From bc710ddcc1d5dadb23d67a89d1e37f423487de80 Mon Sep 17 00:00:00 2001
From: Jacob Alber <jacob.alber@microsoft.com>
Date: Wed, 14 Feb 2024 21:03:45 -0500
Subject: [PATCH] fix: Build break on Ubuntu 2004

The code to generate bad namespaces in examples was interacting poorly with auto.
---
 vowpalwabbit/fb_parser/tests/read_span_tests.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/vowpalwabbit/fb_parser/tests/read_span_tests.cc b/vowpalwabbit/fb_parser/tests/read_span_tests.cc
index cd6316a13cb..5622be90dae 100644
--- a/vowpalwabbit/fb_parser/tests/read_span_tests.cc
+++ b/vowpalwabbit/fb_parser/tests/read_span_tests.cc
@@ -178,13 +178,15 @@ Offset<fb::ExampleCollection> create_bad_ns_root_collection(
 {
   if VW_STD17_CONSTEXPR (multiline)
   {
-    auto inner_examples = {create_bad_ns_root_multiex(builder, w, ns_fac)};
+    // using "auto" here breaks the code coverage build due to template substitution failure
+    std::vector<Offset<fb::MultiExample>> inner_examples = {create_bad_ns_root_multiex(builder, w, ns_fac)};
     return fb::CreateExampleCollection(builder, builder.CreateVector(std::vector<Offset<fb::Example>>()),
         builder.CreateVector(inner_examples), multiline);
   }
   else
   {
-    auto inner_examples = {create_bad_ns_root_example(builder, w, ns_fac)};
+    // using "auto" here breaks the code coverage build due to template substitution failure
+    std::vector<Offset<fb::Example>> inner_examples = {create_bad_ns_root_example(builder, w, ns_fac)};
     return fb::CreateExampleCollection(builder, builder.CreateVector(inner_examples),
         builder.CreateVector(std::vector<Offset<fb::MultiExample>>()), multiline);
   }