Restore behavior of JSON distro block (#643)

grype/presenter/json/test-fixtures/snapshot/TestEmptyJsonPresenter.golden

@@ -34,7 +34,7 @@
   }
  },
  "distro": {
-  "name": "",
+  "name": "centos",
   "version": "8.0",
   "idLike": [
    "rhel"

grype/presenter/json/test-fixtures/snapshot/TestJsonDirsPresenter.golden

@@ -165,7 +165,7 @@
   "target": "/some/path"
  },
  "distro": {
-  "name": "",
+  "name": "centos",
   "version": "8.0",
   "idLike": [
    "rhel"

grype/presenter/json/test-fixtures/snapshot/TestJsonImgsPresenter.golden

@@ -230,7 +230,7 @@
   }
  },
  "distro": {
-  "name": "",
+  "name": "centos",
   "version": "8.0",
   "idLike": [
    "rhel"

grype/presenter/models/distribution.go

@@ -1,6 +1,8 @@
 package models
 
 import (
+	"github.com/anchore/grype/grype/distro"
+	"github.com/anchore/grype/internal/log"
 	"github.com/anchore/syft/syft/linux"
 )
 
@@ -12,14 +14,34 @@ type distribution struct {
 }
 
 // newDistribution creates a struct with the Linux distribution to be represented in JSON.
-func newDistribution(d *linux.Release) distribution {
-	if d == nil {
+func newDistribution(r *linux.Release) distribution {
+	if r == nil {
 		return distribution{}
 	}
 
+	// attempt to use the strong distro type (like the matchers do)
+	d, err := distro.NewFromRelease(*r)
+	if err != nil {
+		log.Warnf("unable to determine linux distribution: %+v", err)
+
+		// as a fallback use the raw release information
+		return distribution{
+			Name:    r.ID,
+			Version: r.VersionID,
+			IDLike:  cleanIDLike(r.IDLike),
+		}
+	}
+
 	return distribution{
-		Name:    d.Name,
-		Version: d.Version,
-		IDLike:  d.IDLike,
+		Name:    d.Name(),
+		Version: d.FullVersion(),
+		IDLike:  cleanIDLike(d.IDLike),
 	}
 }
+
+func cleanIDLike(idLike []string) []string {
+	if idLike == nil {
+		return make([]string, 0)
+	}
+	return idLike
+}

grype/presenter/template/test-fixtures/snapshot/TestPresenter_Present.golden

@@ -1,4 +1,4 @@
-Identified distro as centos version 8.0.
+Identified distro as redhat version 8.0.
     Vulnerability: CVE-1999-0001
     Severity: Low
     Package: package-1 version 1.1.1 (deb)