93 lines
2.5 KiB
Go
93 lines
2.5 KiB
Go
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package sa1025
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import (
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"go/types"
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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/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: "SA1025",
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Run: run,
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Requires: []*analysis.Analyzer{buildir.Analyzer},
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},
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Doc: &lint.RawDocumentation{
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Title: `It is not possible to use \'(*time.Timer).Reset\''s return value correctly`,
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Since: "2019.1",
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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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for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
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for _, block := range fn.Blocks {
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for _, ins := range block.Instrs {
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call, ok := ins.(*ir.Call)
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if !ok {
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continue
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}
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if !irutil.IsCallTo(call.Common(), "(*time.Timer).Reset") {
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continue
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}
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refs := call.Referrers()
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if refs == nil {
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continue
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}
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for _, ref := range irutil.FilterDebug(*refs) {
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ifstmt, ok := ref.(*ir.If)
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if !ok {
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continue
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}
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found := false
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for _, succ := range ifstmt.Block().Succs {
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if len(succ.Preds) != 1 {
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// Merge point, not a branch in the
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// syntactical sense.
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// FIXME(dh): this is broken for if
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// statements a la "if x || y"
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continue
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}
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irutil.Walk(succ, func(b *ir.BasicBlock) bool {
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if !succ.Dominates(b) {
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// We've reached the end of the branch
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return false
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}
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for _, ins := range b.Instrs {
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// TODO(dh): we should check that we're receiving from the
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// channel of a time.Timer to further reduce false
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// positives. Not a key priority, considering the rarity
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// of Reset and the tiny likeliness of a false positive
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//
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// We intentionally don't handle aliases here, because
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// we're only interested in time.Timer.C.
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if ins, ok := ins.(*ir.Recv); ok && types.TypeString(ins.Chan.Type(), nil) == "<-chan time.Time" {
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found = true
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return false
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}
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}
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return true
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})
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}
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if found {
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report.Report(pass, call, "it is not possible to use Reset's return value correctly, as there is a race condition between draining the channel and the new timer expiring")
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}
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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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