TUN-8006: Update quic-go to latest upstream

vendor/golang.org/x/tools/internal/gcimporter/gcimporter.go

@@ -7,6 +7,18 @@
 // Package gcimporter provides various functions for reading
 // gc-generated object files that can be used to implement the
 // Importer interface defined by the Go 1.5 standard library package.
+//
+// The encoding is deterministic: if the encoder is applied twice to
+// the same types.Package data structure, both encodings are equal.
+// This property may be important to avoid spurious changes in
+// applications such as build systems.
+//
+// However, the encoder is not necessarily idempotent. Importing an
+// exported package may yield a types.Package that, while it
+// represents the same set of Go types as the original, may differ in
+// the details of its internal representation. Because of these
+// differences, re-encoding the imported package may yield a
+// different, but equally valid, encoding of the package.
 package gcimporter // import "golang.org/x/tools/internal/gcimporter"
 
 import (

vendor/golang.org/x/tools/internal/gcimporter/iexport.go

@@ -44,12 +44,12 @@ func IExportShallow(fset *token.FileSet, pkg *types.Package) ([]byte, error) {
 	return out.Bytes(), err
 }
 
-// IImportShallow decodes "shallow" types.Package data encoded by IExportShallow
-// in the same executable. This function cannot import data from
+// IImportShallow decodes "shallow" types.Package data encoded by
+// IExportShallow in the same executable. This function cannot import data from
 // cmd/compile or gcexportdata.Write.
-func IImportShallow(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string, insert InsertType) (*types.Package, error) {
+func IImportShallow(fset *token.FileSet, getPackage GetPackageFunc, data []byte, path string, insert InsertType) (*types.Package, error) {
 	const bundle = false
-	pkgs, err := iimportCommon(fset, imports, data, bundle, path, insert)
+	pkgs, err := iimportCommon(fset, getPackage, data, bundle, path, insert)
 	if err != nil {
 		return nil, err
 	}

vendor/golang.org/x/tools/internal/gcimporter/iimport.go

@@ -85,7 +85,7 @@ const (
 // If the export data version is not recognized or the format is otherwise
 // compromised, an error is returned.
 func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (int, *types.Package, error) {
-	pkgs, err := iimportCommon(fset, imports, data, false, path, nil)
+	pkgs, err := iimportCommon(fset, GetPackageFromMap(imports), data, false, path, nil)
 	if err != nil {
 		return 0, nil, err
 	}
@@ -94,10 +94,33 @@ func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []
 
 // IImportBundle imports a set of packages from the serialized package bundle.
 func IImportBundle(fset *token.FileSet, imports map[string]*types.Package, data []byte) ([]*types.Package, error) {
-	return iimportCommon(fset, imports, data, true, "", nil)
+	return iimportCommon(fset, GetPackageFromMap(imports), data, true, "", nil)
 }
 
-func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data []byte, bundle bool, path string, insert InsertType) (pkgs []*types.Package, err error) {
+// A GetPackageFunc is a function that gets the package with the given path
+// from the importer state, creating it (with the specified name) if necessary.
+// It is an abstraction of the map historically used to memoize package creation.
+//
+// Two calls with the same path must return the same package.
+//
+// If the given getPackage func returns nil, the import will fail.
+type GetPackageFunc = func(path, name string) *types.Package
+
+// GetPackageFromMap returns a GetPackageFunc that retrieves packages from the
+// given map of package path -> package.
+//
+// The resulting func may mutate m: if a requested package is not found, a new
+// package will be inserted into m.
+func GetPackageFromMap(m map[string]*types.Package) GetPackageFunc {
+	return func(path, name string) *types.Package {
+		if _, ok := m[path]; !ok {
+			m[path] = types.NewPackage(path, name)
+		}
+		return m[path]
+	}
+}
+
+func iimportCommon(fset *token.FileSet, getPackage GetPackageFunc, data []byte, bundle bool, path string, insert InsertType) (pkgs []*types.Package, err error) {
 	const currentVersion = iexportVersionCurrent
 	version := int64(-1)
 	if !debug {
@@ -195,10 +218,9 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 		if pkgPath == "" {
 			pkgPath = path
 		}
-		pkg := imports[pkgPath]
+		pkg := getPackage(pkgPath, pkgName)
 		if pkg == nil {
-			pkg = types.NewPackage(pkgPath, pkgName)
-			imports[pkgPath] = pkg
+			errorf("internal error: getPackage returned nil package for %s", pkgPath)
 		} else if pkg.Name() != pkgName {
 			errorf("conflicting names %s and %s for package %q", pkg.Name(), pkgName, path)
 		}

vendor/golang.org/x/tools/internal/gcimporter/ureader_yes.go

@@ -12,6 +12,7 @@ package gcimporter
 import (
 	"go/token"
 	"go/types"
+	"sort"
 	"strings"
 
 	"golang.org/x/tools/internal/pkgbits"
@@ -121,6 +122,16 @@ func readUnifiedPackage(fset *token.FileSet, ctxt *types.Context, imports map[st
 		iface.Complete()
 	}
 
+	// Imports() of pkg are all of the transitive packages that were loaded.
+	var imps []*types.Package
+	for _, imp := range pr.pkgs {
+		if imp != nil && imp != pkg {
+			imps = append(imps, imp)
+		}
+	}
+	sort.Sort(byPath(imps))
+	pkg.SetImports(imps)
+
 	pkg.MarkComplete()
 	return pkg
 }
@@ -260,39 +271,9 @@ func (r *reader) doPkg() *types.Package {
 	pkg := types.NewPackage(path, name)
 	r.p.imports[path] = pkg
 
-	imports := make([]*types.Package, r.Len())
-	for i := range imports {
-		imports[i] = r.pkg()
-	}
-	pkg.SetImports(flattenImports(imports))
-
 	return pkg
 }
 
-// flattenImports returns the transitive closure of all imported
-// packages rooted from pkgs.
-func flattenImports(pkgs []*types.Package) []*types.Package {
-	var res []*types.Package
-	seen := make(map[*types.Package]struct{})
-	for _, pkg := range pkgs {
-		if _, ok := seen[pkg]; ok {
-			continue
-		}
-		seen[pkg] = struct{}{}
-		res = append(res, pkg)
-
-		// pkg.Imports() is already flattened.
-		for _, pkg := range pkg.Imports() {
-			if _, ok := seen[pkg]; ok {
-				continue
-			}
-			seen[pkg] = struct{}{}
-			res = append(res, pkg)
-		}
-	}
-	return res
-}
-
 // @@@ Types
 
 func (r *reader) typ() types.Type {