add 'cyclop' linter (#1738)

.golangci.example.yml

@@ -190,6 +190,14 @@ linters-settings:
   gocyclo:
     # minimal code complexity to report, 30 by default (but we recommend 10-20)
     min-complexity: 10
+
+  cyclop:
+    # the maximal code complexity to report
+    max-complexity: 10
+    # the maximal average package complexity. If it's higher than 0.0 (float) the check is enabled (default 0.0)
+    package-average: 0.0
+    # should ignore tests (default false)
+    skip-tests: false
   godot:
     # comments to be checked: `declarations`, `toplevel`, or `all`
     scope: declarations

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/alexkohler/prealloc v0.0.0-20210204145425-77a5b5dd9799
 	github.com/ashanbrown/forbidigo v1.1.0
 	github.com/ashanbrown/makezero v0.0.0-20201205152432-7b7cdbb3025a
+	github.com/bkielbasa/cyclop v1.2.0
 	github.com/bombsimon/wsl/v3 v3.1.0
 	github.com/charithe/durationcheck v0.0.3
 	github.com/daixiang0/gci v0.2.8

pkg/config/config.go

@@ -183,6 +183,11 @@ type LintersSettings struct {
 	Gocyclo struct {
 		MinComplexity int `mapstructure:"min-complexity"`
 	}
+	Cyclop struct {
+		MaxComplexity  int     `mapstructure:"max-complexity"`
+		PackageAverage float64 `mapstructure:"package-average"`
+		SkipTests      bool    `mapstructure:"skip-tests"`
+	}
 	Varcheck struct {
 		CheckExportedFields bool `mapstructure:"exported-fields"`
 	}

pkg/golinters/cyclop.go

@@ -0,0 +1,21 @@
+package golinters
+
+import (
+	"github.com/bkielbasa/cyclop/pkg/analyzer"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+const cyclopName = "cyclop"
+
+func NewCyclop() *goanalysis.Linter {
+	return goanalysis.NewLinter(
+		cyclopName,
+		"checks function and package cyclomatic complexity",
+		[]*analysis.Analyzer{
+			analyzer.NewAnalyzer(),
+		},
+		nil,
+	).WithLoadMode(goanalysis.LoadModeTypesInfo)
+}

pkg/lint/lintersdb/manager.go

@@ -194,6 +194,10 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 		linter.NewConfig(golinters.NewGocyclo()).
 			WithPresets(linter.PresetComplexity).
 			WithURL("https://github.com/alecthomas/gocyclo"),
+		linter.NewConfig(golinters.NewCyclop()).
+			WithLoadForGoAnalysis().
+			WithPresets(linter.PresetComplexity).
+			WithURL("https://github.com/bkielbasa/cyclop"),
 		linter.NewConfig(golinters.NewGocognit()).
 			WithPresets(linter.PresetComplexity).
 			WithURL("https://github.com/uudashr/gocognit"),

test/testdata/cyclop.go

@@ -0,0 +1,30 @@
+// args: -Ecyclop
+package testdata
+
+import "math"
+
+func cyclopComplexFunc() { // ERROR "calculated cyclomatic complexity for function cyclopComplexFunc is 11, max is 10"
+	i := math.MaxInt8
+	if i > 2 {
+		if i > 2 {
+		}
+		if i > 2 {
+		}
+		if i > 2 {
+		}
+		if i > 2 {
+		}
+	} else {
+		if i > 2 {
+		}
+		if i > 2 {
+		}
+		if i > 2 {
+		}
+		if i > 2 {
+		}
+	}
+
+	if i > 2 {
+	}
+}