From 46f65914e3b26f7044ffe6842ecce10b58e2c2aa Mon Sep 17 00:00:00 2001 From: SalvadorC Date: Sat, 20 Mar 2021 23:45:30 +0100 Subject: [PATCH] new rule function-length (#504) --- README.md | 1 + RULES_DESCRIPTIONS.md | 15 ++++ config/config.go | 1 + rule/function-length.go | 153 +++++++++++++++++++++++++++++++++++ test/function-length_test.go | 26 ++++++ testdata/function-length1.go | 104 ++++++++++++++++++++++++ testdata/function-length2.go | 104 ++++++++++++++++++++++++ testdata/function-length3.go | 24 ++++++ 8 files changed, 428 insertions(+) create mode 100644 rule/function-length.go create mode 100644 test/function-length_test.go create mode 100644 testdata/function-length1.go create mode 100644 testdata/function-length2.go create mode 100644 testdata/function-length3.go diff --git a/README.md b/README.md index d92fc95c1..adfecc211 100644 --- a/README.md +++ b/README.md @@ -360,6 +360,7 @@ List of all available rules. The rules ported from `golint` are left unchanged a | [`identical-branches`](./RULES_DESCRIPTIONS.md#identical-branches) | n/a | Spots if-then-else statements with identical `then` and `else` branches | no | no | | [`defer`](./RULES_DESCRIPTIONS.md#defer) | map | Warns on some [defer gotchas](https://blog.learngoprogramming.com/5-gotchas-of-defer-in-go-golang-part-iii-36a1ab3d6ef1) | no | no | | [`unexported-naming`](./RULES_DESCRIPTIONS.md#unexported-naming) | n/a | Warns on wrongly named un-exported symbols | no | no | +| [`function-length`](./RULES_DESCRIPTIONS.md#function-length) | n/a | Warns on functions exceeding the statements or lines max | no | no | ## Configurable rules diff --git a/RULES_DESCRIPTIONS.md b/RULES_DESCRIPTIONS.md index b7dfd768a..990731fda 100644 --- a/RULES_DESCRIPTIONS.md +++ b/RULES_DESCRIPTIONS.md @@ -33,6 +33,7 @@ List of all available rules. - [file-header](#file-header) - [flag-parameter](#flag-parameter) - [function-result-limit](#function-result-limit) + - [function-length](#function-length) - [get-return](#get-return) - [identical-branches](#identical-branches) - [if-return](#if-return) @@ -331,6 +332,20 @@ Example: arguments =[3] ``` +## function-length + +_Description_: Functions too long (with many statements and/or lines) can be hard to understand. + +_Configuration_: (int,int) the maximum allowed statements and lines. Must be non-negative integers. Set to 0 to disable the check + +Example: + +```toml +[rule.function-length] + arguments =[10,0] +``` +Will check for functions exceeding 10 statements and will not check the number of lines of functions + ## get-return _Description_: Typically, functions with names prefixed with _Get_ are supposed to return a value. diff --git a/config/config.go b/config/config.go index 1357bc744..2132988df 100644 --- a/config/config.go +++ b/config/config.go @@ -77,6 +77,7 @@ var allRules = append([]lint.Rule{ &rule.IdenticalBranchesRule{}, &rule.DeferRule{}, &rule.UnexportedNamingRule{}, + &rule.FunctionLength{}, }, defaultRules...) var allFormatters = []lint.Formatter{ diff --git a/rule/function-length.go b/rule/function-length.go new file mode 100644 index 000000000..e1cee21cf --- /dev/null +++ b/rule/function-length.go @@ -0,0 +1,153 @@ +package rule + +import ( + "fmt" + "go/ast" + "reflect" + + "github.com/mgechev/revive/lint" +) + +// FunctionLength lint. +type FunctionLength struct{} + +// Apply applies the rule to given file. +func (r *FunctionLength) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure { + maxStmt, maxLines := r.parseArguments(arguments) + + var failures []lint.Failure + + walker := lintFuncLength{ + file: file, + maxStmt: int(maxStmt), + maxLines: int(maxLines), + onFailure: func(failure lint.Failure) { + failures = append(failures, failure) + }, + } + + ast.Walk(walker, file.AST) + + return failures +} + +// Name returns the rule name. +func (r *FunctionLength) Name() string { + return "function-length" +} + +func (r *FunctionLength) parseArguments(arguments lint.Arguments) (maxStmt int64, maxLines int64) { + if len(arguments) != 2 { + panic(fmt.Sprintf(`invalid configuration for "function-length" rule, expected 2 arguments but got %d`, len(arguments))) + } + + maxStmt, maxStmtOk := arguments[0].(int64) + if !maxStmtOk { + panic(fmt.Sprintf(`invalid configuration value for max statements in "function-length" rule; need int64 but got %T`, arguments[0])) + } + if maxStmt < 0 { + panic(fmt.Sprintf(`the configuration value for max statements in "function-length" rule cannot be negative, got %d`, maxStmt)) + } + + maxLines, maxLinesOk := arguments[1].(int64) + if !maxLinesOk { + panic(fmt.Sprintf(`invalid configuration value for max lines in "function-length" rule; need int64 but got %T`, arguments[1])) + } + if maxLines < 0 { + panic(fmt.Sprintf(`the configuration value for max statements in "function-length" rule cannot be negative, got %d`, maxLines)) + } + + return +} + +type lintFuncLength struct { + file *lint.File + maxStmt int + maxLines int + onFailure func(lint.Failure) +} + +func (w lintFuncLength) Visit(n ast.Node) ast.Visitor { + node, ok := n.(*ast.FuncDecl) + if !ok { + return w + } + + body := node.Body + if body == nil || len(node.Body.List) == 0 { + return nil + } + + if w.maxStmt > 0 { + stmtCount := w.countStmts(node.Body.List) + if stmtCount > w.maxStmt { + w.onFailure(lint.Failure{ + Confidence: 1, + Failure: fmt.Sprintf("maximum number of statements per function exceeded; max %d but got %d", w.maxStmt, stmtCount), + Node: node, + }) + } + } + + if w.maxLines > 0 { + lineCount := w.countLines(node.Body) + if lineCount > w.maxLines { + w.onFailure(lint.Failure{ + Confidence: 1, + Failure: fmt.Sprintf("maximum number of lines per function exceeded; max %d but got %d", w.maxLines, lineCount), + Node: node, + }) + } + } + + return nil +} + +func (w lintFuncLength) countLines(b *ast.BlockStmt) int { + return w.file.ToPosition(b.End()).Line - w.file.ToPosition(b.Pos()).Line - 1 +} + +func (w lintFuncLength) countStmts(b []ast.Stmt) int { + count := 0 + for _, s := range b { + switch stmt := s.(type) { + case *ast.BlockStmt: + count += w.countStmts(stmt.List) + case *ast.IfStmt: + count += 1 + w.countBodyListStmts(stmt) + if stmt.Else != nil { + elseBody, ok := stmt.Else.(*ast.BlockStmt) + if ok { + count += w.countStmts(elseBody.List) + } + } + case *ast.ForStmt, *ast.RangeStmt, + *ast.SwitchStmt, *ast.TypeSwitchStmt, *ast.SelectStmt: + count += 1 + w.countBodyListStmts(stmt) + case *ast.CaseClause: + count += w.countStmts(stmt.Body) + case *ast.AssignStmt: + count += 1 + w.countFuncLitStmts(stmt.Rhs[0]) + case *ast.GoStmt: + count += 1 + w.countFuncLitStmts(stmt.Call.Fun) + case *ast.DeferStmt: + count += 1 + w.countFuncLitStmts(stmt.Call.Fun) + default: + count++ + } + } + + return count +} + +func (w lintFuncLength) countFuncLitStmts(stmt ast.Expr) int { + if block, ok := stmt.(*ast.FuncLit); ok { + return w.countStmts(block.Body.List) + } + return 0 +} + +func (w lintFuncLength) countBodyListStmts(t interface{}) int { + i := reflect.ValueOf(t).Elem().FieldByName(`Body`).Elem().FieldByName(`List`).Interface() + return w.countStmts(i.([]ast.Stmt)) +} diff --git a/test/function-length_test.go b/test/function-length_test.go new file mode 100644 index 000000000..5cabccd0e --- /dev/null +++ b/test/function-length_test.go @@ -0,0 +1,26 @@ +package test + +import ( + "testing" + + "github.com/mgechev/revive/lint" + "github.com/mgechev/revive/rule" +) + +func TestFuncLengthLimitsStatements(t *testing.T) { + testRule(t, "function-length1", &rule.FunctionLength{}, &lint.RuleConfig{ + Arguments: []interface{}{int64(2), int64(100)}, + }) +} + +func TestFuncLengthLimitsLines(t *testing.T) { + testRule(t, "function-length2", &rule.FunctionLength{}, &lint.RuleConfig{ + Arguments: []interface{}{int64(100), int64(5)}, + }) +} + +func TestFuncLengthLimitsDeactivated(t *testing.T) { + testRule(t, "function-length3", &rule.FunctionLength{}, &lint.RuleConfig{ + Arguments: []interface{}{int64(0), int64(0)}, + }) +} diff --git a/testdata/function-length1.go b/testdata/function-length1.go new file mode 100644 index 000000000..e14eafb2a --- /dev/null +++ b/testdata/function-length1.go @@ -0,0 +1,104 @@ +package fixtures + +import ( + "fmt" + ast "go/ast" + "go/token" +) + +func funLengthA() (a int) { // MATCH /maximum number of statements per function exceeded; max 2 but got 5/ + println() + println() + println() + println() + println() +} + +func funLengthB(file *ast.File, fset *token.FileSet, lineLimit, stmtLimit int) []Message { // MATCH /maximum number of statements per function exceeded; max 2 but got 14/ + if true { + a = b + if false { + c = d + for _, f := range list { + _, ok := f.(int64) + if !ok { + continue + } + } + switch a { + case 1: + println() + case 2: + println() + println() + default: + println() + + } + } + } + return +} + +func funLengthC(b []ast.Stmt) int { // MATCH /maximum number of statements per function exceeded; max 2 but got 12/ + count := 0 + for _, s := range b { + switch stmt := s.(type) { + case *ast.BlockStmt: + count += w.countStmts(stmt.List) + case *ast.ForStmt, *ast.RangeStmt, *ast.IfStmt, + *ast.SwitchStmt, *ast.TypeSwitchStmt, *ast.SelectStmt: + count += 1 + w.countBodyListStmts(stmt) + case *ast.CaseClause: + count += w.countStmts(stmt.Body) + case *ast.AssignStmt: + count += 1 + w.countFuncLitStmts(stmt.Rhs[0]) + case *ast.GoStmt: + count += 1 + w.countFuncLitStmts(stmt.Call.Fun) + case *ast.DeferStmt: + count += 1 + w.countFuncLitStmts(stmt.Call.Fun) + default: + fmt.Printf("%T %v\n", stmt, stmt) + count++ + } + } + + return count +} + +func funLengthD(b []ast.Stmt) int { + defer func() { println() }() +} + +func funLengthE(b []ast.Stmt) int { // MATCH /maximum number of statements per function exceeded; max 2 but got 4/ + defer func() { + if true { + println() + } else { + print() + } + }() +} + +func funLengthF(b []ast.Stmt) int { // MATCH /maximum number of statements per function exceeded; max 2 but got 3/ + if true { + println() + } else { + print() + } +} + +func funLengthG(b []ast.Stmt) int { // MATCH /maximum number of statements per function exceeded; max 2 but got 3/ + go func() { + if true { + println() + } else { + + } + }() +} + +func funLengthH(b []ast.Stmt) int { + go func() {}() + println() +} diff --git a/testdata/function-length2.go b/testdata/function-length2.go new file mode 100644 index 000000000..cc28366a6 --- /dev/null +++ b/testdata/function-length2.go @@ -0,0 +1,104 @@ +package fixtures + +import ( + "fmt" + ast "go/ast" + "go/token" +) + +func funLengthA() (a int) { + println() + println() + println() + println() + println() +} + +func funLengthB(file *ast.File, fset *token.FileSet, lineLimit, stmtLimit int) []Message { // MATCH /maximum number of lines per function exceeded; max 5 but got 23/ + if true { + a = b + if false { + c = d + for _, f := range list { + _, ok := f.(int64) + if !ok { + continue + } + } + switch a { + case 1: + println() + case 2: + println() + println() + default: + println() + + } + } + } + return +} + +func funLengthC(b []ast.Stmt) int { // MATCH /maximum number of lines per function exceeded; max 5 but got 23/ + count := 0 + for _, s := range b { + switch stmt := s.(type) { + case *ast.BlockStmt: + count += w.countStmts(stmt.List) + case *ast.ForStmt, *ast.RangeStmt, *ast.IfStmt, + *ast.SwitchStmt, *ast.TypeSwitchStmt, *ast.SelectStmt: + count += 1 + w.countBodyListStmts(stmt) + case *ast.CaseClause: + count += w.countStmts(stmt.Body) + case *ast.AssignStmt: + count += 1 + w.countFuncLitStmts(stmt.Rhs[0]) + case *ast.GoStmt: + count += 1 + w.countFuncLitStmts(stmt.Call.Fun) + case *ast.DeferStmt: + count += 1 + w.countFuncLitStmts(stmt.Call.Fun) + default: + fmt.Printf("%T %v\n", stmt, stmt) + count++ + } + } + + return count +} + +func funLengthD(b []ast.Stmt) int { + defer func() { println() }() +} + +func funLengthE(b []ast.Stmt) int { // MATCH /maximum number of lines per function exceeded; max 5 but got 7/ + defer func() { + if true { + println() + } else { + print() + } + }() +} + +func funLengthF(b []ast.Stmt) int { + if true { + println() + } else { + print() + } +} + +func funLengthG(b []ast.Stmt) int { // MATCH /maximum number of lines per function exceeded; max 5 but got 7/ + go func() { + if true { + println() + } else { + + } + }() +} + +func funLengthH(b []ast.Stmt) int { + go func() {}() + println() +} diff --git a/testdata/function-length3.go b/testdata/function-length3.go new file mode 100644 index 000000000..876bdfa34 --- /dev/null +++ b/testdata/function-length3.go @@ -0,0 +1,24 @@ +package fixtures + +func funLengthA() (a int) { + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() + println() +}