Fix edge case in change tracking

Under certain circumstances, transformers could lose the information
about properties requested by their commands. Make sure this doesn't
happen anymore.

Change-Id: Ib224cd8425760543ae805875024e7886f67825fe
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/lib/corelib/buildgraph/transformer.cpp b/src/lib/corelib/buildgraph/transformer.cpp
index 0e5b4a084..b6e02e708 100644
--- a/src/lib/corelib/buildgraph/transformer.cpp
+++ b/src/lib/corelib/buildgraph/transformer.cpp
@@ -260,6 +260,17 @@ void Transformer::createCommands(ScriptEngine *engine, const ScriptFunctionConst
     }
 }
 
+void Transformer::rescueChangeTrackingData(const TransformerConstPtr &other)
+{
+    if (!other)
+        return;
+    propertiesRequestedInPrepareScript = other->propertiesRequestedInPrepareScript;
+    propertiesRequestedInCommands = other->propertiesRequestedInCommands;
+    propertiesRequestedFromArtifactInPrepareScript
+            = other->propertiesRequestedFromArtifactInPrepareScript;
+    propertiesRequestedFromArtifactInCommands = other->propertiesRequestedFromArtifactInCommands;
+}
+
 void Transformer::load(PersistentPool &pool)
 {
     pool.load(rule);