Recursive expansion of relations and unions (#14)

* Require spaces around negation operator

* Recursive expansion of relations and unions

* Keep unused loadFromManifest in expand_test.go

It's helpful when we need to regenerate expand_test.json

cache/expand.go

@@ -28,8 +28,11 @@ func (c *Cache) ExpandRelation(on model.ObjectName, rn model.RelationName) []mod
 
 	// iterate through relation set, determine if it "unions" with the given relation.
 	for _, r := range rs {
-		if r.Subject != nil && r.Subject.Object == on {
+		switch {
+		case r.Subject != nil && r.Subject.Object == on:
 			results = append(results, r.Subject.Relation)
+		case r.Direct != "":
+			results = append(results, c.ExpandRelation(on, model.RelationName(r.Direct))...)
 		}
 	}
 
@@ -47,15 +50,17 @@ func (c *Cache) ExpandPermission(on model.ObjectName, pn model.PermissionName) [
 	results := []model.RelationName{}
 
 	// starting object type and permission must exist in order to be expanded.
-	if o, ok := c.model.Objects[on]; !ok {
+	o, ok := c.model.Objects[on]
+	if !ok {
 		return results
-	} else if _, ok := o.Permissions[pn]; !ok {
+	}
+	if _, ok := o.Permissions[pn]; !ok {
 		return results
 	}
 
 	p := c.model.Objects[on].Permissions[pn]
 
-	results = append(results, expandUnion(p.Union)...)
+	results = append(results, c.expandUnion(o, p.Union...)...)
 
 	for _, rn := range results {
 		results = append(results, c.ExpandRelation(on, rn)...)
@@ -65,10 +70,21 @@ func (c *Cache) ExpandPermission(on model.ObjectName, pn model.PermissionName) [
 }
 
 // convert union []string to []model.RelationName.
-func expandUnion(u []string) []model.RelationName {
+func (c *Cache) expandUnion(o *model.Object, u ...string) []model.RelationName {
 	result := []model.RelationName{}
 	for _, v := range u {
-		result = append(result, model.RelationName(v))
+		rn := model.RelationName(v)
+		result = append(result, rn)
+
+		exp := lo.FilterMap(o.Relations[rn], func(r *model.Relation, _ int) (string, bool) {
+			if r.Direct == "" {
+				return "", false
+			}
+			_, ok := o.Relations[model.RelationName(r.Direct)]
+			return string(r.Direct), ok
+
+		})
+		result = append(result, c.expandUnion(o, exp...)...)
 	}
 	return result
 }

cache/expand_test.go

@@ -3,18 +3,22 @@ package cache_test
 import (
 	"encoding/json"
 	"os"
+	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/aserto-dev/azm/cache"
 	"github.com/aserto-dev/azm/model"
+	v3 "github.com/aserto-dev/azm/v3"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
 // load model cache from serialized model file.
-func loadModelCache(t *testing.T, filepath string) *cache.Cache {
-	r, err := os.Open(filepath)
+func loadModelCache(t *testing.T, path string) *cache.Cache {
+	r, err := os.Open(path)
 	require.NoError(t, err)
+	defer r.Close()
 
 	var mc model.Model
 	dec := json.NewDecoder(r)
@@ -25,6 +29,25 @@ func loadModelCache(t *testing.T, filepath string) *cache.Cache {
 	return cache.New(&mc)
 }
 
+// helper to regenerate the serialized cache from a manifest.
+func loadFromManifest(t *testing.T, path string) *cache.Cache { // nolint:unused
+	r, err := os.Open(path)
+	require.NoError(t, err)
+	defer r.Close()
+
+	m, err := v3.Load(r)
+	require.NoError(t, err)
+
+	cachefile := strings.TrimSuffix(path, filepath.Ext(path)) + ".json"
+	w, err := os.Create(cachefile)
+	require.NoError(t, err)
+	defer w.Close()
+
+	require.NoError(t, m.Write(w))
+
+	return cache.New(m)
+}
+
 func TestExpandRelation(t *testing.T) {
 	mc := loadModelCache(t, "./expand_test.json")