[dd-apm-ecosystems]

Overview

Enable readability-braces-around-statements in the shared clang-tidy baseline (.clang-tidy), wired into the existing clang-tidy CI step (bin/check-tidy, run from .github/workflows/dev.yml).

Motivation

Reviewers have repeatedly asked contributors to add braces around single-line if/return bodies in C++ changes. This is a recurring, mechanical review comment that a clang-tidy check can enforce automatically instead of a human re-raising it on every PR.

Additional Notes

This repo's src/ tree (the tree scanned by bin/check-tidy) already has no brace-less control statements, so enabling the check requires no source changes here — it is a config-only change. The companion check is also being proposed in httpd-datadog and nginx-datadog, which share this .clang-tidy baseline and do have a small number of existing brace-less statements to fix alongside enabling the check there.

References

Jira ticket:

Contributor Checklist

• I am the author of this pull request and I own it.
• I reviewed every line of this pull request.
• This pull request follows the Contributing Guidelines.

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Additional context (automated analysis)

This PR was opened by an automated clang-tidy-review workflow that scans PR activity across DataDog/dd-trace-cpp, DataDog/httpd-datadog, and DataDog/nginx-datadog for recurring, automatable C++ review themes.

Theme: Missing braces around single-line if/return control-flow bodies (readability-braces-around-statements).

Observed in: 4 occurrences across 2 repos / 4 distinct PRs (recurrence bar requires ≥2 distinct PRs):

• feat: add C language binding #286 (comment) (raised by @xlamorlette-datadog)
• Implement stable session identifier headers for telemetry #295 (comment) (raised by @xlamorlette-datadog)
• fix: observe baggage limits on extraction #313 (comment) (raised by @xlamorlette-datadog; accepted — "fixed in d4c0de6")
• Respect child-scope override for tracing directives httpd-datadog#62 (comment) (raised by @xlamorlette-datadog; accepted via commit 8694cdf "Add braces to multi-line if/return in tracing hooks")

Verification: src/ and include/ in this repo were checked (via GitHub content reads of span.cpp, trace_segment.cpp, tracer.cpp, trace_sampler.cpp, w3c_propagation.cpp, and targeted search_code queries for brace-less if (...) return ...; patterns) and found clean of this pattern already, so this change is config-only and should not fail the existing clang-tidy CI job.

Not actioned this run (reported for completeness):

• readability-magic-numbers — recurring (dd-trace-cpp#286, dd-trace-cpp#330, nginx-datadog#304) but has a high false-positive rate against existing code (e.g. HTTP/protocol version constants, array sizes) and would need case-by-case suppression; skipped per the "require low false-positive rate" guardrail.
• C-style/functional-style casts (cppcoreguidelines-pro-type-cstyle-cast) — recurring (dd-trace-cpp#286, nginx-datadog#304) but src/datadog/trace_sampler.cpp has several pre-existing functional-style casts (int(rule.mechanism), etc.) and clang-tidy here runs over the whole src/ tree (no per-diff scoping mechanism exists), so enabling it now would break CI on pre-existing code.
• Manual new/delete instead of RAII — recurring (httpd-datadog#88, nginx-datadog#304) but the observed instances are deliberate C-API interop with pool-scoped lifetimes (APR/ngx pools), not accidental ownership bugs; bugprone-unused-raii (already enabled) covers the genuine bug case.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	🔄 Running since 2026-10-23T14:43:29.612335Z	f7ccec3	Draft marked ready

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[datadog-datadog-prod-us1-2]

Enabling the new brace-enforcement clang-tidy rule without first fixing existing violations in src/datadog/w3c_propagation.cpp (line 151) and src/datadog/platform_util_unix.cpp (lines 183–186) will break CI, because WarningsAsErrors: '*' turns these diagnostics into hard failures for bin/check-tidy.

_{Open Bits AI session}

_{🤖 Bits Code Review · Commit f7ccec3}

[xlamorlette-datadog]

To allow one-line condition block, such as:

if (env_host && env_host->empty()) env_host = nullopt;

It seems we can try:

CheckOptions:
  - key: readability-braces-around-statements.ShortStatementLines
    value: 1

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-10-23 15:24:40

Comparing candidate commit 6d6d377 in PR branch automated/clang-tidy-missing-braces-2026-10-17 with baseline commit 4c9520b in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 8 metrics, 0 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'