89 lines
2.1 KiB
Go
89 lines
2.1 KiB
Go
package s1036
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import (
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"go/ast"
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"honnef.co/go/tools/analysis/code"
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"honnef.co/go/tools/analysis/edit"
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"honnef.co/go/tools/analysis/lint"
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"honnef.co/go/tools/analysis/report"
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"honnef.co/go/tools/pattern"
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"golang.org/x/tools/go/analysis"
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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: "S1036",
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Run: run,
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Requires: code.RequiredAnalyzers,
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},
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Doc: &lint.RawDocumentation{
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Title: `Unnecessary guard around map access`,
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Text: `
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When accessing a map key that doesn't exist yet, one receives a zero
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value. Often, the zero value is a suitable value, for example when
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using append or doing integer math.
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The following
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if _, ok := m["foo"]; ok {
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m["foo"] = append(m["foo"], "bar")
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} else {
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m["foo"] = []string{"bar"}
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}
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can be simplified to
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m["foo"] = append(m["foo"], "bar")
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and
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if _, ok := m2["k"]; ok {
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m2["k"] += 4
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} else {
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m2["k"] = 4
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}
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can be simplified to
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m["k"] += 4
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`,
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Since: "2020.1",
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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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var checkUnnecessaryGuardQ = pattern.MustParse(`
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(Or
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(IfStmt
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(AssignStmt [(Ident "_") ok@(Ident _)] ":=" indexexpr@(IndexExpr _ _))
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ok
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set@(AssignStmt indexexpr "=" (CallExpr (Builtin "append") indexexpr:values))
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(AssignStmt indexexpr "=" (CompositeLit _ values)))
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(IfStmt
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(AssignStmt [(Ident "_") ok] ":=" indexexpr@(IndexExpr _ _))
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ok
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set@(AssignStmt indexexpr "+=" value)
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(AssignStmt indexexpr "=" value))
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(IfStmt
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(AssignStmt [(Ident "_") ok] ":=" indexexpr@(IndexExpr _ _))
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ok
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set@(IncDecStmt indexexpr "++")
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(AssignStmt indexexpr "=" (IntegerLiteral "1"))))`)
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func run(pass *analysis.Pass) (any, error) {
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for node, m := range code.Matches(pass, checkUnnecessaryGuardQ) {
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if code.MayHaveSideEffects(pass, m.State["indexexpr"].(ast.Expr), nil) {
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continue
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}
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report.Report(pass, node, "unnecessary guard around map access",
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report.ShortRange(),
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report.Fixes(edit.Fix("Simplify map access", edit.ReplaceWithNode(pass.Fset, node, m.State["set"].(ast.Node)))))
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}
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return nil, nil
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}
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