Use values in relationship To/From fields (#2871)

* use pkg values in relationship fields

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* add linter rule for using values in relationships

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* use new cmptest package for comparing relationships

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* create cmptest for common cmp.Diff options in test

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* condense matches for relationship ruleguard

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* remove relationship type from rules

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* restore build tag

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* suggest using values

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* nil check pkgs

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

---------

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

internal/relationship/by_file_ownership.go

@@ -58,9 +58,19 @@ func byFileOwnershipOverlap(catalog *pkg.Collection) []artifact.Relationship {
 			parent := catalog.Package(parentID) // TODO: this is potentially expensive
 			child := catalog.Package(childID)   // TODO: this is potentially expensive
 
+			if parent == nil {
+				log.Tracef("parent package not found: %v", parentID)
+				continue
+			}
+
+			if child == nil {
+				log.Tracef("child package not found: %v", childID)
+				continue
+			}
+
 			edges = append(edges, artifact.Relationship{
-				From: parent,
-				To:   child,
+				From: *parent,
+				To:   *child,
 				Type: artifact.OwnershipByFileOverlapRelationship,
 				Data: ownershipByFilesMetadata{
 					Files: fs,

internal/relationship/by_file_ownership_test.go

@@ -3,8 +3,10 @@ package relationship
 import (
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/stretchr/testify/assert"
 
+	"github.com/anchore/syft/internal/cmptest"
 	"github.com/anchore/syft/syft/artifact"
 	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/pkg"
@@ -143,10 +145,9 @@ func TestOwnershipByFilesRelationship(t *testing.T) {
 			assert.Len(t, relationships, len(expectedRelations))
 			for idx, expectedRelationship := range expectedRelations {
 				actualRelationship := relationships[idx]
-				assert.Equal(t, expectedRelationship.From.ID(), actualRelationship.From.ID())
-				assert.Equal(t, expectedRelationship.To.ID(), actualRelationship.To.ID())
-				assert.Equal(t, expectedRelationship.Type, actualRelationship.Type)
-				assert.Equal(t, expectedRelationship.Data, actualRelationship.Data)
+				if d := cmp.Diff(expectedRelationship, actualRelationship, cmptest.DefaultCommonOptions()...); d != "" {
+					t.Errorf("unexpected relationship (-want, +got): %s", d)
+				}
 			}
 		})
 	}