Fix using QNetworkReply with custom url schemes

Sequential QIODevices are allowed to report atEnd() when they have no
data to read, but add more data later.

To avoid a regression with our own tests, treat a read error from a
sequential device at end, as end-of-data.

Pick-to: 6.4 6.4.0 6.3
Fixes: QTBUG-106461
Change-Id: Iac1233e6daa978c827c37a7fd3131e2fce764111
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/core/net/custom_url_loader_factory.cpp b/src/core/net/custom_url_loader_factory.cpp
index 9873b979a..bd7d7dc58 100644
--- a/src/core/net/custom_url_loader_factory.cpp
+++ b/src/core/net/custom_url_loader_factory.cpp
@@ -380,13 +380,20 @@ private:
             m_totalBytesRead += bytesRead;
             m_client->OnTransferSizeUpdated(m_totalBytesRead);
 
-            if (m_device->atEnd() || (m_maxBytesToRead > 0 && m_totalBytesRead >= m_maxBytesToRead)) {
+            const bool deviceAtEnd = m_device->atEnd();
+            if ((deviceAtEnd && !m_device->isSequential())
+                || (m_maxBytesToRead > 0 && m_totalBytesRead >= m_maxBytesToRead)) {
                 OnTransferComplete(MOJO_RESULT_OK);
                 return true; // Done with reading
             }
 
             if (readResult == 0)
                 return false; // Wait for readyRead
+            if (readResult < 0 && deviceAtEnd && m_device->isSequential()) {
+                // Failure on read, and sequential device claiming to be at end, so treat it as a successful end-of-data.
+                OnTransferComplete(MOJO_RESULT_OK);
+                return true; // Done with reading
+            }
             if (readResult < 0)
                 break;
         }