Configure path prefix via processor abstraction

.golangci.example.yml

@@ -72,6 +72,9 @@ output:
   # make issues output unique by line, default is true
   uniq-by-line: true
 
+  # add a prefix to the output file references; default is no prefix
+  path-prefix: ""
+
 
 # all available settings of specific linters
 linters-settings:

pkg/commands/run.go

@@ -81,6 +81,7 @@ func initFlagSet(fs *pflag.FlagSet, cfg *config.Config, m *lintersdb.Manager, is
 	fs.BoolVar(&oc.PrintLinterName, "print-linter-name", true, wh("Print linter name in issue line"))
 	fs.BoolVar(&oc.UniqByLine, "uniq-by-line", true, wh("Make issues output unique by line"))
 	fs.BoolVar(&oc.PrintWelcomeMessage, "print-welcome", false, wh("Print welcome message"))
+	fs.StringVar(&oc.PathPrefix, "path-prefix", "", wh("Path prefix to add to output"))
 	hideFlag("print-welcome") // no longer used
 
 	// Run config

pkg/config/config.go

@@ -516,10 +516,11 @@ type Config struct {
 	Output struct {
 		Format              string
 		Color               string
-		PrintIssuedLine     bool `mapstructure:"print-issued-lines"`
-		PrintLinterName     bool `mapstructure:"print-linter-name"`
-		UniqByLine          bool `mapstructure:"uniq-by-line"`
-		PrintWelcomeMessage bool `mapstructure:"print-welcome"`
+		PrintIssuedLine     bool   `mapstructure:"print-issued-lines"`
+		PrintLinterName     bool   `mapstructure:"print-linter-name"`
+		UniqByLine          bool   `mapstructure:"uniq-by-line"`
+		PrintWelcomeMessage bool   `mapstructure:"print-welcome"`
+		PathPrefix          string `mapstructure:"path-prefix"`
 	}
 
 	LintersSettings LintersSettings `mapstructure:"linters-settings"`

pkg/lint/runner.go

@@ -79,6 +79,7 @@ func NewRunner(cfg *config.Config, log logutils.Log, goenv *goutil.Env, es *lint
 			processors.NewSourceCode(lineCache, log.Child("source_code")),
 			processors.NewPathShortener(),
 			getSeverityRulesProcessor(&cfg.Severity, log, lineCache),
+			processors.NewPathPrefixer(cfg.Output.PathPrefix),
 		},
 		Log: log,
 	}, nil

pkg/result/processors/path_prefixer.go

@@ -0,0 +1,37 @@
+package processors
+
+import (
+	"path"
+
+	"github.com/golangci/golangci-lint/pkg/result"
+)
+
+// PathPrefixer adds a customizable prefix to every output path
+type PathPrefixer struct {
+	prefix string
+}
+
+var _ Processor = new(PathPrefixer)
+
+// NewPathPrefixer returns a new path prefixer for the provided string
+func NewPathPrefixer(prefix string) *PathPrefixer {
+	return &PathPrefixer{prefix: prefix}
+}
+
+// Name returns the name of this processor
+func (*PathPrefixer) Name() string {
+	return "path_prefixer"
+}
+
+// Process adds the prefix to each path
+func (p *PathPrefixer) Process(issues []result.Issue) ([]result.Issue, error) {
+	if p.prefix != "" {
+		for i := range issues {
+			issues[i].Pos.Filename = path.Join(p.prefix, issues[i].Pos.Filename)
+		}
+	}
+	return issues, nil
+}
+
+// Finish is implemented to satisfy the Processor interface
+func (*PathPrefixer) Finish() {}

pkg/result/processors/path_prefixer_test.go

@@ -0,0 +1,37 @@
+package processors
+
+import (
+	"go/token"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/golangci/golangci-lint/pkg/result"
+)
+
+func TestPathPrefixer_Process(t *testing.T) {
+	paths := func(ps ...string) (issues []result.Issue) {
+		for _, p := range ps {
+			issues = append(issues, result.Issue{Pos: token.Position{Filename: p}})
+		}
+		return
+	}
+	for _, tt := range []struct {
+		name, prefix string
+		issues, want []result.Issue
+	}{
+		{"empty prefix", "", paths("some/path", "cool"), paths("some/path", "cool")},
+		{"prefix", "ok", paths("some/path", "cool"), paths("ok/some/path", "ok/cool")},
+		{"prefix slashed", "ok/", paths("some/path", "cool"), paths("ok/some/path", "ok/cool")},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			r := require.New(t)
+
+			p := NewPathPrefixer(tt.prefix)  //nolint:scopelint
+			got, err := p.Process(tt.issues) //nolint:scopelint
+			r.NoError(err, "prefixer should never error")
+
+			r.Equal(got, tt.want) //nolint:scopelint
+		})
+	}
+}

test/run_test.go

@@ -292,3 +292,22 @@ func TestDisallowedOptionsInConfig(t *testing.T) {
 		r.RunWithYamlConfig(c.cfg, withCommonRunArgs(args...)...).ExpectExitCode(exitcodes.Failure)
 	}
 }
+
+func TestPathPrefix(t *testing.T) {
+	for _, tt := range []struct {
+		Name    string
+		Args    []string
+		Pattern string
+	}{
+		{"empty", nil, "^testdata/withTests/"},
+		{"prefixed", []string{"--path-prefix=cool"}, "^cool/testdata/withTests"},
+	} {
+		t.Run(tt.Name, func(t *testing.T) {
+			testshared.NewLintRunner(t).Run(
+				append(tt.Args, getTestDataDir("withTests"))..., //nolint:scopelint
+			).ExpectOutputRegexp(
+				tt.Pattern, //nolint:scopelint
+			)
+		})
+	}
+}

test/testshared/testshared.go

@@ -66,6 +66,12 @@ func (r *RunResult) ExpectExitCode(possibleCodes ...int) *RunResult {
 	return r
 }
 
+// ExpectOutputRegexp can be called with either a string or compiled regexp
+func (r *RunResult) ExpectOutputRegexp(s interface{}) *RunResult {
+	assert.Regexp(r.t, s, r.output, "exit code is %d", r.exitCode)
+	return r
+}
+
 func (r *RunResult) ExpectOutputContains(s string) *RunResult {
 	assert.Contains(r.t, r.output, s, "exit code is %d", r.exitCode)
 	return r