Fix segfault when coverage runs with annotations disabled

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 6
 
 ## main
 
+* Fix segfault when Ruby coverage is enabled but template annotations are disabled.
+
+    *George Holborn*
+
 * Add `protocol` parameter to `with_request_url` test helper to enable testing with HTTPS protocol.
 
     *Joel Hawksley*

lib/view_component/template.rb

@@ -30,8 +30,10 @@ def initialize(component:, details:, path:)
         # annotation line from compiled source instead.
         lineno =
           if Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR > 0 && details.handler == :erb
-            if coverage_running? && ActionView::Base.annotate_rendered_view_with_filenames
-              @strip_annotation_line = true
+            if coverage_running?
+              # Can't use negative lineno with coverage (causes segfault on Linux).
+              # Strip annotation line if enabled to preserve correct line numbers.
+              @strip_annotation_line = ActionView::Base.annotate_rendered_view_with_filenames
               0
             else
               -1

test/sandbox/test/inline_template_test.rb

@@ -210,6 +210,25 @@ class InlineComponentDerivedFromComponentSupportingVariants < Level2Component
     end
   end
 
+  # Regression test for segfault when coverage is running but annotations are DISABLED.
+  # This is the common case in CI environments.
+  test "file-based templates compile without segfault when coverage is running and annotations disabled" do
+    skip unless Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR > 0
+
+    without_template_annotations do
+      with_coverage_running do
+        # Force recompilation with coverage "enabled" but annotations disabled
+        ViewComponent::CompileCache.cache.delete(ErbComponent)
+
+        # This would segfault in v4.3.0 because it only avoided -1 lineno
+        # when annotations were enabled
+        render_inline(ErbComponent.new(message: "Foo bar"))
+
+        assert_selector("div", text: "Foo bar")
+      end
+    end
+  end
+
   test "inline templates compile without segfault when coverage is running" do
     skip unless Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR > 0