build: drop support for Python 3.9

.github/workflows/python-package.yml

@@ -52,7 +52,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
       - uses: actions/checkout@v7
@@ -80,7 +80,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
       - uses: actions/checkout@v7
@@ -103,7 +103,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
       - uses: actions/checkout@v7
@@ -156,7 +156,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
       - uses: actions/checkout@v7

.github/workflows/release-validation.yml

@@ -180,8 +180,6 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # 3.9 is skipped because burr/cli/__main__.py uses PEP 604 union syntax
-        # (dict | None) which requires Python 3.10+. Tracked separately.
         python-version: ['3.10', '3.11', '3.12']
     steps:
       - uses: actions/checkout@v7

README.md

@@ -49,9 +49,9 @@ pip install "apache-burr[start]"
 ```
 
 > [!NOTE]
-> In version 0.43.0, the optional CLI included with `[start]`, `[learn]`, and
-> `[cli]` requires Python 3.10+. Core library usage remains compatible with
-> Python 3.9.
+> Burr requires Python 3.10+. (Since 0.43.0, the optional CLI included with
+> `[start]`, `[learn]`, and `[cli]` already required Python 3.10+; as of the
+> next release, Python 3.9 is no longer supported anywhere.)
 
 (see [the docs](https://burr.apache.org/getting_started/install/) if you're using poetry)
 

docs/contributing/setup.rst

@@ -63,7 +63,7 @@ The latter command will automatically create and install virtual env if one does
 automatically install the project in editable mode with all developer dependencies defined in dev
 dependency group.
 
-This will install all potential dependencies. Burr will work with ``python >=3.9``.
+This will install all potential dependencies. Burr will work with ``python >=3.10``.
 
 ------------------
 Linting/Pre-Commit

docs/getting_started/install.rst

@@ -35,8 +35,8 @@ simply by running the command ``burr``. Up next we'll write our own application
 
 .. note::
 
-    In version 0.43.0, the optional CLI requires Python 3.10 or newer. The core Burr library remains compatible with
-    Python 3.9.
+    Burr requires Python 3.10 or newer. (Since 0.43.0, the optional CLI already required Python 3.10 or newer; as of
+    the next release, Python 3.9 is no longer supported.)
 
 If you're using poetry, you can't install the ``start`` target directly, due to
 `this issue <https://github.com/python-poetry/poetry/issues/3369>`_.

pyproject.toml

@@ -23,7 +23,7 @@ build-backend = "flit_core.buildapi"
 name = "apache-burr"
 version = "0.43.0"
 dependencies = [] # yes, there are none
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 authors = [
   {name = "Elijah ben Izzy", email = "elijah@apache.org"},
   {name = "Stefan Krawczyk", email = "stefan@apache.org"},

scripts/README.md

@@ -52,7 +52,7 @@ Specifically, we set the following guidelines:
 
 
 Prerequisites:
-- Python 3.9+
+- Python 3.10+
 - `flit` for building (`pip install flit`)
 - `twine` for package validation (`pip install twine`)
 - GPG key configured for signing

scripts/apache_release.py

@@ -717,7 +717,7 @@ def _build_sdist_from_git(version: str, output_dir: str = "dist") -> str:
         unpack_options: dict[str, Any] = {}
         if sys.version_info >= (3, 12):
             # This archive was just produced from our own Git repository. Be
-            # explicit on newer Python versions while retaining Python 3.9-3.11
+            # explicit on newer Python versions while retaining Python 3.10-3.11
             # compatibility, where shutil has no filter argument.
             unpack_options["filter"] = "fully_trusted"
         shutil.unpack_archive(str(source_archive), str(source_tree), format="tar", **unpack_options)

website/src/app/downloads/page.tsx

@@ -293,9 +293,9 @@ export default function DownloadsPage() {
               </pre>
 
               <p className="mt-4 text-xs text-[var(--muted)]">
-                The core library supports Python 3.9+. In 0.43.0,
-                CLI-related extras require Python 3.10+ due to a known
-                compatibility issue. Burr has no required runtime dependencies
+                Burr requires Python 3.10+. (In 0.43.0,
+                CLI-related extras already required Python 3.10+ due to a known
+                compatibility issue; Python 3.9 is no longer supported.) Burr has no required runtime dependencies
                 — extras are opt-in.
               </p>
             </div>