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- package rule
-
- import (
- "go/ast"
- "go/token"
- "strconv"
- "unicode"
- "unicode/utf8"
-
- "github.com/mgechev/revive/lint"
- )
-
- // ErrorStringsRule lints given else constructs.
- type ErrorStringsRule struct{}
-
- // Apply applies the rule to given file.
- func (r *ErrorStringsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
- var failures []lint.Failure
-
- fileAst := file.AST
- walker := lintErrorStrings{
- file: file,
- fileAst: fileAst,
- onFailure: func(failure lint.Failure) {
- failures = append(failures, failure)
- },
- }
-
- ast.Walk(walker, fileAst)
-
- return failures
- }
-
- // Name returns the rule name.
- func (r *ErrorStringsRule) Name() string {
- return "error-strings"
- }
-
- type lintErrorStrings struct {
- file *lint.File
- fileAst *ast.File
- onFailure func(lint.Failure)
- }
-
- func (w lintErrorStrings) Visit(n ast.Node) ast.Visitor {
- ce, ok := n.(*ast.CallExpr)
- if !ok {
- return w
- }
- if !isPkgDot(ce.Fun, "errors", "New") && !isPkgDot(ce.Fun, "fmt", "Errorf") {
- return w
- }
- if len(ce.Args) < 1 {
- return w
- }
- str, ok := ce.Args[0].(*ast.BasicLit)
- if !ok || str.Kind != token.STRING {
- return w
- }
- s, _ := strconv.Unquote(str.Value) // can assume well-formed Go
- if s == "" {
- return w
- }
- clean, conf := lintErrorString(s)
- if clean {
- return w
- }
-
- w.onFailure(lint.Failure{
- Node: str,
- Confidence: conf,
- Category: "errors",
- Failure: "error strings should not be capitalized or end with punctuation or a newline",
- })
- return w
- }
-
- func lintErrorString(s string) (isClean bool, conf float64) {
- const basicConfidence = 0.8
- const capConfidence = basicConfidence - 0.2
- first, firstN := utf8.DecodeRuneInString(s)
- last, _ := utf8.DecodeLastRuneInString(s)
- if last == '.' || last == ':' || last == '!' || last == '\n' {
- return false, basicConfidence
- }
- if unicode.IsUpper(first) {
- // People use proper nouns and exported Go identifiers in error strings,
- // so decrease the confidence of warnings for capitalization.
- if len(s) <= firstN {
- return false, capConfidence
- }
- // Flag strings starting with something that doesn't look like an initialism.
- if second, _ := utf8.DecodeRuneInString(s[firstN:]); !unicode.IsUpper(second) {
- return false, capConfidence
- }
- }
- return true, 0
- }
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