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|
package rule
import (
"fmt"
"go/ast"
"go/token"
"strings"
"github.com/mgechev/revive/lint"
)
// PackageCommentsRule lints the package comments. It complains if
// there is no package comment, or if it is not of the right form.
// This has a notable false positive in that a package comment
// could rightfully appear in a different file of the same package,
// but that's not easy to fix since this linter is file-oriented.
type PackageCommentsRule struct{}
// Apply applies the rule to given file.
func (r *PackageCommentsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
var failures []lint.Failure
if isTest(file) {
return failures
}
onFailure := func(failure lint.Failure) {
failures = append(failures, failure)
}
fileAst := file.AST
w := &lintPackageComments{fileAst, file, onFailure}
ast.Walk(w, fileAst)
return failures
}
// Name returns the rule name.
func (r *PackageCommentsRule) Name() string {
return "package-comments"
}
type lintPackageComments struct {
fileAst *ast.File
file *lint.File
onFailure func(lint.Failure)
}
func (l *lintPackageComments) Visit(_ ast.Node) ast.Visitor {
if l.file.IsTest() {
return nil
}
const ref = styleGuideBase + "#package-comments"
prefix := "Package " + l.fileAst.Name.Name + " "
// Look for a detached package comment.
// First, scan for the last comment that occurs before the "package" keyword.
var lastCG *ast.CommentGroup
for _, cg := range l.fileAst.Comments {
if cg.Pos() > l.fileAst.Package {
// Gone past "package" keyword.
break
}
lastCG = cg
}
if lastCG != nil && strings.HasPrefix(lastCG.Text(), prefix) {
endPos := l.file.ToPosition(lastCG.End())
pkgPos := l.file.ToPosition(l.fileAst.Package)
if endPos.Line+1 < pkgPos.Line {
// There isn't a great place to anchor this error;
// the start of the blank lines between the doc and the package statement
// is at least pointing at the location of the problem.
pos := token.Position{
Filename: endPos.Filename,
// Offset not set; it is non-trivial, and doesn't appear to be needed.
Line: endPos.Line + 1,
Column: 1,
}
l.onFailure(lint.Failure{
Category: "comments",
Position: lint.FailurePosition{
Start: pos,
End: pos,
},
Confidence: 0.9,
Failure: "package comment is detached; there should be no blank lines between it and the package statement",
})
return nil
}
}
if l.fileAst.Doc == nil {
l.onFailure(lint.Failure{
Category: "comments",
Node: l.fileAst,
Confidence: 0.2,
Failure: "should have a package comment, unless it's in another file for this package",
})
return nil
}
s := l.fileAst.Doc.Text()
if ts := strings.TrimLeft(s, " \t"); ts != s {
l.onFailure(lint.Failure{
Category: "comments",
Node: l.fileAst.Doc,
Confidence: 1,
Failure: "package comment should not have leading space",
})
s = ts
}
// Only non-main packages need to keep to this form.
if !l.file.Pkg.IsMain() && !strings.HasPrefix(s, prefix) {
l.onFailure(lint.Failure{
Category: "comments",
Node: l.fileAst.Doc,
Confidence: 1,
Failure: fmt.Sprintf(`package comment should be of the form "%s..."`, prefix),
})
}
return nil
}
|
