zlog/cmd/lint/lint.go

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package main
import (
"flag"
"fmt"
"go/ast"
"go/token"
"go/types"
"os"
"path/filepath"
"strings"
"golang.org/x/tools/go/loader"
)
var (
recursivelyIgnoredPkgs arrayFlag
ignoredPkgs arrayFlag
ignoredFiles arrayFlag
allowedFinishers arrayFlag = []string{"Msg", "Msgf"}
rootPkg string
)
// parse input flags and args
func init() {
flag.Var(&recursivelyIgnoredPkgs, "ignorePkgRecursively", "ignore the specified package and all subpackages recursively")
flag.Var(&ignoredPkgs, "ignorePkg", "ignore the specified package")
flag.Var(&ignoredFiles, "ignoreFile", "ignore the specified file by its path and/or go path (package/file.go)")
flag.Var(&allowedFinishers, "finisher", "allowed finisher for the event chain")
flag.Parse()
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// add zlog to recursively ignored packages
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recursivelyIgnoredPkgs = append(recursivelyIgnoredPkgs, "tuxpa.in/a/zlog")
args := flag.Args()
if len(args) != 1 {
fmt.Fprintln(os.Stderr, "you must provide exactly one package path")
os.Exit(1)
}
rootPkg = args[0]
}
func main() {
// load the package and all its dependencies
conf := loader.Config{}
conf.Import(rootPkg)
p, err := conf.Load()
if err != nil {
fmt.Fprintf(os.Stderr, "Error: unable to load the root package. %s\n", err.Error())
os.Exit(1)
}
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// get the tuxpa.in/a/zlog.Event type
event := getEvent(p)
if event == nil {
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fmt.Fprintln(os.Stderr, "Error: tuxpa.in/a/zlog.Event declaration not found, maybe zlog is not imported in the scanned package?")
os.Exit(1)
}
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// get all selections (function calls) with the tuxpa.in/a/zlog.Event (or pointer) receiver
selections := getSelectionsWithReceiverType(p, event)
// print the violations (if any)
hasViolations := false
for _, s := range selections {
if hasBadFinisher(p, s) {
hasViolations = true
fmt.Printf("Error: missing or bad finisher for log chain, last call: %q at: %s:%v\n", s.fn.Name(), p.Fset.File(s.Pos()).Name(), p.Fset.Position(s.Pos()).Line)
}
}
// if no violations detected, return normally
if !hasViolations {
fmt.Println("No violations found")
return
}
// if violations were detected, return error code
os.Exit(1)
}
func getEvent(p *loader.Program) types.Type {
for _, pkg := range p.AllPackages {
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if strings.HasSuffix(pkg.Pkg.Path(), "tuxpa.in/a/zlog") {
for _, d := range pkg.Defs {
if d != nil && d.Name() == "Event" {
return d.Type()
}
}
}
}
return nil
}
func getSelectionsWithReceiverType(p *loader.Program, targetType types.Type) map[token.Pos]selection {
selections := map[token.Pos]selection{}
for _, z := range p.AllPackages {
for i, t := range z.Selections {
switch o := t.Obj().(type) {
case *types.Func:
// this is not a bug, o.Type() is always *types.Signature, see docs
if vt := o.Type().(*types.Signature).Recv(); vt != nil {
typ := vt.Type()
if pointer, ok := typ.(*types.Pointer); ok {
typ = pointer.Elem()
}
if typ == targetType {
if s, ok := selections[i.Pos()]; !ok || i.End() > s.End() {
selections[i.Pos()] = selection{i, o, z.Pkg}
}
}
}
default:
// skip
}
}
}
return selections
}
func hasBadFinisher(p *loader.Program, s selection) bool {
pkgPath := strings.TrimPrefix(s.pkg.Path(), rootPkg+"/vendor/")
absoluteFilePath := strings.TrimPrefix(p.Fset.File(s.Pos()).Name(), rootPkg+"/vendor/")
goFilePath := pkgPath + "/" + filepath.Base(p.Fset.Position(s.Pos()).Filename)
for _, f := range allowedFinishers {
if f == s.fn.Name() {
return false
}
}
for _, ignoredPkg := range recursivelyIgnoredPkgs {
if strings.HasPrefix(pkgPath, ignoredPkg) {
return false
}
}
for _, ignoredPkg := range ignoredPkgs {
if pkgPath == ignoredPkg {
return false
}
}
for _, ignoredFile := range ignoredFiles {
if absoluteFilePath == ignoredFile {
return false
}
if goFilePath == ignoredFile {
return false
}
}
return true
}
type arrayFlag []string
func (i *arrayFlag) String() string {
return fmt.Sprintf("%v", []string(*i))
}
func (i *arrayFlag) Set(value string) error {
*i = append(*i, value)
return nil
}
type selection struct {
*ast.SelectorExpr
fn *types.Func
pkg *types.Package
}