feat: add interfacebloat (#3024)

Co-authored-by: Fernandez Ludovic <ldez@users.noreply.github.com>

.golangci.reference.yml

@@ -1074,6 +1074,11 @@ linters-settings:
       - pkg: knative.dev/serving/pkg/apis/(\w+)/(v[\w\d]+)
         alias: $1$2
 
+  interfacebloat:
+    # The maximum number of methods allowed for an interface.
+    # Default: 10
+    max: 5
+
   ireturn:
     # ireturn allows using `allow` and `reject` settings at the same time.
     # Both settings are lists of the keywords and regular expressions matched to interface or package names.
@@ -1923,6 +1928,7 @@ linters:
     - ifshort
     - importas
     - ineffassign
+    - interfacebloat
     - interfacer
     - ireturn
     - lll
@@ -2025,6 +2031,7 @@ linters:
     - ifshort
     - importas
     - ineffassign
+    - interfacebloat
     - interfacer
     - ireturn
     - lll

go.mod

@@ -74,6 +74,7 @@ require (
 	github.com/ryancurrah/gomodguard v1.2.4
 	github.com/ryanrolds/sqlclosecheck v0.3.0
 	github.com/sanposhiho/wastedassign/v2 v2.0.6
+	github.com/sashamelentyev/interfacebloat v1.1.0
 	github.com/sashamelentyev/usestdlibvars v1.13.0
 	github.com/securego/gosec/v2 v2.13.1
 	github.com/shazow/go-diff v0.0.0-20160112020656-b6b7b6733b8c

go.sum

@@ -459,6 +459,8 @@ github.com/ryanrolds/sqlclosecheck v0.3.0 h1:AZx+Bixh8zdUBxUA1NxbxVAS78vTPq4rCb8
 github.com/ryanrolds/sqlclosecheck v0.3.0/go.mod h1:1gREqxyTGR3lVtpngyFo3hZAgk0KCtEdgEkHwDbigdA=
 github.com/sanposhiho/wastedassign/v2 v2.0.6 h1:+6/hQIHKNJAUixEj6EmOngGIisyeI+T3335lYTyxRoA=
 github.com/sanposhiho/wastedassign/v2 v2.0.6/go.mod h1:KyZ0MWTwxxBmfwn33zh3k1dmsbF2ud9pAAGfoLfjhtI=
+github.com/sashamelentyev/interfacebloat v1.1.0 h1:xdRdJp0irL086OyW1H/RTZTr1h/tMEOsumirXcOJqAw=
+github.com/sashamelentyev/interfacebloat v1.1.0/go.mod h1:+Y9yU5YdTkrNvoX0xHc84dxiN1iBi9+G8zZIhPVoNjQ=
 github.com/sashamelentyev/usestdlibvars v1.13.0 h1:uObNudVEEHf6JbOJy5bgKJloA1bWjxR9fwgNFpPzKnI=
 github.com/sashamelentyev/usestdlibvars v1.13.0/go.mod h1:D2Wb7niIYmTB+gB8z7kh8tyP5ccof1dQ+SFk+WW5NtY=
 github.com/securego/gosec/v2 v2.13.1 h1:7mU32qn2dyC81MH9L2kefnQyRMUarfDER3iQyMHcjYM=

pkg/config/linters_settings.go

@@ -151,6 +151,7 @@ type LintersSettings struct {
 	Grouper          GrouperSettings
 	Ifshort          IfshortSettings
 	ImportAs         ImportAsSettings
+	InterfaceBloat   InterfaceBloatSettings
 	Ireturn          IreturnSettings
 	Lll              LllSettings
 	MaintIdx         MaintIdxSettings
@@ -454,6 +455,10 @@ type ImportAsAlias struct {
 	Alias string
 }
 
+type InterfaceBloatSettings struct {
+	Max int `mapstructure:"max"`
+}
+
 type IreturnSettings struct {
 	Allow  []string `mapstructure:"allow"`
 	Reject []string `mapstructure:"reject"`

pkg/golinters/interfacebloat.go

@@ -0,0 +1,27 @@
+package golinters
+
+import (
+	"github.com/sashamelentyev/interfacebloat/pkg/analyzer"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/config"
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+func NewInterfaceBloat(settings *config.InterfaceBloatSettings) *goanalysis.Linter {
+	a := analyzer.New()
+
+	cfgMap := make(map[string]map[string]interface{})
+	if settings != nil {
+		cfgMap[a.Name] = map[string]interface{}{
+			analyzer.InterfaceMaxMethodsFlag: settings.Max,
+		}
+	}
+
+	return goanalysis.NewLinter(
+		a.Name,
+		a.Doc,
+		[]*analysis.Analyzer{a},
+		nil,
+	).WithLoadMode(goanalysis.LoadModeSyntax)
+}

pkg/lint/lintersdb/manager.go

@@ -137,6 +137,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 		grouperCfg          *config.GrouperSettings
 		ifshortCfg          *config.IfshortSettings
 		importAsCfg         *config.ImportAsSettings
+		interfaceBloatCfg   *config.InterfaceBloatSettings
 		ireturnCfg          *config.IreturnSettings
 		lllCfg              *config.LllSettings
 		maintIdxCfg         *config.MaintIdxSettings
@@ -209,6 +210,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 		grouperCfg = &m.cfg.LintersSettings.Grouper
 		ifshortCfg = &m.cfg.LintersSettings.Ifshort
 		importAsCfg = &m.cfg.LintersSettings.ImportAs
+		interfaceBloatCfg = &m.cfg.LintersSettings.InterfaceBloat
 		ireturnCfg = &m.cfg.LintersSettings.Ireturn
 		lllCfg = &m.cfg.LintersSettings.Lll
 		maintIdxCfg = &m.cfg.LintersSettings.MaintIdx
@@ -557,6 +559,11 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithPresets(linter.PresetUnused).
 			WithURL("https://github.com/gordonklaus/ineffassign"),
 
+		linter.NewConfig(golinters.NewInterfaceBloat(interfaceBloatCfg)).
+			WithSince("v1.49.0").
+			WithPresets(linter.PresetStyle).
+			WithURL("https://github.com/sashamelentyev/interfacebloat"),
+
 		linter.NewConfig(golinters.NewInterfacer()).
 			WithSince("v1.0.0").
 			WithLoadForGoAnalysis().

test/testdata/interfacebloat.go

@@ -0,0 +1,126 @@
+//golangcitest:args -Einterfacebloat
+package testdata
+
+import "time"
+
+type InterfaceBloatExample01 interface { // want "the interface has more than 10 methods: 11"
+	a01() time.Duration
+	a02()
+	a03()
+	a04()
+	a05()
+	a06()
+	a07()
+	a08()
+	a09()
+	a10()
+	a11()
+}
+
+func InterfaceBloatExample02() {
+	var _ interface { // want "the interface has more than 10 methods: 11"
+		a01() time.Duration
+		a02()
+		a03()
+		a04()
+		a05()
+		a06()
+		a07()
+		a08()
+		a09()
+		a10()
+		a11()
+	}
+}
+
+func InterfaceBloatExample03() interface { // want "the interface has more than 10 methods: 11"
+	a01() time.Duration
+	a02()
+	a03()
+	a04()
+	a05()
+	a06()
+	a07()
+	a08()
+	a09()
+	a10()
+	a11()
+} {
+	return nil
+}
+
+type InterfaceBloatExample04 struct {
+	Foo interface { // want "the interface has more than 10 methods: 11"
+		a01() time.Duration
+		a02()
+		a03()
+		a04()
+		a05()
+		a06()
+		a07()
+		a08()
+		a09()
+		a10()
+		a11()
+	}
+}
+
+type InterfaceBloatSmall01 interface {
+	a01() time.Duration
+	a02()
+	a03()
+	a04()
+	a05()
+}
+
+type InterfaceBloatSmall02 interface {
+	a06()
+	a07()
+	a08()
+	a09()
+	a10()
+	a11()
+}
+
+type InterfaceBloatExample05 interface {
+	InterfaceBloatSmall01
+	InterfaceBloatSmall02
+}
+
+type InterfaceBloatExample06 interface {
+	interface { // want "the interface has more than 10 methods: 11"
+		a01() time.Duration
+		a02()
+		a03()
+		a04()
+		a05()
+		a06()
+		a07()
+		a08()
+		a09()
+		a10()
+		a11()
+	}
+}
+
+type InterfaceBloatTypeGeneric interface {
+	~uint8 | ~uint16 | ~uint32 | ~uint64 | uint |
+		~int8 | ~int16 | ~int32 | ~int64 | int |
+		~float32 | ~float64 |
+		~string
+}
+
+func InterfaceBloatExampleNoProblem() interface {
+	a01() time.Duration
+	a02()
+	a03()
+	a04()
+	a05()
+	a06()
+	a07()
+	a08()
+	a09()
+	a10()
+} {
+	return nil
+}