110 lines
2.4 KiB
Go
110 lines
2.4 KiB
Go
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package sa5001
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import (
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"fmt"
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"go/ast"
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"go/types"
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"honnef.co/go/tools/analysis/code"
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"honnef.co/go/tools/analysis/lint"
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"honnef.co/go/tools/analysis/report"
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"golang.org/x/tools/go/analysis"
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"golang.org/x/tools/go/analysis/passes/inspect"
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)
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var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
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Analyzer: &analysis.Analyzer{
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Name: "SA5001",
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Run: run,
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Requires: []*analysis.Analyzer{inspect.Analyzer},
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},
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Doc: &lint.RawDocumentation{
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Title: `Deferring \'Close\' before checking for a possible error`,
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Since: "2017.1",
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Severity: lint.SeverityWarning,
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MergeIf: lint.MergeIfAny,
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},
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})
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var Analyzer = SCAnalyzer.Analyzer
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func run(pass *analysis.Pass) (any, error) {
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fn := func(node ast.Node) {
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block := node.(*ast.BlockStmt)
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if len(block.List) < 2 {
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return
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}
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for i, stmt := range block.List {
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if i == len(block.List)-1 {
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break
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}
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assign, ok := stmt.(*ast.AssignStmt)
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if !ok {
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continue
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}
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if len(assign.Rhs) != 1 {
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continue
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}
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if len(assign.Lhs) < 2 {
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continue
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}
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if lhs, ok := assign.Lhs[len(assign.Lhs)-1].(*ast.Ident); ok && lhs.Name == "_" {
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continue
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}
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call, ok := assign.Rhs[0].(*ast.CallExpr)
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if !ok {
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continue
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}
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sig, ok := pass.TypesInfo.TypeOf(call.Fun).(*types.Signature)
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if !ok {
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continue
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}
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if sig.Results().Len() < 2 {
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continue
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}
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last := sig.Results().At(sig.Results().Len() - 1)
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// FIXME(dh): check that it's error from universe, not
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// another type of the same name
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if last.Type().String() != "error" {
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continue
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}
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lhs, ok := assign.Lhs[0].(*ast.Ident)
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if !ok {
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continue
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}
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def, ok := block.List[i+1].(*ast.DeferStmt)
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if !ok {
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continue
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}
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sel, ok := def.Call.Fun.(*ast.SelectorExpr)
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if !ok {
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continue
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}
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ident, ok := selectorX(sel).(*ast.Ident)
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if !ok {
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continue
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}
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if pass.TypesInfo.ObjectOf(ident) != pass.TypesInfo.ObjectOf(lhs) {
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continue
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}
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if sel.Sel.Name != "Close" {
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continue
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}
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report.Report(pass, def, fmt.Sprintf("should check error returned from %s() before deferring %s",
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report.Render(pass, call.Fun), report.Render(pass, def.Call)))
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}
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}
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code.Preorder(pass, fn, (*ast.BlockStmt)(nil))
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return nil, nil
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}
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func selectorX(sel *ast.SelectorExpr) ast.Node {
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switch x := sel.X.(type) {
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case *ast.SelectorExpr:
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return selectorX(x)
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default:
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return x
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}
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}
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