From 6df8cf53c6e66183ecbfeb995256b685788b7c9f Mon Sep 17 00:00:00 2001
From: Arsen Musayelyan <moussaelianarsen@gmail.com>
Date: Sun, 1 May 2022 13:54:36 -0700
Subject: [PATCH] Don't close channel if it's already closed

---
 client/main.go | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/client/main.go b/client/main.go
index f6b7b19..79504f4 100644
--- a/client/main.go
+++ b/client/main.go
@@ -106,6 +106,7 @@ func (c *Client) Call(rcvr, method string, arg interface{}, ret interface{}) err
 		c.chs[chID] = make(chan *types.Response, 5)
 		c.chMtx.Unlock()
 
+		channelClosed := false
 		go func() {
 			// Get type of channel elements
 			chElemType := retVal.Type().Elem()
@@ -121,6 +122,8 @@ func (c *Client) Call(rcvr, method string, arg interface{}, ret interface{}) err
 					// Close return channel
 					retVal.Close()
 
+					channelClosed = true
+
 					break
 				}
 				// Get reflect value from channel response
@@ -148,12 +151,14 @@ func (c *Client) Call(rcvr, method string, arg interface{}, ret interface{}) err
 					break
 				}
 			}
-			c.Call("lrpc", "ChannelDone", id, nil)
-			// Close and delete channel
-			c.chMtx.Lock()
-			close(c.chs[chID])
-			delete(c.chs, chID)
-			c.chMtx.Unlock()
+			if !channelClosed {
+				c.Call("lrpc", "ChannelDone", id, nil)
+				// Close and delete channel
+				c.chMtx.Lock()
+				close(c.chs[chID])
+				delete(c.chs, chID)
+				c.chMtx.Unlock()
+			}
 		}()
 	} else {
 		// IF return value is not a pointer, return error