perf(rc): avoid calling config subscribers on duplicate values

[mabdinur]

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[github-actions]

CODEOWNERS have been resolved as:

ddtrace/settings/_config.py                                             @DataDog/apm-core-python
tests/internal/test_settings.py                                         @DataDog/apm-core-python

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 282 ± 5 ms.

The average import time from base is: 289 ± 8 ms.

The import time difference between this PR and base is: -7.5 ± 0.3 ms.

Import time breakdown

The following import paths have shrunk:

ddtrace.auto 2.483 ms (0.88%)

ddtrace.bootstrap.sitecustomize 1.788 ms (0.63%)

ddtrace.bootstrap.preload 1.788 ms (0.63%)

ddtrace.internal.remoteconfig.client 0.791 ms (0.28%)

ddtrace 0.695 ms (0.25%)

ddtrace.internal._unpatched 0.035 ms (0.01%)

json 0.035 ms (0.01%)

json.decoder 0.035 ms (0.01%)

re 0.035 ms (0.01%)

enum 0.035 ms (0.01%)

types 0.035 ms (0.01%)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-07-14 20:21:17

Comparing candidate commit aeb38cf in PR branch munir/avoid-calling-subscriber-on-duplicate-calls with baseline commit df60cba in branch main.

Found 0 performance improvements and 1 performance regressions! Performance is the same for 405 metrics, 2 unstable metrics.

scenario:iastaspectsospath-ospathnormcase_aspect

• 🟥 execution_time [+428.419ns; +490.942ns] or [+12.121%; +13.890%]