refactor(bundlers): delegate wrappers to import-in-the-middle

[BridgeAR]

Separate wrappers for Webpack, esbuild, and Turbopack duplicate export discovery, live-binding, and CommonJS replacement behavior. Their behavior can drift from import-in-the-middle and from each other.

This delegates those contracts to import-in-the-middle's experimental bundler API. dd-trace-js still owns bundler resolution, instrumentation metadata, source-map composition, and watch-file integration.

This draft depends on nodejs/import-in-the-middle#270.

[dd-octo-sts]

Overall package size

Self size: 8.89 MB
Deduped: 9.94 MB
No deduping: 9.94 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 3.5.0 | 442.82 kB | 828.77 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}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.52%. Comparing base (1a21dd3) to head (0fd9965).

❗ There is a different number of reports uploaded between BASE (1a21dd3) and HEAD (0fd9965). Click for more details.

HEAD has 17 uploads less than BASE

Flag	BASE (1a21dd3)	HEAD (0fd9965)
master-coverage	12	0
platform	1	0
llmobs	1	0
appsec	1	0
apm-integrations	1	0
test-optimization	1	0

Additional details and impacted files

@@                                Coverage Diff                                 @@
##           BridgeAR/2026-08-28-turbopack-instrumentation   #10262       +/-   ##
==================================================================================
- Coverage                                          98.71%   69.52%   -29.19%     
==================================================================================
  Files                                               1013      986       -27     
  Lines                                             160794   152589     -8205     
  Branches                                              74       26       -48     
==================================================================================
- Hits                                              158728   106092    -52636     
- Misses                                              2066    46497    +44431     

Flag	Coverage Δ
ai-guard	65.23% <71.60%> (+0.06%)	⬆️
apm-capabilities	63.74% <88.88%> (+0.03%)	⬆️
apm-integrations	?
appsec	?
debugger	69.91% <82.71%> (+0.08%)	⬆️
instrumentation	54.17% <100.00%> (-0.19%)	⬇️
llmobs	?
master-coverage	?
openfeature	66.47% <71.60%> (+0.06%)	⬆️
platform	?
profiling	66.82% <71.60%> (+0.06%)	⬆️
serverless	65.80% <100.00%> (+0.08%)	⬆️
test-optimization	?

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[pr-commenter]

Benchmarks

Benchmark execution time: 2026-09-11 18:44:24

Comparing candidate commit cbf1942 in PR branch BridgeAR/2026-09-08-iitm-bundler-api-v2 with baseline commit 1a27b21 in branch master.

📊 Benchmarking dashboard

Found 1 performance improvements and 0 performance regressions! Performance is the same for 2306 metrics, 6 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 ----------------------------------'

scenario:startup-with-tracer-everything-esm-24

• 🟩 max_rss_usage [-8.886MB; -4.541MB] or [-4.190%; -2.141%]

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 max_rss_usage [-25.842MB; +9.376MB] or [-9.062%; +3.288%]

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

• unstable max_rss_usage [-14.601MB; +30.614MB] or [-6.337%; +13.286%]

scenario:encoders-0.4-immediate-flush-20

• unstable max_rss_usage [-9.359MB; +6.864MB] or [-12.435%; +9.120%]

scenario:llmobs-encode-unicode-mixed-20

• unstable max_rss_usage [-6.433MB; +9.931MB] or [-8.235%; +12.713%]

scenario:plugin-graphql-long-with-depth-off-26

• unstable max_rss_usage [-24.253MB; +31.522MB] or [-11.812%; +15.352%]

scenario:plugin-graphql-long-with-depth-on-max-26

• unstable max_rss_usage [-6.509MB; +40.533MB] or [-2.723%; +16.955%]