87 lines
2.4 KiB
Go
87 lines
2.4 KiB
Go
package sa4017
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import (
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"fmt"
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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/facts/purity"
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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/go/ir"
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"honnef.co/go/tools/go/ir/irutil"
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"honnef.co/go/tools/go/types/typeutil"
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"honnef.co/go/tools/internal/passes/buildir"
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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: "SA4017",
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Run: run,
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Requires: []*analysis.Analyzer{buildir.Analyzer, purity.Analyzer},
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},
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Doc: &lint.RawDocumentation{
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Title: `Discarding the return values of a function without side effects, making the call pointless`,
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Since: "2017.1",
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Severity: lint.SeverityWarning,
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MergeIf: lint.MergeIfAll,
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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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pure := pass.ResultOf[purity.Analyzer].(purity.Result)
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fnLoop:
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for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
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if code.IsInTest(pass, fn) {
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params := fn.Signature.Params()
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for param := range params.Variables() {
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if typeutil.IsPointerToTypeWithName(param.Type(), "testing.B") {
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// Ignore discarded pure functions in code related
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// to benchmarks. Instead of matching BenchmarkFoo
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// functions, we match any function accepting a
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// *testing.B. Benchmarks sometimes call generic
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// functions for doing the actual work, and
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// checking for the parameter is a lot easier and
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// faster than analyzing call trees.
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continue fnLoop
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}
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}
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}
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for _, b := range fn.Blocks {
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for _, ins := range b.Instrs {
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ins, ok := ins.(*ir.Call)
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if !ok {
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continue
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}
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refs := ins.Referrers()
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if refs == nil || len(irutil.FilterDebug(*refs)) > 0 {
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continue
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}
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callee := ins.Common().StaticCallee()
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if callee == nil {
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continue
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}
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if callee.Object() == nil {
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// TODO(dh): support anonymous functions
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continue
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}
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if _, ok := pure[callee.Object().(*types.Func)]; ok {
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if pass.Pkg.Path() == "fmt_test" && callee.Object().(*types.Func).FullName() == "fmt.Sprintf" {
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// special case for benchmarks in the fmt package
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continue
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}
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report.Report(pass, ins, fmt.Sprintf("%s doesn't have side effects and its return value is ignored", callee.Object().Name()))
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}
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}
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}
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}
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return nil, nil
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}
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