feat: add enter and leave checks for traversers

- Improved performance (can short circuit/not continue when done)
- Backwards compatible because added interfaces
- Now generating the implementation for easier updates

go.mod

@@ -11,4 +11,5 @@ require (
 require (
 	github.com/google/go-cmp v0.4.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
+	golang.org/x/tools v0.7.0
 )

go.sum

@@ -6,6 +6,46 @@ github.com/pkg/profile v1.4.0 h1:uCmaf4vVbWAOZz36k1hrQD7ijGRzLwaME8Am/7a4jZI=
 github.com/pkg/profile v1.4.0/go.mod h1:NWz/XGvpEW1FyYQ7fCx4dqYBLlfTcE+A9FLAkNKqjFE=
 github.com/yookoala/realpath v1.0.0 h1:7OA9pj4FZd+oZDsyvXWQvjn5oBdcHRTV44PpdMSuImQ=
 github.com/yookoala/realpath v1.0.0/go.mod h1:gJJMA9wuX7AcqLy1+ffPatSCySA1FQ2S8Ya9AIoYBpE=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.9.0 h1:KENHtAZL2y3NLMYZeHY9DW8HW8V+kQyJsY/V9JlKvCs=
+golang.org/x/mod v0.9.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
+golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
+golang.org/x/tools v0.7.0 h1:W4OVu8VVOaIO0yzWMNdepAulS7YfoS3Zabrm8DOXXU4=
+golang.org/x/tools v0.7.0/go.mod h1:4pg6aUX35JBAogB10C9AtvVL+qowtN4pT3CGSQex14s=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gotest.tools v2.2.0+incompatible h1:VsBPFP1AI068pPrMxtb/S8Zkgf9xEmTLJjfM+P5UIEo=

pkg/visitor/traverser/traverser_gen.go

@@ -0,0 +1,173 @@
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"log"
+	"os"
+	"path/filepath"
+	"text/template"
+
+	phpast "github.com/VKCOM/php-parser/pkg/ast"
+	"golang.org/x/tools/go/packages"
+)
+
+type nodeType struct {
+	// The type name.
+	Name string
+	// The function name.
+	FuncName string
+	// Map of field names to whether the field is an array or not.
+	Traversable map[string]bool
+}
+
+type templData struct {
+	Types []nodeType
+}
+
+var fileTempl = template.Must(
+	template.New("").Parse(`// Code generated by "go generate go run traverser_gen.go"; DO NOT EDIT.
+
+package traverser
+
+import (
+    "github.com/VKCOM/php-parser/pkg/ast"
+    // Importing packages here, so that go mod tidy does not remove the dependency on it.
+    // It is used in traverser_gen.go but that is ignored with go mod tidy.
+	"golang.org/x/tools/go/packages"
+)
+{{range $typ := .Types}}
+func (t *Traverser) {{$typ.FuncName}}(n *ast.{{$typ.Name}}) {
+    if !t.checkEntrance(n) {
+        return
+    }
+
+    n.Accept(t.v)
+{{range $name, $isArray := $typ.Traversable}}
+{{- if $isArray}}
+    for _, nn := range n.{{$name}} {
+        nn.Accept(t)
+    }
+{{else}}
+    t.Traverse(n.{{$name}})
+{{end}}
+{{- end}}
+    t.leave(n)
+}
+{{end}}`),
+)
+
+func main() {
+	ast := astOfFile("../../ast/node.go")
+	nodeTypes := getNodeTypes(ast)
+
+	file, err := os.Create("traverser_impl.go")
+	if err != nil {
+		panic(fmt.Errorf("open 'traverser_impl.go': %w", err))
+	}
+
+	fileTempl.Execute(file, templData{Types: nodeTypes})
+}
+
+func astOfFile(path string) *ast.File {
+	nodesFile, err := filepath.Abs(path)
+	if err != nil {
+		panic(fmt.Errorf("getting '%s' absolute path: %w", path, err))
+	}
+
+	cfg := &packages.Config{
+		Mode:  packages.NeedName | packages.NeedFiles | packages.NeedTypes | packages.NeedTypesInfo | packages.NeedSyntax,
+		Tests: false,
+	}
+	pkgs, err := packages.Load(cfg, fmt.Sprintf("file=%s", nodesFile))
+	if err != nil {
+		panic(fmt.Errorf("loading '%s' package: %w", nodesFile, err))
+	}
+
+	if len(pkgs) == 0 {
+		panic(fmt.Errorf("could not get any package for file '%s'", nodesFile))
+	}
+
+	pkg := pkgs[0]
+	var syntax *ast.File
+	for i, fn := range pkg.GoFiles {
+		if fn == nodesFile {
+			syntax = pkg.Syntax[i]
+			break
+		}
+	}
+
+	if syntax == nil {
+		panic(fmt.Errorf("could not get ast of file: '%s'", nodesFile))
+	}
+
+	return syntax
+}
+
+func getNodeTypes(syntax *ast.File) []nodeType {
+	types := []nodeType{}
+	for _, decl := range syntax.Decls {
+		typedDecl, ok := decl.(*ast.GenDecl)
+		if !ok {
+			log.Printf("%T not *ast.GenDecl", decl)
+			continue
+		}
+
+		for _, spec := range typedDecl.Specs {
+			typedSpec, ok := spec.(*ast.TypeSpec)
+			if !ok {
+				if _, ok := spec.(*ast.ImportSpec); !ok {
+					log.Printf("%T not *ast.TypeSpec", spec)
+				}
+				continue
+			}
+
+			structType, ok := typedSpec.Type.(*ast.StructType)
+			if !ok {
+				log.Printf("%T not *ast.StructType", spec)
+				continue
+			}
+
+			nType := nodeType{
+				Name:        typedSpec.Name.String(),
+				FuncName:    typedSpec.Name.String(),
+				Traversable: map[string]bool{},
+			}
+			if funcName, ok := phpast.TypeToVisitorNameMap[typedSpec.Name.String()]; ok {
+				nType.FuncName = funcName
+			}
+
+			for _, field := range structType.Fields.List {
+				if traversable, isArray := checkType(field.Type); traversable {
+					for _, n := range field.Names {
+						nType.Traversable[n.String()] = isArray
+					}
+				}
+			}
+
+			types = append(types, nType)
+		}
+	}
+
+	return types
+}
+
+func checkType(t ast.Expr) (traversable bool, isArray bool) {
+	switch ft := t.(type) {
+	case *ast.ArrayType:
+		ok, _ := checkType(ft.Elt)
+		return ok, true
+	case *ast.Ident:
+		switch ft.Name {
+		case "Vertex":
+			return true, false
+		default:
+			return false, false
+		}
+	default:
+		return false, false
+	}
+}

pkg/visitor/traverser/traverser_test.go

@@ -0,0 +1,67 @@
+package traverser_test
+
+import (
+	"testing"
+
+	"github.com/VKCOM/php-parser/pkg/ast"
+	"github.com/VKCOM/php-parser/pkg/visitor"
+	"github.com/VKCOM/php-parser/pkg/visitor/traverser"
+)
+
+// testCase is a traverser that does not go into any class statement or its children.
+// If it does, the test fails.
+type testCase struct {
+	t *testing.T
+	visitor.Null
+	traversedFunction bool
+}
+
+var _ ast.Visitor = &testCase{}
+
+func (t *testCase) EnterNode(n ast.Vertex) bool {
+	t.t.Logf("EnterNode: %T", n)
+	if _, ok := n.(*ast.StmtClass); ok {
+		return false
+	}
+
+	return true
+}
+
+func (t *testCase) LeaveNode(n ast.Vertex) {
+	t.t.Logf("LeaveNode: %T", n)
+	if _, ok := n.(*ast.Root); ok {
+		if !t.traversedFunction {
+			t.t.Error("traverser did not traverse function")
+		}
+	}
+}
+
+func (t *testCase) StmtClass(n *ast.StmtClass) {
+	t.t.Errorf("traverser got to class")
+}
+
+func (t *testCase) StmtClassMethod(n *ast.StmtClassMethod) {
+	t.t.Errorf("traverser got to method")
+}
+
+func (t *testCase) StmtFunction(n *ast.StmtFunction) {
+	t.traversedFunction = true
+}
+
+func TestEnterNodeIsRespected(t *testing.T) {
+	tc := &testCase{t: t}
+	tv := traverser.NewTraverser(tc)
+
+	root := &ast.Root{
+		Stmts: []ast.Vertex{
+			&ast.StmtFunction{},
+			&ast.StmtClass{
+				Stmts: []ast.Vertex{
+					&ast.StmtClassMethod{},
+				},
+			},
+		},
+	}
+
+	root.Accept(tv)
+}