3 files changed, 27 insertions, 0 deletions
diff --git a/src/lib/corelib/buildgraph/artifactset.cpp b/src/lib/corelib/buildgraph/artifactset.cpp
index 0010e81fe..eea4ccf65 100644
--- a/src/lib/corelib/buildgraph/artifactset.cpp
+++ b/src/lib/corelib/buildgraph/artifactset.cpp
@@ -53,6 +53,19 @@ ArtifactSet &ArtifactSet::unite(const ArtifactSet &other)
     return *this;
 }
 
+QStringList ArtifactSet::toStringList() const
+{
+    QStringList sl;
+    foreach (Artifact *a, *this)
+        sl += a->filePath();
+    return sl;
+}
+
+QString ArtifactSet::toString() const
+{
+    return QLatin1Char('[') + toStringList().join(QLatin1String(", ")) + QLatin1Char(']');
+}
+
 ArtifactSet ArtifactSet::fromNodeSet(const NodeSet &nodes)
 {
     ArtifactSet result;
diff --git a/src/lib/corelib/buildgraph/artifactset.h b/src/lib/corelib/buildgraph/artifactset.h
index 696859649..5361d706f 100644
--- a/src/lib/corelib/buildgraph/artifactset.h
+++ b/src/lib/corelib/buildgraph/artifactset.h
@@ -31,6 +31,7 @@
 #define QBS_ARTIFACTSET_H
 
 #include <QSet>
+#include <QStringList>
 
 namespace qbs {
 namespace Internal {
@@ -46,6 +47,8 @@ public:
     ArtifactSet(const QSet<Artifact *> &other);
 
     ArtifactSet &unite(const ArtifactSet &other);
+    QStringList toStringList() const;
+    QString toString() const;
 
     static ArtifactSet fromNodeSet(const NodeSet &nodes);
     static ArtifactSet fromNodeList(const QList<Artifact *> &lst);
diff --git a/src/lib/corelib/buildgraph/rulenode.cpp b/src/lib/corelib/buildgraph/rulenode.cpp
index 3ea324238..4bf027bfa 100644
--- a/src/lib/corelib/buildgraph/rulenode.cpp
+++ b/src/lib/corelib/buildgraph/rulenode.cpp
@@ -70,6 +70,17 @@ void RuleNode::apply(const Logger &logger, const ArtifactSet &changedInputs,
     const ArtifactSet removedInputs = m_oldInputArtifacts - allCompatibleInputs;
     result->upToDate = changedInputs.isEmpty() && addedInputs.isEmpty() && removedInputs.isEmpty();
 
+    if (logger.traceEnabled()) {
+        logger.qbsTrace()
+                << "[BG] consider " << (m_rule->isDynamic() ? "dynamic " : "")
+                << (m_rule->multiplex ? "multiplex " : "")
+                << "rule node " << m_rule->toString()
+                << "\n\tchanged: " << changedInputs.toString()
+                << "\n\tcompatible: " << allCompatibleInputs.toString()
+                << "\n\tadded: " << addedInputs.toString()
+                << "\n\tremoved: " << removedInputs.toString();
+    }
+
     ArtifactSet inputs = changedInputs;
     if (product->isMarkedForReapplication(m_rule)) {
         QBS_CHECK(m_rule->multiplex);