no nil strings anymore (#985)

Looks good

package_scanner.nim

@@ -25,7 +25,6 @@ import sets
 import strutils
 
 const
-
   LICENSES = @[
     "Allegro 4 Giftware",
     "Apache License 2.0",
@@ -47,7 +46,6 @@ const
     "ISC",
     "Unlicense"
   ]
-
   VCS_TYPES = @["git", "hg"]
 
 proc canFetchNimbleRepository(name: string, urlJson: JsonNode): bool =
@@ -80,57 +78,43 @@ proc verifyAlias(pdata: JsonNode, result: var int) =
   # TODO: Verify that 'alias' points to a known package.
 
 proc check(): int =
-  var
-    name: string
-
+  var name: string
   echo ""
-
-  let
-    pkg_list = parseJson(readFile(getCurrentDir() / "packages.json"))
-
+  let pkg_list = parseJson(readFile(getCurrentDir() / "packages.json"))
   var names = initSet[string]()
 
   for pdata in pkg_list:
-    name = if pdata.hasKey("name"): pdata["name"].str else: nil
+    name = if pdata.hasKey("name"): pdata["name"].str else: ""
 
     if pdata.hasKey("alias"):
       verifyAlias(pdata, result)
     else:
-      if name.isNil:
+      if name == "":
         echo "E: missing package name"
         result.inc()
-
       elif not pdata.hasKey("method"):
         echo "E: ", name, " has no method"
         result.inc()
-
       elif not (pdata["method"].str in VCS_TYPES):
         echo "E: ", name, " has an unknown method: ", pdata["method"].str
         result.inc()
-
       elif not pdata.hasKey("url"):
         echo "E: ", name, " has no URL"
         result.inc()
-
       elif pdata.hasKey("web") and not canFetchNimbleRepository(name, pdata["web"]):
         result.inc()
-
       elif not pdata.hasKey("tags"):
         echo "E: ", name, " has no tags"
         result.inc()
-
       elif not pdata.hasKey("description"):
         echo "E: ", name, " has no description"
         result.inc()
-
       elif not pdata.hasKey("license"):
         echo "E: ", name, " has no license"
         result.inc()
-
       elif pdata["url"].str.normalize.startsWith("git://github.com/"):
         echo "E: ", name, " has an insecure git:// URL instead of https://"
         result.inc()
-
       else:
         # Other warnings should go here
         if not (pdata["license"].str in LICENSES):