feat: library path messages

print library message during plan (and therefore also install)
will now error if no library specified. This was a bug
introduced when relaxing the strict mode requirement
as library path used to be required, however when making it
optional, if people now include no library or lockfile type
pkgr would not do the right thing

closes: #239 #237

cmd/plan.go

@@ -228,6 +228,7 @@ func planInstall(rv cran.RVersion, exitOnMissing bool) (*cran.PkgNexus, gpsr.Ins
 		"to_install": toInstall,
 		"to_update":  pkgsToUpdateCount,
 	}).Info("package installation plan")
+	log.Infof("Library path to install packages: %s\n", cfg.Library)
 
 	if toInstall > 0 && toInstall != totalPackagesRequired {
 		// log which packages to install, but only if doing an incremental install

configlib/config.go

@@ -50,6 +50,9 @@ func getLibraryPath(lockfileType string, rpath string, rversion cran.RVersion, p
 	case "pkgr":
 	default:
 	}
+	if library == "" {
+		log.Fatal("must specify either a Lockfile Type or  Library path")
+	}
 	return library
 }