s1035.go raw

   1  package s1035
   2  
   3  import (
   4  	"fmt"
   5  	"go/ast"
   6  
   7  	"honnef.co/go/tools/analysis/code"
   8  	"honnef.co/go/tools/analysis/edit"
   9  	"honnef.co/go/tools/analysis/facts/generated"
  10  	"honnef.co/go/tools/analysis/lint"
  11  	"honnef.co/go/tools/analysis/report"
  12  
  13  	"golang.org/x/tools/go/analysis"
  14  	"golang.org/x/tools/go/analysis/passes/inspect"
  15  )
  16  
  17  var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
  18  	Analyzer: &analysis.Analyzer{
  19  		Name:     "S1035",
  20  		Run:      run,
  21  		Requires: []*analysis.Analyzer{inspect.Analyzer, generated.Analyzer},
  22  	},
  23  	Doc: &lint.RawDocumentation{
  24  		Title: `Redundant call to \'net/http.CanonicalHeaderKey\' in method call on \'net/http.Header\'`,
  25  		Text: `
  26  The methods on \'net/http.Header\', namely \'Add\', \'Del\', \'Get\'
  27  and \'Set\', already canonicalize the given header name.`,
  28  		Since:   "2020.1",
  29  		MergeIf: lint.MergeIfAny,
  30  	},
  31  })
  32  
  33  var Analyzer = SCAnalyzer.Analyzer
  34  
  35  func run(pass *analysis.Pass) (interface{}, error) {
  36  	fn := func(node ast.Node) {
  37  		call := node.(*ast.CallExpr)
  38  		callName := code.CallName(pass, call)
  39  		switch callName {
  40  		case "(net/http.Header).Add", "(net/http.Header).Del", "(net/http.Header).Get", "(net/http.Header).Set":
  41  		default:
  42  			return
  43  		}
  44  
  45  		if !code.IsCallTo(pass, call.Args[0], "net/http.CanonicalHeaderKey") {
  46  			return
  47  		}
  48  
  49  		report.Report(pass, call,
  50  			fmt.Sprintf("calling net/http.CanonicalHeaderKey on the 'key' argument of %s is redundant", callName),
  51  			report.FilterGenerated(),
  52  			report.Fixes(edit.Fix("remove call to CanonicalHeaderKey", edit.ReplaceWithNode(pass.Fset, call.Args[0], call.Args[0].(*ast.CallExpr).Args[0]))))
  53  	}
  54  	code.Preorder(pass, fn, (*ast.CallExpr)(nil))
  55  	return nil, nil
  56  }
  57