Build CPython 3.15 (3.15.2) for every platform

Adds a "3.15" row to manifest.json (CPython 3.15.2, PBS 20261026,
Pyodide 315.0.0a2 / pyemscripten-2026.5-wasm32, all three Android ABIs),
which pulls 3.15.2 into the CI build matrix. The row is marked
`prerelease: true`: CPython 3.15 is final, but Pyodide only has an alpha
and pypi.flet.dev has no cp315 mobile wheels yet, so downstream tools
offer it only when it is named explicitly. Flip it to false once those
catch up.

Build fixes needed for 3.15:

* Android: CPython 3.15 moved its tooling from `Android/android.py` to the
  `Platforms/Android` package (`python3 Platforms/Android <cmd>`). The
  build now picks the tool and its `android-env.sh` (for the NDK version
  probe) by minor, and fails loudly if the NDK version cannot be read
  instead of silently skipping the NDK relocation.
* iOS: `Apple/` likewise moved to `Platforms/Apple/`; `build_ios.py`
  runs `python Platforms/Apple build iOS` for 3.15+. Slice names, the
  cross-build layout and the configure lines build_ios.py rewrites are
  unchanged, so `reshape()` needs no change.
* _decimal: 3.15 removed configure's implicit fallback to the bundled
  libmpdec. Without a system libmpdec it now skips _decimal entirely
  (python.org's own 3.15.2 Android tarball ships no _decimal). Android
  3.15 passes `--with-system-libmpdec=no` to `configure-host`; the macOS
  build passes it for every minor, which matches what 3.12-3.14 already
  produced (bundled, statically linked) and keeps a runner's single-arch
  Homebrew mpdecimal out of the universal2 framework. iOS already gets
  mpdecimal from CPython's Apple tool.
* Windows: 3.15 bundles Tcl/Tk 9, whose DLLs are `tcl90.dll`,
  `tcl9tk90.dll` and `libtommath.dll`; the 8.6 `tcl86t`/`tk86t` excludes
  no longer matched them, so they would ship next to the already-pruned
  _tkinter.

Also adds 3.15.2 to the build-python-version dispatch choices, runs the
Android build-details.json checks on 3.15 shards, and refreshes the
comments and READMEs that named the old tool paths. README documents
what `prerelease` means for consumers.

Author: ndonkoHenri

.github/workflows/build-python-version.yml

@@ -17,6 +17,7 @@ on:
           - 3.12.16
           - 3.13.18
           - 3.14.10
+          - 3.15.2
 
 env:
   PYTHON_VERSION: ${{ inputs.python_version || github.event.inputs.python_version }}
@@ -54,8 +55,9 @@ jobs:
         run: |
           mkdir -p dist
 
-          # iOS: 3.14+ uses CPython's in-tree Apple tooling, 3.13 builds from source per
-          # iOS/README.rst, 3.12 uses beeware. Emits normalized ./install + ./support.
+          # iOS: every minor runs CPython's in-tree Apple tooling (3.14 `Apple/`, 3.15+
+          # `Platforms/Apple/`; 3.12/3.13 back-port it via ios_patches/). Emits normalized
+          # ./install + ./support.
           python build_ios.py "$PYTHON_VERSION"
 
           # build_ios.py mutates the CPython-created Python.xcframework after assembly
@@ -127,7 +129,7 @@ jobs:
           tar -czf dist/python-android-mobile-forge-$PYTHON_VERSION.tar.gz install support
           # ABIs come from the manifest (`pythons.<short>.android_abis`) so a
           # future minor only needs a one-line edit there — not a workflow
-          # bump. 3.12 ships armeabi-v7a; 3.13+ are 64-bit only (PEP 738).
+          # bump.
           short="$PYTHON_VERSION_SHORT"
           abis=$(jq -r --arg s "$short" '.pythons[$s].android_abis[]' "$GITHUB_WORKSPACE/manifest.json")
           if [ -z "$abis" ]; then

README.md

@@ -38,9 +38,17 @@ Schema:
 `android_abis` lists the ABIs `package-for-dart.sh` builds for this minor —
 64-bit (`arm64-v8a`, `x86_64`) plus 32-bit `armeabi-v7a`. [PEP 738](https://peps.python.org/pep-0738/)
 makes 64-bit Android the *tested* Tier-3 configuration, but CPython's official
-`Android/android.py` still builds 32-bit ARM (it's in its supported `HOSTS`), so
-all three minors carry `armeabi-v7a`. Drop an ABI from a minor's list to stop
-building it.
+Android tooling (`Android/android.py`, `Platforms/Android` from 3.15) still builds
+32-bit ARM (it's in its supported `HOSTS`), so every minor carries `armeabi-v7a`.
+Drop an ABI from a minor's list to stop building it.
+
+`prerelease: true` marks a minor that downstream tools offer only on request:
+serious_python and flet never pick it as the default or for an open-ended
+`requires-python` that a stable minor also satisfies. It must be named with
+`--python-version X.Y` or `requires-python = "==X.Y.*"`. Use it while a minor's
+ecosystem is still catching up (e.g. 3.15: CPython is final, but Pyodide is still
+`315.0.0a2` and the mobile wheel index has no cp315 builds yet). This repo builds and
+publishes pre-release minors like any other.
 
 The committed file omits `release`; the publish step injects it.
 

android/README.md

@@ -4,7 +4,8 @@ Scripts and CI jobs for building Python for Android.
 
 * Can be run on both Linux and macOS.
 * Python 3.12 uses the legacy patched cross-build flow.
-* Python 3.13+ uses CPython's official `Android/android.py` build flow.
+* Python 3.13+ uses CPython's official Android build flow (`Android/android.py`;
+  3.15 moved it to `Platforms/Android`, run as `python3 Platforms/Android`).
 * Creates Python installation with a structure suitable for https://github.com/flet-dev/mobile-forge.
 
 ## Usage

android/build.sh

@@ -177,23 +177,46 @@ else
         fi
     fi
 
+    # CPython 3.15 moved its Android tooling from Android/android.py to the
+    # Platforms/Android package (run as `python3 Platforms/Android <cmd>`);
+    # the subcommands and the cross-build/<HOST>/prefix output are unchanged.
+    if [ $version_int -ge 315 ]; then
+        cpython_android_dir=Platforms/Android
+        cpython_android_tool=(python3 Platforms/Android)
+    else
+        cpython_android_dir=Android
+        cpython_android_tool=(Android/android.py)
+    fi
+
     # Reuse already-installed NDK by exposing it at the location expected by
-    # CPython's Android/android-env.sh.
+    # CPython's android-env.sh.
     if [ -z "${NDK_HOME:-}" ] && [ -d "$HOME/ndk/r27d" ]; then
         export NDK_HOME="$HOME/ndk/r27d"
     fi
-    cpython_ndk_version=$(sed -n 's/^ndk_version=//p' Android/android-env.sh | head -n1)
+    cpython_ndk_version=$(sed -n 's/^ndk_version=//p' "$cpython_android_dir/android-env.sh" | head -n1)
+    if [ -z "$cpython_ndk_version" ]; then
+        echo "Could not read ndk_version from $cpython_android_dir/android-env.sh"
+        exit 1
+    fi
     if [ -n "${NDK_HOME:-}" ] && [ -d "$NDK_HOME" ] && [ -n "${cpython_ndk_version:-}" ]; then
         mkdir -p "$ANDROID_HOME/ndk"
         if [ ! -e "$ANDROID_HOME/ndk/$cpython_ndk_version" ]; then
             ln -s "$NDK_HOME" "$ANDROID_HOME/ndk/$cpython_ndk_version"
         fi
     fi
 
-    Android/android.py configure-build
-    Android/android.py make-build
-    Android/android.py configure-host "$HOST"
-    Android/android.py make-host "$HOST"
+    "${cpython_android_tool[@]}" configure-build
+    "${cpython_android_tool[@]}" make-build
+    # configure defaults to a system libmpdec, which the Android sysroot doesn't
+    # have. 3.13/3.14 fell back to CPython's bundled copy; 3.15 dropped that
+    # fallback and builds no _decimal at all (python.org's own 3.15 Android
+    # release lacks it), so ask for the bundled copy explicitly.
+    configure_host_args=()
+    if [ $version_int -ge 315 ]; then
+        configure_host_args+=(-- --with-system-libmpdec=no)
+    fi
+    "${cpython_android_tool[@]}" configure-host "$HOST" ${configure_host_args[@]+"${configure_host_args[@]}"}
+    "${cpython_android_tool[@]}" make-host "$HOST"
     cp -a "cross-build/$HOST/prefix/"* "$PREFIX"
 
     # CPython's official Android tooling builds OpenSSL/bzip2/libffi/xz/sqlite

android/tests/test_built_build_details_json.py

@@ -16,7 +16,7 @@
 
 3.13 and 3.12 don't emit a `build-details.json` (it's a 3.14 addition),
 so the relevant `@post_build` class is gated on `PYTHON_VERSION_SHORT`
-via `@requires_python("3.14")` and degrades to a skip on the older
+via `@requires_python("3.14", "3.15")` and degrades to a skip on the older
 matrix shards.
 """
 
@@ -77,11 +77,11 @@ def _resolve(data: dict, path: tuple[str, ...]):
 
 
 @post_build
-@requires_python("3.14")
+@requires_python("3.14", "3.15")
 class BuiltBuildDetailsJsonShape(unittest.TestCase):
     """The shipped `build-details.json` must carry re-anchored paths.
 
-    Gated on 3.14: CPython didn't ship this file pre-3.14, so on 3.12/3.13
+    Gated on 3.14+: CPython didn't ship this file pre-3.14, so on 3.12/3.13
     shards there's nothing to inspect and the class skips wholesale.
     """
 

darwin/README.rst

@@ -21,7 +21,8 @@ iOS — ``build_ios.py <full-version>``
 Every version is built with the **same** mechanism — CPython's in-tree ``Apple`` build
 tool (``python Apple build iOS``) — then ``cross-build/`` is reshaped into the layout above:
 
-* **3.14+** — the ``Apple/`` tooling is native; build straight from the source tarball.
+* **3.14+** — the ``Apple/`` tooling is native; build straight from the source tarball
+  (3.15 moved it to ``Platforms/Apple/``, run as ``python Platforms/Apple build iOS``).
 * **3.13 / 3.12** — the tooling (and, for 3.12, the PEP 730 iOS runtime) isn't upstream
   yet, so a vendored back-port patch (``ios_patches/<short>/Python.patch``, see that
   directory's README) is applied first to add it. No dependency on beeware's

darwin/build_ios.py

@@ -5,6 +5,8 @@
 ``Apple`` build package (``python Apple build iOS``):
 
 * **3.14+** — the ``Apple/`` tooling is native; build straight from the source tarball.
+  3.15 moved it to ``Platforms/Apple/`` (``python Platforms/Apple build iOS``); same
+  subcommands and the same ``cross-build/`` output.
 * **3.13 / 3.12** — the tooling (and, for 3.12, the PEP 730 iOS runtime) isn't upstream yet,
   so we first apply a vendored back-port patch (``ios_patches/<short>/Python.patch``) that
   adds it, then run the identical ``python Apple build iOS``. No dependency on beeware's
@@ -188,7 +190,8 @@ def build(
     # own C deps, and emits cross-build/iOS/Python.xcframework. `build` does not run the
     # (device/simulator) testbed.
     host_python = shutil.which("python3") or sys.executable
-    run([host_python, "Apple", "build", "iOS"], cwd=src, env=env)
+    apple_tool = "Platforms/Apple" if minor >= 15 else "Apple"
+    run([host_python, apple_tool, "build", "iOS"], cwd=src, env=env)
 
     reshape(version, short, src, root)
 

darwin/build_macos.py

@@ -5,7 +5,8 @@
 ``.pkg``) for *all* versions (3.12 / 3.13 / 3.14). Building from source means we get the
 exact micro version even when python.org never published a macOS installer for it.
 
-macOS provides bz2/lzma/sqlite/libffi via the SDK and CPython bundles libmpdec, so the
+macOS provides bz2/lzma/sqlite/libffi via the SDK and CPython bundles libmpdec (selected
+explicitly with ``--with-system-libmpdec=no``, since 3.15 dropped the implicit fallback), so the
 only third-party dependency we must supply is **OpenSSL** — and since no prebuilt
 universal2 macOS OpenSSL exists (cpython-apple-source-deps only ships iOS-family slices,
 Homebrew is single-arch), we build it universal2 from source here.
@@ -352,6 +353,11 @@ def build_python_framework(
         # the _lzma extension builds (the SDK provides no lzma.h).
         f"LIBLZMA_CFLAGS=-I{xz_prefix}/include",
         f"LIBLZMA_LIBS=-L{xz_prefix}/lib -llzma",
+        # Build _decimal against CPython's bundled libmpdec. configure defaults to a
+        # system libmpdec (3.13+); 3.13/3.14 fell back to the bundled copy when none was
+        # found, 3.15 skips _decimal instead (and a runner's single-arch Homebrew
+        # mpdecimal must never be linked into the universal2 framework either).
+        "--with-system-libmpdec=no",
     ]
     if zstd_prefix is not None:
         # _zstd (CPython 3.14+) — SDK provides no zstd.h, so feed the from-source build.

darwin/ios_patches/README.md

@@ -9,7 +9,8 @@ the **same** standard mechanism for every version instead of bespoke build code.
 | `3.13/Python.patch` | `Apple/` build tooling + `iOS/Resources/bin` shims | iOS *runtime* (PEP 730) is already upstream in 3.13 |
 | `3.12/Python.patch` | `Apple/` build tooling **+ the PEP 730 runtime** (`_ios_support.py`, `getpath.c`, `pylifecycle.c`, …) | 3.12 has no iOS support at all upstream |
 
-3.14+ needs **no** patch — the `Apple/` tooling is native there.
+3.14+ needs **no** patch — the `Apple/` tooling is native there (3.15 moved it to
+`Platforms/Apple/`; `build_ios.py` picks the path by minor).
 
 ## Provenance
 

manifest.json

@@ -25,6 +25,14 @@
       "pyodide_platform_tag": "pyemscripten-2026.0-wasm32",
       "android_abis": ["arm64-v8a", "x86_64", "armeabi-v7a"],
       "prerelease": false
+    },
+    "3.15": {
+      "full_version": "3.15.2",
+      "standalone_release_date": "20261026",
+      "pyodide_version": "315.0.0a2",
+      "pyodide_platform_tag": "pyemscripten-2026.5-wasm32",
+      "android_abis": ["arm64-v8a", "x86_64", "armeabi-v7a"],
+      "prerelease": true
     }
   }
 }