v1.15.8.0

Release 1.15.8.0 (29 Oct 2026) -- compared to 1.15.7.0

• ShadingSystem: New read-only system getattribute queries describing how OSL was built: build:platform, build:compiler, build:simd, build:dependencies, build:batched, and hw:batched. New testshade --buildinfo prints them along with the running hardware (mirroring oiiotool --buildinfo), and CI shows this in the job summary. #2186 (by @lgritz / Larry Gritz)
• batch: Fix batched shading, which was broken for LLVM 21+ (the wide void pointer type was mistakenly scalar, corrupting the batched ShaderGlobals layout and wide UDIM texture handle loads). CI's bleeding edge job now tests LLVM 23. #2196 (by @lgritz / Larry Gritz)
• oslc: Fix uninitialized .oso default values for matrix("from", "to") parameters, which could write "nan" into the .oso and make OSLQuery fail to parse the shader and lose its parameters. #2199 (by @ThiagoIze / Thiago Ize)
• optix: Let LLVM choose the PTX ISA version instead of forcing PTX 5.0, which is invalid for newer targets such as sm_75. #2166 (by @tgrant-nv / Tim Grant)
• build: Sync dependency_utils.cmake with OpenImageIO: more robust locally-built dependencies, per-package build logs, and clearer failure messages. #2170 (by @lgritz / Larry Gritz)
• build: Fix Makefile wrapper to properly quote the test regex for make test TEST=.... #2168 (by @lgritz / Larry Gritz)
• ci: Speed up and de-flake Windows CI: cache the LLVM download and retry curl downloads, avoiding Google Drive quota failures #2187, and cache the dependencies built from source, cutting job time from ~30 to ~10 minutes #2188 (by @lgritz / Larry Gritz)
• ci: Test OpenImageIO 3.2, OpenEXR 3.5, and OpenColorIO 2.6 in the "latest releases" job. #2178 (by @lgritz / Larry Gritz)
• ci: Retire old CI runners: drop the 2022 CentOS containers, adding a plain Ubuntu job for the oldest dependencies #2167, and drop MacOS 14 #2177 (by @lgritz / Larry Gritz)
• test: Stop adding a std::abs(Vec3) overload (undefined behavior) in oslnoise_test. #2194 (by @lgritz / Larry Gritz)