fix(esm): skip loader hook registration when instrumentation bails out by BridgeAR · Pull Request #9242 · DataDog/dd-trace-js

BridgeAR · 2026-07-07T22:05:00Z

Summary

--import dd-trace/initialize.mjs on an unsupported runtime, or as a single-step install that defers to a manually-installed copy, still registered the async ESM loader even though the tracer never initialized. With nothing to instrument, that loader can keep a short-lived process from exiting — the hanging --import guardrail children seen on Node 24.

init.js returns the tracer on success and undefined on a bailout, so the registration is now gated on that result. The --import guardrail cases drop the kill timer so a child that fails to exit fails the suite instead of being masked.

`--import dd-trace/initialize.mjs` on an unsupported runtime, or as a single-step install that defers to a manually-installed copy, still registered the async ESM loader even though the tracer never initialized. With nothing to instrument, that loader can keep a short-lived process from exiting — the hanging `--import` guardrail children seen on Node 24. `init.js` returns the tracer on success and `undefined` on a bailout, so gate the registration on that result. The `--import` guardrail cases drop the kill timer so a child that fails to exit fails the suite instead of being masked.

dd-octo-sts · 2026-07-07T22:05:52Z

Overall package size

Self size: 6.65 MB
Deduped: 7.31 MB
No deduping: 7.31 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 3.3.1 | 122.62 kB | 437.94 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | dc-polyfill | 0.1.11 | 25.74 kB | 25.74 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

datadog-datadog-prod-us1 · 2026-07-07T22:07:42Z

Tests

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 96.50% (+0.00%)

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: c02a598 | Docs | Datadog PR Page | Give us feedback!}

pr-commenter · 2026-07-07T22:15:35Z

Benchmarks

Benchmark execution time: 2026-07-07 22:15:31

Comparing candidate commit c02a598 in PR branch BridgeAR/2026-07-07-initialize-skip-loader-on-bailout with baseline commit 221c2fb in branch master.

📊 Benchmarking dashboard

Found 0 performance improvements and 0 performance regressions! Performance is the same for 2315 metrics, 43 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 ----------------------------------'

Unstable benchmarks

These benchmarks have a confidence interval too wide to call a change; treat them as noise rather than signal.

scenario:appsec-appsec-enabled-24

unstable execution_time [-213.529ms; +225.152ms] or [-7.988%; +8.423%]

scenario:appsec-appsec-enabled-26

unstable execution_time [-239.152ms; +245.438ms] or [-9.361%; +9.607%]

scenario:appsec-appsec-enabled-with-attacks-24

unstable execution_time [-154.304ms; +168.669ms] or [-4.976%; +5.439%]

scenario:appsec-appsec-enabled-with-attacks-26

unstable execution_time [-187.083ms; +191.970ms] or [-6.341%; +6.507%]

scenario:appsec-control-20

unstable execution_time [-112.521ms; +125.304ms] or [-6.874%; +7.655%]

scenario:appsec-control-24

unstable execution_time [-120.766ms; +118.419ms] or [-9.726%; +9.537%]

scenario:appsec-control-26

unstable execution_time [-123121.547µs; +123438.714µs] or [-9.985%; +10.011%]

scenario:appsec-iast-no-vulnerability-iast-enabled-always-active-20

unstable execution_time [-16.815ms; +12.237ms] or [-6.459%; +4.700%]

scenario:appsec-iast-no-vulnerability-iast-enabled-default-config-20

unstable execution_time [-14000.845µs; +13022.912µs] or [-5.508%; +5.123%]

scenario:appsec-iast-with-vulnerability-iast-enabled-always-active-20

unstable execution_time [-30.572ms; +33.690ms] or [-5.454%; +6.011%]

scenario:appsec-iast-with-vulnerability-iast-enabled-default-config-20

unstable execution_time [-33.574ms; +37.232ms] or [-6.075%; +6.737%]

scenario:child_process-shell-string-24

unstable execution_time [-14.316ms; +20.245ms] or [-4.355%; +6.159%]

scenario:debugger-line-probe-with-snapshot-default-26

unstable cpu_user_time [-3795.637ms; +4087.778ms] or [-33.419%; +35.991%]
unstable execution_time [-3771.447ms; +4095.453ms] or [-31.148%; +33.824%]
unstable instructions [-33.9G instructions; +36.7G instructions] or [-35.344%; +38.271%]
unstable max_rss_usage [-12239.353KB; +12637.753KB] or [-7.410%; +7.651%]
unstable throughput [-833.208op/s; +785.543op/s] or [-29.450%; +27.765%]

scenario:debugger-line-probe-with-snapshot-minimal-24

unstable cpu_user_time [-1346.239ms; +598.030ms] or [-15.661%; +6.957%]
unstable execution_time [-1379.230ms; +666.438ms] or [-14.790%; +7.146%]
unstable instructions [-11.4G instructions; +5.0G instructions] or [-16.178%; +7.135%]
unstable throughput [-222.351op/s; +373.887op/s] or [-6.343%; +10.666%]

scenario:debugger-line-probe-with-snapshot-minimal-26

unstable cpu_user_time [-1793.434ms; +573.695ms] or [-19.168%; +6.132%]
unstable execution_time [-1822.073ms; +563.693ms] or [-18.099%; +5.599%]
unstable instructions [-16.2G instructions; +5.2G instructions] or [-20.774%; +6.635%]
unstable throughput [-122.295op/s; +403.200op/s] or [-3.753%; +12.374%]

scenario:debugger-line-probe-without-snapshot-24

unstable cpu_user_time [-2.551s; +0.323s] or [-29.056%; +3.681%]
unstable execution_time [-2.561s; +0.339s] or [-26.977%; +3.568%]
unstable instructions [-21.5G instructions; +2.8G instructions] or [-29.863%; +3.942%]
unstable throughput [-93.886op/s; +708.341op/s] or [-2.666%; +20.113%]

scenario:debugger-line-probe-without-snapshot-26

unstable cpu_user_time [-2920.308ms; +4121.986ms] or [-27.620%; +38.986%]
unstable execution_time [-3014.548ms; +4250.784ms] or [-26.674%; +37.613%]
unstable instructions [-25.5G instructions; +36.4G instructions] or [-28.676%; +40.903%]
unstable max_rss_usage [-10.088MB; +12.409MB] or [-6.198%; +7.624%]
unstable throughput [-917.253op/s; +663.768op/s] or [-30.578%; +22.128%]

scenario:dogstatsd-with-tags-20

unstable cpu_user_time [-312.011ms; +393.916ms] or [-6.241%; +7.879%]
unstable execution_time [-312.608ms; +394.625ms] or [-6.161%; +7.777%]
unstable throughput [-137303.096op/s; +106645.009op/s] or [-8.289%; +6.438%]

scenario:plugin-graphql-long-with-depth-off-20

unstable max_rss_usage [-5.921MB; +8.227MB] or [-4.676%; +6.496%]

scenario:plugin-graphql-long-with-depth-on-max-20

unstable cpu_user_time [-728132.638µs; +729818.338µs] or [-5.697%; +5.711%]
unstable execution_time [-733.558ms; +740.062ms] or [-5.613%; +5.663%]
unstable throughput [-3.425op/s; +3.397op/s] or [-5.559%; +5.514%]

scenario:plugin-pg-service-26

unstable execution_time [-63.901ms; +27.968ms] or [-7.012%; +3.069%]

scenario:test-optimization-large-suite-20

unstable max_rss_usage [-5160.165KB; +3899.832KB] or [-6.436%; +4.864%]

codecov · 2026-07-07T22:24:15Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.54%. Comparing base (221c2fb) to head (c02a598).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9242   +/-   ##
=======================================
  Coverage   96.54%   96.54%           
=======================================
  Files         915      915           
  Lines      121018   121020    +2     
  Branches    20840    20925   +85     
=======================================
+ Hits       116835   116839    +4     
+ Misses       4183     4181    -2

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#9242) `--import dd-trace/initialize.mjs` on an unsupported runtime, or as a single-step install that defers to a manually-installed copy, still registered the async ESM loader even though the tracer never initialized. With nothing to instrument, that loader can keep a short-lived process from exiting — the hanging `--import` guardrail children seen on Node 24. `init.js` returns the tracer on success and `undefined` on a bailout, so gate the registration on that result. The `--import` guardrail cases drop the kill timer so a child that fails to exit fails the suite instead of being masked.

github-actions Bot added the semver-patch label Jul 7, 2026

BridgeAR marked this pull request as ready for review July 7, 2026 22:06

BridgeAR requested a review from a team as a code owner July 7, 2026 22:06

juan-fernandez approved these changes Jul 8, 2026

View reviewed changes

CarlesDD approved these changes Jul 8, 2026

View reviewed changes

BridgeAR merged commit 6ffe627 into master Jul 8, 2026
655 checks passed

BridgeAR deleted the BridgeAR/2026-07-07-initialize-skip-loader-on-bailout branch July 8, 2026 11:43

This was referenced Jul 9, 2026

v6.2.0 proposal #9274

Merged

v5.113.0 proposal #9275

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BridgeAR commented Jul 7, 2026

Summary

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Overall package size

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datadog-datadog-prod-us1 Bot commented Jul 7, 2026 • edited by datadog-prod-us1-5 Bot Loading Uh oh! There was an error while loading. Please reload this page.

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pr-commenter Bot commented Jul 7, 2026

Benchmarks

Explanation

More details about the CI and significant changes

Unstable benchmarks

scenario:appsec-appsec-enabled-24

scenario:appsec-appsec-enabled-26

scenario:appsec-appsec-enabled-with-attacks-24

scenario:appsec-appsec-enabled-with-attacks-26

scenario:appsec-control-20

scenario:appsec-control-24

scenario:appsec-control-26

scenario:appsec-iast-no-vulnerability-iast-enabled-always-active-20

scenario:appsec-iast-no-vulnerability-iast-enabled-default-config-20

scenario:appsec-iast-with-vulnerability-iast-enabled-always-active-20

scenario:appsec-iast-with-vulnerability-iast-enabled-default-config-20

scenario:child_process-shell-string-24

scenario:debugger-line-probe-with-snapshot-default-26

scenario:debugger-line-probe-with-snapshot-minimal-24

scenario:debugger-line-probe-with-snapshot-minimal-26

scenario:debugger-line-probe-without-snapshot-24

scenario:debugger-line-probe-without-snapshot-26

scenario:dogstatsd-with-tags-20

scenario:plugin-graphql-long-with-depth-off-20

scenario:plugin-graphql-long-with-depth-on-max-20

scenario:plugin-pg-service-26

scenario:test-optimization-large-suite-20

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datadog-datadog-prod-us1 Bot commented Jul 7, 2026 •

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