78 lines
1.8 KiB
Go
78 lines
1.8 KiB
Go
package rule
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import (
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"fmt"
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"go/ast"
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"github.com/mgechev/revive/lint"
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)
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// UnusedReceiverRule lints unused params in functions.
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type UnusedReceiverRule struct{}
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// Apply applies the rule to given file.
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func (*UnusedReceiverRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
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var failures []lint.Failure
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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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w := lintUnusedReceiverRule{onFailure: onFailure}
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ast.Walk(w, file.AST)
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return failures
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}
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// Name returns the rule name.
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func (*UnusedReceiverRule) Name() string {
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return "unused-receiver"
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}
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type lintUnusedReceiverRule struct {
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onFailure func(lint.Failure)
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}
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func (w lintUnusedReceiverRule) Visit(node ast.Node) ast.Visitor {
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switch n := node.(type) {
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case *ast.FuncDecl:
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if n.Recv == nil {
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return nil // skip this func decl, not a method
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}
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rec := n.Recv.List[0] // safe to access only the first (unique) element of the list
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if len(rec.Names) < 1 {
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return nil // the receiver is anonymous: func (aType) Foo(...) ...
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}
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recID := rec.Names[0]
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if recID.Name == "_" {
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return nil // the receiver is already named _
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}
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// inspect the func body looking for references to the receiver id
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fselect := func(n ast.Node) bool {
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ident, isAnID := n.(*ast.Ident)
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return isAnID && ident.Obj == recID.Obj
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}
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refs2recID := pick(n.Body, fselect, nil)
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if len(refs2recID) > 0 {
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return nil // the receiver is referenced in the func body
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}
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w.onFailure(lint.Failure{
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Confidence: 1,
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Node: recID,
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Category: "bad practice",
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Failure: fmt.Sprintf("method receiver '%s' is not referenced in method's body, consider removing or renaming it as _", recID.Name),
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})
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return nil // full method body already inspected
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}
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return w
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}
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