revive: fix add-constant rule support.

Author: ldez

.golangci.example.yml

@@ -496,14 +496,21 @@ linters-settings:
   rowserrcheck:
     packages:
       - github.com/jmoiron/sqlx
-      -
+
   revive:
     # see https://github.com/mgechev/revive#available-rules for details.
     ignore-generated-header: true
     severity: warning
     rules:
       - name: indent-error-flow
         severity: warning
+      - name: add-constant
+        severity: warning
+        arguments:
+          - maxLitCount: "3"
+            allowStrs: '""'
+            allowInts: "0,1,2"
+            allowFloats: "0.0,0.,1.0,1.,2.0,2."
 
   staticcheck:
     # Select the Go version to target. The default is '1.13'.

pkg/commands/executor.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	"crypto/sha256"
-	"encoding/json"
 	"io"
 	"os"
 	"path/filepath"
@@ -16,6 +15,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
+	"gopkg.in/yaml.v3"
 
 	"github.com/golangci/golangci-lint/internal/cache"
 	"github.com/golangci/golangci-lint/internal/pkgcache"
@@ -194,7 +194,7 @@ func computeConfigSalt(cfg *config.Config) ([]byte, error) {
 	// We don't hash all config fields to reduce meaningless cache
 	// invalidations. At least, it has a huge impact on tests speed.
 
-	lintersSettingsBytes, err := json.Marshal(cfg.LintersSettings)
+	lintersSettingsBytes, err := yaml.Marshal(cfg.LintersSettings)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to json marshal config linter settings")
 	}

pkg/golinters/revive.go

@@ -9,10 +9,12 @@ import (
 	"reflect"
 
 	"github.com/BurntSushi/toml"
+	"github.com/golangci/golangci-lint/pkg/logutils"
 	"github.com/mgechev/dots"
 	reviveConfig "github.com/mgechev/revive/config"
 	"github.com/mgechev/revive/lint"
 	"github.com/mgechev/revive/rule"
+	"github.com/pkg/errors"
 	"golang.org/x/tools/go/analysis"
 
 	"github.com/golangci/golangci-lint/pkg/config"
@@ -31,6 +33,8 @@ type jsonObject struct {
 
 // NewRevive returns a new Revive linter.
 func NewRevive(cfg *config.ReviveSettings) *goanalysis.Linter {
+	reviveDebugf := logutils.Debug("revive")
+
 	var issues []goanalysis.Issue
 
 	analyzer := &analysis.Analyzer{
@@ -56,6 +60,8 @@ func NewRevive(cfg *config.ReviveSettings) *goanalysis.Linter {
 				return nil, err
 			}
 
+			reviveDebugf("revive configuration: %#v", conf)
+
 			formatter, err := reviveConfig.GetFormatter("json")
 			if err != nil {
 				return nil, err
@@ -145,13 +151,13 @@ func getReviveConfig(cfg *config.ReviveSettings) (*lint.Config, error) {
 
 		err := toml.NewEncoder(buf).Encode(rawRoot)
 		if err != nil {
-			return nil, err
+			return nil, errors.Wrap(err, "failed to encode configuration")
 		}
 
 		conf = &lint.Config{}
 		_, err = toml.DecodeReader(buf, conf)
 		if err != nil {
-			return nil, err
+			return nil, errors.Wrap(err, "failed to decode configuration")
 		}
 	}
 
@@ -184,7 +190,7 @@ func createConfigMap(cfg *config.ReviveSettings) map[string]interface{} {
 	for _, s := range cfg.Rules {
 		rawRules[s.Name] = map[string]interface{}{
 			"severity":  s.Severity,
-			"arguments": s.Arguments,
+			"arguments": safeTomlSlice(s.Arguments),
 		}
 	}
 
@@ -195,6 +201,28 @@ func createConfigMap(cfg *config.ReviveSettings) map[string]interface{} {
 	return rawRoot
 }
 
+func safeTomlSlice(r []interface{}) []interface{} {
+	if len(r) == 0 {
+		return nil
+	}
+
+	if _, ok := r[0].(map[interface{}]interface{}); !ok {
+		return r
+	}
+
+	var typed []interface{}
+	for _, elt := range r {
+		item := map[string]interface{}{}
+		for k, v := range elt.(map[interface{}]interface{}) {
+			item[k.(string)] = v
+		}
+
+		typed = append(typed, item)
+	}
+
+	return typed
+}
+
 // This element is not exported by revive, so we need copy the code.
 // Extracted from https://github.com/mgechev/revive/blob/389ba853b0b3587f0c3b71b5f0c61ea4e23928ec/config/config.go#L15
 var defaultRules = []lint.Rule{