(#342) - remove strong distro check (#496)

* add Type conversion to remove strong distro type limit
Signed-off-by: Christopher Angelo Phillips <christopher.phillips@anchore.com>

* update signatures to be correct variable from os-release
Signed-off-by: Christopher Angelo Phillips <christopher.phillips@anchore.com>

syft/distro/distro.go

@@ -19,10 +19,12 @@ func NewDistro(t Type, ver, like string) (Distro, error) {
 	if ver == "" {
 		return Distro{Type: t}, nil
 	}
+
 	verObj, err := hashiVer.NewVersion(ver)
 	if err != nil {
 		return Distro{}, fmt.Errorf("could not create distro version: %w", err)
 	}
+
 	return Distro{
 		Type:       t,
 		Version:    verObj,
@@ -39,7 +41,7 @@ func (d Distro) Name() string {
 // MajorVersion returns the major version value from the pseudo-semantically versioned distro version value.
 func (d Distro) MajorVersion() string {
 	if d.Version == nil {
-		return fmt.Sprint("(version unknown)")
+		return "(version unknown)"
 	}
 	return fmt.Sprintf("%d", d.Version.Segments()[0])
 }

syft/distro/identify.go

@@ -97,11 +97,11 @@ identifyLoop:
 	return distro
 }
 
-func assemble(name, version, like string) *Distro {
+func assemble(id, version, like string) *Distro {
-	distroType, ok := IDMapping[name]
+	distroType, ok := IDMapping[id]
 
 	// Both distro and version must be present
-	if len(name) == 0 && len(version) == 0 {
+	if len(id) == 0 && len(version) == 0 {
 		return nil
 	}
 
@@ -110,15 +110,17 @@ func assemble(name, version, like string) *Distro {
 		distroType, ok = IDMapping[like]
 	}
 
-	if ok {
+	// If we still can't match allow name to be used in constructor
+	if !ok {
+		distroType = Type(id)
+	}
+
 	distro, err := NewDistro(distroType, version, like)
 	if err != nil {
 		return nil
 	}
-		return &distro
-	}
 
-	return nil
+	return &distro
 }
 
 func parseOsRelease(contents string) *Distro {

syft/distro/identify_test.go

@@ -2,16 +2,19 @@ package distro
 
 import (
 	"fmt"
-	hashiVer "github.com/hashicorp/go-version"
 	"io/ioutil"
 	"os"
 	"testing"
 
+	hashiVer "github.com/hashicorp/go-version"
+
 	"github.com/anchore/syft/internal"
 	"github.com/anchore/syft/syft/source"
 	"github.com/stretchr/testify/assert"
 )
 
+const CustomDistro Type = "scientific"
+
 func TestIdentifyDistro(t *testing.T) {
 	tests := []struct {
 		fixture string
@@ -68,8 +71,9 @@ func TestIdentifyDistro(t *testing.T) {
 			Type:    UnknownDistroType,
 		},
 		{
-			fixture: "test-fixtures/os/unmatchable",
+			fixture: "test-fixtures/os/custom",
-			Type:    UnknownDistroType,
+			Type:    CustomDistro,
+			Version: "8.0.0",
 		},
 		{
 			fixture: "test-fixtures/os/opensuse-leap",