slangpy-debug

name	slangpy-debug
description	Debug slangpy compatibility issues by building slangpy from source with a local Slang build. Covers cloning, building, installing, and testing slangpy against your local Slang changes.
argument-hint	[build-type: debug|release]
allowed-tools	["Bash","Read","Write","Edit","Grep","Glob"]

Debugging with slangpy repro steps

When debugging slangpy compatibility issues or testing Slang changes against slangpy, follow these steps to build slangpy from source using your local Slang build.

Prerequisites:

• Python 3.10+ installed
• Slang built in Debug or Release configuration
• Git with submodules support

Step 1: Build Slang

# From Slang repository root
cmake --preset default
cmake --build --preset debug    # or --preset release

Step 2: Clone slangpy Repository

# Clone with submodules (required for slangpy build)
git clone https://github.com/shader-slang/slangpy.git external/slangpy
cd external/slangpy
git submodule update --init --recursive

Read external/slangpy/CLAUDE.md for general information about the repo.

Step 3: Build and Install slangpy with Local Slang

On Windows:

cd external/slangpy
SET CMAKE_ARGS=-DSGL_LOCAL_SLANG=ON -DSGL_LOCAL_SLANG_DIR=../.. -DSGL_LOCAL_SLANG_BUILD_DIR=build/Debug
python.exe -m pip install -e .

On Linux/macOS:

cd external/slangpy
CMAKE_ARGS="-DSGL_LOCAL_SLANG=ON -DSGL_LOCAL_SLANG_DIR=../.. -DSGL_LOCAL_SLANG_BUILD_DIR=build/Debug" python -m pip install -e .

On Windows WSL:

cd external/slangpy
WSLENV+=:CMAKE_ARGS CMAKE_ARGS='-DSGL_LOCAL_SLANG=ON -DSGL_LOCAL_SLANG_DIR=../.. -DSGL_LOCAL_SLANG_BUILD_DIR=build/Debug' python.exe -m pip install -e .

Step 4: Install Test Dependencies

# From external/slangpy directory
python -m pip install -r requirements-dev.txt --user
python -m pip install pytest-xdist --user

Step 5: Run Tests

Write a test case under external/slangpy/slangpy/tests and run it with pytest.

The following example is to run all of the existing slangpy tests:

# From external/slangpy directory
python -m pytest slangpy/tests -ra -n auto --maxprocesses=3
python tools/ci.py unit-test-python

Notes

• Use -DSGL_LOCAL_SLANG_BUILD_DIR=build/Release for Release builds
• The -e flag installs in editable mode, allowing you to modify slangpy source
• Tests run in parallel with -n auto for faster execution
• Some tests may skip if GPU hardware is not available

Troubleshooting

• If tests fail to find slangc, verify the SLANG_BUILD_DIR path is correct
• If import fails, check that slangpy was installed: python -c "import slangpy; print(slangpy.__file__)"
• For GPU-specific test failures, ensure drivers are up to date

Interactive Workflow

If $ARGUMENTS specifies a build type (debug or release), use that. Otherwise default to debug.

1. Check if slangpy is already cloned at external/slangpy/
2. If not, clone it (Step 2)
3. Build and install with the appropriate build type
4. Ask the user what test to run or what issue to investigate