feat: retain go package info when no module declared

Signed-off-by: Weston Steimel <weston.steimel@anchore.com>

syft/pkg/cataloger/golang/parse_go_binary.go

@@ -51,6 +51,7 @@ func parseGoBinary(_ source.FileResolver, _ *generic.Environment, reader source.
 	internal.CloseAndLogError(reader.ReadCloser, reader.RealPath)
 
 	for i, mod := range mods {
+		log.Info(mod.Path)
 		pkgs = append(pkgs, buildGoPkgInfo(reader.Location, mod, archs[i])...)
 	}
 	return pkgs, nil, nil
@@ -179,12 +180,23 @@ func getBuildSettings(settings []debug.BuildSetting) map[string]string {
 	return m
 }
 
+func createMainModuleFromPath(path string) (mod debug.Module) {
+	mod.Path = path
+	mod.Version = devel
+	return
+}
+
 func buildGoPkgInfo(location source.Location, mod *debug.BuildInfo, arch string) []pkg.Package {
 	var pkgs []pkg.Package
 	if mod == nil {
 		return pkgs
 	}
 
+	var empty debug.Module
+	if mod.Main == empty && mod.Path != "" {
+		mod.Main = createMainModuleFromPath(mod.Path)
+	}
+
 	for _, dep := range mod.Deps {
 		if dep == nil {
 			continue
@@ -195,9 +207,6 @@ func buildGoPkgInfo(location source.Location, mod *debug.BuildInfo, arch string)
 		}
 	}
 
-	// NOTE(jonasagx): this use happened originally while creating unit tests. It might never
-	// happen in the wild, but I kept it as a safeguard against empty modules.
-	var empty debug.Module
 	if mod.Main == empty {
 		return pkgs
 	}

syft/pkg/cataloger/golang/scan_binary.go

@@ -33,6 +33,8 @@ func scanFile(reader unionreader.UnionReader, filename string) ([]*debug.BuildIn
 		builds = append(builds, bi)
 	}
 
+	log.Debug(filename)
+
 	archs := getArchs(readers, builds)
 
 	return builds, archs