refactor(rc): decouple enablement from registration

[P403n1x87]

Description

We refactor the RC implementation to separate callback registration from product enablement. Generally, callbacks should be registered on product initialisation, while enablement can be deferred to the moment when the product is enabled. We can look into follow-up work on extending the product plugin interface to automatically discover RC callbacks from products and register them automatically (opt-in).

Additional Notes

Changes mostly contributed by Claude Code

[pr-commenter]

Performance SLOs

Comparing candidate gab/refactor/rc-split-registration-enablement (13edac7) with baseline main (bf95f7c)

📈 Performance Regressions (1 suite)

📈 iastaspectsospath - 24/24

✅ ospathbasename_aspect

Time: ✅ 511.236µs (SLO: <700.000µs 📉 -27.0%) vs baseline: 📈 +19.6%

Memory: ✅ 42.664MB (SLO: <46.000MB -7.3%) vs baseline: +4.5%

---

✅ ospathbasename_noaspect

Time: ✅ 431.585µs (SLO: <700.000µs 📉 -38.3%) vs baseline: -0.9%

Memory: ✅ 42.625MB (SLO: <46.000MB -7.3%) vs baseline: +4.5%

---

✅ ospathjoin_aspect

Time: ✅ 628.267µs (SLO: <700.000µs 📉 -10.2%) vs baseline: +1.0%

Memory: ✅ 42.684MB (SLO: <46.000MB -7.2%) vs baseline: +5.0%

---

✅ ospathjoin_noaspect

Time: ✅ 630.923µs (SLO: <700.000µs -9.9%) vs baseline: ~same

Memory: ✅ 42.625MB (SLO: <46.000MB -7.3%) vs baseline: +4.5%

---

✅ ospathnormcase_aspect

Time: ✅ 347.376µs (SLO: <700.000µs 📉 -50.4%) vs baseline: -1.0%

Memory: ✅ 42.703MB (SLO: <46.000MB -7.2%) vs baseline: +4.6%

---

✅ ospathnormcase_noaspect

Time: ✅ 358.850µs (SLO: <700.000µs 📉 -48.7%) vs baseline: +0.2%

Memory: ✅ 42.585MB (SLO: <46.000MB -7.4%) vs baseline: +4.4%

---

✅ ospathsplit_aspect

Time: ✅ 489.932µs (SLO: <700.000µs 📉 -30.0%) vs baseline: -0.8%

Memory: ✅ 42.802MB (SLO: <46.000MB -7.0%) vs baseline: +4.6%

---

✅ ospathsplit_noaspect

Time: ✅ 497.747µs (SLO: <700.000µs 📉 -28.9%) vs baseline: -0.6%

Memory: ✅ 42.703MB (SLO: <46.000MB -7.2%) vs baseline: +4.3%

---

✅ ospathsplitdrive_aspect

Time: ✅ 378.086µs (SLO: <700.000µs 📉 -46.0%) vs baseline: +1.8%

Memory: ✅ 42.566MB (SLO: <46.000MB -7.5%) vs baseline: +4.1%

---

✅ ospathsplitdrive_noaspect

Time: ✅ 73.554µs (SLO: <700.000µs 📉 -89.5%) vs baseline: +1.5%

Memory: ✅ 42.507MB (SLO: <46.000MB -7.6%) vs baseline: +4.6%

---

✅ ospathsplitext_aspect

Time: ✅ 458.059µs (SLO: <700.000µs 📉 -34.6%) vs baseline: -0.6%

Memory: ✅ 42.625MB (SLO: <46.000MB -7.3%) vs baseline: +4.8%

---

✅ ospathsplitext_noaspect

Time: ✅ 467.228µs (SLO: <700.000µs 📉 -33.3%) vs baseline: +0.5%

Memory: ✅ 42.507MB (SLO: <46.000MB -7.6%) vs baseline: +4.2%

✅ All Tests Passing (2 suites)

✅ iastaspectssplit - 12/12

✅ rsplit_aspect

Time: ✅ 156.546µs (SLO: <250.000µs 📉 -37.4%) vs baseline: +0.9%

Memory: ✅ 42.664MB (SLO: <46.000MB -7.3%) vs baseline: +4.7%

---

✅ rsplit_noaspect

Time: ✅ 157.024µs (SLO: <250.000µs 📉 -37.2%) vs baseline: -6.0%

Memory: ✅ 42.684MB (SLO: <46.000MB -7.2%) vs baseline: +4.8%

---

✅ split_aspect

Time: ✅ 149.250µs (SLO: <250.000µs 📉 -40.3%) vs baseline: -3.2%

Memory: ✅ 42.625MB (SLO: <46.000MB -7.3%) vs baseline: +4.5%

---

✅ split_noaspect

Time: ✅ 153.853µs (SLO: <250.000µs 📉 -38.5%) vs baseline: -6.7%

Memory: ✅ 42.566MB (SLO: <46.000MB -7.5%) vs baseline: +4.7%

---

✅ splitlines_aspect

Time: ✅ 145.590µs (SLO: <250.000µs 📉 -41.8%) vs baseline: -4.4%

Memory: ✅ 42.664MB (SLO: <46.000MB -7.3%) vs baseline: +4.4%

---

✅ splitlines_noaspect

Time: ✅ 150.507µs (SLO: <250.000µs 📉 -39.8%) vs baseline: -6.3%

Memory: ✅ 42.566MB (SLO: <46.000MB -7.5%) vs baseline: +4.5%

---

✅ iastpropagation - 8/8

✅ no-propagation

Time: ✅ 48.378µs (SLO: <60.000µs 📉 -19.4%) vs baseline: +0.4%

Memory: ✅ 39.027MB (SLO: <42.000MB -7.1%) vs baseline: +4.6%

---

✅ propagation_enabled

Time: ✅ 136.035µs (SLO: <190.000µs 📉 -28.4%) vs baseline: +0.6%

Memory: ✅ 39.007MB (SLO: <42.000MB -7.1%) vs baseline: +4.6%

---

✅ propagation_enabled_100

Time: ✅ 1.582ms (SLO: <2.300ms 📉 -31.2%) vs baseline: +1.8%

Memory: ✅ 39.066MB (SLO: <42.000MB -7.0%) vs baseline: +4.5%

---

✅ propagation_enabled_1000

Time: ✅ 29.147ms (SLO: <34.550ms 📉 -15.6%) vs baseline: +1.1%

Memory: ✅ 39.046MB (SLO: <42.000MB -7.0%) vs baseline: +4.5%

ℹ️ Scenarios Missing SLO Configuration (20 scenarios)

The following scenarios exist in candidate data but have no SLO thresholds configured:

• iast_aspects-re_expand_aspect
• iast_aspects-re_expand_noaspect
• iast_aspects-re_findall_aspect
• iast_aspects-re_findall_noaspect
• iast_aspects-re_finditer_aspect
• iast_aspects-re_finditer_noaspect
• iast_aspects-re_fullmatch_aspect
• iast_aspects-re_fullmatch_noaspect
• iast_aspects-re_group_aspect
• iast_aspects-re_group_noaspect
• iast_aspects-re_groups_aspect
• iast_aspects-re_groups_noaspect
• iast_aspects-re_match_aspect
• iast_aspects-re_match_noaspect
• iast_aspects-re_search_aspect
• iast_aspects-re_search_noaspect
• iast_aspects-re_sub_aspect
• iast_aspects-re_sub_noaspect
• iast_aspects-re_subn_aspect
• iast_aspects-re_subn_noaspect

[cit-pr-commenter-54b7da]

Codeowners resolved as

ddtrace/internal/README.md                                              @DataDog/python-guild @DataDog/apm-core-python