Use PotentialNamespace in ancestry

If PotentialNamespace is available for given feature it is used instead
of detector namespace. Detector is empty in such a case.

ancestry.go

@@ -211,9 +211,20 @@ func (b *AncestryBuilder) createLayerIndexedFeature(namespace *layerIndexedNames
 
 func (b *AncestryBuilder) lookupNamespace(feature *database.LayerFeature) (*layerIndexedNamespace, bool) {
 	matchedNamespaces := []*layerIndexedNamespace{}
-	for i, namespace := range b.namespaces {
-		if namespace.Namespace.VersionFormat == feature.VersionFormat {
-			matchedNamespaces = append(matchedNamespaces, &b.namespaces[i])
+	if feature.PotentialNamespace.Name != "" {
+		a := &layerIndexedNamespace{
+			Namespace: database.LayerNamespace{
+				Namespace: feature.PotentialNamespace,
+			},
+			IntroducedIn: b.layerIndex,
+		}
+		matchedNamespaces = append(matchedNamespaces, a)
+	} else {
+
+		for i, namespace := range b.namespaces {
+			if namespace.Namespace.VersionFormat == feature.VersionFormat {
+				matchedNamespaces = append(matchedNamespaces, &b.namespaces[i])
+			}
 		}
 	}
 

ancestry_test.go

@@ -31,6 +31,7 @@ var (
 	aptsources = database.NewNamespaceDetector("apt-sources", "1.0")
 	ubuntu     = *database.NewNamespace("ubuntu:14.04", "dpkg")
 	ubuntu16   = *database.NewNamespace("ubuntu:16.04", "dpkg")
+	rhel7      = *database.NewNamespace("cpe:/o:redhat:enterprise_linux:7::computenode", "rpm")
 	debian     = *database.NewNamespace("debian:7", "dpkg")
 	python2    = *database.NewNamespace("python:2", "pip")
 	sed        = *database.NewSourcePackage("sed", "4.4-2", "dpkg")
@@ -39,6 +40,8 @@ var (
 	tar        = *database.NewBinaryPackage("tar", "1.29b-2", "dpkg")
 	scipy      = *database.NewSourcePackage("scipy", "3.0.0", "pip")
 
+	emptyNamespace = database.Namespace{}
+
 	detectors               = []database.Detector{dpkg, osrelease, rpm}
 	multinamespaceDetectors = []database.Detector{dpkg, osrelease, pip}
 )
@@ -97,10 +100,11 @@ func (b *layerBuilder) addNamespace(detector database.Detector, ns database.Name
 	return b
 }
 
-func (b *layerBuilder) addFeature(detector database.Detector, f database.Feature) *layerBuilder {
+func (b *layerBuilder) addFeature(detector database.Detector, f database.Feature, ns database.Namespace) *layerBuilder {
 	b.layer.Features = append(b.layer.Features, database.LayerFeature{
-		Feature: f,
-		By:      detector,
+		Feature:            f,
+		By:                 detector,
+		PotentialNamespace: ns,
 	})
 
 	return b
@@ -112,39 +116,43 @@ var testImage = []*database.Layer{
 	// ubuntu namespace
 	newLayerBuilder("1").addNamespace(osrelease, ubuntu).layer,
 	// install sed
-	newLayerBuilder("2").addFeature(dpkg, sed).layer,
+	newLayerBuilder("2").addFeature(dpkg, sed, emptyNamespace).layer,
 	// install tar
-	newLayerBuilder("3").addFeature(dpkg, sed).addFeature(dpkg, tar).layer,
+	newLayerBuilder("3").addFeature(dpkg, sed, emptyNamespace).addFeature(dpkg, tar, emptyNamespace).layer,
 	// remove tar
-	newLayerBuilder("4").addFeature(dpkg, sed).layer,
+	newLayerBuilder("4").addFeature(dpkg, sed, emptyNamespace).layer,
 	// upgrade ubuntu
 	newLayerBuilder("5").addNamespace(osrelease, ubuntu16).layer,
 	// no change to the detectable files
 	newLayerBuilder("6").layer,
 	// change to the package installer database but no features are affected.
-	newLayerBuilder("7").addFeature(dpkg, sed).layer,
+	newLayerBuilder("7").addFeature(dpkg, sed, emptyNamespace).layer,
 }
 
 var invalidNamespace = []*database.Layer{
 	// add package without namespace, this indicates that the namespace detector
 	// could not detect the namespace.
-	newLayerBuilder("0").addFeature(dpkg, sed).layer,
+	newLayerBuilder("0").addFeature(dpkg, sed, emptyNamespace).layer,
 }
 
 var noMatchingNamespace = []*database.Layer{
-	newLayerBuilder("0").addFeature(rpm, sedByRPM).addFeature(dpkg, sed).addNamespace(osrelease, ubuntu).layer,
+	newLayerBuilder("0").addFeature(rpm, sedByRPM, emptyNamespace).addFeature(dpkg, sed, emptyNamespace).addNamespace(osrelease, ubuntu).layer,
 }
 
 var multiplePackagesOnFirstLayer = []*database.Layer{
-	newLayerBuilder("0").addFeature(dpkg, sed).addFeature(dpkg, tar).addFeature(dpkg, sedBin).addNamespace(osrelease, ubuntu16).layer,
+	newLayerBuilder("0").addFeature(dpkg, sed, emptyNamespace).addFeature(dpkg, tar, emptyNamespace).addFeature(dpkg, sedBin, emptyNamespace).addNamespace(osrelease, ubuntu16).layer,
 }
 
 var twoNamespaceDetectorsWithSameResult = []*database.Layer{
-	newLayerBuilderWithoutDetector("0").addDetectors(dpkg, aptsources, osrelease).addFeature(dpkg, sed).addNamespace(aptsources, ubuntu).addNamespace(osrelease, ubuntu).layer,
+	newLayerBuilderWithoutDetector("0").addDetectors(dpkg, aptsources, osrelease).addFeature(dpkg, sed, emptyNamespace).addNamespace(aptsources, ubuntu).addNamespace(osrelease, ubuntu).layer,
 }
 
 var sameVersionFormatDiffName = []*database.Layer{
-	newLayerBuilder("0").addFeature(dpkg, sed).addNamespace(aptsources, ubuntu).addNamespace(osrelease, debian).layer,
+	newLayerBuilder("0").addFeature(dpkg, sed, emptyNamespace).addNamespace(aptsources, ubuntu).addNamespace(osrelease, debian).layer,
+}
+
+var potentialFeatureNamespace = []*database.Layer{
+	newLayerBuilder("0").addFeature(rpm, sed, rhel7).layer,
 }
 
 func TestAddLayer(t *testing.T) {
@@ -262,6 +270,10 @@ func TestAddLayer(t *testing.T) {
 			title:            "noMatchingNamespace",
 			image:            noMatchingNamespace,
 			expectedAncestry: *newAncestryBuilder(ancestryName([]string{"0"})).addDetectors(detectors...).addLayer("0", ancestryFeature(ubuntu, sed, osrelease, dpkg)).ancestry,
+		}, {
+			title:            "featureWithPotentialNamespace",
+			image:            potentialFeatureNamespace,
+			expectedAncestry: *newAncestryBuilder(ancestryName([]string{"0"})).addDetectors(detectors...).addLayer("0", ancestryFeature(rhel7, sed, database.Detector{}, rpm)).ancestry,
 		},
 	}
 

database/pgsql/ancestry/ancestry_feature.go

@@ -50,7 +50,7 @@ func FindAncestryFeatures(tx *sql.Tx, ancestryID int64, detectors detector.Detec
 	for rows.Next() {
 		var (
 			featureDetectorID   int64
-			namespaceDetectorID int64
+			namespaceDetectorID sql.NullInt64
 			feature             database.NamespacedFeature
 			// index is used to determine which layer the feature belongs to.
 			index sql.NullInt64
@@ -81,9 +81,14 @@ func FindAncestryFeatures(tx *sql.Tx, ancestryID int64, detectors detector.Detec
 			return nil, database.ErrInconsistent
 		}
 
-		nsDetector, ok := detectors.ByID[namespaceDetectorID]
-		if !ok {
-			return nil, database.ErrInconsistent
+		var nsDetector database.Detector
+		if !namespaceDetectorID.Valid {
+			nsDetector = database.Detector{}
+		} else {
+			nsDetector, ok = detectors.ByID[namespaceDetectorID.Int64]
+			if !ok {
+				return nil, database.ErrInconsistent
+			}
 		}
 
 		featureMap[index.Int64] = append(featureMap[index.Int64], database.AncestryFeature{
@@ -120,9 +125,11 @@ func InsertAncestryFeatures(tx *sql.Tx, ancestryLayerID int64, layer database.An
 			return database.ErrMissingEntities
 		}
 
-		namespaceDetectorID, ok := detectors.ByValue[layer.Features[index].NamespaceBy]
-		if !ok {
-			return database.ErrMissingEntities
+		var namespaceDetectorID sql.NullInt64
+		var ok bool
+		namespaceDetectorID.Int64, ok = detectors.ByValue[layer.Features[index].NamespaceBy]
+		if ok {
+			namespaceDetectorID.Valid = true
 		}
 
 		featureDetectorID, ok := detectors.ByValue[layer.Features[index].FeatureBy]

database/pgsql/migrations/00001_initial_schema.go

@@ -127,7 +127,7 @@ var (
 				ancestry_layer_id INT NOT NULL REFERENCES ancestry_layer ON DELETE CASCADE,
 				namespaced_feature_id INT NOT NULL REFERENCES namespaced_feature ON DELETE CASCADE,
 				feature_detector_id INT NOT NULL REFERENCES detector ON DELETE CASCADE,
-				namespace_detector_id INT NOT NULL REFERENCES detector ON DELETE CASCADE,
+				namespace_detector_id INT REFERENCES detector ON DELETE CASCADE,
 				UNIQUE (ancestry_layer_id, namespaced_feature_id));`,
 
 			`CREATE TABLE IF NOT EXISTS ancestry_detector(