From 2121370f81ca8cc960a3cb716b0a751a3a437333 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Klimczak?=
 <bartlomiej.klimczak88@gmail.com>
Date: Wed, 17 Feb 2021 09:48:29 +0100
Subject: [PATCH] add 'cyclop' linter (#1738)

---
 .golangci.example.yml         |  8 ++++++++
 go.mod                        |  1 +
 go.sum                        |  2 ++
 pkg/config/config.go          |  5 +++++
 pkg/golinters/cyclop.go       | 21 +++++++++++++++++++++
 pkg/lint/lintersdb/manager.go |  4 ++++
 test/testdata/cyclop.go       | 30 ++++++++++++++++++++++++++++++
 7 files changed, 71 insertions(+)
 create mode 100644 pkg/golinters/cyclop.go
 create mode 100644 test/testdata/cyclop.go

diff --git a/.golangci.example.yml b/.golangci.example.yml
index 8e8c8ba7e486..e39ecd062f92 100644
--- a/.golangci.example.yml
+++ b/.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
diff --git a/go.mod b/go.mod
index 0e0e4ea29b14..f321a6d18856 100644
--- a/go.mod
+++ b/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
diff --git a/go.sum b/go.sum
index 2e1d4d63be94..84c2950e8ccc 100644
--- a/go.sum
+++ b/go.sum
@@ -41,6 +41,8 @@ github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kBD4zp0CCIs=
 github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJmJgSg28kpZDP6UIiPt0e0Oz0kqKNGyRaWEPv84=
+github.com/bkielbasa/cyclop v1.2.0 h1:7Jmnh0yL2DjKfw28p86YTd/B4lRGcNuu12sKE35sM7A=
+github.com/bkielbasa/cyclop v1.2.0/go.mod h1:qOI0yy6A7dYC4Zgsa72Ppm9kONl0RoIlPbzot9mhmeI=
 github.com/bombsimon/wsl/v3 v3.1.0 h1:E5SRssoBgtVFPcYWUOFJEcgaySgdtTNYzsSKDOY7ss8=
 github.com/bombsimon/wsl/v3 v3.1.0/go.mod h1:st10JtZYLE4D5sC7b8xV4zTKZwAQjCH/Hy2Pm1FNZIc=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
diff --git a/pkg/config/config.go b/pkg/config/config.go
index 2a0050a2e6d1..314c81fd2db6 100644
--- a/pkg/config/config.go
+++ b/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"`
 	}
diff --git a/pkg/golinters/cyclop.go b/pkg/golinters/cyclop.go
new file mode 100644
index 000000000000..df1dd4835467
--- /dev/null
+++ b/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)
+}
diff --git a/pkg/lint/lintersdb/manager.go b/pkg/lint/lintersdb/manager.go
index 0960a3d8de7f..499563d8726c 100644
--- a/pkg/lint/lintersdb/manager.go
+++ b/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"),
diff --git a/test/testdata/cyclop.go b/test/testdata/cyclop.go
new file mode 100644
index 000000000000..2551758f62d3
--- /dev/null
+++ b/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 {
+	}
+}