From 785ec9a5caa653ec91ca13e1301a1fbb88968334 Mon Sep 17 00:00:00 2001
From: thc1006 <84045975+thc1006@users.noreply.github.com>
Date: Mon, 18 May 2026 21:31:21 +0800
Subject: [PATCH] [CODE HEALTH] Fix clang-tidy narrowing-conversions warnings
 in otlp_populate_attribute_utils

After the clang-tidy v22 upgrade in #4066, four narrowing-conversion
warnings surfaced in otlp_populate_attribute_utils.cc at the four
uint64_t to int64_t call sites passing to proto set_int_value.

The original code suppressed via NOLINT(cppcoreguidelines-narrowing-conversions).
In clang-tidy v22 both bugprone-narrowing-conversions and
cppcoreguidelines-narrowing-conversions are registered as separate
aliases, and NOLINT for one alias does not suppress the report under
the other. So an alias-name-rename approach cannot silence the warnings
with a single NOLINT.

Replace the four NOLINT-suppressed implicit narrowings with explicit
static_cast<int64_t> conversions, matching the pattern established in
and makes the narrowing explicit at the call site.

The fifth NOLINT at line ~297 (uint32_t to int64_t) is signed widening,
not narrowing; clang-tidy v22 emits no diagnostic there. Left untouched.

Ratchet:
* abiv1-preview warning_limit lowered from 418 to 414
* abiv2-preview warning_limit lowered from 424 to 420

Part of #2053

Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>
---
 .github/workflows/clang-tidy.yaml                |  4 ++--
 CHANGELOG.md                                     |  3 +++
 .../otlp/src/otlp_populate_attribute_utils.cc    | 16 ++++++++--------
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/.github/workflows/clang-tidy.yaml b/.github/workflows/clang-tidy.yaml
index 19ec7f1573..2cc9b91eaa 100644
--- a/.github/workflows/clang-tidy.yaml
+++ b/.github/workflows/clang-tidy.yaml
@@ -17,9 +17,9 @@ jobs:
       matrix:
         include:
           - cmake_options: all-options-abiv1-preview
-            warning_limit: 389
+            warning_limit: 385
           - cmake_options: all-options-abiv2-preview
-            warning_limit: 395
+            warning_limit: 391
     env:
       CC: /usr/bin/clang-22
       CXX: /usr/bin/clang++-22
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e57d7fa70b..d953ee278b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,9 @@ Increment the:
 * [CODE HEALTH] Fix IWYU Clang22 warnings
   [#4083](https://github.com/open-telemetry/opentelemetry-cpp/pull/4083)
 
+* [CODE HEALTH] Fix clang-tidy narrowing-conversions warnings in otlp_populate_attribute_utils
+  [#4090](https://github.com/open-telemetry/opentelemetry-cpp/pull/4090)
+
 * [CODE HEALTH] Remove unused alias declarations
   [#4091](https://github.com/open-telemetry/opentelemetry-cpp/pull/4091)
 
diff --git a/exporters/otlp/src/otlp_populate_attribute_utils.cc b/exporters/otlp/src/otlp_populate_attribute_utils.cc
index 75e47998ab..1fa384553a 100644
--- a/exporters/otlp/src/otlp_populate_attribute_utils.cc
+++ b/exporters/otlp/src/otlp_populate_attribute_utils.cc
@@ -75,8 +75,8 @@ void OtlpPopulateAttributeUtils::PopulateAnyValue(
   }
   else if (nostd::holds_alternative<uint64_t>(value))
   {
-    proto_value->set_int_value(
-        nostd::get<uint64_t>(value));  // NOLINT(cppcoreguidelines-narrowing-conversions)
+    // uint64_t narrowed to int64_t; OTLP int_value is signed, behavior intentional.
+    proto_value->set_int_value(static_cast<int64_t>(nostd::get<uint64_t>(value)));
   }
   else if (nostd::holds_alternative<double>(value))
   {
@@ -166,10 +166,10 @@ void OtlpPopulateAttributeUtils::PopulateAnyValue(
   else if (nostd::holds_alternative<nostd::span<const uint64_t>>(value))
   {
     auto array_value = proto_value->mutable_array_value();
+    // uint64_t narrowed to int64_t; OTLP int_value is signed, behavior intentional.
     for (const auto &val : nostd::get<nostd::span<const uint64_t>>(value))
     {
-      array_value->add_values()->set_int_value(
-          val);  // NOLINT(cppcoreguidelines-narrowing-conversions)
+      array_value->add_values()->set_int_value(static_cast<int64_t>(val));
     }
   }
   else if (nostd::holds_alternative<nostd::span<const double>>(value))
@@ -235,8 +235,8 @@ void OtlpPopulateAttributeUtils::PopulateAnyValue(
   }
   else if (nostd::holds_alternative<uint64_t>(value))
   {
-    proto_value->set_int_value(
-        nostd::get<uint64_t>(value));  // NOLINT(cppcoreguidelines-narrowing-conversions)
+    // uint64_t narrowed to int64_t; OTLP int_value is signed, behavior intentional.
+    proto_value->set_int_value(static_cast<int64_t>(nostd::get<uint64_t>(value)));
   }
   else if (nostd::holds_alternative<double>(value))
   {
@@ -311,10 +311,10 @@ void OtlpPopulateAttributeUtils::PopulateAnyValue(
   else if (nostd::holds_alternative<std::vector<uint64_t>>(value))
   {
     auto array_value = proto_value->mutable_array_value();
+    // uint64_t narrowed to int64_t; OTLP int_value is signed, behavior intentional.
     for (const auto &val : nostd::get<std::vector<uint64_t>>(value))
     {
-      array_value->add_values()->set_int_value(
-          val);  // NOLINT(cppcoreguidelines-narrowing-conversions)
+      array_value->add_values()->set_int_value(static_cast<int64_t>(val));
     }
   }
   else if (nostd::holds_alternative<std::vector<double>>(value))