Machine architecture checks

- Prevent running on 32bit Windows or 32bit Python on 64bit Windows
- Support i386 for AppImage
- Support building Linux System packages on i386
- Support installing JDK for armv7/8
- Let users know when Android SDK must be manually installed

src/briefcase/commands/base.py

@@ -107,6 +107,7 @@ class BaseCommand(ABC):
     cmd_line = "briefcase {command} {platform} {output_format}"
     supported_host_os = {"Darwin", "Linux", "Windows"}
     supported_host_os_reason = f"This command is not supported on {platform.system()}."
+    supports_32bit_python = False
     # defined by platform-specific subclasses
     command: str
     description: str

src/briefcase/exceptions.py

@@ -103,6 +103,18 @@ def __init__(self, tool):
         super().__init__(msg=f"Unable to locate {tool!r}. Has it been installed?")
 
 
+class IncompatibleToolError(BriefcaseCommandError):
+    def __init__(self, tool: str, env_var: str):
+        self.tool = tool
+        super().__init__(
+            msg=f"""\
+Briefcase cannot install {tool} on this machine.
+
+Install {tool} manually and specify the installation directory in the {env_var} environment variable.
+            """
+        )
+
+
 class NonManagedToolError(BriefcaseCommandError):
     def __init__(self, tool):
         self.tool = tool

src/briefcase/integrations/android_sdk.py

@@ -15,6 +15,7 @@
 from briefcase.console import InputDisabled, select_option
 from briefcase.exceptions import (
     BriefcaseCommandError,
+    IncompatibleToolError,
     InvalidDeviceError,
     MissingToolError,
 )
@@ -57,15 +58,28 @@ def __init__(self, tools: ToolCache, root_path: Path):
 
     @property
     def cmdline_tools_url(self) -> str:
-        """The Android SDK Command-Line Tools URL appropriate to the current operating
-        system."""
-        platform_name = self.tools.host_os.lower()
-        if self.tools.host_os.lower() == "darwin":
-            platform_name = "mac"
-        elif self.tools.host_os.lower() == "windows":  # pragma: no branch
-            platform_name = "win"
+        """The Android SDK Command-Line Tools URL appropriate for the current machine.
 
-        return f"https://dl.google.com/android/repository/commandlinetools-{platform_name}-{self.cmdline_tools_version}_latest.zip"  # noqa: E501
+        The SDK largely only supports typical development environments; if a machine is
+        using an unsupported architecture, `sdkmanager` will error while installing the
+        emulator as a dependency of the build-tools. However, for some of the platforms
+        that are unsupported by sdkmanager, users can set up their own SDK install.
+        """
+        try:
+            platform_name = {
+                "Darwin": {"x86_64": "mac", "arm64": "mac"},
+                "Linux": {"x86_64": "linux"},
+                "Windows": {"AMD64": "win"},
+            }[self.tools.host_os][self.tools.host_arch]
+        except KeyError as e:
+            raise IncompatibleToolError(
+                tool=self.full_name, env_var="ANDROID_HOME"
+            ) from e
+
+        return (
+            f"https://dl.google.com/android/repository/commandlinetools-"
+            f"{platform_name}-{self.cmdline_tools_version}_latest.zip"
+        )
 
     @property
     def cmdline_tools_path(self) -> Path:
@@ -74,11 +88,11 @@ def cmdline_tools_path(self) -> Path:
     @property
     def cmdline_tools_version(self) -> str:
         # This is the version of the Android SDK Command-line tools that
-        # are current as of May 2022. These tools can generally self-update,
+        # are current as of July 2023. These tools can generally self-update,
         # so using a fixed download URL isn't a problem.
         # However, if/when this version number is changed, ensure that the
         # checks done during verification include any required upgrade steps.
-        return "8092744"
+        return "9477386"
 
     @property
     def cmdline_tools_version_path(self) -> Path:

src/briefcase/integrations/java.py

@@ -5,18 +5,22 @@
 import subprocess
 from pathlib import Path
 
-from briefcase.exceptions import BriefcaseCommandError, MissingToolError
+from briefcase.exceptions import (
+    BriefcaseCommandError,
+    IncompatibleToolError,
+    MissingToolError,
+)
 from briefcase.integrations.base import ManagedTool, ToolCache
 
 
 class JDK(ManagedTool):
     name = "java"
     full_name = "Java JDK"
 
-    # As of 12 May 2023, 17.0.7+7 is the current OpenJDK
+    # As of July 2023, 17.0.8+7 is the current OpenJDK
     # https://adoptium.net/temurin/releases/
     JDK_MAJOR_VER = "17"
-    JDK_RELEASE = "17.0.7"
+    JDK_RELEASE = "17.0.8"
     JDK_BUILD = "7"
     JDK_INSTALL_DIR_NAME = f"java{JDK_MAJOR_VER}"
 
@@ -26,23 +30,30 @@ def __init__(self, tools: ToolCache, java_home: Path):
 
     @property
     def OpenJDK_download_url(self):
-        arch = {
-            "x86_64": "x64",  # Linux\macOS x86-64
-            "aarch64": "aarch64",  # Linux arm64
-            "armv6l": "arm",  # Linux arm
-            "arm64": "aarch64",  # macOS arm64
-            "AMD64": "x64",  # Windows x86-64
-        }.get(self.tools.host_arch)
-
-        platform = {
-            "Darwin": "mac",
-            "Windows": "windows",
-            "Linux": "linux",
-        }.get(self.tools.host_os)
-
-        extension = {
-            "Windows": "zip",
-        }.get(self.tools.host_os, "tar.gz")
+        """The OpenJDK download URL appropriate for the current machine."""
+        try:
+            arch = {
+                "armv7l": "arm",  # Linux armv7
+                "armv8l": "arm",  # Linux armv8
+                "aarch64": "aarch64",  # Linux arm64
+                "arm64": "aarch64",  # macOS arm64
+                "x86_64": "x64",  # Linux/macOS x86-64
+                "AMD64": "x64",  # Windows x86-64
+            }[self.tools.host_arch]
+
+            platform = {
+                "Darwin": "mac",
+                "Windows": "windows",
+                "Linux": "linux",
+            }[self.tools.host_os]
+
+            extension = {
+                "Darwin": "tar.gz",
+                "Linux": "tar.gz",
+                "Windows": "zip",
+            }[self.tools.host_os]
+        except KeyError as e:
+            raise IncompatibleToolError(tool=self.full_name, env_var="JAVA_HOME") from e
 
         return (
             f"https://github.com/adoptium/temurin{self.JDK_MAJOR_VER}-binaries/"
@@ -64,15 +75,15 @@ def version_from_path(cls, tools: ToolCache, java_path: str | Path) -> str:
 
         :param tools: ToolCache of available tools
         :param java_path: File path to a candidate JDK install
-        :return: JDK release version; e.g. "17.0.7"
+        :return: JDK release version; e.g. "17.0.8"
         """
         output = tools.subprocess.check_output(
             [
                 os.fsdecode(Path(java_path) / "bin" / "javac"),
                 "-version",
             ],
         )
-        # javac's output should look like "javac 17.0.7\n"
+        # javac's output should look like "javac 17.0.8\n"
         return output.strip("\n").split(" ")[1]
 
     @classmethod
@@ -279,7 +290,7 @@ def install(self):
 
             jdk_zip_path.unlink()  # Zip file no longer needed once unpacked.
 
-            # The tarball will unpack into <briefcase data dir>/tools/jdk-17.0.7+7
+            # The tarball will unpack into <briefcase data dir>/tools/jdk-17.0.8+7
             # (or whatever name matches the current release).
             # We turn this into <briefcase data dir>/tools/java so we have a consistent name.
             java_unpack_path = (

src/briefcase/integrations/linuxdeploy.py

@@ -11,6 +11,7 @@
     BriefcaseCommandError,
     CorruptToolError,
     MissingToolError,
+    UnsupportedHostError,
 )
 from briefcase.integrations.base import ManagedTool, Tool, ToolCache
 
@@ -48,6 +49,18 @@ def download_url(self) -> str:
     def file_path(self) -> Path:
         """The folder on the local filesystem that contains the file_name."""
 
+    @classmethod
+    def arch(cls, host_os: str, host_arch: str):
+        # always use the x86-64 arch on macOS since Docker
+        # containers are always run in an x86-64 VM
+        arch = host_arch if host_os != "Darwin" else "x86_64"
+        try:
+            return {"x86_64": "x86_64", "i686": "i386"}[arch]
+        except KeyError as e:
+            raise UnsupportedHostError(
+                f"Linux AppImages cannot be built on {host_arch}."
+            ) from e
+
     def exists(self) -> bool:
         return (self.file_path / self.file_name).is_file()
 
@@ -208,7 +221,7 @@ class LinuxDeployQtPlugin(LinuxDeployPluginBase, ManagedTool):
 
     @property
     def file_name(self) -> str:
-        return f"linuxdeploy-plugin-qt-{self.tools.host_arch}.AppImage"
+        return f"linuxdeploy-plugin-qt-{self.arch(self.tools.host_os, self.tools.host_arch)}.AppImage"
 
     @property
     def download_url(self) -> str:
@@ -319,7 +332,7 @@ def file_path(self) -> Path:
 
     @property
     def file_name(self) -> str:
-        return f"linuxdeploy-{self.tools.host_arch}.AppImage"
+        return f"linuxdeploy-{self.arch(self.tools.host_os, self.tools.host_arch)}.AppImage"
 
     @property
     def download_url(self) -> str:

src/briefcase/platforms/linux/appimage.py

@@ -44,7 +44,8 @@ def project_path(self, app):
 
     def binary_name(self, app):
         safe_name = app.formal_name.replace(" ", "_")
-        return f"{safe_name}-{app.version}-{self.tools.host_arch}.AppImage"
+        arch = LinuxDeploy.arch(self.tools.host_os, self.tools.host_arch)
+        return f"{safe_name}-{app.version}-{arch}.AppImage"
 
     def binary_path(self, app):
         return self.bundle_path(app) / self.binary_name(app)
@@ -134,6 +135,8 @@ def verify_app_tools(self, app: AppConfig):
 
 
 class LinuxAppImageMixin(LinuxAppImageMostlyPassiveMixin):
+    supports_32bit_python = True
+
     def verify_host(self):
         """If we're *not* using Docker, verify that we're actually on Linux."""
         super().verify_host()

src/briefcase/platforms/linux/system.py

@@ -34,6 +34,7 @@ class LinuxSystemPassiveMixin(LinuxMixin):
     # Docker exists. It is used by commands that are "passive" from the
     # perspective of the build system (e.g., Run).
     output_format = "system"
+    supports_32bit_python = True
     supported_host_os = {"Darwin", "Linux"}
     supported_host_os_reason = (
         "Linux system projects can only be built on Linux, or on macOS using Docker."
@@ -61,6 +62,7 @@ def linux_arch(self):
             "x86_64": "amd64",
             "aarch64": "arm64",
             "armv6l": "armhf",
+            "i686": "i386",
         }.get(self.tools.host_arch, self.tools.host_arch)
 
     def build_path(self, app):

src/briefcase/platforms/windows/__init__.py

@@ -8,7 +8,7 @@
 
 from briefcase.commands import CreateCommand, PackageCommand, RunCommand
 from briefcase.config import AppConfig, parsed_version
-from briefcase.exceptions import BriefcaseCommandError
+from briefcase.exceptions import BriefcaseCommandError, UnsupportedHostError
 from briefcase.integrations.windows_sdk import WindowsSDK
 from briefcase.integrations.wix import WiX
 
@@ -27,15 +27,34 @@ def distribution_path(self, app):
         suffix = "zip" if app.packaging_format == "zip" else "msi"
         return self.dist_path / f"{app.formal_name}-{app.version}.{suffix}"
 
+    def verify_host(self):
+        super().verify_host()
+        # the stub app only supports x86-64 right now
+        if self.tools.host_arch != "AMD64":
+            raise UnsupportedHostError(
+                f"Windows applications cannot be built on {self.tools.host_arch}."
+            )
+        # Python is 32bit if its pointers can only address with 32 bits or fewer.
+        # 64bit Python is required to ensure 64bit wheels are installed/created for the app.
+        if self.tools.sys.maxsize <= 2**32:
+            raise UnsupportedHostError(
+                """\
+Windows applications cannot be built on a 32bit version of Python.
+
+Install a 64bit version of Python and run Briefcase again.
+"""
+            )
+
 
 class WindowsCreateCommand(CreateCommand):
     def support_package_filename(self, support_revision):
         return f"python-{self.python_version_tag}.{support_revision}-embed-amd64.zip"
 
     def support_package_url(self, support_revision):
         return (
-            f"https://www.python.org/ftp/python/{self.python_version_tag}.{support_revision}/"
-            + self.support_package_filename(support_revision)
+            f"https://www.python.org/ftp/python/"
+            f"{self.python_version_tag}.{support_revision}/"
+            f"{self.support_package_filename(support_revision)}"
         )
 
     def output_format_template_context(self, app: AppConfig):