Bug Fix: Added Validation Pass for Rendering Driver Availability

[TheAenema]

Godot has switched to D3D12 as the default rendering driver in recent versions on the Windows platform, while Redot still defaults to Vulkan. This mismatch causes crashes when loading newer Godot projects in Redot due to the absence of validation for the renderer setting in the project configuration.

This PR implements a minimal validation to prevent the crash and provides users with a clear error message explaining the incompatibility and suggesting a solution.

Summary by CodeRabbit

• Bug Fixes
  • Engine now validates the selected rendering driver at startup. If an unavailable driver is chosen, a clear error lists supported drivers and advises updating project settings; startup proceeds normally when a valid driver is selected.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 2efcbab3-68de-4a9f-9f4b-196fcffbc2b6

📥 Commits

Reviewing files that changed from the base of the PR and between 85993f5 and 15c7502.

📒 Files selected for processing (1)

• main/main.cpp

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Walkthrough

The PR adds validation to verify that a user-selected rendering driver is actually supported by the current engine build. During Main::setup(), after normalizing the driver name, the code checks availability against compile-time backend macros and the dummy driver. If unavailable, it constructs and displays a list of valid options before exiting through the error path.

Changes

Rendering Driver Validation

Layer / File(s)

Summary

Rendering driver availability validation main/main.cpp

Declares rendering_driver_available flag and implements availability check during Main::setup(). Validates the selected driver against build-enabled macros (D3D12_ENABLED, VULKAN_ENABLED, GLES3_ENABLED, dummy), and if unavailable, builds a deduplicated list of supported drivers from display server registrations, prints an error message describing valid options, and transfers to the error cleanup path.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Suggested labels

bug

Suggested reviewers

• Arctis-Fireblight

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding validation for rendering driver availability to prevent crashes from unsupported drivers.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 Infer (1.2.0)

main/main.cpp

In file included from main/main.cpp:39:
main/main.h:41:10: fatal error: 'core/os/thread.h' file not found
41 | #include "core/os/thread.h"
| ^~~~~~~~~~~~~~~~~~
1 error generated.
Error: the following clang command did not run successfully:
/opt/infer-linux-x86_64-v1.2.0/lib/infer/facebook-clang-plugins/clang/install/bin/clang-18
@/tmp/coderabbit-infer/15c75020e8b0d27985f512d4ef5e207fa3ad9ba8-18b7c19417a461e4/tmp/clang_command_.tmp.ec9c6c.txt
++Contents of '/tmp/coderabbit-infer/15c75020e8b0d27985f512d4ef5e207fa3ad9ba8-18b7c19417a461e4/tmp/clang_command_.tmp.ec9c6c.txt':
"-cc1" "-load"
"/opt/infer-linux-x86_64-v1.2.0/lib/infer/infer/bin/../../facebook-clang-plugins/libtooling/build/FacebookClangPlugin.dylib"
"-add-plugin" "BiniouASTExporter" "-plugin-arg-BiniouASTExporter" "-"
"-plugin-arg-BiniouASTExporter" "PREPEND_CURRENT_DIR=1"
"-plugin-arg-BiniouASTExporter" "MAX_STRING_SIZE=65535" "-cc1" "-triple"
"x86_64-unknown-linux-gnu" "-emi

... [truncated 1079 characters] ...

plugins/clang/install/lib/clang/18/include"
"-internal-isystem" "/usr/local/include" "-internal-isystem"
"/usr/lib/gcc/x86_64-linux-gnu/12/../../../../x86_64-linux-gnu/include"
"-internal-externc-isystem" "/usr/include/x86_64-linux-gnu"
"-internal-externc-isystem" "/include" "-internal-externc-isystem"
"/usr/include" "-Wno-ignored-optimization-argument" "-Wno-everything"
"-fdeprecated-macro" "-ferror-limit" "19" "-fgnuc-version=4.2.1"
"-fskip-odr-check-in-gmf" "-fcxx-exceptions" "-fexceptions"
"-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-o"
"/tmp/coderabbit-infer/18b7c19417a461e4/file.o" "-x" "c++"
"main/main.cpp" "-O0" "-fno-builtin" "-include"
"/opt/infer-linux-x86_64-v1.2.0/lib/infer/infer/bin/../lib/clang_wrappers/global_defines.h"
"-Wno-everything"

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@main/main.cpp`:
- Around line 2603-2617: The availability check fails to mark the Metal backend
available; update the same conditional blocks that set
rendering_driver_available to also handle the "metal" rendering_driver when the
METAL_ENABLED macro is defined. Specifically, add an `#ifdef` METAL_ENABLED block
that checks if rendering_driver == "metal" and sets rendering_driver_available =
true (and mirror the same change in the other similar occurrence around the
later block referenced), ensuring checks reference the rendering_driver variable
and rendering_driver_available flag so valid Metal builds aren't aborted.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 464ef6e4-4f3c-4073-935e-732e2a208f5a

📥 Commits

Reviewing files that changed from the base of the PR and between a8f52d2 and 85993f5.

📒 Files selected for processing (1)

• main/main.cpp

[AR-DEV-1]

LGTM