lib.Distro: Fix os-release and cascade macros

expand_macros() looks up each %{name} via getattr with '-' turned into '_',
but macro_names advertises two names that don't resolve: 'os-release' has
no corresponding attribute, and 'os-cascade' resolves to the list property
os_cascade, which str.replace() rejects. Both macros are listed in the
platform info help output, yet always fail when used in a format string.

The space-joined cascade string is the cascade property, and 'cascade' is
the macro name the make recipes and scripts already use, together with the
--format default in cmds/platform/CmdInfo.py.

Before the App.distro_* properties moved to Distro, the advertised macro
names were derived from the distro_* attribute names, so the advertised
macro was %{cascade}; the hand-written macro_names replaced it with the
list attribute's name.

- Add the missing os_release attribute as an alias of os_release_str
- Advertise the 'cascade' macro in macro_names instead of 'os-cascade',
  leaving os_cascade as the purely programmatic list
- Update the platform info help expected output accordingly
- Add unit tests for the os-release field parsers, the derived properties,
  and the expansion of every advertised macro

Signed-off-by: Jan Lindemann <jan@janware.com>
Assisted-by: unsloth/Qwen3.8-27B-GGUF:Q4_K_M with pi.dev v0.85.1

test/unit/python/jw/pkg/lib/Distro/Makefile

@@ -0,0 +1,7 @@
+TOPDIR = ../../../../../../..
+
+include $(TOPDIR)/make/proj.mk
+include $(JWBDIR)/make/py-run.mk
+
+all:
+test: run

test/unit/python/jw/pkg/lib/Distro/test.py

@@ -0,0 +1,153 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Iterable, cast, override
+
+from jw.pkg.lib.Distro import Distro
+
+if TYPE_CHECKING:
+    from jw.pkg.lib.ExecContext import ExecContext
+    from jw.pkg.lib.Package import Package
+
+OS_RELEASE_UBUNTU = """\
+NAME="Ubuntu"
+VERSION="24.04.2 LTS (Noble Numbat)"
+ID=ubuntu
+ID_LIKE=debian
+PRETTY_NAME="Ubuntu 24.04.2 LTS"
+VERSION_ID="24.04"
+VERSION_CODENAME=noble
+HOME_URL="https://www.ubuntu.com/"
+"""
+
+OS_RELEASE_SUSE = """\
+NAME="openSUSE Tumbleweed"
+# VERSION="20260901"
+ID=opensuse-tumbleweed
+ID_LIKE="opensuse suse"
+PRETTY_NAME="openSUSE Tumbleweed"
+VERSION_ID="20260901"
+HOME_URL="https://www.opensuse.org/"
+"""
+
+class DummyDistro(Distro):
+
+    @override
+    async def _ref(self) -> None:
+        pass
+
+    @override
+    async def _dup(self, download_only: bool) -> None:
+        pass
+
+    @override
+    async def _reboot_required(self, verbose: bool) -> bool:
+        return False
+
+    @override
+    async def _select_by_name(self, names: Iterable[str]) -> Iterable[Package]:
+        return []
+
+    @override
+    async def _install(self, names: Iterable[str], only_update: bool) -> None:
+        pass
+
+    @override
+    async def _delete(self, names: Iterable[str]) -> None:
+        pass
+
+    @override
+    async def _pkg_files(self, name: str) -> Iterable[str]:
+        return []
+
+def distro(os_release_str: str) -> Distro:
+    # -- The execution context is stored but not used by the properties
+    # under test, so a dummy object is sufficient
+    return DummyDistro(
+        ec = cast('ExecContext', object()),
+        id = Distro.parse_os_release_field_id(os_release_str),
+        os_release_str = os_release_str
+    )
+
+# -- parse_os_release_field --
+
+assert Distro.parse_os_release_field('ID', OS_RELEASE_UBUNTU) == 'ubuntu'
+assert Distro.parse_os_release_field('VERSION_CODENAME', OS_RELEASE_UBUNTU) == \
+    'noble'
+# Quoted values are de-quoted
+assert Distro.parse_os_release_field('NAME', OS_RELEASE_UBUNTU) == 'Ubuntu'
+# ID must not match ID_LIKE
+assert Distro.parse_os_release_field('ID_LIKE', OS_RELEASE_UBUNTU) == 'debian'
+
+try:
+    Distro.parse_os_release_field('NO_SUCH_KEY', OS_RELEASE_UBUNTU)
+    assert False, 'Should have raised'
+except Exception:
+    pass
+
+# -- parse_os_release_field_id --
+
+assert Distro.parse_os_release_field_id(OS_RELEASE_UBUNTU) == 'ubuntu'
+assert Distro.parse_os_release_field_id(OS_RELEASE_SUSE) == 'suse'
+
+# -- Properties --
+
+d = distro(OS_RELEASE_UBUNTU)
+assert d.id == 'ubuntu'
+assert d.name == 'Ubuntu'
+assert d.codename == 'noble'
+assert d.os == 'ubuntu-noble'
+assert d.pkg_ext == 'debian'
+assert d.os_cascade == ['os', 'linux', 'pkg-debian', 'pm-apt', 'ubuntu', 'ubuntu-noble']
+assert d.cascade == 'os linux pkg-debian pm-apt ubuntu ubuntu-noble'
+
+s = distro(OS_RELEASE_SUSE)
+assert s.id == 'suse'
+assert s.codename == 'tumbleweed'
+assert s.os == 'suse-tumbleweed'
+assert s.pkg_ext == 'rpm'
+assert s.os_cascade == [
+    'os', 'linux', 'pkg-rpm', 'pm-zypper', 'suse', 'suse-tumbleweed'
+]
+
+# A codename with a version number cascades down to its prefixes
+v = distro('ID=fake\nVERSION_CODENAME=1.2.3\n')
+assert v.os_cascade == ['os', 'fake-1.2', 'fake-1', 'fake', 'fake-1.2.3']
+
+# -- expand_macros --
+
+assert d.expand_macros('%{id}') == 'ubuntu'
+assert d.expand_macros('%{name}') == 'Ubuntu'
+assert d.expand_macros('%{os}') == 'ubuntu-noble'
+assert d.expand_macros('%{codename}') == 'noble'
+assert d.expand_macros('%{pkg-ext}') == 'debian'
+assert d.expand_macros('%{cascade}') == d.cascade
+# %{os-release} expands to the whole /etc/os-release content
+assert d.expand_macros('%{os-release}') == d.os_release_str
+assert d.expand_macros('%{os-release}') == OS_RELEASE_UBUNTU
+assert d.os_release == d.os_release_str
+
+# A mix of macros and literal text
+assert d.expand_macros('running on %{id} (%{codename}) now') == \
+    'running on ubuntu (noble) now'
+
+# List input expands entry by entry
+assert d.expand_macros(['%{id}', '%{name}']) == ['ubuntu', 'Ubuntu']
+
+# An unknown macro raises
+try:
+    d.expand_macros('%{no-such-macro}')
+    assert False, 'Should have raised'
+except Exception:
+    pass
+
+# -- macros --
+
+# -- The doubled percent escapes to a single one when the macros are
+# embedded in an argparse help string
+assert Distro.macros() == ['%%{' + name + '}' for name in Distro.macro_names]
+for macro in Distro.macros():
+    # -- Every advertised macro must expand without error once the
+    # argparse help escaping has been undone
+    d.expand_macros(macro.replace('%%', '%'))
+
+print('All Distro tests passed')