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Copy pathlint.go
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706 lines (626 loc) · 15.4 KB
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// Package lint provides the foundation for tools like staticcheck
package lint // import "honnef.co/go/tools/lint"
import (
"fmt"
"go/ast"
"go/token"
"go/types"
"io"
"os"
"path/filepath"
"sort"
"strings"
"sync"
"time"
"unicode"
"golang.org/x/tools/go/packages"
"honnef.co/go/tools/config"
"honnef.co/go/tools/ssa"
"honnef.co/go/tools/ssa/ssautil"
)
type Job struct {
Program *Program
checker string
check Check
problems []Problem
duration time.Duration
}
type Ignore interface {
Match(p Problem) bool
}
type LineIgnore struct {
File string
Line int
Checks []string
matched bool
pos token.Pos
}
func (li *LineIgnore) Match(p Problem) bool {
if p.Position.Filename != li.File || p.Position.Line != li.Line {
return false
}
for _, c := range li.Checks {
if m, _ := filepath.Match(c, p.Check); m {
li.matched = true
return true
}
}
return false
}
func (li *LineIgnore) String() string {
matched := &qu
6870
ot;not matched"
if li.matched {
matched = "matched"
}
return fmt.Sprintf("%s:%d %s (%s)", li.File, li.Line, strings.Join(li.Checks, ", "), matched)
}
type FileIgnore struct {
File string
Checks []string
}
func (fi *FileIgnore) Match(p Problem) bool {
if p.Position.Filename != fi.File {
return false
}
for _, c := range fi.Checks {
if m, _ := filepath.Match(c, p.Check); m {
return true
}
}
return false
}
type GlobIgnore struct {
Pattern string
Checks []string
}
func (gi *GlobIgnore) Match(p Problem) bool {
if gi.Pattern != "*" {
pkgpath := p.Package.Types.Path()
if strings.HasSuffix(pkgpath, "_test") {
pkgpath = pkgpath[:len(pkgpath)-len("_test")]
}
name := filepath.Join(pkgpath, filepath.Base(p.Position.Filename))
if m, _ := filepath.Match(gi.Pattern, name); !m {
return false
}
}
for _, c := range gi.Checks {
if m, _ := filepath.Match(c, p.Check); m {
return true
}
}
return false
}
type Program struct {
SSA *ssa.Program
InitialPackages []*Pkg
InitialFunctions []*ssa.Function
AllPackages []*packages.Package
AllFunctions []*ssa.Function
Files []*ast.File
GoVersion int
tokenFileMap map[*token.File]*ast.File
astFileMap map[*ast.File]*Pkg
packagesMap map[string]*packages.Package
genMu sync.RWMutex
generatedMap map[string]bool
}
func (prog *Program) Fset() *token.FileSet {
return prog.InitialPackages[0].Fset
}
type Func func(*Job)
type Severity uint8
const (
Error Severity = iota
Warning
Ignored
)
// Problem represents a problem in some source code.
type Problem struct {
Position token.Position // position in source file
Text string // the prose that describes the problem
Check string
Checker string
Package *Pkg
Severity Severity
}
func (p *Problem) String() string {
if p.Check == "" {
return p.Text
}
return fmt.Sprintf("%s (%s)", p.Text, p.Check)
}
type Checker interface {
Name() string
Prefix() string
Init(*Program)
Checks() []Check
}
type Check struct {
Fn Func
ID string
FilterGenerated bool
}
// A Linter lints Go source code.
type Linter struct {
Checkers []Checker
Ignores []Ignore
GoVersion int
ReturnIgnored bool
Config config.Config
MaxConcurrentJobs int
PrintStats bool
automaticIgnores []Ignore
}
func (l *Linter) ignore(p Problem) bool {
ignored := false
for _, ig := range l.automaticIgnores {
// We cannot short-circuit these, as we want to record, for
// each ignore, whether it matched or not.
if ig.Match(p) {
ignored = true
}
}
if ignored {
// no need to execute other ignores if we've already had a
// match.
return true
}
for _, ig := range l.Ignores {
// We can short-circuit here, as we aren't tracking any
// information.
if ig.Match(p) {
return true
}
}
return false
}
func (prog *Program) File(node Positioner) *ast.File {
return prog.tokenFileMap[prog.SSA.Fset.File(node.Pos())]
}
func (j *Job) File(node Positioner) *ast.File {
return j.Program.File(node)
}
func parseDirective(s string) (cmd string, args []string) {
if !strings.HasPrefix(s, "//lint:") {
return "", nil
}
s = strings.TrimPrefix(s, "//lint:")
fields := strings.Split(s, " ")
return fields[0], fields[1:]
}
type PerfStats struct {
PackageLoading time.Duration
SSABuild time.Duration
OtherInitWork time.Duration
CheckerInits map[string]time.Duration
Jobs []JobStat
}
type JobStat struct {
Job string
Duration time.Duration
}
func (stats *PerfStats) Print(w io.Writer) {
fmt.Fprintln(w, "Package loading:", stats.PackageLoading)
fmt.Fprintln(w, "SSA build:", stats.SSABuild)
fmt.Fprintln(w, "Other init work:", stats.OtherInitWork)
fmt.Fprintln(w, "Checker inits:")
for checker, d := range stats.CheckerInits {
fmt.Fprintf(w, "\t%s: %s\n", checker, d)
}
fmt.Fprintln(w)
fmt.Fprintln(w, "Jobs:")
sort.Slice(stats.Jobs, func(i, j int) bool {
return stats.Jobs[i].Duration < stats.Jobs[j].Duration
})
var total time.Duration
for _, job := range stats.Jobs {
fmt.Fprintf(w, "\t%s: %s\n", job.Job, job.Duration)
total += job.Duration
}
fmt.Fprintf(w, "\tTotal: %s\n", total)
}
func (l *Linter) Lint(initial []*packages.Package, stats *PerfStats) []Problem {
allPkgs := allPackages(initial)
t := time.Now()
ssaprog, _ := ssautil.Packages(allPkgs, ssa.GlobalDebug)
ssaprog.Build()
if stats != nil {
stats.SSABuild = time.Since(t)
}
t = time.Now()
pkgMap := map[*ssa.Package]*Pkg{}
var pkgs []*Pkg
for _, pkg := range initial {
ssapkg := ssaprog.Package(pkg.Types)
var cfg config.Config
if len(pkg.GoFiles) != 0 {
path := pkg.GoFiles[0]
dir := filepath.Dir(path)
var err error
// OPT(dh): we're rebuilding the entire config tree for
// each package. for example, if we check a/b/c and
// a/b/c/d, we'll process a, a/b, a/b/c, a, a/b, a/b/c,
// a/b/c/d – we should cache configs per package and only
// load the new levels.
cfg, err = config.Load(dir)
if err != nil {
// FIXME(dh): we couldn't load the config, what are we
// supposed to do? probably tell the user somehow
}
cfg = cfg.Merge(l.Config)
}
pkg := &Pkg{
SSA: ssapkg,
Package: pkg,
Config: cfg,
}
pkgMap[ssapkg] = pkg
pkgs = append(pkgs, pkg)
}
prog := &Program{
SSA: ssaprog,
InitialPackages: pkgs,
AllPackages: allPkgs,
GoVersion: l.GoVersion,
tokenFileMap: map[*token.File]*ast.File{},
astFileMap: map[*ast.File]*Pkg{},
generatedMap: map[string]bool{},
}
prog.packagesMap = map[string]*packages.Package{}
for _, pkg := range allPkgs {
prog.packagesMap[pkg.Types.Path()] = pkg
}
isInitial := map[*types.Package]struct{}{}
for _, pkg := range pkgs {
isInitial[pkg.Types] = struct{}{}
}
for fn := range ssautil.AllFunctions(ssaprog) {
if fn.Pkg == nil {
continue
}
prog.AllFunctions = append(prog.AllFunctions, fn)
if _, ok := isInitial[fn.Pkg.Pkg]; ok {
prog.InitialFunctions = append(prog.InitialFunctions, fn)
}
}
for _, pkg := range pkgs {
prog.Files = append(prog.Files, pkg.Syntax...)
ssapkg := ssaprog.Package(pkg.Types)
for _, f := range pkg.Syntax {
prog.astFileMap[f] = pkgMap[ssapkg]
}
}
for _, pkg := range allPkgs {
for _, f := range pkg.Syntax {
tf := pkg.Fset.File(f.Pos())
prog.tokenFileMap[tf] = f
}
}
var out []Problem
l.automaticIgnores = nil
for _, pkg := range initial {
for _, f := range pkg.Syntax {
cm := ast.NewCommentMap(pkg.Fset, f, f.Comments)
for node, cgs := range cm {
for _, cg := range cgs {
for _, c := range cg.List {
if !strings.HasPrefix(c.Text, "//lint:") {
continue
}
cmd, args := parseDirective(c.Text)
switch cmd {
case "ignore", "file-ignore":
if len(args) < 2 {
// FIXME(dh): this causes duplicated warnings when using megacheck
p := Problem{
Position: prog.DisplayPosition(c.Pos()),
Text: "malformed linter directive; missing the required reason field?",
Check: "",
Checker: "lint",
Package: nil,
}
out = append(out, p)
continue
}
default:
// unknown directive, ignore
continue
}
checks := strings.Split(args[0], ",")
pos := prog.DisplayPosition(node.Pos())
var ig Ignore
switch cmd {
case "ignore":
ig = &LineIgnore{
File: pos.Filename,
Line: pos.Line,
Checks: checks,
pos: c.Pos(),
}
case "file-ignore":
ig = &FileIgnore{
File: pos.Filename,
Checks: checks,
}
}
l.automaticIgnores = append(l.automaticIgnores, ig)
}
}
}
}
}
sizes := struct {
types int
defs int
uses int
implicits int
selections int
scopes int
}{}
for _, pkg := range pkgs {
sizes.types += len(pkg.TypesInfo.Types)
sizes.defs += len(pkg.TypesInfo.Defs)
sizes.uses += len(pkg.TypesInfo.Uses)
sizes.implicits += len(pkg.TypesInfo.Implicits)
sizes.selections += len(pkg.TypesInfo.Selections)
sizes.scopes += len(pkg.TypesInfo.Scopes)
}
if stats != nil {
stats.OtherInitWork = time.Since(t)
}
for _, checker := range l.Checkers {
t := time.Now()
checker.Init(prog)
if stats != nil {
stats.CheckerInits[checker.Name()] = time.Since(t)
}
}
var jobs []*Job
var allChecks []string
for _, checker := range l.Checkers {
checks := checker.Checks()
for _, check := range checks {
allChecks = append(allChecks, check.ID)
j := &Job{
Program: prog,
checker: checker.Name(),
check: check,
}
jobs = append(jobs, j)
}
}
max := len(jobs)
if l.MaxConcurrentJobs > 0 {
max = l.MaxConcurrentJobs
}
sem := make(chan struct{}, max)
wg := &sync.WaitGroup{}
for _, j := range jobs {
wg.Add(1)
go func(j *Job) {
defer wg.Done()
sem <- struct{}{}
defer func() { <-sem }()
fn := j.check.Fn
if fn == nil {
return
}
t := time.Now()
fn(j)
j.duration = time.Since(t)
}(j)
}
wg.Wait()
for _, j := range jobs {
if stats != nil {
stats.Jobs = append(stats.Jobs, JobStat{j.check.ID, j.duration})
}
for _, p := range j.problems {
allowedChecks := FilterChecks(allChecks, p.Package.Config.Checks)
if l.ignore(p) {
p.Severity = Ignored
}
// TODO(dh): support globs in check white/blacklist
// OPT(dh): this approach doesn't actually disable checks,
// it just discards their results. For the moment, that's
// fine. None of our checks are super expensive. In the
// future, we may want to provide opt-in expensive
// analysis, which shouldn't run at all. It may be easiest
// to implement this in the individual checks.
if (l.ReturnIgnored || p.Severity != Ignored) && allowedChecks[p.Check] {
out = append(out, p)
}
}
}
for _, ig := range l.automaticIgnores {
ig, ok := ig.(*LineIgnore)
if !ok {
continue
}
if ig.matched {
continue
}
couldveMatched := false
for f, pkg := range prog.astFileMap {
if prog.Fset().Position(f.Pos()).Filename != ig.File {
continue
}
allowedChecks := FilterChecks(allChecks, pkg.Config.Checks)
for _, c := range ig.Checks {
if !allowedChecks[c] {
continue
}
couldveMatched = true
break
}
break
}
if !couldveMatched {
// The ignored checks were disabled for the containing package.
// Don't flag the ignore for not having matched.
continue
}
p := Problem{
Position: prog.DisplayPosition(ig.pos),
Text: "this linter directive didn't match anything; should it be removed?",
Check: "",
Checker: "lint",
Package: nil,
}
out = append(out, p)
}
sort.Slice(out, func(i int, j int) bool {
pi, pj := out[i].Position, out[j].Position
if pi.Filename != pj.Filename {
return pi.Filename < pj.Filename
}
if pi.Line != pj.Line {
return pi.Line < pj.Line
}
if pi.Column != pj.Column {
return pi.Column < pj.Column
}
return out[i].Text < out[j].Text
})
if l.PrintStats && stats != nil {
stats.Print(os.Stderr)
}
if len(out) < 2 {
return out
}
uniq := make([]Problem, 0, len(out))
uniq = append(uniq, out[0])
prev := out[0]
for _, p := range out[1:] {
if prev.Position == p.Position && prev.Text == p.Text {
continue
}
prev = p
uniq = append(uniq, p)
}
return uniq
}
func FilterChecks(allChecks []string, checks []string) map[string]bool {
// OPT(dh): this entire computation could be cached per package
allowedChecks := map[string]bool{}
for _, check := range checks {
b := true
if len(check) > 1 && check[0] == '-' {
b = false
check = check[1:]
}
if check == "*" || check == "all" {
// Match all
for _, c := range allChecks {
allowedChecks[c] = b
}
} else if strings.HasSuffix(check, "*") {
// Glob
prefix := check[:len(check)-1]
isCat := strings.IndexFunc(prefix, func(r rune) bool { return unicode.IsNumber(r) }) == -1
for _, c := range allChecks {
idx := strings.IndexFunc(c, func(r rune) bool { return unicode.IsNumber(r) })
if isCat {
// Glob is S*, which should match S1000 but not SA1000
cat := c[:idx]
if prefix == cat {
allowedChecks[c] = b
}
} else {
// Glob is S1*
if strings.HasPrefix(c, prefix) {
allowedChecks[c] = b
}
}
}
} else {
// Literal check name
allowedChecks[check] = b
}
}
return allowedChecks
}
func (prog *Program) Package(path string) *packages.Package {
return prog.packagesMap[path]
}
// Pkg represents a package being linted.
type Pkg struct {
SSA *ssa.Package
*packages.Package
Config config.Config
}
type Positioner interface {
Pos() token.Pos
}
func (prog *Program) DisplayPosition(p token.Pos) token.Position {
// Only use the adjusted position if it points to another Go file.
// This means we'll point to the original file for cgo files, but
// we won't point to a YACC grammar file.
pos := prog.Fset().PositionFor(p, false)
adjPos := prog.Fset().PositionFor(p, true)
if filepath.Ext(adjPos.Filename) == ".go" {
return adjPos
}
return pos
}
func (prog *Program) isGenerated(path string) bool {
// This function isn't very efficient in terms of lock contention
// and lack of parallelism, but it really shouldn't matter.
// Projects consists of thousands of files, and have hundreds of
// errors. That's not a lot of calls to isGenerated.
prog.genMu.RLock()
if b, ok := prog.generatedMap[path]; ok {
prog.genMu.RUnlock()
return b
}
prog.genMu.RUnlock()
prog.genMu.Lock()
defer prog.genMu.Unlock()
// recheck to avoid doing extra work in case of race
if b, ok := prog.generatedMap[path]; ok {
return b
}
f, err := os.Open(path)
if err != nil {
return false
}
defer f.Close()
b := isGenerated(f)
prog.generatedMap[path] = b
return b
}
func (j *Job) Errorf(n Positioner, format string, args ...interface{}) *Problem {
tf := j.Program.SSA.Fset.File(n.Pos())
f := j.Program.tokenFileMap[tf]
pkg := j.Program.astFileMap[f]
pos := j.Program.DisplayPosition(n.Pos())
if j.Program.isGenerated(pos.Filename) && j.check.FilterGenerated {
return nil
}
problem := Problem{
Position: pos,
Text: fmt.Sprintf(format, args...),
Check: j.check.ID,
Checker: j.checker,
Package: pkg,
}
j.problems = append(j.problems, problem)
return &j.problems[len(j.problems)-1]
}
func (j *Job) NodePackage(node Positioner) *Pkg {
f := j.File(node)
return j.Program.astFileMap[f]
}
func allPackages(pkgs []*packages.Package) []*packages.Package {
var out []*packages.Package
packages.Visit(
pkgs,
func(pkg *packages.Package) bool {
out = append(out, pkg)
return true
},
nil,
)
return out
}