Add atomic<->granular schema change fixup

Author: jpbetz

internal/fixture/state.go

@@ -385,6 +385,33 @@ func (f UpdateObject) preprocess(parser Parser) (Operation, error) {
 	return f, nil
 }
 
+// ChangeParser is a type of operation. It simulates making changes a schema without versioning
+// the schema. This can be used to test the behavior of making backward compatible schema changes,
+// e.g. setting "elementRelationship: atomic" on an existing struct. It also may be used to ensure
+// that backward incompatible changes are detected appropriately.
+type ChangeParser struct {
+	Parser *typed.Parser
+}
+
+var _ Operation = &ChangeParser{}
+
+func (cs ChangeParser) run(state *State) error {
+	state.Parser = cs.Parser
+	// Swap the schema in for use with the live object so it merges.
+	// If the schema is incompatible, this will fail validation.
+
+	liveWithNewSchema, err := typed.AsTyped(state.Live.AsValue(), &cs.Parser.Schema,  state.Live.TypeRef())
+	if err != nil {
+		return err
+	}
+	state.Live = liveWithNewSchema
+	return nil
+}
+
+func (cs ChangeParser) preprocess(_ Parser) (Operation, error) {
+	return cs, nil
+}
+
 // TestCase is the list of operations that need to be run, as well as
 // the object/managedfields as they are supposed to look like after all
 // the operations have been successfully performed. If Object/Managed is

merge/schema_change_test.go

@@ -0,0 +1,129 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package merge_test
+
+import (
+	"testing"
+
+	"sigs.k8s.io/structured-merge-diff/v4/fieldpath"
+	. "sigs.k8s.io/structured-merge-diff/v4/internal/fixture"
+	"sigs.k8s.io/structured-merge-diff/v4/merge"
+	"sigs.k8s.io/structured-merge-diff/v4/typed"
+)
+
+
+var structParser = func() *typed.Parser {
+	oldParser, err := typed.NewParser(`types:
+- name: v1
+  map:
+    fields:
+      - name: struct
+        type:
+          namedType: struct
+- name: struct
+  map:
+    fields:
+    - name: numeric
+      type:
+        scalar: numeric
+    - name: string
+      type:
+        scalar: string`)
+	if err != nil {
+		panic(err)
+	}
+	return oldParser
+}()
+
+var structWithAtomicParser = func() *typed.Parser {
+	newParser, err := typed.NewParser( `types:
+- name: v1
+  map:
+    fields:
+      - name: struct
+        type:
+          namedType: struct
+- name: struct
+  map:
+    fields:
+    - name: numeric
+      type:
+        scalar: numeric
+    - name: string
+      type:
+        scalar: string
+    elementRelationship: atomic`)
+	if err != nil {
+		panic(err)
+	}
+	return newParser
+}()
+
+func TestSchemaChanges(t *testing.T) {
+	tests := map[string]TestCase{
+		"change-struct-to-atomic": {
+			Ops: []Operation{
+				Apply{
+					Manager: "one",
+					Object: `
+						struct:
+						  numeric: 1
+					`,
+					APIVersion: "v1",
+				},
+				ChangeParser{Parser: structWithAtomicParser},
+				Apply{
+					Manager: "two",
+					Object: `
+						struct:
+						  string: "string"
+					`,
+					APIVersion: "v1",
+					Conflicts:merge.Conflicts{
+						merge.Conflict{Manager: "one", Path: _P("struct")},
+					},
+				},
+				ForceApply{
+					Manager: "two",
+					Object: `
+						struct:
+						  string: "string"
+					`,
+					APIVersion: "v1",
+				},
+			},
+			Object: `
+				struct:
+				  string: "string"
+			`,
+			APIVersion: "v1",
+			Managed: fieldpath.ManagedFields{
+				"two": fieldpath.NewVersionedSet(_NS(
+					_P("struct"),
+				), "v1", true),
+			},
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			if err := test.Test(structParser); err != nil {
+				t.Fatal(err)
+			}
+		})
+	}
+}

merge/update.go

@@ -122,13 +122,16 @@ func (s *Updater) update(oldObject, newObject *typed.TypedValue, version fieldpa
 // this is a CREATE call).
 func (s *Updater) Update(liveObject, newObject *typed.TypedValue, version fieldpath.APIVersion, managers fieldpath.ManagedFields, manager string) (*typed.TypedValue, fieldpath.ManagedFields, error) {
 	var err error
+	managers, err = s.fixupManagedFields(liveObject, managers)
+	if err != nil {
+		return nil, fieldpath.ManagedFields{}, err
+	}
 	if s.enableUnions {
 		newObject, err = liveObject.NormalizeUnions(newObject)
 		if err != nil {
 			return nil, fieldpath.ManagedFields{}, err
 		}
 	}
-	managers = shallowCopyManagers(managers)
 	managers, compare, err := s.update(liveObject, newObject, version, managers, manager, true)
 	if err != nil {
 		return nil, fieldpath.ManagedFields{}, err
@@ -141,24 +144,63 @@ func (s *Updater) Update(liveObject, newObject *typed.TypedValue, version fieldp
 	if ignored == nil {
 		ignored = fieldpath.NewSet()
 	}
-	managers[manager] = fieldpath.NewVersionedSet(
-		managers[manager].Set().Union(compare.Modified).Union(compare.Added).Difference(compare.Removed).RecursiveDifference(ignored),
-		version,
-		false,
-	)
+	managers[manager] = fieldpath.NewVersionedSet(managers[manager].Set().Union(compare.Modified).Union(compare.Added).Difference(compare.Removed).RecursiveDifference(ignored), version, false)
 	if managers[manager].Set().Empty() {
 		delete(managers, manager)
 	}
 	return newObject, managers, nil
 }
 
+// fixupManagedFields attempts to fix up the managed fields to be compatible with the live state of
+// the schema.
+// This is needed when an "unversioned" change are made to a schema that impact the managedFields.
+// By "unversionsed" we mean that a specific version of a schema was directly modified (introduction
+// of new versions does not require fixup).
+//
+// Supported schema changes:
+// - Changing a type to "atomic": All field manager that managed any granular fields become managers
+//   of the atomic to ensure a conflict if any of the fields they previously managed are changed.
+//   Granular managed fields of the struct are removed.
+//
+// TODO: Changes to add support for:
+// - Change a type from "atomic" to "granular", "set" or "map". All field manager that managed the
+//   atomic become managers of all child fields to ensure a conflict if any child field is changed.
+//
+// Potential future optimization: Write a SHA-256 hash to managedFields that can be compared
+// with the current hash of the live schemas to determine if any fixup is needed.
+func (s *Updater) fixupManagedFields(liveObject *typed.TypedValue, managers fieldpath.ManagedFields) (fieldpath.ManagedFields, error) {
+	result := fieldpath.ManagedFields{}
+	for manager, versionedSet := range managers {
+		tv, err := s.Converter.Convert(liveObject, versionedSet.APIVersion())
+		if s.Converter.IsMissingVersionError(err) { // okay to skip, obsolete versions will be deleted automatically anyway
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+		fixedFieldSet, err := typed.FixupFieldManagers(versionedSet.Set(), tv)
+		if err != nil {
+			return nil, err
+		}
+		if fixedFieldSet != nil {
+			result[manager] = fieldpath.NewVersionedSet(fixedFieldSet, versionedSet.APIVersion(), versionedSet.Applied())
+		} else {
+			result[manager] = versionedSet
+		}
+	}
+	return result, nil
+}
+
 // Apply should be called when Apply is run, given the current object as
 // well as the configuration that is applied. This will merge the object
 // and return it. If the object hasn't changed, nil is returned (the
 // managers can still have changed though).
 func (s *Updater) Apply(liveObject, configObject *typed.TypedValue, version fieldpath.APIVersion, managers fieldpath.ManagedFields, manager string, force bool) (*typed.TypedValue, fieldpath.ManagedFields, error) {
-	managers = shallowCopyManagers(managers)
 	var err error
+	managers, err = s.fixupManagedFields(liveObject, managers)
+	if err != nil {
+		return nil, fieldpath.ManagedFields{}, err
+	}
 	if s.enableUnions {
 		configObject, err = configObject.NormalizeUnionsApply(configObject)
 		if err != nil {
@@ -204,14 +246,6 @@ func (s *Updater) Apply(liveObject, configObject *typed.TypedValue, version fiel
 	return newObject, managers, nil
 }
 
-func shallowCopyManagers(managers fieldpath.ManagedFields) fieldpath.ManagedFields {
-	newManagers := fieldpath.ManagedFields{}
-	for manager, set := range managers {
-		newManagers[manager] = set
-	}
-	return newManagers
-}
-
 // prune will remove a field, list or map item, iff:
 // * applyingManager applied it last time
 // * applyingManager didn't apply it this time