diff --git a/autotests/input/syntax/brokenlang.xml b/autotests/input/syntax/brokenlang.xml
new file mode 100644
--- /dev/null
+++ b/autotests/input/syntax/brokenlang.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE language SYSTEM "language.dtd">
+<language name="Broken Syntax" section="Others" version="1" kateversion="5.0">
+  <highlighting>
+    <list name="keywords"
+     fier />
+      </context>
+    </contexts>
+
+    <itemDatas>
+      <itemData name="Normal Text" defStyleNum="dsNormal" />
+      <iteng>
+  <general>
+    <keywl
+</language>
diff --git a/autotests/syntaxrepository_test.cpp b/autotests/syntaxrepository_test.cpp
--- a/autotests/syntaxrepository_test.cpp
+++ b/autotests/syntaxrepository_test.cpp
@@ -158,7 +158,7 @@
             State initialState;
             hl.setDefinition(def);
             const auto state = hl.highlightLine(QLatin1String("This should not crash } ] ) !"), initialState);
-            QVERIFY(!def.isValid() || state != initialState);
+            QVERIFY(!def.isValid() || state != initialState || def.name() == QLatin1String("Broken Syntax"));
         }
     }
 
@@ -310,7 +310,7 @@
                     formatIds.insert(format.id());
                 }
             }
-            QVERIFY(!def.isValid() || !formatIds.isEmpty());
+            QVERIFY(!def.isValid() || def.name() == QLatin1String("Broken Syntax") || !formatIds.isEmpty());
 
             // ensure all ids are there from 1..size
             for (int i = 1; i <= formatIds.size(); ++i) {
diff --git a/autotests/test-config.h.in b/autotests/test-config.h.in
--- a/autotests/test-config.h.in
+++ b/autotests/test-config.h.in
@@ -41,9 +41,11 @@
  */
 void initRepositorySearchPaths(KSyntaxHighlighting::Repository &repository)
 {
-#ifdef HAS_SYNTAX_RESOURCE
-    Q_UNUSED(repository)
-#else
+    // add extra search path for e.g. broken highlighting test
+    repository.addCustomSearchPath(QStringLiteral(TESTSRCDIR "/input"));
+
+    // handle no-resources case
+#ifndef HAS_SYNTAX_RESOURCE
     repository.addCustomSearchPath(QStringLiteral("@CMAKE_SOURCE_DIR@/data"));
     repository.addCustomSearchPath(QStringLiteral("@CMAKE_BINARY_DIR@/data/generated"));
 #endif
diff --git a/src/lib/abstracthighlighter.cpp b/src/lib/abstracthighlighter.cpp
--- a/src/lib/abstracthighlighter.cpp
+++ b/src/lib/abstracthighlighter.cpp
@@ -118,13 +118,13 @@
 
     // verify definition, deal with no highlighting being enabled
     d->ensureDefinitionLoaded();
-    if (!d->m_definition.isValid()) {
+    const auto defData = DefinitionData::get(d->m_definition);
+    if (!d->m_definition.isValid() || !defData->isLoaded()) {
         applyFormat(0, text.size(), Format());
         return State();
     }
 
     // verify/initialize state
-    auto defData = DefinitionData::get(d->m_definition);
     auto newState = state;
     auto stateData = StateData::get(newState);
     const DefinitionRef currentDefRef(d->m_definition);
diff --git a/src/lib/definition.cpp b/src/lib/definition.cpp
--- a/src/lib/definition.cpp
+++ b/src/lib/definition.cpp
@@ -320,8 +320,11 @@
 
 Context* DefinitionData::initialContext() const
 {
-    Q_ASSERT(!contexts.isEmpty());
-    return contexts.first();
+    Context* c = nullptr;
+    if (!contexts.isEmpty()) {
+        c = contexts.first();
+    }
+    return c;
 }
 
 Context* DefinitionData::contextByName(const QString& wantedName) const