Drop support for Python 3.8

.github/workflows/pip.yml

@@ -69,11 +69,6 @@ jobs:
       - uses: ilammy/msvc-dev-cmd@v1
       - uses: lukka/[email protected]
 
-      - uses: actions/setup-python@v5
-        with:
-          python-version: 3.8
-        if: runner.os == 'macOS' && runner.arch == 'ARM64'
-
       ########################################################################
       # flatbuffers
       ########################################################################
@@ -214,7 +209,7 @@ jobs:
         uses: pypa/[email protected]
         env:
           CIBW_BUILD: "cp3*-${{ matrix.platform_tag }}"
-          CIBW_SKIP: "cp3{5,6,7}*"
+          CIBW_SKIP: "cp3{5,6,7,8}*"
           CIBW_ENVIRONMENT_MACOS: >
             CMAKE_PREFIX_PATH='${{ github.workspace }}/opt'
             Python_ROOT_DIR=''

cmake/FindHalide_LLVM.cmake

@@ -9,12 +9,29 @@ set(CMAKE_MAP_IMPORTED_CONFIG_MINSIZEREL MinSizeRel Release RelWithDebInfo "")
 set(CMAKE_MAP_IMPORTED_CONFIG_RELWITHDEBINFO RelWithDebInfo Release MinSizeRel "")
 set(CMAKE_MAP_IMPORTED_CONFIG_RELEASE Release MinSizeRel RelWithDebInfo "")
 
-find_package(LLVM CONFIG)
+set(llvm_paths "")
+foreach (
+    template IN ITEMS
+    "/opt/homebrew/opt/llvm@@VERSION@" # Homebrew on macOS
+    "/usr/lib/llvm-@VERSION@" # Debian/Ubuntu packages
+    "/usr/local/lib/llvm-@VERSION@" # Third-party packages
+    "/opt/llvm-@VERSION@" # Third-party packages
+)
+    foreach (VERSION RANGE 18 21) # inclusive!
+        string(CONFIGURE "${template}" path @ONLY)
+        list(APPEND llvm_paths "${path}")
+    endforeach ()
+endforeach ()
+list(REVERSE llvm_paths) # search more recent versions first
+
+find_package(LLVM PATHS ${llvm_paths})
 
 # Neither LLVM_VERSION nor LLVM_PACKAGE_VERSION work as find_package arguments
 # in git/development builds as they include a "git" suffix. This applies at
 # time of writing to versions 18-21, inclusive.
-set(Halide_LLVM_VERSION "${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}")
+if (LLVM_FOUND)
+    set(Halide_LLVM_VERSION "${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}")
+endif ()
 
 if (NOT DEFINED Halide_LLVM_SHARED_LIBS)
     # Normally, we don't like making decisions for our users. However,

doc/BuildingHalideWithCMake.md

@@ -147,7 +147,7 @@ building the core pieces of Halide.
 | [flatbuffers] | `~=23.5.26`        | `WITH_SERIALIZATION=ON`    |                                                     |
 | [wabt]        | `==1.0.36`         | `Halide_WASM_BACKEND=wabt` | Does not have a stable API; exact version required. |
 | [V8]          | trunk              | `Halide_WASM_BACKEND=V8`   | Difficult to build. See [WebAssembly.md]            |
-| [Python]      | `>=3.8`            | `WITH_PYTHON_BINDINGS=ON`  |                                                     |
+| [Python]      | `>=3.9`            | `WITH_PYTHON_BINDINGS=ON`  |                                                     |
 | [pybind11]    | `~=2.11.1`         | `WITH_PYTHON_BINDINGS=ON`  |                                                     |
 
 Halide maintains the following compatibility policy with LLVM: Halide version

doc/Python.md

@@ -31,7 +31,7 @@
   * [License](#license)
 <!-- TOC -->
 
-Halide provides Python bindings for most of its public API. Python 3.8 (or
+Halide provides Python bindings for most of its public API. Python 3.9 (or
 higher) is required. The Python bindings are supported on 64-bit Linux, OSX, and
 Windows systems.
 
@@ -88,9 +88,7 @@ $ python3 -m pip install -r requirements.txt
 Then build and install Halide:
 
 ```shell
-$ cmake -G Ninja -S . -B build \
-        -DCMAKE_BUILD_TYPE=Release \ 
-        -DWITH_PYTHON_BINDINGS=ON
+$ cmake -G Ninja -S . -B build -DCMAKE_BUILD_TYPE=Release
 $ cmake --build build
 $ cmake --install build --prefix .local
 ```

pyproject.toml

@@ -1,7 +1,7 @@
 [build-system]
 requires = [
-    "scikit-build-core==0.10.5",
-    "pybind11==2.11.1",
+    "scikit-build-core==0.11.5",
+    "pybind11>=2.11.1",
 ]
 build-backend = "scikit_build_core.build"
 
@@ -12,10 +12,10 @@ maintainers = [{ name = "Alex Reinking", email = "[email protected]" }]
 description = "Halide is a programming language designed to make it easier to write high-performance image and array processing code."
 license = { file = "LICENSE.txt" }
 readme = "./packaging/pip/README.md"
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dependencies = [
-    "numpy",
-    "imageio",
+    "numpy>=2",
+    "imageio>=2",
 ]
 dynamic = ['version']
 keywords = [
@@ -45,7 +45,6 @@ classifiers = [
     "Programming Language :: C++",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
@@ -61,6 +60,13 @@ classifiers = [
     "Topic :: Software Development :: Libraries",
 ]
 
+[project.optional-dependencies]
+dev = [
+    "pillow>=11.3",
+    "scipy>=1.12",
+    "tbump>=6.11",
+]
+
 [project.urls]
 Homepage = "https://halide-lang.org"
 Documentation = "https://github.com/halide/Halide/blob/main/doc/Python.md"
@@ -72,7 +78,7 @@ Repository = "https://github.com/halide/Halide.git"
 cmake.version = ">=3.28"
 wheel.install-dir = "halide"
 sdist.include = ["dependencies/"]
-sdist.exclude = [".github/", "apps/", "test/", "tutorial/"]
+sdist.exclude = [".github/", "apps/", "test/", "tutorial/", "dependencies/update-*.sh"]
 metadata.version.provider = "scikit_build_core.metadata.setuptools_scm"
 
 [tool.scikit-build.cmake.define]

python_bindings/CMakeLists.txt

@@ -44,7 +44,7 @@ cmake_dependent_option(
 # Development.Module and Development.Embed. We don't need the Embed
 # part, so only requesting Module avoids failures when Embed is not
 # available, as is the case in the manylinux Docker images.
-find_package(Python 3.8 REQUIRED Interpreter Development.Module)
+find_package(Python 3.9 REQUIRED Interpreter Development.Module)
 
 if (WITH_PYTHON_BINDINGS)
     find_package(pybind11 2.11.1 REQUIRED)

requirements.txt

@@ -1,12 +1,31 @@
-build
-cmake>=3.28
-imageio
-ninja
-numpy
-pillow
-pybind11==2.11.1
-scikit-build-core==0.10.5
-scipy
-setuptools>=43
+# This file was autogenerated by uv via the following command:
+#    uv pip compile pyproject.toml --extra dev -o requirements.txt
+cli-ui==0.19.0
+    # via tbump
+colorama==0.4.6
+    # via cli-ui
+docopt==0.6.2
+    # via tbump
+imageio==2.37.0
+    # via halide (pyproject.toml)
+numpy==2.3.1
+    # via
+    #   halide (pyproject.toml)
+    #   imageio
+    #   scipy
+pillow==11.3.0
+    # via
+    #   halide (pyproject.toml)
+    #   imageio
+schema==0.7.7
+    # via tbump
+scipy==1.16.0
+    # via halide (pyproject.toml)
+tabulate==0.9.0
+    # via cli-ui
 tbump==6.11.0
-wheel
+    # via halide (pyproject.toml)
+tomlkit==0.11.8
+    # via tbump
+unidecode==1.4.0
+    # via cli-ui

test/autoschedulers/li2018/CMakeLists.txt

@@ -26,7 +26,7 @@ if (WITH_PYTHON_BINDINGS)
     if (Halide_TARGET MATCHES "webgpu")
         message(WARNING "li2018_gradient_autoscheduler_test_py is not supported with WebGPU.")
     else()
-        find_package(Python 3.8 REQUIRED COMPONENTS Interpreter Development.Module)
+        find_package(Python 3.9 REQUIRED COMPONENTS Interpreter Development.Module)
 
         add_test(
             NAME li2018_gradient_autoscheduler_test_py