WIP

6 files changed, 90 insertions, 65 deletions

diff --git a/entity/dag/common_test.go b/entity/dag/common_test.go
index f78b09e9..51acfa49 100644
--- a/entity/dag/common_test.go
+++ b/entity/dag/common_test.go
@@ -88,6 +88,18 @@ func unmarshaler(raw json.RawMessage, resolvers entity.Resolvers) (Operation, er
 }
 
 /*
+  Entity
+*/
+
+type Foo struct {
+	*Entity
+}
+
+func wrapper(e *Entity) *Foo {
+	return &Foo{Entity: e}
+}
+
+/*
   Identities + repo + definition
 */
 
diff --git a/entity/dag/entity.go b/entity/dag/entity.go
index ca674ad7..03b97aa0 100644
--- a/entity/dag/entity.go
+++ b/entity/dag/entity.go
@@ -33,6 +33,19 @@ type Definition struct {
 	FormatVersion uint
 }
 
+type Actions[EntityT entity.Interface] struct {
+	Wrap             func(e *Entity) EntityT
+	New              func() EntityT
+	Read             func(repo repository.ClockedRepo, id entity.Id) (EntityT, error)
+	ReadWithResolver func(repo repository.ClockedRepo, resolvers entity.Resolvers, id entity.Id) (EntityT, error)
+	ReadAll          func(repo repository.ClockedRepo) <-chan StreamedEntity[EntityT]
+	ListLocalIds     func(repo repository.Repo) ([]entity.Id, error)
+	Fetch            func(repo repository.Repo, remote string) (string, error)
+	Push             func(repo repository.Repo, remote string) (string, error)
+	Pull             func(repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, mergeAuthor identity.Interface) error
+	MergeAll         func(repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, mergeAuthor identity.Interface) <-chan entity.MergeResult
+}
+
 // Entity is a data structure stored in a chain of git objects, supporting actions like Push, Pull and Merge.
 type Entity struct {
 	// A Lamport clock is a logical clock that allow to order event
@@ -59,32 +72,32 @@ func New(definition Definition) *Entity {
 }
 
 // Read will read and decode a stored local Entity from a repository
-func Read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, id entity.Id) (*Entity, error) {
+func Read[EntityT entity.Interface](def Definition, wrapper func(e *Entity) EntityT, repo repository.ClockedRepo, resolvers entity.Resolvers, id entity.Id) (EntityT, error) {
 	if err := id.Validate(); err != nil {
-		return nil, errors.Wrap(err, "invalid id")
+		return *new(EntityT), errors.Wrap(err, "invalid id")
 	}
 
 	ref := fmt.Sprintf("refs/%s/%s", def.Namespace, id.String())
 
-	return read(def, repo, resolvers, ref)
+	return read[EntityT](def, wrapper, repo, resolvers, ref)
 }
 
 // readRemote will read and decode a stored remote Entity from a repository
-func readRemote(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, id entity.Id) (*Entity, error) {
+func readRemote[EntityT entity.Interface](def Definition, wrapper func(e *Entity) EntityT, repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, id entity.Id) (EntityT, error) {
 	if err := id.Validate(); err != nil {
-		return nil, errors.Wrap(err, "invalid id")
+		return *new(EntityT), errors.Wrap(err, "invalid id")
 	}
 
 	ref := fmt.Sprintf("refs/remotes/%s/%s/%s", def.Namespace, remote, id.String())
 
-	return read(def, repo, resolvers, ref)
+	return read[EntityT](def, wrapper, repo, resolvers, ref)
 }
 
 // read fetch from git and decode an Entity at an arbitrary git reference.
-func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, ref string) (*Entity, error) {
+func read[EntityT entity.Interface](def Definition, wrapper func(e *Entity) EntityT, repo repository.ClockedRepo, resolvers entity.Resolvers, ref string) (EntityT, error) {
 	rootHash, err := repo.ResolveRef(ref)
 	if err != nil {
-		return nil, err
+		return *new(EntityT), err
 	}
 
 	// Perform a breadth-first search to get a topological order of the DAG where we discover the
@@ -104,7 +117,7 @@ func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolver
 
 		commit, err := repo.ReadCommit(hash)
 		if err != nil {
-			return nil, err
+			return *new(EntityT), err
 		}
 
 		BFSOrder = append(BFSOrder, commit)
@@ -137,26 +150,26 @@ func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolver
 		// can have no parents. Said otherwise, the DAG need to have exactly
 		// one leaf.
 		if !isFirstCommit && len(commit.Parents) == 0 {
-			return nil, fmt.Errorf("multiple leafs in the entity DAG")
+			return *new(EntityT), fmt.Errorf("multiple leafs in the entity DAG")
 		}
 
 		opp, err := readOperationPack(def, repo, resolvers, commit)
 		if err != nil {
-			return nil, err
+			return *new(EntityT), err
 		}
 
 		err = opp.Validate()
 		if err != nil {
-			return nil, err
+			return *new(EntityT), err
 		}
 
 		if isMerge && len(opp.Operations) > 0 {
-			return nil, fmt.Errorf("merge commit cannot have operations")
+			return *new(EntityT), fmt.Errorf("merge commit cannot have operations")
 		}
 
 		// Check that the create lamport clock is set (not checked in Validate() as it's optional)
 		if isFirstCommit && opp.CreateTime <= 0 {
-			return nil, fmt.Errorf("creation lamport time not set")
+			return *new(EntityT), fmt.Errorf("creation lamport time not set")
 		}
 
 		// make sure that the lamport clocks causality match the DAG topology
@@ -167,7 +180,7 @@ func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolver
 			}
 
 			if parentPack.EditTime >= opp.EditTime {
-				return nil, fmt.Errorf("lamport clock ordering doesn't match the DAG")
+				return *new(EntityT), fmt.Errorf("lamport clock ordering doesn't match the DAG")
 			}
 
 			// to avoid an attack where clocks are pushed toward the uint64 rollover, make sure
@@ -175,7 +188,7 @@ func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolver
 			// we ignore merge commits here to allow merging after a loooong time without breaking anything,
 			// as long as there is one valid chain of small hops, it's fine.
 			if !isMerge && opp.EditTime-parentPack.EditTime > 1_000_000 {
-				return nil, fmt.Errorf("lamport clock jumping too far in the future, likely an attack")
+				return *new(EntityT), fmt.Errorf("lamport clock jumping too far in the future, likely an attack")
 			}
 		}
 
@@ -187,11 +200,11 @@ func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolver
 	for _, opp := range oppMap {
 		err = repo.Witness(fmt.Sprintf(creationClockPattern, def.Namespace), opp.CreateTime)
 		if err != nil {
-			return nil, err
+			return *new(EntityT), err
 		}
 		err = repo.Witness(fmt.Sprintf(editClockPattern, def.Namespace), opp.EditTime)
 		if err != nil {
-			return nil, err
+			return *new(EntityT), err
 		}
 	}
 
@@ -232,13 +245,13 @@ func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolver
 		}
 	}
 
-	return &Entity{
+	return wrapper(&Entity{
 		Definition: def,
 		ops:        ops,
 		lastCommit: rootHash,
 		createTime: createTime,
 		editTime:   editTime,
-	}, nil
+	}), nil
 }
 
 // readClockNoCheck fetch from git, read and witness the clocks of an Entity at an arbitrary git reference.
@@ -293,14 +306,14 @@ func readClockNoCheck(def Definition, repo repository.ClockedRepo, ref string) e
 	return nil
 }
 
-type StreamedEntity struct {
-	Entity *Entity
+type StreamedEntity[EntityT entity.Interface] struct {
+	Entity EntityT
 	Err    error
 }
 
 // ReadAll read and parse all local Entity
-func ReadAll(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers) <-chan StreamedEntity {
-	out := make(chan StreamedEntity)
+func ReadAll[EntityT entity.Interface](def Definition, wrapper func(e *Entity) EntityT, repo repository.ClockedRepo, resolvers entity.Resolvers) <-chan StreamedEntity[EntityT] {
+	out := make(chan StreamedEntity[EntityT])
 
 	go func() {
 		defer close(out)
@@ -309,19 +322,19 @@ func ReadAll(def Definition, repo repository.ClockedRepo, resolvers entity.Resol
 
 		refs, err := repo.ListRefs(refPrefix)
 		if err != nil {
-			out <- StreamedEntity{Err: err}
+			out <- StreamedEntity[EntityT]{Err: err}
 			return
 		}
 
 		for _, ref := range refs {
-			e, err := read(def, repo, resolvers, ref)
+			e, err := read[EntityT](def, wrapper, repo, resolvers, ref)
 
 			if err != nil {
-				out <- StreamedEntity{Err: err}
+				out <- StreamedEntity[EntityT]{Err: err}
 				return
 			}
 
-			out <- StreamedEntity{Entity: e}
+			out <- StreamedEntity[EntityT]{Entity: e}
 		}
 	}()
 
diff --git a/entity/dag/entity_actions.go b/entity/dag/entity_actions.go
index c971f316..2a2bf87f 100644
--- a/entity/dag/entity_actions.go
+++ b/entity/dag/entity_actions.go
@@ -32,13 +32,13 @@ func Push(def Definition, repo repository.Repo, remote string) (string, error) {
 
 // Pull will do a Fetch + MergeAll
 // Contrary to MergeAll, this function will return an error if a merge fail.
-func Pull(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, author identity.Interface) error {
+func Pull[EntityT entity.Interface](def Definition, wrapper func(e *Entity) EntityT, repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, author identity.Interface) error {
 	_, err := Fetch(def, repo, remote)
 	if err != nil {
 		return err
 	}
 
-	for merge := range MergeAll(def, repo, resolvers, remote, author) {
+	for merge := range MergeAll(def, wrapper, repo, resolvers, remote, author) {
 		if merge.Err != nil {
 			return merge.Err
 		}
@@ -68,7 +68,7 @@ func Pull(def Definition, repo repository.ClockedRepo, resolvers entity.Resolver
 //
 // Note: an author is necessary for the case where a merge commit is created, as this commit will
 // have an author and may be signed if a signing key is available.
-func MergeAll(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, author identity.Interface) <-chan entity.MergeResult {
+func MergeAll[EntityT entity.Interface](def Definition, wrapper func(e *Entity) EntityT, repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, author identity.Interface) <-chan entity.MergeResult {
 	out := make(chan entity.MergeResult)
 
 	go func() {
@@ -82,7 +82,7 @@ func MergeAll(def Definition, repo repository.ClockedRepo, resolvers entity.Reso
 		}
 
 		for _, remoteRef := range remoteRefs {
-			out <- merge(def, repo, resolvers, remoteRef, author)
+			out <- merge[EntityT](def, wrapper, repo, resolvers, remoteRef, author)
 		}
 	}()
 
@@ -91,14 +91,14 @@ func MergeAll(def Definition, repo repository.ClockedRepo, resolvers entity.Reso
 
 // merge perform a merge to make sure a local Entity is up-to-date.
 // See MergeAll for more details.
-func merge(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, remoteRef string, author identity.Interface) entity.MergeResult {
+func merge[EntityT entity.Interface](def Definition, wrapper func(e *Entity) EntityT, repo repository.ClockedRepo, resolvers entity.Resolvers, remoteRef string, author identity.Interface) entity.MergeResult {
 	id := entity.RefToId(remoteRef)
 
 	if err := id.Validate(); err != nil {
 		return entity.NewMergeInvalidStatus(id, errors.Wrap(err, "invalid ref").Error())
 	}
 
-	remoteEntity, err := read(def, repo, resolvers, remoteRef)
+	remoteEntity, err := read[EntityT](def, wrapper, repo, resolvers, remoteRef)
 	if err != nil {
 		return entity.NewMergeInvalidStatus(id,
 			errors.Wrapf(err, "remote %s is not readable", def.Typename).Error())
@@ -197,7 +197,7 @@ func merge(def Definition, repo repository.ClockedRepo, resolvers entity.Resolve
 	// an empty operationPack.
 	// First step is to collect those clocks.
 
-	localEntity, err := read(def, repo, resolvers, localRef)
+	localEntity, err := read[EntityT](def, wrapper, repo, resolvers, localRef)
 	if err != nil {
 		return entity.NewMergeError(err, id)
 	}
diff --git a/entity/dag/entity_actions_test.go b/entity/dag/entity_actions_test.go
index e6888148..d93059de 100644
--- a/entity/dag/entity_actions_test.go
+++ b/entity/dag/entity_actions_test.go
@@ -11,10 +11,10 @@ import (
 	"github.com/MichaelMure/git-bug/repository"
 )
 
-func allEntities(t testing.TB, bugs <-chan StreamedEntity) []*Entity {
+func allEntities(t testing.TB, bugs <-chan StreamedEntity[*Foo]) []*Foo {
 	t.Helper()
 
-	var result []*Entity
+	var result []*Foo
 	for streamed := range bugs {
 		require.NoError(t, streamed.Err)
 
@@ -36,10 +36,10 @@ func TestEntityPushPull(t *testing.T) {
 	_, err = Push(def, repoA, "remote")
 	require.NoError(t, err)
 
-	err = Pull(def, repoB, resolvers, "remote", id1)
+	err = Pull(def, wrapper, repoB, resolvers, "remote", id1)
 	require.NoError(t, err)
 
-	entities := allEntities(t, ReadAll(def, repoB, resolvers))
+	entities := allEntities(t, ReadAll(def, wrapper, repoB, resolvers))
 	require.Len(t, entities, 1)
 
 	// B --> remote --> A
@@ -52,10 +52,10 @@ func TestEntityPushPull(t *testing.T) {
 	_, err = Push(def, repoB, "remote")
 	require.NoError(t, err)
 
-	err = Pull(def, repoA, resolvers, "remote", id1)
+	err = Pull(def, wrapper, repoA, resolvers, "remote", id1)
 	require.NoError(t, err)
 
-	entities = allEntities(t, ReadAll(def, repoB, resolvers))
+	entities = allEntities(t, ReadAll(def, wrapper, repoB, resolvers))
 	require.Len(t, entities, 2)
 }
 
@@ -85,7 +85,7 @@ func TestListLocalIds(t *testing.T) {
 	listLocalIds(t, def, repoA, 2)
 	listLocalIds(t, def, repoB, 0)
 
-	err = Pull(def, repoB, resolvers, "remote", id1)
+	err = Pull(def, wrapper, repoB, resolvers, "remote", id1)
 	require.NoError(t, err)
 
 	listLocalIds(t, def, repoA, 2)
@@ -228,7 +228,7 @@ func TestMerge(t *testing.T) {
 	_, err = Fetch(def, repoB, "remote")
 	require.NoError(t, err)
 
-	results := MergeAll(def, repoB, resolvers, "remote", id1)
+	results := MergeAll(def, wrapper, repoB, resolvers, "remote", id1)
 
 	assertMergeResults(t, []entity.MergeResult{
 		{
@@ -246,7 +246,7 @@ func TestMerge(t *testing.T) {
 	// SCENARIO 2
 	// if the remote and local Entity have the same state, nothing is changed
 
-	results = MergeAll(def, repoB, resolvers, "remote", id1)
+	results = MergeAll(def, wrapper, repoB, resolvers, "remote", id1)
 
 	assertMergeResults(t, []entity.MergeResult{
 		{
@@ -272,7 +272,7 @@ func TestMerge(t *testing.T) {
 	err = e2A.Commit(repoA)
 	require.NoError(t, err)
 
-	results = MergeAll(def, repoA, resolvers, "remote", id1)
+	results = MergeAll(def, wrapper, repoA, resolvers, "remote", id1)
 
 	assertMergeResults(t, []entity.MergeResult{
 		{
@@ -297,7 +297,7 @@ func TestMerge(t *testing.T) {
 	_, err = Fetch(def, repoB, "remote")
 	require.NoError(t, err)
 
-	results = MergeAll(def, repoB, resolvers, "remote", id1)
+	results = MergeAll(def, wrapper, repoB, resolvers, "remote", id1)
 
 	assertMergeResults(t, []entity.MergeResult{
 		{
@@ -324,10 +324,10 @@ func TestMerge(t *testing.T) {
 	err = e2A.Commit(repoA)
 	require.NoError(t, err)
 
-	e1B, err := Read(def, repoB, resolvers, e1A.Id())
+	e1B, err := Read(def, wrapper, repoB, resolvers, e1A.Id())
 	require.NoError(t, err)
 
-	e2B, err := Read(def, repoB, resolvers, e2A.Id())
+	e2B, err := Read(def, wrapper, repoB, resolvers, e2A.Id())
 	require.NoError(t, err)
 
 	e1B.Append(newOp1(id1, "barbarfoofoo"))
@@ -344,7 +344,7 @@ func TestMerge(t *testing.T) {
 	_, err = Fetch(def, repoB, "remote")
 	require.NoError(t, err)
 
-	results = MergeAll(def, repoB, resolvers, "remote", id1)
+	results = MergeAll(def, wrapper, repoB, resolvers, "remote", id1)
 
 	assertMergeResults(t, []entity.MergeResult{
 		{
@@ -365,7 +365,7 @@ func TestMerge(t *testing.T) {
 	_, err = Fetch(def, repoA, "remote")
 	require.NoError(t, err)
 
-	results = MergeAll(def, repoA, resolvers, "remote", id1)
+	results = MergeAll(def, wrapper, repoA, resolvers, "remote", id1)
 
 	assertMergeResults(t, []entity.MergeResult{
 		{
@@ -396,10 +396,10 @@ func TestRemove(t *testing.T) {
 	err = Remove(def, repoA, e.Id())
 	require.NoError(t, err)
 
-	_, err = Read(def, repoA, resolvers, e.Id())
+	_, err = Read(def, wrapper, repoA, resolvers, e.Id())
 	require.Error(t, err)
 
-	_, err = readRemote(def, repoA, resolvers, "remote", e.Id())
+	_, err = readRemote(def, wrapper, repoA, resolvers, "remote", e.Id())
 	require.Error(t, err)
 
 	// Remove is idempotent
diff --git a/entity/dag/entity_test.go b/entity/dag/entity_test.go
index e399b6c7..c457eb21 100644
--- a/entity/dag/entity_test.go
+++ b/entity/dag/entity_test.go
@@ -9,7 +9,7 @@ import (
 func TestWriteRead(t *testing.T) {
 	repo, id1, id2, resolver, def := makeTestContext()
 
-	entity := New(def)
+	entity := wrapper(New(def))
 	require.False(t, entity.NeedCommit())
 
 	entity.Append(newOp1(id1, "foo"))
@@ -24,16 +24,16 @@ func TestWriteRead(t *testing.T) {
 	require.NoError(t, entity.CommitAsNeeded(repo))
 	require.False(t, entity.NeedCommit())
 
-	read, err := Read(def, repo, resolver, entity.Id())
+	read, err := Read(def, wrapper, repo, resolver, entity.Id())
 	require.NoError(t, err)
 
-	assertEqualEntities(t, entity, read)
+	assertEqualEntities(t, entity.Entity, read.Entity)
 }
 
 func TestWriteReadMultipleAuthor(t *testing.T) {
 	repo, id1, id2, resolver, def := makeTestContext()
 
-	entity := New(def)
+	entity := wrapper(New(def))
 
 	entity.Append(newOp1(id1, "foo"))
 	entity.Append(newOp2(id2, "bar"))
@@ -43,10 +43,10 @@ func TestWriteReadMultipleAuthor(t *testing.T) {
 	entity.Append(newOp2(id1, "foobar"))
 	require.NoError(t, entity.CommitAsNeeded(repo))
 
-	read, err := Read(def, repo, resolver, entity.Id())
+	read, err := Read(def, wrapper, repo, resolver, entity.Id())
 	require.NoError(t, err)
 
-	assertEqualEntities(t, entity, read)
+	assertEqualEntities(t, entity.Entity, read.Entity)
 }
 
 func assertEqualEntities(t *testing.T, a, b *Entity) {
diff --git a/entity/dag/example_test.go b/entity/dag/example_test.go
index b1511dc6..a263eb2b 100644
--- a/entity/dag/example_test.go
+++ b/entity/dag/example_test.go
@@ -200,7 +200,11 @@ type ProjectConfig struct {
 }
 
 func NewProjectConfig() *ProjectConfig {
-	return &ProjectConfig{Entity: dag.New(def)}
+	return wrapper(dag.New(def))
+}
+
+func wrapper(e *dag.Entity) *ProjectConfig {
+	return &ProjectConfig{Entity: e}
 }
 
 // a Definition describes a few properties of the Entity, a sort of configuration to manipulate the
@@ -282,11 +286,7 @@ func (pc ProjectConfig) Compile() *Snapshot {
 
 // Read is a helper to load a ProjectConfig from a Repository
 func Read(repo repository.ClockedRepo, id entity.Id) (*ProjectConfig, error) {
-	e, err := dag.Read(def, repo, simpleResolvers(repo), id)
-	if err != nil {
-		return nil, err
-	}
-	return &ProjectConfig{Entity: e}, nil
+	return dag.Read(def, wrapper, repo, simpleResolvers(repo), id)
 }
 
 func simpleResolvers(repo repository.ClockedRepo) entity.Resolvers {
@@ -331,7 +331,7 @@ func Example_entity() {
 	_ = confRene.Commit(repoRene)
 
 	// Isaac pull and read the config
-	_ = dag.Pull(def, repoIsaac, simpleResolvers(repoIsaac), "origin", isaac)
+	_ = dag.Pull(def, wrapper, repoIsaac, simpleResolvers(repoIsaac), "origin", isaac)
 	confIsaac, _ := Read(repoIsaac, confRene.Id())
 
 	// Compile gives the current state of the config