github.com/amarpal/go-tools@v0.0.0-20240422043104-40142f59f616/stylecheck/st1017/st1017.go (about)

     1  package st1017
     2  
     3  import (
     4  	"go/ast"
     5  
     6  	"github.com/amarpal/go-tools/analysis/code"
     7  	"github.com/amarpal/go-tools/analysis/edit"
     8  	"github.com/amarpal/go-tools/analysis/facts/generated"
     9  	"github.com/amarpal/go-tools/analysis/lint"
    10  	"github.com/amarpal/go-tools/analysis/report"
    11  	"github.com/amarpal/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:     "ST1017",
    20  		Run:      run,
    21  		Requires: []*analysis.Analyzer{inspect.Analyzer, generated.Analyzer},
    22  	},
    23  	Doc: &lint.Documentation{
    24  		Title: `Don't use Yoda conditions`,
    25  		Text: `Yoda conditions are conditions of the kind \"if 42 == x\", where the
    26  literal is on the left side of the comparison. These are a common
    27  idiom in languages in which assignment is an expression, to avoid bugs
    28  of the kind \"if (x = 42)\". In Go, which doesn't allow for this kind of
    29  bug, we prefer the more idiomatic \"if x == 42\".`,
    30  		Since:   "2019.2",
    31  		MergeIf: lint.MergeIfAny,
    32  	},
    33  })
    34  
    35  var Analyzer = SCAnalyzer.Analyzer
    36  
    37  var (
    38  	checkYodaConditionsQ = pattern.MustParse(`(BinaryExpr left@(TrulyConstantExpression _) tok@(Or "==" "!=") right@(Not (TrulyConstantExpression _)))`)
    39  	checkYodaConditionsR = pattern.MustParse(`(BinaryExpr right tok left)`)
    40  )
    41  
    42  func run(pass *analysis.Pass) (interface{}, error) {
    43  	fn := func(node ast.Node) {
    44  		if _, edits, ok := code.MatchAndEdit(pass, checkYodaConditionsQ, checkYodaConditionsR, node); ok {
    45  			report.Report(pass, node, "don't use Yoda conditions",
    46  				report.FilterGenerated(),
    47  				report.Fixes(edit.Fix("un-Yoda-fy", edits...)))
    48  		}
    49  	}
    50  	code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
    51  	return nil, nil
    52  }