Add decorder linter (#2453)

.golangci.example.yml

@@ -107,6 +107,27 @@ linters-settings:
     # should ignore tests (default false)
     skip-tests: false
 
+  decorder:
+    # required order of type, const, var and func declarations inside a file
+    # default: types before constants before variables before functions
+    dec-order:
+      - type
+      - const
+      - var
+      - func
+
+    # if true, order of declarations is not checked at all
+    # default: true (disabled)
+    disable-dec-order-check: false
+
+    # if true, init func can be anywhere in file (must not be declared before all other functions)
+    # default: true (disabled)
+    disable-init-func-first-check: false
+
+    # if true, multiple global type, const and var declarations are allowed
+    # default: true (disabled)
+    disable-dec-num-check: false
+
   dogsled:
     # checks assignments with too many blank identifiers; default is 2
     max-blank-identifiers: 2

go.mod

@@ -92,6 +92,7 @@ require (
 	github.com/uudashr/gocognit v1.0.5
 	github.com/valyala/quicktemplate v1.7.0
 	github.com/yeya24/promlinter v0.1.0
+	gitlab.com/bosi/decorder v0.2.0
 	golang.org/x/tools v0.1.8
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 	honnef.co/go/tools v0.2.2

pkg/config/linters_settings.go

@@ -3,6 +3,12 @@ package config
 import "github.com/pkg/errors"
 
 var defaultLintersSettings = LintersSettings{
+	Decorder: DecorderSettings{
+		DecOrder:                  []string{"type", "const", "var", "func"},
+		DisableDecNumCheck:        true,
+		DisableDecOrderCheck:      true,
+		DisableInitFuncFirstCheck: true,
+	},
 	Dogsled: DogsledSettings{
 		MaxBlankIdentifiers: 2,
 	},
@@ -85,6 +91,7 @@ var defaultLintersSettings = LintersSettings{
 type LintersSettings struct {
 	BiDiChk          BiDiChkSettings
 	Cyclop           Cyclop
+	Decorder         DecorderSettings
 	Depguard         DepGuardSettings
 	Dogsled          DogsledSettings
 	Dupl             DuplSettings
@@ -173,6 +180,13 @@ type DepGuardSettings struct {
 	PackagesWithErrorMessage map[string]string `mapstructure:"packages-with-error-message"`
 }
 
+type DecorderSettings struct {
+	DecOrder                  []string `mapstructure:"dec-order"`
+	DisableDecNumCheck        bool     `mapstructure:"disable-dec-num-check"`
+	DisableDecOrderCheck      bool     `mapstructure:"disable-dec-order-check"`
+	DisableInitFuncFirstCheck bool     `mapstructure:"disable-init-func-first-check"`
+}
+
 type DogsledSettings struct {
 	MaxBlankIdentifiers int `mapstructure:"max-blank-identifiers"`
 }

pkg/golinters/decorder.go

@@ -0,0 +1,38 @@
+package golinters
+
+import (
+	"strings"
+
+	"gitlab.com/bosi/decorder"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/config"
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+func NewDecorder(settings *config.DecorderSettings) *goanalysis.Linter {
+	a := decorder.Analyzer
+
+	analyzers := []*analysis.Analyzer{a}
+
+	// disable all rules/checks by default
+	cfg := map[string]interface{}{
+		"disable-dec-num-check":         true,
+		"disable-dec-order-check":       true,
+		"disable-init-func-first-check": true,
+	}
+
+	if settings != nil {
+		cfg["dec-order"] = strings.Join(settings.DecOrder, ",")
+		cfg["disable-dec-num-check"] = settings.DisableDecNumCheck
+		cfg["disable-dec-order-check"] = settings.DisableDecOrderCheck
+		cfg["disable-init-func-first-check"] = settings.DisableInitFuncFirstCheck
+	}
+
+	return goanalysis.NewLinter(
+		a.Name,
+		a.Doc,
+		analyzers,
+		map[string]map[string]interface{}{a.Name: cfg},
+	).WithLoadMode(goanalysis.LoadModeSyntax)
+}

pkg/lint/lintersdb/manager.go

@@ -102,6 +102,7 @@ func enableLinterConfigs(lcs []*linter.Config, isEnabled func(lc *linter.Config)
 func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 	var bidichkCfg *config.BiDiChkSettings
 	var cyclopCfg *config.Cyclop
+	var decorderCfg *config.DecorderSettings
 	var errchkjsonCfg *config.ErrChkJSONSettings
 	var errorlintCfg *config.ErrorLintSettings
 	var exhaustiveCfg *config.ExhaustiveSettings
@@ -131,6 +132,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 		bidichkCfg = &m.cfg.LintersSettings.BiDiChk
 		cyclopCfg = &m.cfg.LintersSettings.Cyclop
 		errchkjsonCfg = &m.cfg.LintersSettings.ErrChkJSON
+		decorderCfg = &m.cfg.LintersSettings.Decorder
 		errorlintCfg = &m.cfg.LintersSettings.ErrorLint
 		exhaustiveCfg = &m.cfg.LintersSettings.Exhaustive
 		exhaustiveStructCfg = &m.cfg.LintersSettings.ExhaustiveStruct
@@ -189,6 +191,11 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithPresets(linter.PresetComplexity).
 			WithURL("https://github.com/bkielbasa/cyclop"),
 
+		linter.NewConfig(golinters.NewDecorder(decorderCfg)).
+			WithSince("v1.44.0").
+			WithPresets(linter.PresetFormatting, linter.PresetStyle).
+			WithURL("https://gitlab.com/bosi/decorder"),
+
 		linter.NewConfig(golinters.NewDeadcode()).
 			WithSince("v1.0.0").
 			WithLoadForGoAnalysis().

test/testdata/configs/decorder.yml

@@ -0,0 +1,10 @@
+linters-settings:
+  decorder:
+    dec-order:
+      - type
+      - const
+      - var
+      - func
+    disable-dec-order-check: false
+    disable-init-func-first-check: false
+    disable-dec-num-check: false

test/testdata/decorder.go

@@ -0,0 +1,21 @@
+// args: -Edecorder
+// config_path: testdata/configs/decorder.yml
+package testdata
+
+import "math"
+
+const (
+	decoc = math.MaxInt64
+	decod = 1
+)
+
+var decoa = 1
+var decob = 1 // ERROR "multiple \"var\" declarations are not allowed; use parentheses instead"
+
+type decoe int // ERROR "type must not be placed after const"
+
+func decof() {
+	const decog = 1
+}
+
+func init() {} // ERROR "init func must be the first function in file"

test/testdata/decorder_default.go

@@ -0,0 +1,20 @@
+// args: -Edecorder
+package testdata
+
+import "math"
+
+const (
+	decoh = math.MaxInt64
+	decoi = 1
+)
+
+var decoj = 1
+var decok = 1
+
+type decol int
+
+func decom() {
+	const decon = 1
+}
+
+func init() {}