fix: anchore#953 Derive language from pURL - https://github.com/ancho…

…re/syft… (anchore#957)

Signed-off-by: Christopher Phillips <christopher.phillips@anchore.com>

internal/formats/common/cyclonedxhelpers/component.go

@@ -86,6 +86,10 @@ func decodeComponent(c *cyclonedx.Component) *pkg.Package {
 		p.Type = pkg.TypeFromPURL(p.PURL)
 	}
 
+	if p.Language == "" {
+		p.Language = pkg.LanguageFromPURL(p.PURL)
+	}
+
 	return p
 }
 

internal/formats/common/cyclonedxhelpers/component_test.go

@@ -191,3 +191,31 @@ func Test_deriveBomRef(t *testing.T) {
 		})
 	}
 }
+
+func Test_decodeComponent(t *testing.T) {
+	javaComponentWithNoSyftProperties := cyclonedx.Component{
+		Name:       "ch.qos.logback/logback-classic",
+		Version:    "1.2.3",
+		PackageURL: "pkg:maven/ch.qos.logback/logback-classic@1.2.3",
+		Type:       "library",
+		BOMRef:     "pkg:maven/ch.qos.logback/logback-classic@1.2.3",
+	}
+
+	tests := []struct {
+		name      string
+		component cyclonedx.Component
+		want      pkg.Language
+	}{
+		{
+			name:      "derive language from pURL if missing",
+			component: javaComponentWithNoSyftProperties,
+			want:      pkg.Java,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, decodeComponent(&tt.component).Language)
+		})
+	}
+}

syft/pkg/cataloger/catalog.go

@@ -70,6 +70,13 @@ func Catalog(resolver source.FileResolver, release *linux.Release, catalogers ..
 			// generate PURL (note: this is excluded from package ID, so is safe to mutate)
 			p.PURL = pkg.URL(p, release)
 
+			// if we were not able to identify the language we have an opportunity
+			// to try and get this value from the PURL. Worst case we assert that
+			// we could not identify the language at either stage and set UnknownLanguage
+			if p.Language == "" {
+				p.Language = pkg.LanguageFromPURL(p.PURL)
+			}
+
 			// create file-to-package relationships for files owned by the package
 			owningRelationships, err := packageFileOwnershipRelationships(p, resolver)
 			if err != nil {

syft/pkg/language.go

@@ -11,7 +11,7 @@ type Language string
 
 const (
 	// the full set of supported programming languages
-	UnknownLanguage Language = "UnknownLanguage"
+	UnknownLanguage Language = ""
 	Java            Language = "java"
 	JavaScript      Language = "javascript"
 	Python          Language = "python"

test/integration/encode_decode_cycle_test.go

@@ -7,6 +7,7 @@ import (
 	"github.com/anchore/syft/internal/formats/cyclonedxxml"
 	"github.com/anchore/syft/internal/formats/syftjson"
 	"github.com/anchore/syft/syft/source"
+	"github.com/google/go-cmp/cmp"
 	"regexp"
 	"testing"
 
@@ -21,20 +22,26 @@ import (
 )
 
 // TestEncodeDecodeEncodeCycleComparison is testing for differences in how SBOM documents get encoded on multiple cycles.
-// By encding and decoding the sbom we can compare the differences between the set of resulting objects. However,
+// By encoding and decoding the sbom we can compare the differences between the set of resulting objects. However,
 // this requires specific comparisons being done, and select redactions/omissions being made. Additionally, there are
 // already unit tests on each format encoder-decoder for properly functioning comparisons in depth, so there is no need
 // to do an object-to-object comparison. For this reason this test focuses on a bytes-to-bytes comparison after an
 // encode-decode-encode loop which will detect lossy behavior in both directions.
 func TestEncodeDecodeEncodeCycleComparison(t *testing.T) {
+	// use second image for relationships
+	images := []string{"image-pkg-coverage", "image-owning-package"}
 	tests := []struct {
 		formatOption sbom.FormatID
 		redactor     func(in []byte) []byte
 		json         bool
 	}{
 		{
 			formatOption: syftjson.ID,
-			json:         true,
+			redactor: func(in []byte) []byte {
+				in = regexp.MustCompile("\"(id|parent)\": \"[^\"]+\",").ReplaceAll(in, []byte{})
+				return in
+			},
+			json: true,
 		},
 		{
 			formatOption: cyclonedxjson.ID,
@@ -55,9 +62,8 @@ func TestEncodeDecodeEncodeCycleComparison(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		// use second image for relationships
-		for _, image := range []string{"image-pkg-coverage", "image-owning-package"} {
-			t.Run(fmt.Sprintf("%s/%s", test.formatOption, image), func(t *testing.T) {
+		t.Run(fmt.Sprintf("%s", test.formatOption), func(t *testing.T) {
+			for _, image := range images {
 				originalSBOM, _ := catalogFixtureImage(t, image, source.SquashedScope)
 
 				format := syft.FormatByID(test.formatOption)
@@ -81,15 +87,15 @@ func TestEncodeDecodeEncodeCycleComparison(t *testing.T) {
 				if test.json {
 					s1 := string(by1)
 					s2 := string(by2)
-					assert.JSONEq(t, s1, s2)
-				} else {
-					if !assert.True(t, bytes.Equal(by1, by2)) {
-						dmp := diffmatchpatch.New()
-						diffs := dmp.DiffMain(string(by1), string(by2), true)
-						t.Errorf("diff: %s", dmp.DiffPrettyText(diffs))
+					if diff := cmp.Diff(s1, s2); diff != "" {
+						t.Errorf("Encode/Decode mismatch (-want +got):\n%s", diff)
 					}
+				} else if !assert.True(t, bytes.Equal(by1, by2)) {
+					dmp := diffmatchpatch.New()
+					diffs := dmp.DiffMain(string(by1), string(by2), true)
+					t.Errorf("diff: %s", dmp.DiffPrettyText(diffs))
 				}
-			})
-		}
+			}
+		})
 	}
 }