[CODE HEALTH] Fix clang-tidy narrowing-conversions warnings in otlp_populate_attribute_utils by thc1006 · Pull Request #4090 · open-telemetry/opentelemetry-cpp

thc1006 · 2026-05-18T13:31:57Z

Summary

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

Line	Branch
~78	scalar `uint64_t` (PopulateAnyValue first overload)
~169	`nostd::span<const uint64_t>` array
~234	scalar `uint64_t` (PopulateAnyValue second overload)
~312	`std::vector<uint64_t>` array

Why static_cast, not a NOLINT rename

An earlier attempt to fix these by renaming the existing NOLINT(cppcoreguidelines-narrowing-conversions) to the new bugprone- alias name did not work: in clang-tidy v22 both names are registered as separate aliases, and NOLINT for one alias does not suppress reporting under the other. The warning simply flips to the other alias name. A single-name NOLINT cannot silence the diagnostic.

This PR instead replaces the four implicit narrowings with explicit static_cast<int64_t> conversions, matching the pattern established in the prior narrowing-cleanup PRs #3989, #3997, and #4013. This eliminates the alias dependency entirely and makes each narrowing explicit at the call site. No runtime behavior change — implicit narrowing under two's-complement was already producing the same bit pattern.

A fifth NOLINT at line ~297 (a uint32_t to int64_t conversion, which is signed widening rather than narrowing) is left untouched. clang-tidy v22 emits no warning there, and removing the dead NOLINT is out of scope.

Ratchet

all-options-abiv1-preview warning_limit lowered from 418 to 414
all-options-abiv2-preview warning_limit lowered from 424 to 420

Verification

Counts measured against artifacts of the most recent successful CI run on main (workflow clang-tidy.yaml, run 26018587378):

Preset	Before (count / limit)	After (predicted)
abiv1-preview	418 / 418	414 / 414
abiv2-preview	424 / 424	420 / 420

Test plan

CI clang-tidy job passes both abiv1-preview and abiv2-preview at the new limits
CI Format job passes (single-line static_cast expressions fit within 100 chars)
No behavioral change to OtlpPopulateAttributeUtils::PopulateAnyValue; existing tests in exporters/otlp/test/otlp_recordable_test.cc still cover the modified branches via type-parameterized tests over uint64_t

Part of #2053

Copilot

Pull request overview

Updates OTLP exporter code to align existing clang-tidy suppression comments with the clang-tidy v22 check name, and adjusts CI warning limits accordingly. This is a code health/CI maintenance change intended to keep the clang-tidy ratchet stable after the LLVM/clang-tidy 22 upgrade.

Changes:

Renames four NOLINT suppressions in otlp_populate_attribute_utils.cc from the old alias to bugprone-narrowing-conversions.
Lowers clang-tidy workflow warning limits for all-options-abiv1-preview and all-options-abiv2-preview.
Adds a corresponding CHANGELOG.md entry.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
exporters/otlp/src/otlp_populate_attribute_utils.cc	Updates four narrowing-conversion `NOLINT` suppressions to match clang-tidy v22’s check name.
CHANGELOG.md	Adds an Unreleased entry for the code health change.
.github/workflows/clang-tidy.yaml	Lowers the warning limits to reflect the reduced warning count.

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

  {
-    proto_value->set_int_value(
-        nostd::get<uint64_t>(value));  // NOLINT(cppcoreguidelines-narrowing-conversions)
+    proto_value->set_int_value(static_cast<int64_t>(nostd::get<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));


    {
-      array_value->add_values()->set_int_value(
-          val);  // NOLINT(cppcoreguidelines-narrowing-conversions)
+      array_value->add_values()->set_int_value(static_cast<int64_t>(val));


codecov · 2026-05-18T15:41:36Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.99%. Comparing base (026af08) to head (785ec9a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4090      +/-   ##
==========================================
- Coverage   81.99%   81.99%   -0.00%     
==========================================
  Files         385      385              
  Lines       16023    16019       -4     
==========================================
- Hits        13137    13133       -4     
  Misses       2886     2886

Files with missing lines	Coverage Δ
...xporters/otlp/src/otlp_populate_attribute_utils.cc	`92.71% <100.00%> (-0.20%)`	⬇️

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Eliminate the 29 misc-unused-alias-decls warnings flagged by clang-tidy across 27 files in examples, exporters, sdk, and tests. The most common pattern was a file-scope `namespace nostd = opentelemetry::nostd;` declaration that was never referenced via the file-scope alias path (uses of `nostd::` resolved through the surrounding OPENTELEMETRY_BEGIN_NAMESPACE namespace nesting instead). No behavior change. Removed declarations were genuinely dead per clang-tidy. Where removing an alias affected sibling-line alignment (e.g. `using M = ...` next to the removed alias), clang-format auto-collapsed the alignment. Ratchet: * abiv1-preview warning_limit lowered from 418 to 389 * abiv2-preview warning_limit lowered from 424 to 395 A 30th misc-unused-alias-decls site at exporters/otlp/src/otlp_populate_attribute_utils.cc:30 is intentionally not touched in this PR to avoid conflicting with the in-flight open-telemetry#4090. It can be cleaned up in a follow-up after open-telemetry#4090 lands. Part of open-telemetry#2053 Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>

Eliminate 29 misc-unused-alias-decls warnings flagged by clang-tidy v22 across 27 files in examples, exporters, sdk, and tests. The dominant pattern was a file-scope `namespace nostd = opentelemetry::nostd;` declaration never referenced via the file-scope alias path (uses of `nostd::` resolved through OPENTELEMETRY_BEGIN_NAMESPACE namespace nesting instead). Also remove 4 unused type-alias `using M = std::map<std::string, std::string>;` declarations in storage tests, observed by Copilot review. clang-tidy does not flag these (misc-unused-alias-decls targets only namespace aliases, not type aliases), but they are genuinely dead code in the same spirit and the same files this PR already touches. No behavior change. Removed declarations were genuinely unused. clang-format auto-collapsed adjacent orphan alignment whitespace where removing a line left aligned siblings. Ratchet: * abiv1-preview warning_limit lowered from 418 to 389 * abiv2-preview warning_limit lowered from 424 to 395 A 30th misc-unused-alias-decls site at exporters/otlp/src/otlp_populate_attribute_utils.cc:30 is intentionally not touched in this PR to avoid conflicting with the in-flight open-telemetry#4090. It can be cleaned up in a trivial follow-up after open-telemetry#4090 lands. Part of open-telemetry#2053 Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>

Eliminate 29 misc-unused-alias-decls warnings flagged by clang-tidy v22 across 27 files in examples, exporters, sdk, and tests. The dominant pattern was a file-scope `namespace nostd = opentelemetry::nostd;` declaration never referenced via the file-scope alias path (uses of `nostd::` resolved through OPENTELEMETRY_BEGIN_NAMESPACE namespace nesting instead). Also remove 4 unused type-alias `using M = std::map<std::string, std::string>;` declarations in storage tests, observed by Copilot review. clang-tidy does not flag these (misc-unused-alias-decls targets only namespace aliases, not type aliases), but they are genuinely dead code in the same spirit and the same files this PR already touches. Also remove 9 now-unused #include directives that IWYU flagged as a consequence of the alias removals: when an alias like `namespace http_client = opentelemetry::ext::http::client;` is removed, the include that brought the namespace into scope is no longer needed. Same logic for several `opentelemetry/common/attribute_value.h` includes that supported `namespace common = opentelemetry::common;` aliases, and `<map>` after removing the unused `using M = ...` from async_metric_storage_test.cc. No behavior change. Removed declarations were genuinely unused. clang-format auto-collapsed adjacent orphan alignment whitespace where removing a line left aligned siblings. Ratchet: * abiv1-preview warning_limit lowered from 418 to 389 * abiv2-preview warning_limit lowered from 424 to 395 A 30th misc-unused-alias-decls site at exporters/otlp/src/otlp_populate_attribute_utils.cc:30 is intentionally not touched in this PR to avoid conflicting with the in-flight open-telemetry#4090. It can be cleaned up in a trivial follow-up after open-telemetry#4090 lands. Part of open-telemetry#2053 Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>

…opulate_attribute_utils After the clang-tidy v22 upgrade in open-telemetry#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 open-telemetry#2053 Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>

Copilot AI review requested due to automatic review settings May 18, 2026 13:31

thc1006 requested a review from a team as a code owner May 18, 2026 13:31

thc1006 force-pushed the codehealth/otlp-narrowing-nolint-alias branch from b15a543 to e9fc36b Compare May 18, 2026 13:32

Copilot started reviewing on behalf of thc1006 May 18, 2026 13:32 View session

Copilot AI reviewed May 18, 2026

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Comment thread CHANGELOG.md Outdated

thc1006 force-pushed the codehealth/otlp-narrowing-nolint-alias branch from e9fc36b to cc4c581 Compare May 18, 2026 14:16

thc1006 changed the title ~~[CODE HEALTH] Update bugprone-narrowing-conversions NOLINT suppressions in otlp_populate_attribute_utils~~ [CODE HEALTH] Fix clang-tidy narrowing-conversions warnings in otlp_populate_attribute_utils May 18, 2026

thc1006 requested a review from Copilot May 18, 2026 14:18

Copilot AI reviewed May 18, 2026

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thc1006 force-pushed the codehealth/otlp-narrowing-nolint-alias branch from cc4c581 to 2c3d074 Compare May 18, 2026 14:32

Copilot started reviewing on behalf of thc1006 May 18, 2026 14:46 View session

thc1006 mentioned this pull request May 18, 2026

[CODE HEALTH] Remove unused alias declarations #4091

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thc1006 force-pushed the codehealth/otlp-narrowing-nolint-alias branch from 2c3d074 to 785ec9a Compare May 19, 2026 16:35

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[CODE HEALTH] Fix clang-tidy narrowing-conversions warnings in otlp_populate_attribute_utils#4090

[CODE HEALTH] Fix clang-tidy narrowing-conversions warnings in otlp_populate_attribute_utils#4090
thc1006 wants to merge 1 commit into
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thc1006:codehealth/otlp-narrowing-nolint-alias

thc1006 commented May 18, 2026 •

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thc1006 commented May 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Why static_cast, not a NOLINT rename

Ratchet

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thc1006 commented May 18, 2026 •

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