printer := NewGitHub(buf)
 
 	err := printer.Print(issues)
 	require.NoError(t, err)
 
-	expected := `::warning file=path/to/filea.go,line=10,col=4::some issue (linter-a)
-::error file=path/to/fileb.go,line=300,col=9::another issue (linter-b)
+	expected := `::debug::problem matcher definition file: /tmp/golangci-lint-action-problem-matchers.json
+::add-matcher::/tmp/golangci-lint-action-problem-matchers.json
+warning	path/to/filea.go:10:4:	some issue (linter-a)
+error	path/to/fileb.go:300:9:	another issue (linter-b)
+::remove-matcher owner=golangci-lint-action::
 `
 
 	assert.Equal(t, expected, buf.String())
 }
 
-func Test_formatIssueAsGithub(t *testing.T) {
+func Test_formatIssueAsGitHub(t *testing.T) {
 	sampleIssue := result.Issue{
 		FromLinter: "sample-linter",
 		Text:       "some issue",
@@ -67,13 +83,13 @@ func Test_formatIssueAsGithub(t *testing.T) {
 			Column:   4,
 		},
 	}
-	require.Equal(t, "::error file=path/to/file.go,line=10,col=4::some issue (sample-linter)", formatIssueAsGithub(&sampleIssue))
+	require.Equal(t, "error\tpath/to/file.go:10:4:\tsome issue (sample-linter)", formatIssueAsGitHub(&sampleIssue))
 
 	sampleIssue.Pos.Column = 0
-	require.Equal(t, "::error file=path/to/file.go,line=10::some issue (sample-linter)", formatIssueAsGithub(&sampleIssue))
+	require.Equal(t, "error\tpath/to/file.go:10:\tsome issue (sample-linter)", formatIssueAsGitHub(&sampleIssue))
 }
 
-func Test_formatIssueAsGithub_Windows(t *testing.T) {
+func Test_formatIssueAsGitHub_Windows(t *testing.T) {
 	if runtime.GOOS != "windows" {
 		t.Skip("Skipping test on non Windows")
 	}
@@ -88,8 +104,99 @@ func Test_formatIssueAsGithub_Windows(t *testing.T) {
 			Column:   4,
 		},
 	}
-	require.Equal(t, "::error file=path/to/file.go,line=10,col=4::some issue (sample-linter)", formatIssueAsGithub(&sampleIssue))
+	require.Equal(t, "error\tpath/to/file.go:10:4:\tsome issue (sample-linter)", formatIssueAsGitHub(&sampleIssue))
 
 	sampleIssue.Pos.Column = 0
-	require.Equal(t, "::error file=path/to/file.go,line=10::some issue (sample-linter)", formatIssueAsGithub(&sampleIssue))
+	require.Equal(t, "error\tpath/to/file.go:10:\tsome issue (sample-linter)", formatIssueAsGitHub(&sampleIssue))
+}
+
+func Test_generateProblemMatcher(t *testing.T) {
+	pattern := generateProblemMatcher().Matchers[0].Pattern[0]
+
+	exp := regexp.MustCompile(pattern.Regexp)
+
+	testCases := []struct {
+		desc     string
+		line     string
+		expected string
+	}{
+		{
+			desc: "error",
+			line: "error\tpath/to/filea.go:10:4:\tsome issue (sample-linter)",
+			expected: `File: path/to/filea.go
+Line: 10
+Column: 4
+Severity: error
+Message: some issue (sample-linter)`,
+		},
+		{
+			desc: "warning",
+			line: "warning\tpath/to/fileb.go:1:4:\tsome issue (sample-linter)",
+			expected: `File: path/to/fileb.go
+Line: 1
+Column: 4
+Severity: warning
+Message: some issue (sample-linter)`,
+		},
+		{
+			desc: "no column",
+			line: "error\t \tpath/to/fileb.go:40:\t Foo bar",
+			expected: `File: path/to/fileb.go
+Line: 40
+Column: 
+Severity: error
+Message: Foo bar`,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			assert.True(t, exp.MatchString(test.line), test.line)
+
+			actual := exp.ReplaceAllString(test.line, createReplacement(&pattern))
+
+			assert.Equal(t, test.expected, actual)
+		})
+	}
+}
+
+func createReplacement(pattern *GitHubPattern) string {
+	var repl []string
+
+	if pattern.File > 0 {
+		repl = append(repl, fmt.Sprintf("File: $%d", pattern.File))
+	}
+
+	if pattern.FromPath > 0 {
+		repl = append(repl, fmt.Sprintf("FromPath: $%d", pattern.FromPath))
+	}
+
+	if pattern.Line > 0 {
+		repl = append(repl, fmt.Sprintf("Line: $%d", pattern.Line))
+	}
+
+	if pattern.Column > 0 {
+		repl = append(repl, fmt.Sprintf("Column: $%d", pattern.Column))
+	}
+
+	if pattern.Severity > 0 {
+		repl = append(repl, fmt.Sprintf("Severity: $%d", pattern.Severity))
+	}
+
+	if pattern.Code > 0 {
+		repl = append(repl, fmt.Sprintf("Code: $%d", pattern.Code))
+	}
+
+	if pattern.Message > 0 {
+		repl = append(repl, fmt.Sprintf("Message: $%d", pattern.Message))
+	}
+
+	if pattern.Loop {
+		repl = append(repl, fmt.Sprintf("Loop: $%v", pattern.Loop))
+	}
+
+	return strings.Join(repl, "\n")
 }

pkg/printers/printer_test.go

@@ -173,18 +173,22 @@ func TestPrinter_Print_file(t *testing.T) {
 func TestPrinter_Print_multiple(t *testing.T) {
 	logger := logutils.NewStderrLog("skip")
 
+	t.Cleanup(func() {
+		_ = os.RemoveAll(filepath.Join(t.TempDir(), filenameGitHubActionProblemMatchers))
+	})
+
 	var issues []result.Issue
 	unmarshalFile(t, "in-issues.json", &issues)
 
 	data := &report.Data{}
 	unmarshalFile(t, "in-report-data.json", data)
 
-	outputPath := filepath.Join(t.TempDir(), "github-actions.txt")
+	outputPath := filepath.Join(t.TempDir(), "teamcity.txt")
 
 	cfg := &config.Output{
 		Formats: []config.OutputFormat{
 			{
-				Format: "github-actions",
+				Format: "teamcity",
 				Path:   outputPath,
 			},
 			{
@@ -210,7 +214,7 @@ func TestPrinter_Print_multiple(t *testing.T) {
 	err = p.Print(issues)
 	require.NoError(t, err)
 
-	goldenGitHub, err := os.ReadFile(filepath.Join("testdata", "golden-github-actions.txt"))
+	goldenGitHub, err := os.ReadFile(filepath.Join("testdata", "golden-teamcity.txt"))
 	require.NoError(t, err)
 
 	actual, err := os.ReadFile(outputPath)