fix(http2): fix possible race condition when handling http2 stream on almost timed out session by improving timeout out algorithm; (#7186)

lib/adapters/http.js

@@ -87,7 +87,15 @@ class Http2Sessions {
 
     const session = connect(authority, options);
 
-    session.once('close', () => {
+    let removed;
+
+    const removeSession = () => {
+      if (removed) {
+        return;
+      }
+
+      removed = true;
+
       let entries = authoritySessions, len = entries.length, i = len;
 
       while (i--) {
@@ -99,9 +107,41 @@ class Http2Sessions {
           }
         }
       }
-    });
+    };
 
-    Http2Sessions.setTimeout(session, options.sessionTimeout);
+    const originalRequestFn = session.request;
+
+    const {sessionTimeout} = options;
+
+    if(sessionTimeout != null) {
+
+      let timer;
+      let streamsCount = 0;
+
+      session.request = function () {
+        const stream = originalRequestFn.apply(this, arguments);
+
+        streamsCount++;
+
+        if (timer) {
+          clearTimeout(timer);
+          timer = null;
+        }
+
+        stream.once('close', () => {
+          if (!--streamsCount) {
+            timer = setTimeout(() => {
+              timer = null;
+              removeSession();
+            }, sessionTimeout);
+          }
+        });
+
+        return stream;
+      }
+    }
+
+    session.once('close', removeSession);
 
     let entries = this.sessions[authority], entry = [
       session,
@@ -112,12 +152,6 @@ class Http2Sessions {
 
     return session;
   }
-
-  static setTimeout(session, timeout = 1000) {
-    session && session.setTimeout(timeout, () => {
-      session.close();
-    });
-  }
 }
 
 const http2Sessions = new Http2Sessions();
@@ -284,10 +318,12 @@ export default isHttpAdapterSupported && function httpAdapter(config) {
     let rejected = false;
     let req;
 
-    httpVersion = Number(httpVersion);
+    httpVersion = +httpVersion;
+
     if (Number.isNaN(httpVersion)) {
       throw TypeError(`Invalid protocol version: '${config.httpVersion}' is not a number`);
     }
+
     if (httpVersion !== 1 && httpVersion !== 2) {
       throw TypeError(`Unsupported protocol version '${httpVersion}'`);
     }