package main
import (
"go/ast"
"go/token"
"go/types"
"golang.org/x/tools/go/analysis"
)
var PanicAnalyzer = &analysis.Analyzer{
Name: "panic",
Doc: "finds goroutines that do not initialize the panic handler",
Run: runPanic,
}
func runPanic(pass *analysis.Pass) (interface{}, error) {
methods := make(map[token.Pos]string)
for _, file := range pass.Files {
ast.Inspect(file, func(n ast.Node) bool {
g, ok := n.(*ast.GoStmt)
if !ok {
return true
}
var block *ast.BlockStmt
expr := g.Call.Fun
if e, ok := expr.(*ast.ParenExpr); ok {
expr = e.X
}
switch e := expr.(type) {
case *ast.FuncLit:
block = e.Body
case *ast.SelectorExpr:
sel, ok := pass.TypesInfo.Selections[e]
if ok {
f, ok := sel.Obj().(*types.Func)
if ok {
methods[f.Pos()] = f.Name()
}
}
case *ast.Ident:
block = inlineFuncBody(e)
}
if block == nil {
return true
}
if !isPanicHandlerInstall(block.List[0]) {
pass.Report(panicDiag(block.Pos()))
}
return true
})
}
for _, file := range pass.Files {
ast.Inspect(file, func(n ast.Node) bool {
f, ok := n.(*ast.FuncDecl)
if !ok {
return false
}
_, found := methods[f.Name.Pos()]
if !found {
return false
}
delete(methods, f.Name.Pos())
if !isPanicHandlerInstall(f.Body.List[0]) {
pass.Report(panicDiag(f.Body.Pos()))
}
return false
})
}
return nil, nil
}
func panicDiag(pos token.Pos) analysis.Diagnostic {
return analysis.Diagnostic{
Pos: pos,
Category: "panic",
Message: "missing defer log.PanicHandler() as first statement",
}
}
func inlineFuncBody(s *ast.Ident) *ast.BlockStmt {
d, ok := s.Obj.Decl.(*ast.AssignStmt)
if !ok {
return nil
}
for _, r := range d.Rhs {
if f, ok := r.(*ast.FuncLit); ok {
return f.Body
}
}
return nil
}
func isPanicHandlerInstall(stmt ast.Stmt) bool {
d, ok := stmt.(*ast.DeferStmt)
if !ok {
return false
}
s, ok := d.Call.Fun.(*ast.SelectorExpr)
if !ok {
return false
}
i, ok := s.X.(*ast.Ident)
if !ok {
return false
}
return i.Name == "log" && s.Sel.Name == "PanicHandler"
}
// golang-lint required plugin api
type analyzerPlugin struct{}
// This must be implemented
func (*analyzerPlugin) GetAnalyzers() []*analysis.Analyzer {
return []*analysis.Analyzer{
PanicAnalyzer,
}
}
// This must be defined and named 'AnalyzerPlugin'
var AnalyzerPlugin analyzerPlugin
