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