s1037.go raw

   1  package s1037
   2  
   3  import (
   4  	"go/ast"
   5  
   6  	"honnef.co/go/tools/analysis/code"
   7  	"honnef.co/go/tools/analysis/edit"
   8  	"honnef.co/go/tools/analysis/facts/generated"
   9  	"honnef.co/go/tools/analysis/lint"
  10  	"honnef.co/go/tools/analysis/report"
  11  	"honnef.co/go/tools/pattern"
  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:     "S1037",
  20  		Run:      run,
  21  		Requires: []*analysis.Analyzer{inspect.Analyzer, generated.Analyzer},
  22  	},
  23  	Doc: &lint.RawDocumentation{
  24  		Title: `Elaborate way of sleeping`,
  25  		Text: `Using a select statement with a single case receiving
  26  from the result of \'time.After\' is a very elaborate way of sleeping that
  27  can much simpler be expressed with a simple call to time.Sleep.`,
  28  		Since:   "2020.1",
  29  		MergeIf: lint.MergeIfAny,
  30  	},
  31  })
  32  
  33  var Analyzer = SCAnalyzer.Analyzer
  34  
  35  var (
  36  	checkElaborateSleepQ = pattern.MustParse(`(SelectStmt (CommClause (UnaryExpr "<-" (CallExpr (Symbol "time.After") [arg])) body))`)
  37  	checkElaborateSleepR = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "time") (Ident "Sleep")) [arg])`)
  38  )
  39  
  40  func run(pass *analysis.Pass) (interface{}, error) {
  41  	fn := func(node ast.Node) {
  42  		if m, ok := code.Match(pass, checkElaborateSleepQ, node); ok {
  43  			if body, ok := m.State["body"].([]ast.Stmt); ok && len(body) == 0 {
  44  				report.Report(pass, node, "should use time.Sleep instead of elaborate way of sleeping",
  45  					report.ShortRange(),
  46  					report.FilterGenerated(),
  47  					report.Fixes(edit.Fix("Use time.Sleep", edit.ReplaceWithPattern(pass.Fset, node, checkElaborateSleepR, m.State))))
  48  			} else {
  49  				// TODO(dh): we could make a suggested fix if the body
  50  				// doesn't declare or shadow any identifiers
  51  				report.Report(pass, node, "should use time.Sleep instead of elaborate way of sleeping",
  52  					report.ShortRange(),
  53  					report.FilterGenerated())
  54  			}
  55  		}
  56  	}
  57  	code.Preorder(pass, fn, (*ast.SelectStmt)(nil))
  58  	return nil, nil
  59  }
  60