From 6cfa8a96b668aad7a4e5baa82e9786769fbd5cef Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Thu, 1 Jul 2021 17:32:49 +0200
Subject: [PATCH] Do not buffer further output when `readData()` is called on
 empty buffer

See comment; otherwise calls to `readAll()` with no `bytesAvailable()`
like done in the `syncthingctl` tests fail sporadically as async read
operations are started concurrently.
---
 connector/syncthingprocess.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/connector/syncthingprocess.cpp b/connector/syncthingprocess.cpp
index bf2a9d8..4c1c84f 100644
--- a/connector/syncthingprocess.cpp
+++ b/connector/syncthingprocess.cpp
@@ -674,8 +674,7 @@ qint64 SyncthingProcess::readData(char *data, qint64 maxSize)
         return 0;
     }
     if (!m_process->bytesBuffered) {
-        bufferOutput();
-        return 0;
+        return 0; // do *not* invoke bufferOutput() here; an async read operation is already pending
     }
 
     const auto bytesAvailable = m_process->bytesBuffered - m_process->bytesRead;