From 6f0a31166d495bcbe4ce2fb5b6ff114724aa1874 Mon Sep 17 00:00:00 2001
From: Tobias Hunger <tobias.hunger@qt.io>
Date: Tue, 14 Mar 2017 12:27:57 +0100
Subject: [PATCH] ToolChains: Write compatibility information for QtC 4.2

This avoids turning all toolchains into C++ when going from Qt Creator 4.3
to Qt Creator 4.2 and back.

Change-Id: I607606f76d958c634ab27cb6db3bf35a1236b2b6
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
---
 src/plugins/projectexplorer/toolchain.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/plugins/projectexplorer/toolchain.cpp b/src/plugins/projectexplorer/toolchain.cpp
index bc69b898561..cb636437046 100644
--- a/src/plugins/projectexplorer/toolchain.cpp
+++ b/src/plugins/projectexplorer/toolchain.cpp
@@ -225,6 +225,15 @@ QVariantMap ToolChain::toMap() const
     result.insert(QLatin1String(ID_KEY), idToSave);
     result.insert(QLatin1String(DISPLAY_NAME_KEY), displayName());
     result.insert(QLatin1String(AUTODETECT_KEY), isAutoDetected());
+    // <Compatibility with QtC 4.2>
+    int oldLanguageId = -1;
+    if (language() == ProjectExplorer::Constants::C_LANGUAGE_ID)
+        oldLanguageId = 1;
+    else if (language() == ProjectExplorer::Constants::CXX_LANGUAGE_ID)
+        oldLanguageId = 2;
+    if (oldLanguageId >= 0)
+        result.insert(LANGUAGE_KEY_V1, oldLanguageId);
+    // </Compatibility>
     result.insert(QLatin1String(LANGUAGE_KEY_V2), language().toSetting());
     return result;
 }