feat: add warning about disabled and deprecated linters (level 2) (golangci#4742)

Author: ldez

docs/src/docs/product/roadmap.mdx

@@ -47,8 +47,11 @@ A linter can be deprecated for various reasons, e.g. the linter stops working wi
 
 The deprecation of a linter will follow 3 phases:
 
-1. **Display of a warning message**: The linter can still be used (unless it's completely non-functional), but it's recommended to remove it from your configuration.
-2. **Display of an error message**: At this point, you should remove the linter. The original implementation is replaced by a placeholder that does nothing.
+1. **Display of a warning message**: The linter can still be used (unless it's completely non-functional),
+  but it's recommended to remove it from your configuration.
+2. **Display of an error message**: At this point, you should remove the linter.
+  The original implementation is replaced by a placeholder that does nothing.
+  The linter is NOT enabled when using `enable-all` and should be removed from the `disable` option.
 3. **Removal of the linter** from golangci-lint.
 
 Each phase corresponds to a minor version:

pkg/lint/lintersdb/validator.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/golangci/golangci-lint/pkg/config"
+	"github.com/golangci/golangci-lint/pkg/lint/linter"
 	"github.com/golangci/golangci-lint/pkg/logutils"
 )
 
@@ -38,17 +39,30 @@ func (v Validator) Validate(cfg *config.Config) error {
 }
 
 func (v Validator) validateLintersNames(cfg *config.Linters) error {
-	allNames := cfg.Enable
-	allNames = append(allNames, cfg.Disable...)
-
 	var unknownNames []string
 
-	for _, name := range allNames {
+	for _, name := range cfg.Enable {
 		if v.m.GetLinterConfigs(name) == nil {
 			unknownNames = append(unknownNames, name)
 		}
 	}
 
+	for _, name := range cfg.Disable {
+		lcs := v.m.GetLinterConfigs(name)
+		if len(lcs) == 0 {
+			unknownNames = append(unknownNames, name)
+			continue
+		}
+
+		for _, lc := range lcs {
+			if lc.IsDeprecated() && lc.Deprecation.Level > linter.DeprecationWarning {
+				v.m.log.Warnf("The linter %q is deprecated (step 2) and deactivated. "+
+					"It should be removed from the list of disabled linters. "+
+					"https://golangci-lint.run/product/roadmap/#linter-deprecation-cycle", lc.Name())
+			}
+		}
+	}
+
 	if len(unknownNames) > 0 {
 		return fmt.Errorf("unknown linters: '%v', run 'golangci-lint help linters' to see the list of supported linters",
 			strings.Join(unknownNames, ","))

test/run_test.go

@@ -100,8 +100,6 @@ func TestCgoOk(t *testing.T) {
 		WithNoConfig().
 		WithArgs("--timeout=3m",
 			"--enable-all",
-			"-D",
-			"nosnakecase",
 		).
 		WithArgs("--go=1.22"). // TODO(ldez) remove this line when we will run go1.23 on the CI. (related to intrange, copyloopvar)
 		WithTargetPath(testdataDir, "cgo").