tests: add Python 3.15 pre-release testing

Author: parthea

.github/workflows/gapic-generator-tests.yml

@@ -18,7 +18,9 @@ env:
   SHOWCASE_VERSION: 0.35.0
   PROTOC_VERSION: 3.20.2
   LATEST_STABLE_PYTHON: 3.14
-  ALL_PYTHON: "['3.10', '3.11', '3.12', '3.13', '3.14']"
+  PREVIEW_PYTHON: 3.15
+  ALL_PYTHON: "['3.10', '3.11', '3.12', '3.13', '3.14', '3.15']"
+  TRIMMED_PYTHON: "['3.10', '3.14', '3.15']"
 
 jobs:
   check_changes:
@@ -47,6 +49,8 @@ jobs:
     outputs:
       all_python: ${{ env.ALL_PYTHON }}
       latest_stable_python: ${{ env.LATEST_STABLE_PYTHON }}
+      preview_python: ${{ env.PREVIEW_PYTHON }}
+      trimmed_python: $${{ env.TRIMMED_PYTHON }}
     steps:
       - run: echo "Initializing config for gapic-generator"
 
@@ -65,6 +69,16 @@ jobs:
         uses: actions/setup-python@v6
         with:
           python-version: "${{ matrix.python }}"
+          allow-prereleases: true
+          # Caches compiled wheels locally to prevent building heavy libraries 
+          # like grpcio from scratch on every run (critical for Python 3.15+
+          cache: 'pip'
+          cache-dependency-path: '**/requirements*.txt'
+        # Workaround: Allows libcst to compile on Python 3.15+ while PyO3 catches up
+        # Can be removed once libcst releases a version with native Python 3.15 wheels
+        # Follow https://github.com/Instagram/LibCST/issues/1445
+        env:
+          PYO3_USE_ABI3_FORWARD_COMPATIBILITY: "1"
       - name: Install System Deps & Protoc
         run: |
           sudo apt-get update && sudo apt-get install -y curl pandoc unzip
@@ -132,10 +146,20 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
-      - name: Set up Python
+      - name: Set up Python ${{ needs.python_config.outputs.preview_python }}
         uses: actions/setup-python@v6
         with:
-          python-version: ${{ needs.python_config.outputs.latest_stable_python }}
+          python-version: ${{ needs.python_config.outputs.preview_python }}
+          allow-prereleases: true
+          # Caches compiled wheels locally to prevent building heavy libraries 
+          # like grpcio from scratch on every run (critical for Python 3.15+
+          cache: 'pip'
+          cache-dependency-path: '**/requirements*.txt'
+        # Workaround: Allows libcst to compile on Python 3.15+ while PyO3 catches up
+        # Can be removed once libcst releases a version with native Python 3.15 wheels
+        # Follow https://github.com/Instagram/LibCST/issues/1445
+        env:
+          PYO3_USE_ABI3_FORWARD_COMPATIBILITY: "1"
       - name: Install System Deps
         run: sudo apt-get update && sudo apt-get install -y pandoc
       - name: Run Goldens (Prerelease)
@@ -150,14 +174,24 @@ jobs:
     needs: python_config
     strategy:
       matrix:
-        python: ["3.10", "3.14"]
+        python: ${{ fromJSON(needs.python_config.outputs.trimmed_python) }}
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python }}
+          allow-prereleases: true
+          # Caches compiled wheels locally to prevent building heavy libraries 
+          # like grpcio from scratch on every run (critical for Python 3.15+
+          cache: 'pip'
+          cache-dependency-path: '**/requirements*.txt'
+        # Workaround: Allows libcst to compile on Python 3.15+ while PyO3 catches up
+        # Can be removed once libcst releases a version with native Python 3.15 wheels
+        # Follow https://github.com/Instagram/LibCST/issues/1445
+        env:
+          PYO3_USE_ABI3_FORWARD_COMPATIBILITY: "1"
       # This fixes the Pandoc error
       - name: Install System Deps & Protoc
         run: |

packages/gapic-generator/gapic/templates/noxfile.py.j2

@@ -30,14 +30,12 @@ ALL_PYTHON = [
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 

packages/gapic-generator/noxfile.py

@@ -50,9 +50,10 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 )
 
-NEWEST_PYTHON = ALL_PYTHON[-1]
+NEWEST_PYTHON = ALL_PYTHON[-2]
 
 
 @nox.session(python=ALL_PYTHON)

packages/gapic-generator/tests/integration/goldens/asset/noxfile.py

@@ -37,14 +37,12 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 

packages/gapic-generator/tests/integration/goldens/credentials/noxfile.py

@@ -37,14 +37,12 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 

packages/gapic-generator/tests/integration/goldens/eventarc/noxfile.py

@@ -37,14 +37,12 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 

packages/gapic-generator/tests/integration/goldens/logging/noxfile.py

@@ -37,14 +37,12 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 

packages/gapic-generator/tests/integration/goldens/logging_internal/noxfile.py

@@ -37,14 +37,12 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 

packages/gapic-generator/tests/integration/goldens/redis/noxfile.py

@@ -37,14 +37,12 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 

packages/gapic-generator/tests/integration/goldens/redis_selective/noxfile.py

@@ -37,14 +37,12 @@
     "3.12",
     "3.13",
     "3.14",
+    "3.15",
 ]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
-# Switch this to Python 3.15 alpha1
-# https://peps.python.org/pep-0790/
-PREVIEW_PYTHON_VERSION = "3.14"
+PREVIEW_PYTHON_VERSION = "3.15"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()