feat: automatic Go version detection (golangci#2669)

* feat: disable unsupported go1.18 govet analyzers
* fix: inactivate interfacer with go1.18

Author: ldez

.golangci.example.yml

@@ -66,8 +66,8 @@ run:
 
   # Define the Go version limit.
   # Mainly related to generics support in go1.18.
-  # Default: 1.17
-  go: 1.18
+  # Default: use Go version from the go.mod file, fallback on the env var `GOVERSION`, fallback on 1.17
+  go: '1.18'
 
 
 # output configuration options

.golangci.yml

@@ -130,6 +130,7 @@ issues:
 
 run:
   timeout: 5m
+  go: '1.17' # TODO(ldez): we force to use an old version of Go for the CI and the tests.
   skip-dirs:
     - test/testdata_etc
     - internal/cache

pkg/commands/executor.go

@@ -110,6 +110,10 @@ func NewExecutor(version, commit, date string) *Executor {
 		e.log.Fatalf("Can't read config: %s", err)
 	}
 
+	if commandLineCfg.Run.Go == "" && e.cfg.Run.Go == "" {
+		e.cfg.Run.Go = config.DetectGoVersion()
+	}
+
 	// recreate after getting config
 	e.DBManager = lintersdb.NewManager(e.cfg, e.log).WithCustomLinters()
 

pkg/commands/run.go

@@ -95,7 +95,7 @@ func initFlagSet(fs *pflag.FlagSet, cfg *config.Config, m *lintersdb.Manager, is
 		"Modules download mode. If not empty, passed as -mod=<mode> to go tools")
 	fs.IntVar(&rc.ExitCodeIfIssuesFound, "issues-exit-code",
 		exitcodes.IssuesFound, wh("Exit code when issues were found"))
-	fs.StringVar(&rc.Go, "go", "1.17", wh("Targeted Go version"))
+	fs.StringVar(&rc.Go, "go", "", wh("Targeted Go version"))
 	fs.StringSliceVar(&rc.BuildTags, "build-tags", nil, wh("Build tags"))
 
 	fs.DurationVar(&rc.Timeout, "deadline", defaultTimeout, wh("Deadline for total work"))

pkg/config/config.go

@@ -1,5 +1,13 @@
 package config
 
+import (
+	"os"
+	"strings"
+
+	hcversion "github.com/hashicorp/go-version"
+	"github.com/ldez/gomoddirectives"
+)
+
 // Config encapsulates the config data specified in the golangci yaml config file.
 type Config struct {
 	cfgDir string // The directory containing the golangci config file.
@@ -31,3 +39,32 @@ func NewDefault() *Config {
 type Version struct {
 	Format string `mapstructure:"format"`
 }
+
+func IsGreaterThanOrEqualGo118(v string) bool {
+	v1, err := hcversion.NewVersion(strings.TrimPrefix(v, "go"))
+	if err != nil {
+		return false
+	}
+
+	limit, err := hcversion.NewVersion("1.18")
+	if err != nil {
+		return false
+	}
+
+	return v1.GreaterThanOrEqual(limit)
+}
+
+func DetectGoVersion() string {
+	file, _ := gomoddirectives.GetModuleFile()
+
+	if file != nil && file.Go != nil && file.Go.Version != "" {
+		return file.Go.Version
+	}
+
+	v := os.Getenv("GOVERSION")
+	if v != "" {
+		return v
+	}
+
+	return "1.17"
+}

pkg/config/linters_settings.go

@@ -374,7 +374,8 @@ type GoSecSettings struct {
 }
 
 type GovetSettings struct {
-	CheckShadowing bool `mapstructure:"check-shadowing"`
+	Go             string `mapstructure:"-"`
+	CheckShadowing bool   `mapstructure:"check-shadowing"`
 	Settings       map[string]map[string]interface{}
 
 	Enable     []string
@@ -383,7 +384,7 @@ type GovetSettings struct {
 	DisableAll bool `mapstructure:"disable-all"`
 }
 
-func (cfg GovetSettings) Validate() error {
+func (cfg *GovetSettings) Validate() error {
 	if cfg.EnableAll && cfg.DisableAll {
 		return errors.New("enable-all and disable-all can't be combined")
 	}

pkg/golinters/govet.go

@@ -119,7 +119,46 @@ var (
 	}
 )
 
+func NewGovet(cfg *config.GovetSettings) *goanalysis.Linter {
+	var settings map[string]map[string]interface{}
+	if cfg != nil {
+		settings = cfg.Settings
+	}
+	return goanalysis.NewLinter(
+		"govet",
+		"Vet examines Go source code and reports suspicious constructs, "+
+			"such as Printf calls whose arguments do not align with the format string",
+		analyzersFromConfig(cfg),
+		settings,
+	).WithLoadMode(goanalysis.LoadModeTypesInfo)
+}
+
+func analyzersFromConfig(cfg *config.GovetSettings) []*analysis.Analyzer {
+	if cfg == nil {
+		return defaultAnalyzers
+	}
+
+	if cfg.CheckShadowing {
+		// Keeping for backward compatibility.
+		cfg.Enable = append(cfg.Enable, shadow.Analyzer.Name)
+	}
+
+	var enabledAnalyzers []*analysis.Analyzer
+	for _, a := range allAnalyzers {
+		if isAnalyzerEnabled(a.Name, cfg, defaultAnalyzers) {
+			enabledAnalyzers = append(enabledAnalyzers, a)
+		}
+	}
+
+	return enabledAnalyzers
+}
+
 func isAnalyzerEnabled(name string, cfg *config.GovetSettings, defaultAnalyzers []*analysis.Analyzer) bool {
+	if (name == nilness.Analyzer.Name || name == unusedwrite.Analyzer.Name) &&
+		config.IsGreaterThanOrEqualGo118(cfg.Go) {
+		return false
+	}
+
 	if cfg.EnableAll {
 		for _, n := range cfg.Disable {
 			if n == name {
@@ -128,58 +167,28 @@ func isAnalyzerEnabled(name string, cfg *config.GovetSettings, defaultAnalyzers
 		}
 		return true
 	}
+
 	// Raw for loops should be OK on small slice lengths.
 	for _, n := range cfg.Enable {
 		if n == name {
 			return true
 		}
 	}
+
 	for _, n := range cfg.Disable {
 		if n == name {
 			return false
 		}
 	}
+
 	if cfg.DisableAll {
 		return false
 	}
+
 	for _, a := range defaultAnalyzers {
 		if a.Name == name {
 			return true
 		}
 	}
 	return false
 }
-
-func analyzersFromConfig(cfg *config.GovetSettings) []*analysis.Analyzer {
-	if cfg == nil {
-		return defaultAnalyzers
-	}
-
-	if cfg.CheckShadowing {
-		// Keeping for backward compatibility.
-		cfg.Enable = append(cfg.Enable, shadow.Analyzer.Name)
-	}
-
-	var enabledAnalyzers []*analysis.Analyzer
-	for _, a := range allAnalyzers {
-		if isAnalyzerEnabled(a.Name, cfg, defaultAnalyzers) {
-			enabledAnalyzers = append(enabledAnalyzers, a)
-		}
-	}
-
-	return enabledAnalyzers
-}
-
-func NewGovet(cfg *config.GovetSettings) *goanalysis.Linter {
-	var settings map[string]map[string]interface{}
-	if cfg != nil {
-		settings = cfg.Settings
-	}
-	return goanalysis.NewLinter(
-		"govet",
-		"Vet examines Go source code and reports suspicious constructs, "+
-			"such as Printf calls whose arguments do not align with the format string",
-		analyzersFromConfig(cfg),
-		settings,
-	).WithLoadMode(goanalysis.LoadModeTypesInfo)
-}

pkg/lint/linter/config.go

@@ -1,9 +1,6 @@
 package linter
 
 import (
-	"strings"
-
-	hcversion "github.com/hashicorp/go-version"
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/packages"
 
@@ -126,14 +123,17 @@ func (lc *Config) Name() string {
 }
 
 func (lc *Config) WithNoopFallback(cfg *config.Config) *Config {
-	if isGreaterThanOrEqualGo118(cfg) {
+	if cfg != nil && config.IsGreaterThanOrEqualGo118(cfg.Run.Go) {
 		lc.Linter = &Noop{
 			name: lc.Linter.Name(),
 			desc: lc.Linter.Desc(),
 			run: func(pass *analysis.Pass) (interface{}, error) {
 				return nil, nil
 			},
 		}
+
+		lc.LoadMode = 0
+		return lc.WithLoadFiles()
 	}
 
 	return lc
@@ -145,21 +145,3 @@ func NewConfig(linter Linter) *Config {
 	}
 	return lc.WithLoadFiles()
 }
-
-func isGreaterThanOrEqualGo118(cfg *config.Config) bool {
-	if cfg == nil {
-		return false
-	}
-
-	v1, err := hcversion.NewVersion(strings.TrimPrefix(cfg.Run.Go, "go"))
-	if err != nil {
-		return false
-	}
-
-	limit, err := hcversion.NewVersion("1.18")
-	if err != nil {
-		return false
-	}
-
-	return v1.GreaterThanOrEqual(limit)
-}

pkg/lint/linter/linter.go

@@ -22,7 +22,6 @@ type Noop struct {
 
 func (n Noop) Run(_ context.Context, lintCtx *Context) ([]result.Issue, error) {
 	lintCtx.Log.Warnf("%s is disabled because of go1.18."+
-		" If you are not using go1.18, you can set `go: go1.17` in the `run` section."+
 		" You can track the evolution of the go1.18 support by following the https://github.com/golangci/golangci-lint/issues/2649.", n.name)
 	return nil, nil
 }

pkg/lint/lintersdb/manager.go

@@ -164,6 +164,10 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 		unusedCfg = &m.cfg.LintersSettings.Unused
 		varnamelenCfg = &m.cfg.LintersSettings.Varnamelen
 		wrapcheckCfg = &m.cfg.LintersSettings.Wrapcheck
+
+		if govetCfg != nil {
+			govetCfg.Go = m.cfg.Run.Go
+		}
 	}
 
 	const megacheckName = "megacheck"
@@ -446,7 +450,8 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithLoadForGoAnalysis().
 			WithPresets(linter.PresetStyle).
 			WithURL("https://github.com/mvdan/interfacer").
-			Deprecated("The repository of the linter has been archived by the owner.", "v1.38.0", ""),
+			Deprecated("The repository of the linter has been archived by the owner.", "v1.38.0", "").
+			WithNoopFallback(m.cfg),
 
 		linter.NewConfig(golinters.NewIreturn(ireturnCfg)).
 			WithSince("v1.43.0").