Add funlen linter (#603)

.golangci.example.yml

@@ -78,6 +78,11 @@ linters-settings:
     # path to a file containing a list of functions to exclude from checking
     # see https://github.com/kisielk/errcheck#excluding-functions for details
     exclude: /path/to/file.txt
+
+  funlen:
+    lines: 60
+    statements: 40
+
   govet:
     # report about shadowed variables
     check-shadowing: true

.golangci.yml

@@ -46,6 +46,7 @@ linters:
     - maligned
     - prealloc
     - gochecknoglobals
+    - funlen
 
 run:
   skip-dirs:

README.md

@@ -208,6 +208,7 @@ Disabled by default linters:
 bodyclose: checks whether HTTP response body is closed successfully [fast: false, auto-fix: false]
 depguard: Go linter that checks if package imports are in a list of acceptable packages [fast: true, auto-fix: false]
 dupl: Tool for code clone detection [fast: true, auto-fix: false]
+funlen: Tool for detection of long functions [fast: true, auto-fix: false]
 gochecknoglobals: Checks that no globals are present in Go code [fast: true, auto-fix: false]
 gochecknoinits: Checks that no init functions are present in Go code [fast: true, auto-fix: false]
 goconst: Finds repeated strings that could be replaced by a constant [fast: true, auto-fix: false]
@@ -440,6 +441,7 @@ golangci-lint help linters
 - [gocritic](https://github.com/go-critic/go-critic) - The most opinionated Go source code linter
 - [gochecknoinits](https://github.com/leighmcculloch/gochecknoinits) - Checks that no init functions are present in Go code
 - [gochecknoglobals](https://github.com/leighmcculloch/gochecknoglobals) - Checks that no globals are present in Go code
+- [funlen](https://github.com/ultraware/funlen) - Tool for detection of long functions
 
 ## Configuration
 
@@ -629,6 +631,11 @@ linters-settings:
     # path to a file containing a list of functions to exclude from checking
     # see https://github.com/kisielk/errcheck#excluding-functions for details
     exclude: /path/to/file.txt
+
+  funlen:
+    lines: 60
+    statements: 40
+
   govet:
     # report about shadowed variables
     check-shadowing: true
@@ -859,6 +866,7 @@ linters:
     - maligned
     - prealloc
     - gochecknoglobals
+    - funlen
 
 run:
   skip-dirs:
@@ -999,6 +1007,7 @@ Thanks to developers and authors of used linters:
 - [kyoh86](https://github.com/kyoh86)
 - [go-critic](https://github.com/go-critic)
 - [leighmcculloch](https://github.com/leighmcculloch)
+- [ultraware](https://github.com/ultraware)
 
 ## Changelog
 

go.mod

@@ -49,6 +49,7 @@ require (
 	github.com/spf13/pflag v1.0.1
 	github.com/spf13/viper v1.0.2
 	github.com/stretchr/testify v1.2.2
+	github.com/ultraware/funlen v0.0.1
 	github.com/timakin/bodyclose v0.0.0-00010101000000-87058b9bfcec
 	github.com/valyala/quicktemplate v1.1.1
 	golang.org/x/crypto v0.0.0-20190313024323-a1f597ede03a // indirect

go.sum

@@ -164,6 +164,8 @@ github.com/spf13/viper v1.0.2 h1:Ncr3ZIuJn322w2k1qmzXDnkLAdQMlJqBa9kfAH+irso=
 github.com/spf13/viper v1.0.2/go.mod h1:A8kyI5cUJhb8N+3pkfONlcEcZbueH6nhAm0Fq7SrnBM=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/ultraware/funlen v0.0.1 h1:UeC9tpM4wNWzUJfan8z9sFE4QCzjjzlCZmuJN+aOkH0=
+github.com/ultraware/funlen v0.0.1/go.mod h1:Dp4UiAus7Wdb9KUZsYWZEWiRzGuM2kXM1lPbfaF6xhA=
 github.com/timakin/bodyclose v0.0.0-00010101000000-87058b9bfcec h1:Ha5Eixh5Dgi14hDFFWsxoB/jR95rHjB1biKdK9VKkbQ=
 github.com/timakin/bodyclose v0.0.0-00010101000000-87058b9bfcec/go.mod h1:Qimiffbc6q9tBWlVV6x0P9sat/ao1xEkREYPPj9hphk=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=

pkg/config/config.go

@@ -164,6 +164,10 @@ type LintersSettings struct {
 	Unused struct {
 		CheckExported bool `mapstructure:"check-exported"`
 	}
+	Funlen struct {
+		Lines      int
+		Statements int
+	}
 
 	Lll      LllSettings
 	Unparam  UnparamSettings

pkg/golinters/funlen.go

@@ -0,0 +1,46 @@
+package golinters
+
+import (
+	"context"
+	"go/token"
+
+	"github.com/golangci/golangci-lint/pkg/lint/linter"
+	"github.com/golangci/golangci-lint/pkg/result"
+
+	"github.com/ultraware/funlen"
+)
+
+type Funlen struct{}
+
+func (Funlen) Name() string {
+	return "funlen"
+}
+
+func (Funlen) Desc() string {
+	return "Tool for detection of long functions"
+}
+
+func (f Funlen) Run(ctx context.Context, lintCtx *linter.Context) ([]result.Issue, error) {
+	var issues []funlen.Message
+	for _, file := range lintCtx.ASTCache.GetAllValidFiles() {
+		issues = append(issues, funlen.Run(file.F, file.Fset, lintCtx.Settings().Funlen.Lines, lintCtx.Settings().Funlen.Statements)...)
+	}
+
+	if len(issues) == 0 {
+		return nil, nil
+	}
+
+	res := make([]result.Issue, len(issues))
+	for k, i := range issues {
+		res[k] = result.Issue{
+			Pos: token.Position{
+				Filename: i.Pos.Filename,
+				Line:     i.Pos.Line,
+			},
+			Text:       i.Message,
+			FromLinter: f.Name(),
+		}
+	}
+
+	return res, nil
+}

pkg/lint/lintersdb/manager.go

@@ -237,6 +237,10 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithPresets(linter.PresetStyle).
 			WithSpeed(10).
 			WithURL("https://github.com/leighmcculloch/gochecknoglobals"),
+		linter.NewConfig(golinters.Funlen{}).
+			WithPresets(linter.PresetStyle).
+			WithSpeed(10).
+			WithURL("https://github.com/ultraware/funlen"),
 	}
 
 	isLocalRun := os.Getenv("GOLANGCI_COM_RUN") == ""

test/testdata/funlen.go

@@ -0,0 +1,43 @@
+//args: -Efunlen
+//config: linters-settings.funlen.lines=20
+//config: linters-settings.funlen.statements=10
+package testdata
+
+func TooManyLines() { // ERROR "Function 'TooManyLines' is too long \(22 > 20\)"
+	t := struct {
+		A string
+		B string
+		C string
+		D string
+		E string
+		F string
+		G string
+		H string
+		I string
+	}{
+		`a`,
+		`b`,
+		`c`,
+		`d`,
+		`e`,
+		`f`,
+		`g`,
+		`h`,
+		`i`,
+	}
+	_ = t
+}
+
+func TooManyStatements() { // ERROR "Function 'TooManyStatements' has too many statements \(11 > 10\)"
+	a := 1
+	b := a
+	c := b
+	d := c
+	e := d
+	f := e
+	g := f
+	h := g
+	i := h
+	j := i
+	_ = j
+}

vendor/github.com/ultraware/funlen/LICENSE

@@ -0,0 +1,7 @@
+Copyright 2018 Ultraware Consultancy and Development B.V.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/ultraware/funlen/README.md

@@ -0,0 +1,69 @@
+# Funlen linter
+
+Funlen is a linter that checks for long functions. It can checks both on the number of lines and the number of statements.
+
+The default limits are 50 lines and 35 statements. You can configure these with the `-l` and `-s` flags.
+
+Example code:
+
+```go
+package main
+
+import "fmt"
+
+func fiveStatements() {
+    fmt.Println(1)
+    fmt.Println(2)
+    fmt.Println(3)
+    fmt.Println(4)
+    fmt.Println(5)
+}
+
+func sevenLines() {
+    fmt.Println(1)
+
+    fmt.Println(2)
+
+    fmt.Println(3)
+
+    fmt.Println(4)
+}
+```
+
+Reults in:
+
+```
+$ funlen -l=6 -s=4 .
+main.go:5:6:Function 'fiveStatements' has too many statements (5 > 4)
+main.go:13:6:Function 'sevenLines' is too long (7 > 6)
+```
+
+## Installation guide
+
+```bash
+go get git.ultraware.nl/NiseVoid/funlen
+```
+
+### Gometalinter
+
+You can add funlen to gometalinter and enable it.
+
+`.gometalinter.json`:
+
+```json
+{
+	"Linters": {
+		"funlen": "funlen -l=50 -s=35:PATH:LINE:COL:MESSAGE"
+	},
+
+	"Enable": [
+		"funlen"
+	]
+}
+```
+
+commandline:
+
+```bash
+gometalinter --linter "funlen:funlen -l=50 -s=35:PATH:LINE:COL:MESSAGE" --enable "funlen"
+```

vendor/github.com/ultraware/funlen/main.go

@@ -0,0 +1,98 @@
+package funlen
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"reflect"
+)
+
+const defaultLineLimit = 60
+const defaultStmtLimit = 40
+
+// Run runs this linter on the provided code
+func Run(file *ast.File, fset *token.FileSet, lineLimit, stmtLimit int) []Message {
+	if lineLimit == 0 {
+		lineLimit = defaultLineLimit
+	}
+	if stmtLimit == 0 {
+		stmtLimit = defaultStmtLimit
+	}
+
+	var msgs []Message
+	for _, f := range file.Decls {
+		decl, ok := f.(*ast.FuncDecl)
+		if !ok {
+			continue
+		}
+
+		if stmts := parseStmts(decl.Body.List); stmts > stmtLimit {
+			msgs = append(msgs, makeStmtMessage(fset, decl.Name, stmts, stmtLimit))
+			continue
+		}
+
+		if lines := getLines(fset, decl); lines > lineLimit {
+			msgs = append(msgs, makeLineMessage(fset, decl.Name, lines, lineLimit))
+		}
+	}
+
+	return msgs
+}
+
+// Message contains a message
+type Message struct {
+	Pos     token.Position
+	Message string
+}
+
+func makeLineMessage(fset *token.FileSet, funcInfo *ast.Ident, lines, lineLimit int) Message {
+	return Message{
+		fset.Position(funcInfo.Pos()),
+		fmt.Sprintf("Function '%s' is too long (%d > %d)\n", funcInfo.Name, lines, lineLimit),
+	}
+}
+
+func makeStmtMessage(fset *token.FileSet, funcInfo *ast.Ident, stmts, stmtLimit int) Message {
+	return Message{
+		fset.Position(funcInfo.Pos()),
+		fmt.Sprintf("Function '%s' has too many statements (%d > %d)\n", funcInfo.Name, stmts, stmtLimit),
+	}
+}
+
+func getLines(fset *token.FileSet, f *ast.FuncDecl) int { // nolint: interfacer
+	return fset.Position(f.End()).Line - fset.Position(f.Pos()).Line - 1
+}
+
+func parseStmts(s []ast.Stmt) (total int) {
+	for _, v := range s {
+		total++
+		switch stmt := v.(type) {
+		case *ast.BlockStmt:
+			total += parseStmts(stmt.List) - 1
+		case *ast.ForStmt, *ast.RangeStmt, *ast.IfStmt,
+			*ast.SwitchStmt, *ast.TypeSwitchStmt, *ast.SelectStmt:
+			total += parseBodyListStmts(stmt)
+		case *ast.CaseClause:
+			total += parseStmts(stmt.Body)
+		case *ast.AssignStmt:
+			total += checkInlineFunc(stmt.Rhs[0])
+		case *ast.GoStmt:
+			total += checkInlineFunc(stmt.Call.Fun)
+		case *ast.DeferStmt:
+			total += checkInlineFunc(stmt.Call.Fun)
+		}
+	}
+	return
+}
+
+func checkInlineFunc(stmt ast.Expr) int {
+	if block, ok := stmt.(*ast.FuncLit); ok {
+		return parseStmts(block.Body.List)
+	}
+	return 0
+}
+
+func parseBodyListStmts(t interface{}) int {
+	i := reflect.ValueOf(t).Elem().FieldByName(`Body`).Elem().FieldByName(`List`).Interface()
+	return parseStmts(i.([]ast.Stmt))
+}

vendor/modules.txt

@@ -183,6 +183,8 @@ github.com/stretchr/testify/assert
 github.com/stretchr/testify/require
 # github.com/timakin/bodyclose v0.0.0-00010101000000-87058b9bfcec
 github.com/timakin/bodyclose/passes/bodyclose
+# github.com/ultraware/funlen v0.0.1
+github.com/ultraware/funlen
 # github.com/valyala/bytebufferpool v1.0.0
 github.com/valyala/bytebufferpool
 # github.com/valyala/quicktemplate v1.1.1