Add maintidx linter

.golangci.example.yml

@@ -590,6 +590,12 @@ linters-settings:
     # tab width in spaces. Default to 1.
     tab-width: 1
 
+  maintidx:
+    # Show functions with maintainability index lower than N.
+    # A high index indicates better maintainability (it's kind of the opposite of complexity).
+    # default: 20
+    under: 100
+
   makezero:
     # Allow only slices initialized with a length of zero. Default is false.
     always: false

go.mod

@@ -91,6 +91,7 @@ require (
 	github.com/ultraware/whitespace v0.0.4
 	github.com/uudashr/gocognit v1.0.5
 	github.com/valyala/quicktemplate v1.7.0
+	github.com/yagipy/maintidx v1.0.0
 	github.com/yeya24/promlinter v0.1.0
 	gitlab.com/bosi/decorder v0.2.1
 	golang.org/x/tools v0.1.9-0.20211228192929-ee1ca4ffc4da

pkg/config/linters_settings.go

@@ -51,6 +51,9 @@ var defaultLintersSettings = LintersSettings{
 		LineLength: 120,
 		TabWidth:   1,
 	},
+	MaintIdx: MaintIdxSettings{
+		Under: 20,
+	},
 	Nakedret: NakedretSettings{
 		MaxFuncLines: 30,
 	},
@@ -128,6 +131,7 @@ type LintersSettings struct {
 	ImportAs         ImportAsSettings
 	Ireturn          IreturnSettings
 	Lll              LllSettings
+	MaintIdx         MaintIdxSettings
 	Makezero         MakezeroSettings
 	Maligned         MalignedSettings
 	Misspell         MisspellSettings
@@ -389,6 +393,10 @@ type LllSettings struct {
 	TabWidth   int `mapstructure:"tab-width"`
 }
 
+type MaintIdxSettings struct {
+	Under int `mapstructure:"under"`
+}
+
 type MakezeroSettings struct {
 	Always bool
 }

pkg/golinters/maintidx.go

@@ -0,0 +1,32 @@
+package golinters
+
+import (
+	"github.com/yagipy/maintidx"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/config"
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+func NewMaintIdx(cfg *config.MaintIdxSettings) *goanalysis.Linter {
+	analyzer := maintidx.Analyzer
+
+	cfgMap := map[string]map[string]interface{}{
+		analyzer.Name: {"under": 20},
+	}
+
+	if cfg != nil {
+		cfgMap[analyzer.Name] = map[string]interface{}{
+			"under": cfg.Under,
+		}
+	}
+
+	return goanalysis.NewLinter(
+		analyzer.Name,
+		analyzer.Doc,
+		[]*analysis.Analyzer{
+			analyzer,
+		},
+		cfgMap,
+	).WithLoadMode(goanalysis.LoadModeSyntax)
+}

pkg/lint/lintersdb/manager.go

@@ -114,6 +114,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 	var ifshortCfg *config.IfshortSettings
 	var importAsCfg *config.ImportAsSettings
 	var ireturnCfg *config.IreturnSettings
+	var maintIdxCfg *config.MaintIdxSettings
 	var nilNilCfg *config.NilNilSettings
 	var nlreturnCfg *config.NlreturnSettings
 	var predeclaredCfg *config.PredeclaredSettings
@@ -143,6 +144,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 		ifshortCfg = &m.cfg.LintersSettings.Ifshort
 		importAsCfg = &m.cfg.LintersSettings.ImportAs
 		ireturnCfg = &m.cfg.LintersSettings.Ireturn
+		maintIdxCfg = &m.cfg.LintersSettings.MaintIdx
 		nilNilCfg = &m.cfg.LintersSettings.NilNil
 		nlreturnCfg = &m.cfg.LintersSettings.Nlreturn
 		predeclaredCfg = &m.cfg.LintersSettings.Predeclared
@@ -439,6 +441,11 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithSince("v1.8.0").
 			WithPresets(linter.PresetStyle),
 
+		linter.NewConfig(golinters.NewMaintIdx(maintIdxCfg)).
+			WithSince("v1.44.0").
+			WithPresets(linter.PresetComplexity).
+			WithURL("https://github.com/yagipy/maintidx"),
+
 		linter.NewConfig(golinters.NewMakezero()).
 			WithSince("v1.34.0").
 			WithPresets(linter.PresetStyle, linter.PresetBugs).

test/testdata/configs/maintidx_under_100.yml

@@ -0,0 +1,3 @@
+linters-settings:
+  maintidx:
+    under: 100

test/testdata/maintidx.go

@@ -0,0 +1,196 @@
+//args: -Emaintidx
+package testdata
+
+func over20() {
+}
+
+func under20() { // ERROR "Function name: under20, Cyclomatic Complexity: 76, Halstead Volume: 1636.00, Maintainability Index: 17"
+	for true {
+		if false {
+			if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			}
+		} else if false {
+			if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			}
+		} else if false {
+			if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			}
+		} else if false {
+			if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			}
+		} else {
+			if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else if false {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			} else {
+				n := 0
+				switch n {
+				case 0:
+				case 1:
+				default:
+				}
+			}
+		}
+	}
+}