Revert "[BE] Update Python min version to 3.10 (#162310)"

This reverts commit 9f5a644f0768258bc81f8b38492754d297399f74.

Reverted https://github.com/pytorch/pytorch/pull/162310 on behalf of https://github.com/malfet due to Broke lint, but to the best of my knowledge it's no longer possible to run lint for all files on PRs ([comment](https://github.com/pytorch/pytorch/pull/162310#issuecomment-3319289031))

.ci/docker/build.sh

@@ -262,10 +262,13 @@ case "$tag" in
     TRITON_CPU=yes
     ;;
   pytorch-linux-jammy-linter)
-    PYTHON_VERSION=3.10
+    # TODO: Use 3.9 here because of this issue https://github.com/python/mypy/issues/13627.
+    # We will need to update mypy version eventually, but that's for another day. The task
+    # would be to upgrade mypy to 1.0.0 with Python 3.11
+    PYTHON_VERSION=3.9
     ;;
-  pytorch-linux-jammy-cuda12.8-cudnn9-py3.10-linter)
-    PYTHON_VERSION=3.10
+  pytorch-linux-jammy-cuda12.8-cudnn9-py3.9-linter)
+    PYTHON_VERSION=3.9
     CUDA_VERSION=12.8.1
     ;;
   pytorch-linux-jammy-aarch64-py3.10-gcc11)

.github/workflows/docker-builds.yml

@@ -70,7 +70,7 @@ jobs:
           pytorch-linux-jammy-py3-clang18-asan,
           pytorch-linux-jammy-py3-clang12-onnx,
           pytorch-linux-jammy-linter,
-          pytorch-linux-jammy-cuda12.8-cudnn9-py3.10-linter,
+          pytorch-linux-jammy-cuda12.8-cudnn9-py3.9-linter,
           pytorch-linux-jammy-py3-clang12-executorch,
           pytorch-linux-jammy-py3.12-triton-cpu,
           pytorch-linux-noble-riscv64-py3.12-gcc14

.github/workflows/lint.yml

@@ -53,7 +53,7 @@ jobs:
     with:
       timeout: 120
       runner: "${{ needs.get-label-type.outputs.label-type }}linux.2xlarge"
-      docker-image: ci-image:pytorch-linux-jammy-cuda12.8-cudnn9-py3.10-linter
+      docker-image: ci-image:pytorch-linux-jammy-cuda12.8-cudnn9-py3.9-linter
       # NB: A shallow checkout won't work here because calculate-docker-image requires a full checkout
       # to run git rev-parse HEAD~:.ci/docker when a new image is needed
       fetch-depth: 0
@@ -264,10 +264,10 @@ jobs:
         with:
           submodules: false
           fetch-depth: 1
-      - name: Setup Python 3.10
+      - name: Setup Python 3.9
         uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
         with:
-          python-version: '3.10'
+          python-version: '3.9'
           architecture: x64
           cache: pip
       - name: Install dependencies

pyproject.toml

@@ -53,7 +53,7 @@ dev = [
 name = "torch"
 description = "Tensors and Dynamic neural networks in Python with strong GPU acceleration"
 readme = "README.md"
-requires-python = ">=3.10"
+requires-python = ">=3.9"
 # TODO: change to `license = "BSD-3-Clause"` and enable PEP 639 after pinning setuptools>=77
 # FIXME: As of 2025.06.20, it is hard to ensure the minimum version of setuptools in our CI environment.
 # TOML-table-based license deprecated in setuptools>=77, and the deprecation warning will be changed
@@ -74,6 +74,7 @@ classifiers = [
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Programming Language :: C++",
     "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",

setup.py

@@ -256,7 +256,7 @@ import platform
 
 
 # Also update `project.requires-python` in pyproject.toml when changing this
-python_min_version = (3, 10, 0)
+python_min_version = (3, 9, 0)
 python_min_version_str = ".".join(map(str, python_min_version))
 if sys.version_info < python_min_version:
     print(
@@ -1029,7 +1029,7 @@ def build_deps() -> None:
         CWD / "third_party/valgrind-headers/callgrind.h",
         CWD / "third_party/valgrind-headers/valgrind.h",
     ]
-    for sym_file, orig_file in zip(sym_files, orig_files, strict=True):
+    for sym_file, orig_file in zip(sym_files, orig_files):
         same = False
         if sym_file.exists():
             if filecmp.cmp(sym_file, orig_file):