Stop exceptions in generator constructors from aborting the binary

Fixes #2615

2 files changed, 23 insertions, 6 deletions

diff --git a/src/catch2/generators/catch_generators.cpp b/src/catch2/generators/catch_generators.cpp
index 7cc5aa8a..3514e9f6 100644
--- a/src/catch2/generators/catch_generators.cpp
+++ b/src/catch2/generators/catch_generators.cpp
@@ -27,9 +27,16 @@ namespace Detail {
 
     GeneratorUntypedBase::~GeneratorUntypedBase() = default;
 
-    auto acquireGeneratorTracker(StringRef generatorName, SourceLineInfo const& lineInfo ) -> IGeneratorTracker& {
+    IGeneratorTracker* acquireGeneratorTracker(StringRef generatorName, SourceLineInfo const& lineInfo ) {
         return getResultCapture().acquireGeneratorTracker( generatorName, lineInfo );
     }
 
+    IGeneratorTracker* createGeneratorTracker( StringRef generatorName,
+                                 SourceLineInfo lineInfo,
+                                 GeneratorBasePtr&& generator ) {
+        return getResultCapture().createGeneratorTracker(
+            generatorName, lineInfo, CATCH_MOVE( generator ) );
+    }
+
 } // namespace Generators
 } // namespace Catch
diff --git a/src/catch2/generators/catch_generators.hpp b/src/catch2/generators/catch_generators.hpp
index ec8f2795..79a23b12 100644
--- a/src/catch2/generators/catch_generators.hpp
+++ b/src/catch2/generators/catch_generators.hpp
@@ -204,18 +204,28 @@ namespace Detail {
         return makeGenerators( value( T( CATCH_FORWARD( val ) ) ), CATCH_FORWARD( moreGenerators )... );
     }
 
-    auto acquireGeneratorTracker( StringRef generatorName, SourceLineInfo const& lineInfo ) -> IGeneratorTracker&;
+    IGeneratorTracker* acquireGeneratorTracker( StringRef generatorName,
+                                                SourceLineInfo const& lineInfo );
+    IGeneratorTracker* createGeneratorTracker( StringRef generatorName,
+                                               SourceLineInfo lineInfo,
+                                               GeneratorBasePtr&& generator );
 
     template<typename L>
     auto generate( StringRef generatorName, SourceLineInfo const& lineInfo, L const& generatorExpression ) -> typename decltype(generatorExpression())::type {
         using UnderlyingType = typename decltype(generatorExpression())::type;
 
-        IGeneratorTracker& tracker = acquireGeneratorTracker( generatorName, lineInfo );
-        if (!tracker.hasGenerator()) {
-            tracker.setGenerator(Catch::Detail::make_unique<Generators<UnderlyingType>>(generatorExpression()));
+        IGeneratorTracker* tracker = acquireGeneratorTracker( generatorName, lineInfo );
+        // Creation of tracker is delayed after generator creation, so
+        // that constructing generator can fail without breaking everything.
+        if (!tracker) {
+            tracker = createGeneratorTracker(
+                generatorName,
+                lineInfo,
+                Catch::Detail::make_unique<Generators<UnderlyingType>>(
+                    generatorExpression() ) );
         }
 
-        auto const& generator = static_cast<IGenerator<UnderlyingType> const&>( *tracker.getGenerator() );
+        auto const& generator = static_cast<IGenerator<UnderlyingType> const&>( *tracker->getGenerator() );
         return generator.get();
     }