Initialize command info cache

Author: Kapil Borle

Engine/Helper.cs

@@ -156,9 +156,27 @@ public void Initialize()
             runspacePool.SetMaxRunspaces(3);
             runspacePool.Open();
 
-            IEnumerable<CommandInfo> aliases = this.invokeCommand.GetCommands("*", CommandTypes.Alias, true);
+            // set up command info cache
+            foreach (var cmdInfo in this.invokeCommand.GetCommands("*", CommandTypes.All, true))
+            {
+                if (!commandInfoCache.ContainsKey(cmdInfo.Name))
+                {
+                    commandInfoCache.AddOrUpdate(cmdInfo.Name, key => cmdInfo, (key, value) => cmdInfo);
+                }
+                else
+                {
+                    var version = commandInfoCache[cmdInfo.Name].Version;
+                    if (cmdInfo.Version != null
+                        && (version == null
+                            || cmdInfo.Version > commandInfoCache[cmdInfo.Name].Version))
+                    {
+                        commandInfoCache[cmdInfo.Name] = cmdInfo;
+                    }
+                }
+            }
 
-            foreach (AliasInfo aliasInfo in aliases)
+            // set up alias cache
+            foreach (AliasInfo aliasInfo in commandInfoCache.Values.Where(cmdInfo => cmdInfo.CommandType == CommandTypes.Alias))
             {
                 if (!CmdletToAliasDictionary.ContainsKey(aliasInfo.Definition))
                 {