From af240bff581be1ad63c7ed15fa182f23a3809fa2 Mon Sep 17 00:00:00 2001
From: mkoohafkan <michael.koohafkan@gmail.com>
Date: Mon, 5 Aug 2019 15:55:06 -0700
Subject: [PATCH] cleaner error when unloading fails

---
 R/connect.r | 10 ++++++----
 R/zzz.r     | 10 ++++++++--
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/R/connect.r b/R/connect.r
index e68c127..3541e01 100644
--- a/R/connect.r
+++ b/R/connect.r
@@ -192,10 +192,12 @@ hql_unload = function() {
 	if (hql_is_loaded()) {
 		dllpath = normalizePath(file.path(hql.paths$install,
 			hql.paths$dll), mustWork = TRUE)
-		lapply(dllpath, dyn.unload)
-		if (hql_is_loaded()) {
-			stop("HDFql DLLs could not be unloaded.")
-		}
+    for (dll in dllpath) {
+      dyn.unload(dll)
+      if (dll %in% sapply(getLoadedDLLs(), function(x) normalizePath(x[["path"]], mustWork = FALSE))) {
+        stop("Error unloading HDFql shared library object ", dll)
+      }
+    }
 		rm(list = "wrapper", envir = hql)
 	}
   invisible(NULL)
diff --git a/R/zzz.r b/R/zzz.r
index 7dd9785..eb1550c 100644
--- a/R/zzz.r
+++ b/R/zzz.r
@@ -15,9 +15,15 @@
 }
 
 .onUnload = function(libpath) {
-  hql_unload()
+  tryCatch(hql_unload(),
+    error = function(e) {
+      warning(packageName(), " could not be unloaded cleanly\n", e$message)
+    })
 }
 
 .onDetach = function(libpath) {
-  hql_unload()
+  tryCatch(hql_unload(),
+    error = function(e) {
+      warning(packageName(), " could not be unloaded cleanly\n", e$message)
+    })
 }