58 lines
1.7 KiB
Go
58 lines
1.7 KiB
Go
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package sa4027
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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/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: "SA4027",
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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: `\'(*net/url.URL).Query\' returns a copy, modifying it doesn't change the URL`,
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Text: `\'(*net/url.URL).Query\' parses the current value of \'net/url.URL.RawQuery\'
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and returns it as a map of type \'net/url.Values\'. Subsequent changes to
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this map will not affect the URL unless the map gets encoded and
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assigned to the URL's \'RawQuery\'.
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As a consequence, the following code pattern is an expensive no-op:
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\'u.Query().Add(key, value)\'.`,
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Since: "2021.1",
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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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var ineffectiveURLQueryAddQ = pattern.MustParse(`(CallExpr (SelectorExpr (CallExpr (SelectorExpr recv (Ident "Query")) []) (Ident meth)) _)`)
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func run(pass *analysis.Pass) (any, error) {
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// TODO(dh): We could make this check more complex and detect
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// pointless modifications of net/url.Values in general, but that
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// requires us to get the state machine correct, else we'll cause
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// false positives.
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for node, m := range code.Matches(pass, ineffectiveURLQueryAddQ) {
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if !code.IsOfPointerToTypeWithName(pass, m.State["recv"].(ast.Expr), "net/url.URL") {
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continue
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}
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switch m.State["meth"].(string) {
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case "Add", "Del", "Set":
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default:
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continue
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}
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report.Report(pass, node, "(*net/url.URL).Query returns a copy, modifying it doesn't change the URL")
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}
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return nil, nil
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}
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