Revert #5609

[mdavis36]

Reverting #5609

Discussion on failing builds : teams

[github-actions]

Description

• Reverts PR Check for required environment before attempting installation #5609 that added comprehensive prerequisite validation system

• Removes all prerequisite validation code from setup.py and tools/prereqs/ module

• Eliminates NCCL include directory detection and LLVM project-local installation logic

• Updates build requirements and documentation to remove validation dependencies

Changes walkthrough

	Relevant files
Bug fix	16 files setup.py Remove prerequisite validation from setup.py                          +0/-23    __init__.py Delete prerequisite validation package                                      +0/-96    build_tools.py Delete CMake and Ninja validation                                                +0/-140  compiler.py Delete C++ compiler validation                                                      +0/-102  exceptions.py Delete prerequisite validation exceptions                                +0/-23    git.py Delete git submodules validation                                                  +0/-137  llvm.py Delete LLVM validation                                                                      +0/-238  nccl.py Delete NCCL validation for distributed builds                        +0/-311  platform.py Delete platform detection utilities                                            +0/-129  python_packages.py Delete Python packages validation                                                +0/-375  python_version.py Delete Python version validation                                                  +0/-114  requirements.py Delete centralized requirements definitions                            +0/-269  validate.py Delete validation orchestrator                                                      +0/-168  utils.py Remove NCCL include directory functions                                    +0/-34    setup.py Remove prerequisite validation from main setup                      +0/-30    CMakeLists.txt Remove NCCL and LLVM detection from CMake                                +0/-34
Documentation	1 files README.md Update documentation to remove validation info                      +4/-17
Configuration changes	2 files pyproject.toml Remove pybind11 from build requirements                                    +1/-1      requirements.txt Simplify build dependencies                                                            +1/-3

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🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review

Incomplete revert The get_pip_nccl_include_dir function was removed from utils.py, but there may be other references to NCCL include directory handling that should be reviewed for consistency with the revert. def cmake(config, relative_path): from tools.memory import get_available_memory_gb # make build directories cwd = os.path.dirname(os.path.abspath(__file__)) cmake_build_dir = ( os.path.join(cwd, "build") if not config.build_dir else config.build_dir ) if not os.path.exists(cmake_build_dir): os.makedirs(cmake_build_dir) install_prefix = ( config.install_dir if config.install_dir else get_default_install_prefix() ) from tools.gen_nvfuser_version import ( get_pytorch_cmake_prefix, get_pytorch_use_distributed, ) # this is used to suppress import error. # so we can get the right pytorch prefix for cmake import logging logger = logging.getLogger("nvfuser") logger_level = logger.getEffectiveLevel() logger.setLevel(logging.CRITICAL) Build requirements consistency The pyproject.toml was updated to remove pybind11[global]>=2.0 requirement, but requirements.txt still includes pybind11[global]. This inconsistency should be verified to ensure build dependencies are properly specified. [build-system] requires = ["setuptools>=42", "wheel", "ninja", "cmake>=3.18"] build-backend = "setuptools.build_meta:__legacy__"

[greptile-apps]

Greptile Summary

This PR cleanly reverts PR #5609, which added prerequisite validation for build dependencies. The revert removes ~2,248 lines including the entire python/tools/prereqs/ module and associated integration code.

Key Changes:

• Deleted 10 validation modules (python/tools/prereqs/*.py) that checked Python version, CMake, Ninja, GCC, LLVM, PyTorch, NCCL, and git submodules
• Removed validation calls from setup.py and python/setup.py that ran before build
• Reverted CMakeLists.txt changes: removed project-local .llvm/ search logic and NCCL include path handling
• Restored requirements.txt to minimal dependencies (removed cmake>=3.18 and versioned pybind11[global]>=2.0)
• Updated README.md to restore original compiler support (GCC 12.4+, clang 16+) vs the stricter requirements (GCC 13+, clang 19+)
• Removed get_pip_nccl_include_dir() function from python/utils.py

Revert Quality:
The revert is clean and complete - all 20 files touched by PR #5609 have been properly reverted. No prereqs-related code remains in the codebase. The python/tools/prereqs/ directory has been fully deleted.

Impact:
Users will no longer get early validation errors with actionable guidance. Instead, builds may fail with cryptic CMake/linker errors if prerequisites are missing. This returns the project to its pre-validation state.

Confidence Score: 5/5

• This PR is safe to merge - it's a clean, complete revert with no issues
• The revert perfectly undoes all changes from PR Check for required environment before attempting installation #5609 (2,248 lines removed across 20 files). All prerequisite validation code has been cleanly removed with no remnants, stale imports, or broken references. The codebase returns to its exact pre-validation state.
• No files require special attention - all changes are clean deletions/reverts

Important Files Changed

Filename	Overview
python/setup.py	Removed prerequisite validation logic and environment variable documentation - clean revert
setup.py	Removed deprecation warning and prerequisite validation from root setup - clean revert
CMakeLists.txt	Removed NCCL include path and project-local LLVM search logic - clean revert
requirements.txt	Removed cmake and pybind11 version constraints, reverted to original minimal dependencies
README.md	Removed prerequisite validation section, restored original GCC 12.4 support and clang 16+ support
python/utils.py	Removed get_pip_nccl_include_dir() function and related NCCL path logic - clean revert

Sequence Diagram

sequenceDiagram
    participant User
    participant Setup as setup.py / python/setup.py
    participant Utils as python/utils.py
    participant CMake as CMakeLists.txt
    participant PreReqs as python/tools/prereqs/*
    
    Note over User,PreReqs: Before Revert (PR #5609)
    User->>Setup: pip install --no-build-isolation -e python -v
    Setup->>PreReqs: validate_prerequisites()
    PreReqs->>PreReqs: Check Python, CMake, Ninja, GCC 13+, LLVM 18.1+, etc.
    alt Validation Fails
        PreReqs-->>Setup: raise Exception
        Setup-->>User: Exit with error message
    else Validation Succeeds
        PreReqs-->>Setup: Success
        Setup->>Utils: cmake(config)
        Utils->>Utils: get_pip_nccl_include_dir()
        Utils->>CMake: Pass -DNCCL_INCLUDE_DIR
        CMake->>CMake: Search .llvm/ for project-local LLVM
        CMake-->>User: Build completes
    end
    
    Note over User,PreReqs: After Revert (This PR)
    User->>Setup: pip install --no-build-isolation -e python -v
    Setup->>Utils: cmake(config)
    Note over PreReqs: prereqs module deleted
    Utils->>CMake: No NCCL_INCLUDE_DIR passed
    CMake->>CMake: Standard LLVM search only
    CMake-->>User: Build completes (or fails with cryptic errors)

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[xwang233]

!build