[ci] Drop support of Python < 3.9 (#8737)

Author: feisuzhu

.github/workflows/perf.yml

@@ -43,7 +43,7 @@ jobs:
             /home/dev/taichi/.github/workflows/scripts/build.py
 
         env:
-          PY: '3.8'
+          PY: '3.11'
           PROJECT_NAME: taichi
           TAICHI_CMAKE_ARGS: >-
             -DTI_WITH_OPENGL:BOOL=ON
@@ -82,7 +82,7 @@ jobs:
             /home/dev/taichi/.github/workflows/scripts/unix-perf-mon.sh
 
         env:
-          PY: '3.8'
+          PY: '3.11'
           BENCHMARK_UPLOAD_TOKEN: ${{ secrets.BENCHMARK_UPLOAD_TOKEN }}
           GITHUB_EVENT_ACTION: ${{ github.event.action }}
           GITHUB_TOKEN: ${{ secrets.GARDENER_PAT }}

.github/workflows/pull_request.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v4
         with:
-          python-version: 3.8
+          python-version: 3.11
       - name: Install Dependencies
         run: pip install semver GitPython PyGithub
 

.github/workflows/release.yml

@@ -56,17 +56,11 @@ jobs:
       - id: set-matrix
         run: |
           if [ -n "$RELEASE_VERSION" ]; then
-            # For production release, we run on five python versions.
-            echo 'matrix={"include":[{"name":"taichi","python":"3.7"},{"name":"taichi","python":"3.8"},{"name":"taichi","python":"3.9"},{"name":"taichi","python":"3.10"},{"name":"taichi","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
-
-            # M1 only supports 3.8, 3.9, and 3.10(conda), so change matrix.
-            echo 'matrix_osx={"include":[{"name":"taichi","python":"3.8"},{"name":"taichi","python":"3.9"},{"name":"taichi","python":"3.10"},{"name":"taichi","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
+            echo 'matrix={"include":[{"name":"taichi","python":"3.9"},{"name":"taichi","python":"3.10"},{"name":"taichi","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
+            echo 'matrix_osx={"include":[{"name":"taichi","python":"3.10"},{"name":"taichi","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
           else
-            # For nightly release, we run on three python versions.
-            echo 'matrix={"include":[{"name":"taichi-nightly","python":"3.7"},{"name":"taichi-nightly","python":"3.8"},{"name":"taichi-nightly","python":"3.9"},{"name":"taichi-nightly","python":"3.10"},{"name":"taichi-nightly","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
-
-            # M1 only supports 3.8 and 3.10(conda), so change matrix.
-            echo 'matrix_osx={"include":[{"name":"taichi-nightly","python":"3.8"},{"name":"taichi-nightly","python":"3.9"},{"name":"taichi-nightly","python":"3.10"},{"name":"taichi-nightly","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
+            echo 'matrix={"include":[{"name":"taichi-nightly","python":"3.9"},{"name":"taichi-nightly","python":"3.10"},{"name":"taichi-nightly","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
+            echo 'matrix_osx={"include":[{"name":"taichi-nightly","python":"3.9"},{"name":"taichi-nightly","python":"3.10"},{"name":"taichi-nightly","python":"3.11"},{"name":"taichi","python":"3.12"}]}"' >> $GITHUB_OUTPUT
           fi
 
   build_and_test_linux:

conda/conda_env.yaml

@@ -6,4 +6,4 @@
 
 name: taichi-dev
 dependencies:
-  - python=3.8  # Replace this with your favorite Python version
+  - python=3.11  # Replace this with your favorite Python version

docs/lang/articles/faqs/install.md

@@ -35,11 +35,11 @@ sidebar_position: 2
   ERROR: No matching distribution found for taichi
   ```
 
-  - Make sure you're using Python version 3.7/3.8/3.9/3.10:
+  - Make sure you're using Python version 3.9/3.10:
 
     ```bash
     python3 -c "import sys;print(sys.version[:sys.version.find('.', 2)])"
-    # 3.7, 3.8, 3.9, or 3.10
+    # 3.9, or 3.10
     ```
 
   - Make sure your Python executable is 64-bit:

docs/lang/articles/get-started/hello_world.md

@@ -13,7 +13,7 @@ Additionally, Taichi also has an ahead-of-time (AOT) system for exporting code t
 
 ## Prerequisites
 
-- Python: 3.7/3.8/3.9/3.10 (64-bit)
+- Python: 3.9/3.10 (64-bit)
 - OS: Windows, OS X, and Linux (64-bit)
 
 ## Installation

setup.py

@@ -29,8 +29,6 @@
     "Intended Audience :: Science/Research",
     "Intended Audience :: Developers",
     "License :: OSI Approved :: Apache Software License",
-    "Programming Language :: Python :: 3.7",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",