fix #243: support Scopelint linter

Author: jirfag

Gopkg.lock

@@ -199,6 +199,7 @@ lll: Reports long lines [fast: true]
 unparam: Reports unused function parameters [fast: false]
 nakedret: Finds naked returns in functions greater than a specified function length [fast: true]
 prealloc: Finds slice declarations that could potentially be preallocated [fast: true]
+scopelint: Scopelint checks for unpinned variables in go programs [fast: true]
 ```
 
 Pass `-E/--enable` to enable linter and `-D/--disable` to disable:
@@ -398,6 +399,7 @@ golangci-lint help linters
 - [unparam](https://github.com/mvdan/unparam) - Reports unused function parameters
 - [nakedret](https://github.com/alexkohler/nakedret) - Finds naked returns in functions greater than a specified function length
 - [prealloc](https://github.com/alexkohler/prealloc) - Finds slice declarations that could potentially be preallocated
+- [scopelint](https://github.com/kyoh86/scopelint) - Scopelint checks for unpinned variables in go programs
 
 ## Configuration
 
@@ -807,6 +809,7 @@ Thanks to developers and authors of used linters:
 - [client9](https://github.com/client9)
 - [walle](https://github.com/walle)
 - [alexkohler](https://github.com/alexkohler)
+- [kyoh86](https://github.com/kyoh86)
 
 ## Changelog
 

README.md

@@ -0,0 +1,139 @@
+package golinters
+
+import (
+	"context"
+	"fmt"
+	"go/ast"
+	"go/token"
+
+	"github.com/golangci/golangci-lint/pkg/lint/linter"
+	"github.com/golangci/golangci-lint/pkg/result"
+)
+
+type Scopelint struct{}
+
+func (Scopelint) Name() string {
+	return "scopelint"
+}
+
+func (Scopelint) Desc() string {
+	return "Scopelint checks for unpinned variables in go programs"
+}
+
+func (lint Scopelint) Run(ctx context.Context, lintCtx *linter.Context) ([]result.Issue, error) {
+	var res []result.Issue
+
+	for _, f := range lintCtx.ASTCache.GetAllValidFiles() {
+		n := Node{
+			fset:          f.Fset,
+			dangerObjects: map[*ast.Object]struct{}{},
+			unsafeObjects: map[*ast.Object]struct{}{},
+			skipFuncs:     map[*ast.FuncLit]struct{}{},
+			issues:        &res,
+		}
+		ast.Walk(&n, f.F)
+	}
+
+	return res, nil
+}
+
+// The code below is copy-pasted from https://github.com/kyoh86/scopelint
+
+// Node represents a Node being linted.
+type Node struct {
+	fset          *token.FileSet
+	dangerObjects map[*ast.Object]struct{}
+	unsafeObjects map[*ast.Object]struct{}
+	skipFuncs     map[*ast.FuncLit]struct{}
+	issues        *[]result.Issue
+}
+
+// Visit method is invoked for each node encountered by Walk.
+// If the result visitor w is not nil, Walk visits each of the children
+// of node with the visitor w, followed by a call of w.Visit(nil).
+//nolint:gocyclo
+func (f *Node) Visit(node ast.Node) ast.Visitor {
+	switch typedNode := node.(type) {
+	case *ast.ForStmt:
+		switch init := typedNode.Init.(type) {
+		case *ast.AssignStmt:
+			for _, lh := range init.Lhs {
+				switch tlh := lh.(type) {
+				case *ast.Ident:
+					f.unsafeObjects[tlh.Obj] = struct{}{}
+				}
+			}
+		}
+
+	case *ast.RangeStmt:
+		// Memory variables declarated in range statement
+		switch k := typedNode.Key.(type) {
+		case *ast.Ident:
+			f.unsafeObjects[k.Obj] = struct{}{}
+		}
+		switch v := typedNode.Value.(type) {
+		case *ast.Ident:
+			f.unsafeObjects[v.Obj] = struct{}{}
+		}
+
+	case *ast.UnaryExpr:
+		if typedNode.Op == token.AND {
+			switch ident := typedNode.X.(type) {
+			case *ast.Ident:
+				if _, unsafe := f.unsafeObjects[ident.Obj]; unsafe {
+					f.errorf(ident, "Using a reference for the variable on range scope %s", formatCode(ident.Name, nil))
+				}
+			}
+		}
+
+	case *ast.Ident:
+		if _, obj := f.dangerObjects[typedNode.Obj]; obj {
+			// It is the naked variable in scope of range statement.
+			f.errorf(node, "Using the variable on range scope %s in function literal", formatCode(typedNode.Name, nil))
+			break
+		}
+
+	case *ast.CallExpr:
+		// Ignore func literals that'll be called immediately.
+		switch funcLit := typedNode.Fun.(type) {
+		case *ast.FuncLit:
+			f.skipFuncs[funcLit] = struct{}{}
+		}
+
+	case *ast.FuncLit:
+		if _, skip := f.skipFuncs[typedNode]; !skip {
+			dangers := map[*ast.Object]struct{}{}
+			for d := range f.dangerObjects {
+				dangers[d] = struct{}{}
+			}
+			for u := range f.unsafeObjects {
+				dangers[u] = struct{}{}
+			}
+			return &Node{
+				fset:          f.fset,
+				dangerObjects: dangers,
+				unsafeObjects: f.unsafeObjects,
+				skipFuncs:     f.skipFuncs,
+				issues:        f.issues,
+			}
+		}
+	}
+	return f
+}
+
+// The variadic arguments may start with link and category types,
+// and must end with a format string and any arguments.
+// It returns the new Problem.
+//nolint:interfacer
+func (f *Node) errorf(n ast.Node, format string, args ...interface{}) {
+	pos := f.fset.Position(n.Pos())
+	f.errorfAt(pos, format, args...)
+}
+
+func (f *Node) errorfAt(pos token.Position, format string, args ...interface{}) {
+	*f.issues = append(*f.issues, result.Issue{
+		Pos:        pos,
+		Text:       fmt.Sprintf(format, args...),
+		FromLinter: Scopelint{}.Name(),
+	})
+}

pkg/golinters/scopelint.go

@@ -83,6 +83,7 @@ func TestGetEnabledLintersSet(t *testing.T) {
 	m := NewManager()
 	es := NewEnabledSet(m, NewValidator(m), nil, nil)
 	for _, c := range cases {
+		c := c
 		t.Run(c.name, func(t *testing.T) {
 			defaultLinters := []linter.Config{}
 			for _, ln := range c.def {

pkg/lint/lintersdb/enabled_set_test.go

@@ -49,6 +49,7 @@ func (m Manager) GetLinterConfig(name string) *linter.Config {
 func enableLinterConfigs(lcs []linter.Config, isEnabled func(lc *linter.Config) bool) []linter.Config {
 	var ret []linter.Config
 	for _, lc := range lcs {
+		lc := lc
 		lc.EnabledByDefault = isEnabled(&lc)
 		ret = append(ret, lc)
 	}
@@ -186,6 +187,10 @@ func (Manager) GetAllSupportedLinterConfigs() []linter.Config {
 			WithPresets(linter.PresetPerformance).
 			WithSpeed(8).
 			WithURL("https://github.com/alexkohler/prealloc"),
+		linter.NewConfig(golinters.Scopelint{}).
+			WithPresets(linter.PresetBugs).
+			WithSpeed(8).
+			WithURL("https://github.com/kyoh86/scopelint"),
 	}
 
 	isLocalRun := os.Getenv("GOLANGCI_COM_RUN") == ""

pkg/lint/lintersdb/manager.go

@@ -222,6 +222,7 @@ func (r Runner) processLintResults(inCh <-chan lintRes) <-chan lintRes {
 		// finalize processors: logging, clearing, no heavy work here
 
 		for _, p := range r.Processors {
+			p := p
 			sw.TrackStage(p.Name(), func() {
 				p.Finish()
 			})
@@ -273,6 +274,7 @@ func (r *Runner) processIssues(issues []result.Issue, sw *timeutils.Stopwatch) [
 	for _, p := range r.Processors {
 		var newIssues []result.Issue
 		var err error
+		p := p
 		sw.TrackStage(p.Name(), func() {
 			newIssues, err = p.Process(issues)
 		})

pkg/lint/runner.go

@@ -33,6 +33,7 @@ func (p *Tab) Print(ctx context.Context, issues <-chan result.Issue) error {
 	w := tabwriter.NewWriter(logutils.StdOut, 0, 0, 2, ' ', 0)
 
 	for i := range issues {
+		i := i
 		p.printIssue(&i, w)
 	}
 

pkg/printers/tab.go

@@ -38,6 +38,7 @@ func (p Text) SprintfColored(ca color.Attribute, format string, args ...interfac
 
 func (p *Text) Print(ctx context.Context, issues <-chan result.Issue) error {
 	for i := range issues {
+		i := i
 		p.printIssue(&i)
 
 		if !p.printIssuedLine {

pkg/printers/text.go

@@ -148,6 +148,7 @@ func (e *rangeExpander) Visit(node ast.Node) ast.Visitor {
 	var foundRange *ignoredRange
 	for _, r := range e.inlineRanges {
 		if r.To == nodeStartLine-1 && nodeStartPos.Column == r.col {
+			r := r
 			foundRange = &r
 			break
 		}

pkg/result/processors/nolint.go

@@ -153,6 +153,7 @@ func TestNolintAliases(t *testing.T) {
 
 	p := newTestNolintProcessor(getOkLogger(ctrl))
 	for _, line := range []int{47, 49, 51} {
+		line := line
 		t.Run(fmt.Sprintf("line-%d", line), func(t *testing.T) {
 			processAssertEmpty(t, p, newNolintFileIssue(line, "gosec"))
 		})

pkg/result/processors/nolint_test.go

@@ -9,6 +9,7 @@ import (
 func filterIssues(issues []result.Issue, filter func(i *result.Issue) bool) []result.Issue {
 	retIssues := make([]result.Issue, 0, len(issues))
 	for _, i := range issues {
+		i := i
 		if filter(&i) {
 			retIssues = append(retIssues, i)
 		}
@@ -20,6 +21,7 @@ func filterIssues(issues []result.Issue, filter func(i *result.Issue) bool) []re
 func filterIssuesErr(issues []result.Issue, filter func(i *result.Issue) (bool, error)) ([]result.Issue, error) {
 	retIssues := make([]result.Issue, 0, len(issues))
 	for _, i := range issues {
+		i := i
 		ok, err := filter(&i)
 		if err != nil {
 			return nil, fmt.Errorf("can't filter issue %#v: %s", i, err)
@@ -36,6 +38,7 @@ func filterIssuesErr(issues []result.Issue, filter func(i *result.Issue) (bool,
 func transformIssues(issues []result.Issue, transform func(i *result.Issue) *result.Issue) []result.Issue {
 	retIssues := make([]result.Issue, 0, len(issues))
 	for _, i := range issues {
+		i := i
 		newI := transform(&i)
 		if newI != nil {
 			retIssues = append(retIssues, *newI)

pkg/result/processors/utils.go

@@ -368,6 +368,7 @@ func TestEnabledLinters(t *testing.T) {
 	}
 
 	for _, c := range cases {
+		c := c
 		t.Run(c.name, func(t *testing.T) {
 			runArgs := []string{"-v"}
 			if !c.noImplicitFast {

test/run_test.go

@@ -0,0 +1,17 @@
+// args: -Escopelint
+package testdata
+
+import "fmt"
+
+func ScopelintTest() {
+	values := []string{"a", "b", "c"}
+	var funcs []func()
+	for _, val := range values {
+		funcs = append(funcs, func() {
+			fmt.Println(val) // ERROR "Using the variable on range scope `val` in function literal"
+		})
+	}
+	for _, f := range funcs {
+		f()
+	}
+}