fix: #953 Derive language from pURL - https://github.com/anchore/syft… (#957)

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

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 {