src

Go monorepo.
git clone git://code.dwrz.net/src
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sa5004.go (1363B)

      1 package sa5004
      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/lint"
      9 	"honnef.co/go/tools/analysis/report"
     10 	"honnef.co/go/tools/pattern"
     11 
     12 	"golang.org/x/tools/go/analysis"
     13 )
     14 
     15 var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
     16 	Analyzer: &analysis.Analyzer{
     17 		Name:     "SA5004",
     18 		Run:      run,
     19 		Requires: code.RequiredAnalyzers,
     20 	},
     21 	Doc: &lint.RawDocumentation{
     22 		Title:    `\"for { select { ...\" with an empty default branch spins`,
     23 		Since:    "2017.1",
     24 		Severity: lint.SeverityWarning,
     25 		MergeIf:  lint.MergeIfAny,
     26 	},
     27 })
     28 
     29 var Analyzer = SCAnalyzer.Analyzer
     30 
     31 var query = pattern.MustParse(`(ForStmt nil nil nil (SelectStmt body))`)
     32 
     33 func run(pass *analysis.Pass) (any, error) {
     34 	for _, m := range code.Matches(pass, query) {
     35 		for _, c := range m.State["body"].([]ast.Stmt) {
     36 			// FIXME this leaves behind an empty line, and possibly
     37 			// comments in the default branch. We can't easily fix
     38 			// either.
     39 			if comm, ok := c.(*ast.CommClause); ok && comm.Comm == nil && len(comm.Body) == 0 {
     40 				report.Report(pass, comm,
     41 					"should not have an empty default case in a for+select loop; the loop will spin",
     42 					report.Fixes(edit.Fix("Remove empty default branch", edit.Delete(comm))))
     43 				// there can only be one default case
     44 				break
     45 			}
     46 		}
     47 	}
     48 	return nil, nil
     49 }