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revive/rule/import-shadowing.go
SalvadorC 2ce440cf96 new rule: import shadowing (#114)
* Adds rule superfluous-else (an extension of indent-error-flow)

* Fix superfluous-else rule struct namming.

* Adds superfuous-else rule to the rules table

* Adds confusing-naming rule

* adds multifile test

* clean-up

* fix config.go

* clean master

* new ADS rule: newerr

* ADS-print working version

* ads-print final version

* ads-lost-err working version

* fix ads-print

* removes ads rules from master

* new rule: import-shadowing

* removes ads rules from master

* new rule: import-shadowing

* fix defaults

* adds explanations on the rule implementation
2019-03-27 11:46:20 -07:00

103 lines
2.7 KiB
Go

package rule
import (
"fmt"
"go/ast"
"go/token"
"strings"
"github.com/mgechev/revive/lint"
)
// ImportShadowingRule lints given else constructs.
type ImportShadowingRule struct{}
// Apply applies the rule to given file.
func (r *ImportShadowingRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
var failures []lint.Failure
importNames := map[string]struct{}{}
for _, imp := range file.AST.Imports {
importNames[getName(imp)] = struct{}{}
}
fileAst := file.AST
walker := importShadowing{
importNames: importNames,
onFailure: func(failure lint.Failure) {
failures = append(failures, failure)
},
alreadySeen: map[*ast.Object]struct{}{},
}
ast.Walk(walker, fileAst)
return failures
}
// Name returns the rule name.
func (r *ImportShadowingRule) Name() string {
return "import-shadowing"
}
func getName(imp *ast.ImportSpec) string {
const pathSep = "/"
const strDelim = `"`
if imp.Name != nil {
return imp.Name.Name
}
path := imp.Path.Value
i := strings.LastIndex(path, pathSep)
if i == -1 {
return strings.Trim(path, strDelim)
}
return strings.Trim(path[i+1:], strDelim)
}
type importShadowing struct {
importNames map[string]struct{}
onFailure func(lint.Failure)
alreadySeen map[*ast.Object]struct{}
}
// Visit visits AST nodes and checks if id nodes (ast.Ident) shadow an import name
func (w importShadowing) Visit(n ast.Node) ast.Visitor {
switch n := n.(type) {
case *ast.AssignStmt:
if n.Tok == token.DEFINE {
return w // analyze variable declarations of the form id := expr
}
return nil // skip assigns of the form id = expr (not an id declaration)
case *ast.CallExpr, // skip call expressions (not an id declaration)
*ast.ImportSpec, // skip import section subtree because we already have the list of imports
*ast.KeyValueExpr, // skip analysis of key-val expressions ({key:value}): ids of such expressions, even the same of an import name, do not shadow the import name
*ast.ReturnStmt, // skip skipping analysis of returns, ids in expression were already analyzed
*ast.SelectorExpr, // skip analysis of selector expressions (anId.otherId): because if anId shadows an import name, it was already detected, and otherId does not shadows the import name
*ast.StructType: // skip analysis of struct type because struct fields can not shadow an import name
return nil
case *ast.Ident:
id := n.Name
if id == "_" {
return w // skip _ id
}
_, isImportName := w.importNames[id]
_, alreadySeen := w.alreadySeen[n.Obj]
if isImportName && !alreadySeen {
w.onFailure(lint.Failure{
Confidence: 1,
Node: n,
Category: "namming",
Failure: fmt.Sprintf("The name '%s' shadows an import name", id),
})
w.alreadySeen[n.Obj] = struct{}{}
}
}
return w
}