feat: report unknowns in sbom (#2998)

Signed-off-by: Keith Zantow <kzantow@gmail.com>
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
Co-authored-by: Alex Goodman <wagoodman@users.noreply.github.com>

syft/pkg/cataloger/dart/parse_pubspec_lock.go

@@ -9,6 +9,7 @@ import (
 	"gopkg.in/yaml.v3"
 
 	"github.com/anchore/syft/internal/log"
+	"github.com/anchore/syft/internal/unknown"
 	"github.com/anchore/syft/syft/artifact"
 	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/pkg"
@@ -85,7 +86,7 @@ func parsePubspecLock(_ context.Context, _ file.Resolver, _ *generic.Environment
 		)
 	}
 
-	return pkgs, nil, nil
+	return pkgs, nil, unknown.IfEmptyf(pkgs, "unable to determine packages")
 }
 
 func (p *pubspecLockPackage) getVcsURL() string {

syft/pkg/cataloger/dart/parse_pubspec_lock_test.go

@@ -106,3 +106,10 @@ func TestParsePubspecLock(t *testing.T) {
 
 	pkgtest.TestFileParser(t, fixture, parsePubspecLock, expected, expectedRelationships)
 }
+
+func Test_corruptPubspecLock(t *testing.T) {
+	pkgtest.NewCatalogTester().
+		FromFile(t, "test-fixtures/corrupt/pubspec.lock").
+		WithError().
+		TestParser(t, parsePubspecLock)
+}

syft/pkg/cataloger/dart/test-fixtures/corrupt/pubspec.lock

@@ -0,0 +1,7 @@
+pa
+kages:
+  ale:
+    dependency: transitive
+    descr
+s  ps:
+  dart: ">=2.12.0 <3.0.0"