From 6963a2ec43cd30d05ad81bdadd512885307ffd0d Mon Sep 17 00:00:00 2001
From: Fernandez Ludovic <ldez@users.noreply.github.com>
Date: Tue, 22 Mar 2022 12:39:29 +0100
Subject: [PATCH] feat: Automatic Go version detection

---
 .golangci.yml                 |  1 +
 pkg/commands/executor.go      |  4 ++++
 pkg/commands/run.go           |  2 +-
 pkg/config/config.go          | 22 ++++++++++++++++++++++
 pkg/lint/linter/config.go     |  3 +++
 pkg/lint/linter/linter.go     |  1 -
 test/fix_test.go              |  1 +
 test/linters_test.go          |  1 +
 test/testshared/testshared.go |  5 ++++-
 9 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/.golangci.yml b/.golangci.yml
index a17d2b119bad..4427980c5835 100644
--- a/.golangci.yml
+++ b/.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
diff --git a/pkg/commands/executor.go b/pkg/commands/executor.go
index 0ad37dde6ffc..4dee789cd945 100644
--- a/pkg/commands/executor.go
+++ b/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.DetectGo()
+	}
+
 	// recreate after getting config
 	e.DBManager = lintersdb.NewManager(e.cfg, e.log).WithCustomLinters()
 
diff --git a/pkg/commands/run.go b/pkg/commands/run.go
index 61f86ee52368..f4716d184819 100644
--- a/pkg/commands/run.go
+++ b/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"))
diff --git a/pkg/config/config.go b/pkg/config/config.go
index 49df4e495228..224807390ac6 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -1,5 +1,12 @@
 package config
 
+import (
+	"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 +38,18 @@ func NewDefault() *Config {
 type Version struct {
 	Format string `mapstructure:"format"`
 }
+
+func DetectGo() string {
+	const defaultGo = "1.17"
+
+	file, err := gomoddirectives.GetModuleFile()
+	if err != nil {
+		return defaultGo
+	}
+
+	if file != nil && file.Go != nil {
+		return file.Go.Version
+	}
+
+	return defaultGo
+}
diff --git a/pkg/lint/linter/config.go b/pkg/lint/linter/config.go
index e86a5dc44b9b..184b00cc7269 100644
--- a/pkg/lint/linter/config.go
+++ b/pkg/lint/linter/config.go
@@ -134,6 +134,9 @@ func (lc *Config) WithNoopFallback(cfg *config.Config) *Config {
 				return nil, nil
 			},
 		}
+
+		lc.LoadMode = 0
+		return lc.WithLoadFiles()
 	}
 
 	return lc
diff --git a/pkg/lint/linter/linter.go b/pkg/lint/linter/linter.go
index 04f0f6aeb81b..01e2196911e0 100644
--- a/pkg/lint/linter/linter.go
+++ b/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
 }
diff --git a/test/fix_test.go b/test/fix_test.go
index 3d1144d5e6d7..ce61d85f2d59 100644
--- a/test/fix_test.go
+++ b/test/fix_test.go
@@ -43,6 +43,7 @@ func TestFix(t *testing.T) {
 			t.Parallel()
 
 			args := []string{
+				"--go=1.17", //  TODO(ldez): we force to use an old version of Go for the CI and the tests.
 				"--disable-all", "--print-issued-lines=false", "--print-linter-name=false", "--out-format=line-number",
 				"--allow-parallel-runners", "--fix",
 				input,
diff --git a/test/linters_test.go b/test/linters_test.go
index a80baa6a511c..19c315ffef57 100644
--- a/test/linters_test.go
+++ b/test/linters_test.go
@@ -179,6 +179,7 @@ func saveConfig(t *testing.T, cfg map[string]interface{}) (cfgPath string, finis
 func testOneSource(t *testing.T, sourcePath string) {
 	args := []string{
 		"run",
+		"--go=1.17", //  TODO(ldez): we force to use an old version of Go for the CI and the tests.
 		"--allow-parallel-runners",
 		"--disable-all",
 		"--print-issued-lines=false",
diff --git a/test/testshared/testshared.go b/test/testshared/testshared.go
index fa70c23131ae..9291532be429 100644
--- a/test/testshared/testshared.go
+++ b/test/testshared/testshared.go
@@ -98,7 +98,10 @@ func (r *LintRunner) Run(args ...string) *RunResult {
 func (r *LintRunner) RunCommand(command string, args ...string) *RunResult {
 	r.Install()
 
-	runArgs := append([]string{command}, "--internal-cmd-test")
+	runArgs := append([]string{command},
+		"--go=1.17", //  TODO(ldez): we force to use an old version of Go for the CI and the tests.
+		"--internal-cmd-test",
+	)
 	runArgs = append(runArgs, args...)
 
 	defer func(startedAt time.Time) {