+++ /dev/null
-package apidiff
-
-import (
- "fmt"
- "go/types"
- "reflect"
-)
-
-func (d *differ) checkCompatible(otn *types.TypeName, old, new types.Type) {
- switch old := old.(type) {
- case *types.Interface:
- if new, ok := new.(*types.Interface); ok {
- d.checkCompatibleInterface(otn, old, new)
- return
- }
-
- case *types.Struct:
- if new, ok := new.(*types.Struct); ok {
- d.checkCompatibleStruct(otn, old, new)
- return
- }
-
- case *types.Chan:
- if new, ok := new.(*types.Chan); ok {
- d.checkCompatibleChan(otn, old, new)
- return
- }
-
- case *types.Basic:
- if new, ok := new.(*types.Basic); ok {
- d.checkCompatibleBasic(otn, old, new)
- return
- }
-
- case *types.Named:
- panic("unreachable")
-
- default:
- d.checkCorrespondence(otn, "", old, new)
- return
-
- }
- // Here if old and new are different kinds of types.
- d.typeChanged(otn, "", old, new)
-}
-
-func (d *differ) checkCompatibleChan(otn *types.TypeName, old, new *types.Chan) {
- d.checkCorrespondence(otn, ", element type", old.Elem(), new.Elem())
- if old.Dir() != new.Dir() {
- if new.Dir() == types.SendRecv {
- d.compatible(otn, "", "removed direction")
- } else {
- d.incompatible(otn, "", "changed direction")
- }
- }
-}
-
-func (d *differ) checkCompatibleBasic(otn *types.TypeName, old, new *types.Basic) {
- // Certain changes to numeric types are compatible. Approximately, the info must
- // be the same, and the new values must be a superset of the old.
- if old.Kind() == new.Kind() {
- // old and new are identical
- return
- }
- if compatibleBasics[[2]types.BasicKind{old.Kind(), new.Kind()}] {
- d.compatible(otn, "", "changed from %s to %s", old, new)
- } else {
- d.typeChanged(otn, "", old, new)
- }
-}
-
-// All pairs (old, new) of compatible basic types.
-var compatibleBasics = map[[2]types.BasicKind]bool{
- {types.Uint8, types.Uint16}: true,
- {types.Uint8, types.Uint32}: true,
- {types.Uint8, types.Uint}: true,
- {types.Uint8, types.Uint64}: true,
- {types.Uint16, types.Uint32}: true,
- {types.Uint16, types.Uint}: true,
- {types.Uint16, types.Uint64}: true,
- {types.Uint32, types.Uint}: true,
- {types.Uint32, types.Uint64}: true,
- {types.Uint, types.Uint64}: true,
- {types.Int8, types.Int16}: true,
- {types.Int8, types.Int32}: true,
- {types.Int8, types.Int}: true,
- {types.Int8, types.Int64}: true,
- {types.Int16, types.Int32}: true,
- {types.Int16, types.Int}: true,
- {types.Int16, types.Int64}: true,
- {types.Int32, types.Int}: true,
- {types.Int32, types.Int64}: true,
- {types.Int, types.Int64}: true,
- {types.Float32, types.Float64}: true,
- {types.Complex64, types.Complex128}: true,
-}
-
-// Interface compatibility:
-// If the old interface has an unexported method, the new interface is compatible
-// if its exported method set is a superset of the old. (Users could not implement,
-// only embed.)
-//
-// If the old interface did not have an unexported method, the new interface is
-// compatible if its exported method set is the same as the old, and it has no
-// unexported methods. (Adding an unexported method makes the interface
-// unimplementable outside the package.)
-//
-// TODO: must also check that if any methods were added or removed, every exposed
-// type in the package that implemented the interface in old still implements it in
-// new. Otherwise external assignments could fail.
-func (d *differ) checkCompatibleInterface(otn *types.TypeName, old, new *types.Interface) {
- // Method sets are checked in checkCompatibleDefined.
-
- // Does the old interface have an unexported method?
- if unexportedMethod(old) != nil {
- d.checkMethodSet(otn, old, new, additionsCompatible)
- } else {
- // Perform an equivalence check, but with more information.
- d.checkMethodSet(otn, old, new, additionsIncompatible)
- if u := unexportedMethod(new); u != nil {
- d.incompatible(otn, u.Name(), "added unexported method")
- }
- }
-}
-
-// Return an unexported method from the method set of t, or nil if there are none.
-func unexportedMethod(t *types.Interface) *types.Func {
- for i := 0; i < t.NumMethods(); i++ {
- if m := t.Method(i); !m.Exported() {
- return m
- }
- }
- return nil
-}
-
-// We need to check three things for structs:
-// 1. The set of exported fields must be compatible. This ensures that keyed struct
-// literals continue to compile. (There is no compatibility guarantee for unkeyed
-// struct literals.)
-// 2. The set of exported *selectable* fields must be compatible. This includes the exported
-// fields of all embedded structs. This ensures that selections continue to compile.
-// 3. If the old struct is comparable, so must the new one be. This ensures that equality
-// expressions and uses of struct values as map keys continue to compile.
-//
-// An unexported embedded struct can't appear in a struct literal outside the
-// package, so it doesn't have to be present, or have the same name, in the new
-// struct.
-//
-// Field tags are ignored: they have no compile-time implications.
-func (d *differ) checkCompatibleStruct(obj types.Object, old, new *types.Struct) {
- d.checkCompatibleObjectSets(obj, exportedFields(old), exportedFields(new))
- d.checkCompatibleObjectSets(obj, exportedSelectableFields(old), exportedSelectableFields(new))
- // Removing comparability from a struct is an incompatible change.
- if types.Comparable(old) && !types.Comparable(new) {
- d.incompatible(obj, "", "old is comparable, new is not")
- }
-}
-
-// exportedFields collects all the immediate fields of the struct that are exported.
-// This is also the set of exported keys for keyed struct literals.
-func exportedFields(s *types.Struct) map[string]types.Object {
- m := map[string]types.Object{}
- for i := 0; i < s.NumFields(); i++ {
- f := s.Field(i)
- if f.Exported() {
- m[f.Name()] = f
- }
- }
- return m
-}
-
-// exportedSelectableFields collects all the exported fields of the struct, including
-// exported fields of embedded structs.
-//
-// We traverse the struct breadth-first, because of the rule that a lower-depth field
-// shadows one at a higher depth.
-func exportedSelectableFields(s *types.Struct) map[string]types.Object {
- var (
- m = map[string]types.Object{}
- next []*types.Struct // embedded structs at the next depth
- seen []*types.Struct // to handle recursive embedding
- )
- for cur := []*types.Struct{s}; len(cur) > 0; cur, next = next, nil {
- seen = append(seen, cur...)
- // We only want to consider unambiguous fields. Ambiguous fields (where there
- // is more than one field of the same name at the same level) are legal, but
- // cannot be selected.
- for name, f := range unambiguousFields(cur) {
- // Record an exported field we haven't seen before. If we have seen it,
- // it occurred a lower depth, so it shadows this field.
- if f.Exported() && m[name] == nil {
- m[name] = f
- }
- // Remember embedded structs for processing at the next depth,
- // but only if we haven't seen the struct at this depth or above.
- if !f.Anonymous() {
- continue
- }
- t := f.Type().Underlying()
- if p, ok := t.(*types.Pointer); ok {
- t = p.Elem().Underlying()
- }
- if t, ok := t.(*types.Struct); ok && !contains(seen, t) {
- next = append(next, t)
- }
- }
- }
- return m
-}
-
-func contains(ts []*types.Struct, t *types.Struct) bool {
- for _, s := range ts {
- if types.Identical(s, t) {
- return true
- }
- }
- return false
-}
-
-// Given a set of structs at the same depth, the unambiguous fields are the ones whose
-// names appear exactly once.
-func unambiguousFields(structs []*types.Struct) map[string]*types.Var {
- fields := map[string]*types.Var{}
- seen := map[string]bool{}
- for _, s := range structs {
- for i := 0; i < s.NumFields(); i++ {
- f := s.Field(i)
- name := f.Name()
- if seen[name] {
- delete(fields, name)
- } else {
- seen[name] = true
- fields[name] = f
- }
- }
- }
- return fields
-}
-
-// Anything removed or change from the old set is an incompatible change.
-// Anything added to the new set is a compatible change.
-func (d *differ) checkCompatibleObjectSets(obj types.Object, old, new map[string]types.Object) {
- for name, oldo := range old {
- newo := new[name]
- if newo == nil {
- d.incompatible(obj, name, "removed")
- } else {
- d.checkCorrespondence(obj, name, oldo.Type(), newo.Type())
- }
- }
- for name := range new {
- if old[name] == nil {
- d.compatible(obj, name, "added")
- }
- }
-}
-
-func (d *differ) checkCompatibleDefined(otn *types.TypeName, old *types.Named, new types.Type) {
- // We've already checked that old and new correspond.
- d.checkCompatible(otn, old.Underlying(), new.Underlying())
- // If there are different kinds of types (e.g. struct and interface), don't bother checking
- // the method sets.
- if reflect.TypeOf(old.Underlying()) != reflect.TypeOf(new.Underlying()) {
- return
- }
- // Interface method sets are checked in checkCompatibleInterface.
- if _, ok := old.Underlying().(*types.Interface); ok {
- return
- }
-
- // A new method set is compatible with an old if the new exported methods are a superset of the old.
- d.checkMethodSet(otn, old, new, additionsCompatible)
- d.checkMethodSet(otn, types.NewPointer(old), types.NewPointer(new), additionsCompatible)
-}
-
-const (
- additionsCompatible = true
- additionsIncompatible = false
-)
-
-func (d *differ) checkMethodSet(otn *types.TypeName, oldt, newt types.Type, addcompat bool) {
- // TODO: find a way to use checkCompatibleObjectSets for this.
- oldMethodSet := exportedMethods(oldt)
- newMethodSet := exportedMethods(newt)
- msname := otn.Name()
- if _, ok := oldt.(*types.Pointer); ok {
- msname = "*" + msname
- }
- for name, oldMethod := range oldMethodSet {
- newMethod := newMethodSet[name]
- if newMethod == nil {
- var part string
- // Due to embedding, it's possible that the method's receiver type is not
- // the same as the defined type whose method set we're looking at. So for
- // a type T with removed method M that is embedded in some other type U,
- // we will generate two "removed" messages for T.M, one for its own type
- // T and one for the embedded type U. We want both messages to appear,
- // but the messageSet dedup logic will allow only one message for a given
- // object. So use the part string to distinguish them.
- if receiverNamedType(oldMethod).Obj() != otn {
- part = fmt.Sprintf(", method set of %s", msname)
- }
- d.incompatible(oldMethod, part, "removed")
- } else {
- obj := oldMethod
- // If a value method is changed to a pointer method and has a signature
- // change, then we can get two messages for the same method definition: one
- // for the value method set that says it's removed, and another for the
- // pointer method set that says it changed. To keep both messages (since
- // messageSet dedups), use newMethod for the second. (Slight hack.)
- if !hasPointerReceiver(oldMethod) && hasPointerReceiver(newMethod) {
- obj = newMethod
- }
- d.checkCorrespondence(obj, "", oldMethod.Type(), newMethod.Type())
- }
- }
-
- // Check for added methods.
- for name, newMethod := range newMethodSet {
- if oldMethodSet[name] == nil {
- if addcompat {
- d.compatible(newMethod, "", "added")
- } else {
- d.incompatible(newMethod, "", "added")
- }
- }
- }
-}
-
-// exportedMethods collects all the exported methods of type's method set.
-func exportedMethods(t types.Type) map[string]types.Object {
- m := map[string]types.Object{}
- ms := types.NewMethodSet(t)
- for i := 0; i < ms.Len(); i++ {
- obj := ms.At(i).Obj()
- if obj.Exported() {
- m[obj.Name()] = obj
- }
- }
- return m
-}
-
-func receiverType(method types.Object) types.Type {
- return method.Type().(*types.Signature).Recv().Type()
-}
-
-func receiverNamedType(method types.Object) *types.Named {
- switch t := receiverType(method).(type) {
- case *types.Pointer:
- return t.Elem().(*types.Named)
- case *types.Named:
- return t
- default:
- panic("unreachable")
- }
-}
-
-func hasPointerReceiver(method types.Object) bool {
- _, ok := receiverType(method).(*types.Pointer)
- return ok
-}
projects / dotfiles / .git / blobdiff