s1024.go raw

   1  package s1024
   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:     "S1024",
  20  		Run:      run,
  21  		Requires: []*analysis.Analyzer{inspect.Analyzer, generated.Analyzer},
  22  	},
  23  	Doc: &lint.RawDocumentation{
  24  		Title: `Replace \'x.Sub(time.Now())\' with \'time.Until(x)\'`,
  25  		Text: `The \'time.Until\' helper has the same effect as using \'x.Sub(time.Now())\'
  26  but is easier to read.`,
  27  		Before:  `x.Sub(time.Now())`,
  28  		After:   `time.Until(x)`,
  29  		Since:   "2017.1",
  30  		MergeIf: lint.MergeIfAny,
  31  	},
  32  })
  33  
  34  var Analyzer = SCAnalyzer.Analyzer
  35  
  36  var (
  37  	checkTimeUntilQ = pattern.MustParse(`(CallExpr (Symbol "(time.Time).Sub") [(CallExpr (Symbol "time.Now") [])])`)
  38  	checkTimeUntilR = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "time") (Ident "Until")) [arg])`)
  39  )
  40  
  41  func run(pass *analysis.Pass) (interface{}, error) {
  42  	fn := func(node ast.Node) {
  43  		if _, ok := code.Match(pass, checkTimeUntilQ, node); ok {
  44  			if sel, ok := node.(*ast.CallExpr).Fun.(*ast.SelectorExpr); ok {
  45  				r := pattern.NodeToAST(checkTimeUntilR.Root, map[string]interface{}{"arg": sel.X}).(ast.Node)
  46  				report.Report(pass, node, "should use time.Until instead of t.Sub(time.Now())",
  47  					report.FilterGenerated(),
  48  					report.MinimumStdlibVersion("go1.8"),
  49  					report.Fixes(edit.Fix("replace with call to time.Until", edit.ReplaceWithNode(pass.Fset, node, r))))
  50  			} else {
  51  				report.Report(pass, node, "should use time.Until instead of t.Sub(time.Now())",
  52  					report.MinimumStdlibVersion("go1.8"),
  53  					report.FilterGenerated())
  54  			}
  55  		}
  56  	}
  57  	code.Preorder(pass, fn, (*ast.CallExpr)(nil))
  58  	return nil, nil
  59  }
  60