Replication: Detect RTTI on GCC/Clang in CheckedEntityCast

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Problem

CheckedEntityCast<T> (added in 75263da) uses dynamic_cast only under #if defined(_CPPRTTI). MSVC is the only compiler that defines _CPPRTTI. GCC and Clang signal RTTI with __GXX_RTTI, so on Linux every build falls through to the /GR- fallback, even with RTTI on. That fallback needs T::kTypeName, and any typed wrapper instantiated on a type without one fails to compile. ReplicationManager::GetEntity<T>, GetViewerAs<T>, ForEach<T> and EntityCollection all go through this cast.

HogwartsMP's Linux server hits this: its entity types register by name constants and don't declare kTypeName.

Failed HogwartsMP build: https://github.com/hogwarts-mp/mod/actions/runs/36290998653/job/108540951455

replication_manager.h:46:93: error: 'kTypeName' is not a member of 'HogwartsMP::Shared::HumanEntity'

Windows builds were unaffected. The framework's own CI only instantiates the cast on TextLabelEntity, which does declare kTypeName, so it didn't catch this.

Change

#if defined(_CPPRTTI) || defined(__GXX_RTTI)

MSVC behaviour doesn't change. GCC and Clang with RTTI on now use dynamic_cast like MSVC does. Builds with /GR- or -fno-rtti still use the type-id check.

Testing

Not compiled locally on Linux (no GCC toolchain here). GCC and Clang define __GXX_RTTI whenever RTTI is on and leave it undefined under -fno-rtti.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: be77dcdc-5bcd-44c9-81f9-0d4b93c518d5

📥 Commits

Reviewing files that changed from the base of the PR and between c8a58ff and 9e35721.

📒 Files selected for processing (1)

• code/framework/src/networking/replication/replication_manager.h

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Walkthrough

CheckedEntityCast now detects RTTI support with _CPPRTTI or __GXX_RTTI. Builds without RTTI continue to use the registered-type-ID fallback.

Changes

Entity casting

Layer / File(s)	Summary
RTTI detection and fallback code/framework/src/networking/replication/replication_manager.h	CheckedEntityCast uses dynamic_cast when _CPPRTTI or __GXX_RTTI indicates RTTI is enabled. Comments describe compiler coverage and the fallback’s T::kTypeName requirement.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~8 minutes

Change: Bug fix

Suggested reviewers: segfaultd

Merge Risk: ⚪ Minimal · up to 9e357

RTTI-enabled GCC/Clang builds use polymorphic entity casts, while RTTI-disabled builds retain the registered-type-ID fallback. The inspected callers are compatible, and no actionable merge risk is established.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 9e357

On GCC and Clang builds with RTTI enabled, typed entity lookups can now accept subclasses where the previous fallback required an exact registered type. No authorization bypass is demonstrated, but the effect on external consumers is unknown.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The changed type matching is reachable through typed replication APIs in GCC/Clang RTTI builds. The supplied evidence does not establish which external callers, if any, expose those APIs to attacker-controlled identifiers.

Trust Boundaries and Controls

• observed — The fallback compares a registered type ID, while the RTTI branch checks C++ type compatibility. The wrappers apply either check after obtaining an entity pointer; they do not themselves establish caller authority.

Hardening Proposals

• proposed — Document the exact-type versus subtype-matching distinction so consumers that require an exact registered type can check it explicitly.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding GCC/Clang RTTI detection to CheckedEntityCast.

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✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Create a new PR

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_{A rabbit checks each cast with care
RTTI paths now reach the lair
When RTTI sleeps, the IDs stay
The fallback still knows the way
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Addressed with alternative approach downstream.