From 5efd327dd4a638f63396ff22e908f16a8d6b9f20 Mon Sep 17 00:00:00 2001
From: Sergio Losilla <38527108+loximann@users.noreply.github.com>
Date: Thu, 2 Jun 2022 17:11:12 +0300
Subject: [PATCH] Fix crash when running with --list-listeners and no
 registered listeners (#2442)

Co-authored-by: Sergio Losilla <sergio.losilla@nt-bnct.com>
---
 src/catch2/reporters/catch_reporter_combined_tu.cpp | 7 ++++++-
 tests/ExtraTests/CMakeLists.txt                     | 5 ++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/catch2/reporters/catch_reporter_combined_tu.cpp b/src/catch2/reporters/catch_reporter_combined_tu.cpp
index 0625943310..2d6e112c2b 100644
--- a/src/catch2/reporters/catch_reporter_combined_tu.cpp
+++ b/src/catch2/reporters/catch_reporter_combined_tu.cpp
@@ -154,6 +154,12 @@ namespace Catch {
 
     void defaultListListeners( std::ostream& out,
                                std::vector<ListenerDescription> const& descriptions ) {
+        out << "Registered listeners:\n";
+
+        if(descriptions.empty()) {
+            return;
+        }
+
         const auto maxNameLen =
             std::max_element( descriptions.begin(),
                               descriptions.end(),
@@ -163,7 +169,6 @@ namespace Catch {
                               } )
                 ->name.size();
 
-        out << "Registered listeners:\n";
         for ( auto const& desc : descriptions ) {
             out << TextFlow::Column( static_cast<std::string>( desc.name ) +
                                      ':' )
diff --git a/tests/ExtraTests/CMakeLists.txt b/tests/ExtraTests/CMakeLists.txt
index e533ad4a44..f33bd7c117 100644
--- a/tests/ExtraTests/CMakeLists.txt
+++ b/tests/ExtraTests/CMakeLists.txt
@@ -459,7 +459,10 @@ add_test(
   NAME TestSpecs::OverrideFailureWithEmptySpec
   COMMAND $<TARGET_FILE:NoTests> --allow-running-no-tests
 )
-
+add_test(
+  NAME List::Listeners::WorksWithoutRegisteredListeners
+  COMMAND $<TARGET_FILE:NoTests> --list-listeners
+)
 set( EXTRA_TEST_BINARIES
     PrefixedMacros
     DisabledMacros