Fix: Update resource name when child span is active in store for Next.js

[crysmags]

What does this PR do?

When OpenTelemetry TracerProvider was enabled, Next.js routes showed only HTTP method as resource name ("GET") instead of full path ("GET /api/hello").

Motivation

This is related to #1750 and escalation https://datadoghq.atlassian.net/browse/APMS-17880.

Root Cause
The Next.js plugin builds resource names in two stages:
bindStart() - Creates HTTP span with method-only resource name
pageLoad() - Updates with full path
The plugin stored requests in a WeakMap using span objects as keys: this._requests.set(span, req).
When TracerProvider enabled, OTel creates child spans (e.g., "resolve page components") that become active in async context between bindStart and pageLoad. The pageLoad method would then retrieve a different span object (the child) from storage, causing WeakMap lookup to fail since it requires an exact object identity (===).
This is a change from an object-based WeakMap to ID-based Map with parent span fallback in order to handle the case where a child span is created and the context storage has changed. There is a cleanup in finish that will prevent memory leaks since we are now using a Map.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.80%. Comparing base (31a2890) to head (5035e06).
⚠️ Report is 5 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7000   +/-   ##
=======================================
  Coverage   84.80%   84.80%           
=======================================
  Files         514      514           
  Lines       21987    21987           
=======================================
  Hits        18646    18646           
  Misses       3341     3341           

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[github-actions]

Overall package size

Self size: 13.63 MB
Deduped: 113.82 MB
No deduping: 128.84 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.7.0 | 35.02 MB | 35.02 MB | | @datadog/native-appsec | 10.3.0 | 20.73 MB | 20.74 MB | | @datadog/pprof | 5.12.0 | 11.19 MB | 11.57 MB | | @datadog/native-iast-taint-tracking | 4.1.0 | 9.01 MB | 9.02 MB | | @opentelemetry/resources | 1.30.1 | 557.67 kB | 7.71 MB | | @opentelemetry/core | 1.30.1 | 908.66 kB | 7.16 MB | | protobufjs | 7.5.4 | 2.95 MB | 5.83 MB | | @datadog/wasm-js-rewriter | 5.0.1 | 2.82 MB | 3.53 MB | | @datadog/native-metrics | 3.1.1 | 1.02 MB | 1.43 MB | | @opentelemetry/api-logs | 0.208.0 | 199.48 kB | 1.42 MB | | @opentelemetry/api | 1.9.0 | 1.22 MB | 1.22 MB | | jsonpath-plus | 10.3.0 | 617.18 kB | 1.08 MB | | import-in-the-middle | 1.15.0 | 127.66 kB | 856.24 kB | | lru-cache | 10.4.3 | 804.3 kB | 804.3 kB | | @datadog/openfeature-node-server | 0.2.0 | 118.51 kB | 437.19 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | source-map | 0.7.6 | 185.63 kB | 185.63 kB | | pprof-format | 2.2.1 | 163.06 kB | 163.06 kB | | @datadog/sketches-js | 2.1.1 | 109.9 kB | 109.9 kB | | @isaacs/ttlcache | 2.1.3 | 90.79 kB | 90.79 kB | | lodash.sortby | 4.7.0 | 75.76 kB | 75.76 kB | | ignore | 7.0.5 | 63.38 kB | 63.38 kB | | istanbul-lib-coverage | 3.2.2 | 34.37 kB | 34.37 kB | | rfdc | 1.4.1 | 27.15 kB | 27.15 kB | | dc-polyfill | 0.1.10 | 26.73 kB | 26.73 kB | | tlhunter-sorted-set | 0.1.0 | 24.94 kB | 24.94 kB | | shell-quote | 1.8.3 | 23.74 kB | 23.74 kB | | limiter | 1.1.5 | 23.17 kB | 23.17 kB | | retry | 0.13.1 | 18.85 kB | 18.85 kB | | semifies | 1.0.0 | 15.84 kB | 15.84 kB | | jest-docblock | 29.7.0 | 8.99 kB | 12.76 kB | | crypto-randomuuid | 1.0.0 | 11.18 kB | 11.18 kB | | ttl-set | 1.0.0 | 4.61 kB | 9.69 kB | | mutexify | 1.4.0 | 5.71 kB | 8.74 kB | | path-to-regexp | 0.1.12 | 6.6 kB | 6.6 kB | | module-details-from-path | 1.0.4 | 3.96 kB | 3.96 kB | | escape-string-regexp | 5.0.0 | 3.66 kB | 3.66 kB |

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

[datadog-datadog-prod-us1]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

<sub>This comment will be updated automatically if new data arrives.
* Fix with Cursor requires Datadog plugin ≥v2.17.0
🔗 Commit SHA: 5035e06 | Docs | Datadog PR Page | Was this helpful? Give us feedback!</sub>

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-12-10 15:13:57

Comparing candidate commit 5035e06 in PR branch crysmags/next-otel-fix with baseline commit 31a2890 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 292 metrics, 28 unstable metrics.

[BridgeAR]

LGTM with minor improvements :)