refactor: moves code related to AST from rule.utils into astutils package

internal/astutils/ast_utils.go

@@ -2,8 +2,12 @@
 package astutils
 
 import (
+	"bytes"
+	"fmt"
 	"go/ast"
+	"go/printer"
 	"go/token"
+	"regexp"
 	"slices"
 )
 
@@ -78,9 +82,80 @@ func getFieldTypeName(typ ast.Expr) string {
 	}
 }
 
-// IsStringLiteral returns true if the given expression is a string literal, false otherwise
+// IsStringLiteral returns true if the given expression is a string literal, false otherwise.
 func IsStringLiteral(e ast.Expr) bool {
 	sl, ok := e.(*ast.BasicLit)
 
 	return ok && sl.Kind == token.STRING
 }
+
+// IsCgoExported returns true if the given function declaration is exported as Cgo function, false otherwise.
+func IsCgoExported(f *ast.FuncDecl) bool {
+	if f.Recv != nil || f.Doc == nil {
+		return false
+	}
+
+	cgoExport := regexp.MustCompile(fmt.Sprintf("(?m)^//export %s$", regexp.QuoteMeta(f.Name.Name)))
+	for _, c := range f.Doc.List {
+		if cgoExport.MatchString(c.Text) {
+			return true
+		}
+	}
+	return false
+}
+
+// IsIdent returns true if the given expression is the identifier with name ident, false otherwise.
+func IsIdent(expr ast.Expr, ident string) bool {
+	id, ok := expr.(*ast.Ident)
+	return ok && id.Name == ident
+}
+
+// IsPkgDotName returns true if the given expression is a selector expression of the form <pkg>.<name>, false otherwise.
+func IsPkgDotName(expr ast.Expr, pkg, name string) bool {
+	sel, ok := expr.(*ast.SelectorExpr)
+	return ok && IsIdent(sel.X, pkg) && IsIdent(sel.Sel, name)
+}
+
+// PickNodes yields a list of nodes by picking them from a sub-ast with root node n.
+// Nodes are selected by applying the selector function
+func PickNodes(n ast.Node, selector func(n ast.Node) bool) []ast.Node {
+	var result []ast.Node
+
+	if n == nil {
+		return result
+	}
+
+	onSelect := func(n ast.Node) {
+		result = append(result, n)
+	}
+	p := picker{selector: selector, onSelect: onSelect}
+	ast.Walk(p, n)
+	return result
+}
+
+type picker struct {
+	selector func(n ast.Node) bool
+	onSelect func(n ast.Node)
+}
+
+func (p picker) Visit(node ast.Node) ast.Visitor {
+	if p.selector == nil {
+		return nil
+	}
+
+	if p.selector(node) {
+		p.onSelect(node)
+	}
+
+	return p
+}
+
+var gofmtConfig = &printer.Config{Tabwidth: 8}
+
+// GoFmt returns a string representation of an AST subtree.
+func GoFmt(x any) string {
+	buf := bytes.Buffer{}
+	fs := token.NewFileSet()
+	gofmtConfig.Fprint(&buf, fs, x)
+	return buf.String()
+}

rule/atomic.go

@@ -5,6 +5,7 @@ import (
 	"go/token"
 	"go/types"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -76,9 +77,9 @@ func (w atomic) Visit(node ast.Node) ast.Visitor {
 			broken := false
 
 			if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
-				broken = gofmt(left) == gofmt(uarg.X)
+				broken = astutils.GoFmt(left) == astutils.GoFmt(uarg.X)
 			} else if star, ok := left.(*ast.StarExpr); ok {
-				broken = gofmt(star.X) == gofmt(arg)
+				broken = astutils.GoFmt(star.X) == astutils.GoFmt(arg)
 			}
 
 			if broken {

rule/confusing_naming.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -190,7 +191,7 @@ func (w *lintConfusingNames) Visit(n ast.Node) ast.Visitor {
 		// Exclude naming warnings for functions that are exported to C but
 		// not exported in the Go API.
 		// See https://github.com/golang/lint/issues/144.
-		if ast.IsExported(v.Name.Name) || !isCgoExported(v) {
+		if ast.IsExported(v.Name.Name) || !astutils.IsCgoExported(v) {
 			checkMethodName(getStructName(v.Recv), v.Name, w)
 		}
 	case *ast.TypeSpec:

rule/confusing_results.go

@@ -3,6 +3,7 @@ package rule
 import (
 	"go/ast"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -28,7 +29,7 @@ func (*ConfusingResultsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Fai
 
 		lastType := ""
 		for _, result := range funcDecl.Type.Results.List {
-			resultTypeName := gofmt(result.Type)
+			resultTypeName := astutils.GoFmt(result.Type)
 
 			if resultTypeName == lastType {
 				failures = append(failures, lint.Failure{

rule/constant_logical_expr.go

@@ -4,6 +4,7 @@ import (
 	"go/ast"
 	"go/token"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -40,7 +41,7 @@ func (w *lintConstantLogicalExpr) Visit(node ast.Node) ast.Visitor {
 			return w
 		}
 
-		subExpressionsAreNotEqual := gofmt(n.X) != gofmt(n.Y)
+		subExpressionsAreNotEqual := astutils.GoFmt(n.X) != astutils.GoFmt(n.Y)
 		if subExpressionsAreNotEqual {
 			return w // nothing to say
 		}

rule/context_as_argument.go

@@ -5,6 +5,7 @@ import (
 	"go/ast"
 	"strings"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -28,7 +29,7 @@ func (r *ContextAsArgumentRule) Apply(file *lint.File, _ lint.Arguments) []lint.
 		// Flag any that show up after the first.
 		isCtxStillAllowed := true
 		for _, arg := range fnArgs {
-			argIsCtx := isPkgDot(arg.Type, "context", "Context")
+			argIsCtx := astutils.IsPkgDotName(arg.Type, "context", "Context")
 			if argIsCtx && !isCtxStillAllowed {
 				failures = append(failures, lint.Failure{
 					Node:       arg,
@@ -40,7 +41,7 @@ func (r *ContextAsArgumentRule) Apply(file *lint.File, _ lint.Arguments) []lint.
 				break // only flag one
 			}
 
-			typeName := gofmt(arg.Type)
+			typeName := astutils.GoFmt(arg.Type)
 			// a parameter of type context.Context is still allowed if the current arg type is in the allow types LookUpTable
 			_, isCtxStillAllowed = r.allowTypes[typeName]
 		}

rule/context_keys_type.go

@@ -5,6 +5,7 @@ import (
 	"go/ast"
 	"go/types"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -51,15 +52,7 @@ func (w lintContextKeyTypes) Visit(n ast.Node) ast.Visitor {
 
 func checkContextKeyType(w lintContextKeyTypes, x *ast.CallExpr) {
 	f := w.file
-	sel, ok := x.Fun.(*ast.SelectorExpr)
-	if !ok {
-		return
-	}
-	pkg, ok := sel.X.(*ast.Ident)
-	if !ok || pkg.Name != "context" {
-		return
-	}
-	if sel.Sel.Name != "WithValue" {
+	if !astutils.IsPkgDotName(x.Fun, "context", "WithValue") {
 		return
 	}
 

rule/datarace.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -111,7 +112,7 @@ func (w lintFunctionForDataRaces) Visit(node ast.Node) ast.Visitor {
 			return ok
 		}
 
-		ids := pick(funcLit.Body, selectIDs)
+		ids := astutils.PickNodes(funcLit.Body, selectIDs)
 		for _, id := range ids {
 			id := id.(*ast.Ident)
 			_, isRangeID := w.rangeIDs[id.Obj]

rule/defer.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -106,7 +107,7 @@ func (w lintDeferRule) Visit(node ast.Node) ast.Visitor {
 			w.newFailure("return in a defer function has no effect", n, 1.0, lint.FailureCategoryLogic, deferOptionReturn)
 		}
 	case *ast.CallExpr:
-		isCallToRecover := isIdent(n.Fun, "recover")
+		isCallToRecover := astutils.IsIdent(n.Fun, "recover")
 		switch {
 		case !w.inADefer && isCallToRecover:
 			// func fn() { recover() }
@@ -122,7 +123,7 @@ func (w lintDeferRule) Visit(node ast.Node) ast.Visitor {
 		}
 		return nil // no need to analyze the arguments of the function call
 	case *ast.DeferStmt:
-		if isIdent(n.Call.Fun, "recover") {
+		if astutils.IsIdent(n.Call.Fun, "recover") {
 			// defer recover()
 			//
 			// confidence is not truly 1 because this could be in a correctly-deferred func,

rule/enforce_map_style.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -101,8 +102,7 @@ func (r *EnforceMapStyleRule) Apply(file *lint.File, _ lint.Arguments) []lint.Fa
 				return true
 			}
 
-			ident, ok := v.Fun.(*ast.Ident)
-			if !ok || ident.Name != "make" {
+			if !astutils.IsIdent(v.Fun, "make") {
 				return true
 			}
 

rule/enforce_repeated_arg_type_style.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -130,8 +131,8 @@ func (r *EnforceRepeatedArgTypeStyleRule) Apply(file *lint.File, _ lint.Argument
 				if fn.Type.Params != nil {
 					var prevType ast.Expr
 					for _, field := range fn.Type.Params.List {
-						prevTypeStr := gofmt(prevType)
-						currentTypeStr := gofmt(field.Type)
+						prevTypeStr := astutils.GoFmt(prevType)
+						currentTypeStr := astutils.GoFmt(field.Type)
 						if currentTypeStr == prevTypeStr {
 							failures = append(failures, lint.Failure{
 								Confidence: 1,
@@ -163,8 +164,8 @@ func (r *EnforceRepeatedArgTypeStyleRule) Apply(file *lint.File, _ lint.Argument
 				if fn.Type.Results != nil {
 					var prevType ast.Expr
 					for _, field := range fn.Type.Results.List {
-						prevTypeStr := gofmt(prevType)
-						currentTypeStr := gofmt(field.Type)
+						prevTypeStr := astutils.GoFmt(prevType)
+						currentTypeStr := astutils.GoFmt(field.Type)
 						if field.Names != nil && currentTypeStr == prevTypeStr {
 							failures = append(failures, lint.Failure{
 								Confidence: 1,

rule/enforce_slice_style.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -117,8 +118,7 @@ func (r *EnforceSliceStyleRule) Apply(file *lint.File, _ lint.Arguments) []lint.
 				return true
 			}
 
-			ident, ok := v.Fun.(*ast.Ident)
-			if !ok || ident.Name != "make" {
+			if !astutils.IsIdent(v.Fun, "make") {
 				return true
 			}
 

rule/error_naming.go

@@ -6,6 +6,7 @@ import (
 	"go/token"
 	"strings"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -56,7 +57,7 @@ func (w lintErrors) Visit(_ ast.Node) ast.Visitor {
 			if !ok {
 				continue
 			}
-			if !isPkgDot(ce.Fun, "errors", "New") && !isPkgDot(ce.Fun, "fmt", "Errorf") {
+			if !astutils.IsPkgDotName(ce.Fun, "errors", "New") && !astutils.IsPkgDotName(ce.Fun, "fmt", "Errorf") {
 				continue
 			}
 

rule/error_return.go

@@ -3,6 +3,7 @@ package rule
 import (
 	"go/ast"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -21,15 +22,15 @@ func (*ErrorReturnRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure
 		}
 
 		funcResults := funcDecl.Type.Results.List
-		isLastResultError := isIdent(funcResults[len(funcResults)-1].Type, "error")
+		isLastResultError := astutils.IsIdent(funcResults[len(funcResults)-1].Type, "error")
 		if isLastResultError {
 			continue
 		}
 
 		// An error return parameter should be the last parameter.
 		// Flag any error parameters found before the last.
 		for _, r := range funcResults[:len(funcResults)-1] {
-			if isIdent(r.Type, "error") {
+			if astutils.IsIdent(r.Type, "error") {
 				failures = append(failures, lint.Failure{
 					Category:   lint.FailureCategoryStyle,
 					Confidence: 0.9,

rule/errorf.go

@@ -6,6 +6,7 @@ import (
 	"regexp"
 	"strings"
 
+	"github.com/mgechev/revive/internal/astutils"
 	"github.com/mgechev/revive/lint"
 )
 
@@ -47,7 +48,7 @@ func (w lintErrorf) Visit(n ast.Node) ast.Visitor {
 	if !ok || len(ce.Args) != 1 {
 		return w
 	}
-	isErrorsNew := isPkgDot(ce.Fun, "errors", "New")
+	isErrorsNew := astutils.IsPkgDotName(ce.Fun, "errors", "New")
 	var isTestingError bool
 	se, ok := ce.Fun.(*ast.SelectorExpr)
 	if ok && se.Sel.Name == "Error" {
@@ -60,7 +61,7 @@ func (w lintErrorf) Visit(n ast.Node) ast.Visitor {
 	}
 	arg := ce.Args[0]
 	ce, ok = arg.(*ast.CallExpr)
-	if !ok || !isPkgDot(ce.Fun, "fmt", "Sprintf") {
+	if !ok || !astutils.IsPkgDotName(ce.Fun, "fmt", "Sprintf") {
 		return w
 	}
 	errorfPrefix := "fmt"