fix: let taiwan and asia-ntsc answer each other

kronos tags the ST-V BIOS epr-19854.ic8 taiwan, mednafen_stv tags it
asia-ntsc, the SMPC area Mednafen names for Taiwan (ss.cpp:1119,
2363-2364). As siblings under asia they never matched, so a request in
one spelling dropped the file tagged in the other, and --region
taiwan,us dropped the Saturn sega_101.bin. AREA_TERRITORIES relates
each area to the territory it serves, china for asia-pal included, in
region.py and its installer copy.

install.ps1

@@ -8,7 +8,7 @@ param(
 
 $ErrorActionPreference = "Stop"
 $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-$defaultInstallSha256 = "22737fbb470a63a8d3630f52ffee1535e57f96a2f1fea969e58368e06ca35f06"
+$defaultInstallSha256 = "c1f70fb54ba84b75f434a04cdb41998e342210bb804276dda286a333efd80733"
 $maximumInstallerBytes = 2MB
 $installerExit = 0
 $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -137,6 +137,10 @@ REGION_ALIASES: dict[str, str] = {
     "auto": WORLD_REGION,
     "gb": "uk",
 }
+AREA_TERRITORIES: dict[str, frozenset] = {
+    "asia-ntsc": frozenset({"taiwan"}),
+    "asia-pal": frozenset({"china"}),
+}
 _REGION_PARENT = {
     member: parent for parent, members in REGION_TREE.items() for member in members
 }
@@ -2116,7 +2120,13 @@ def canonical_region(raw: str) -> str:
 
 
 def _region_comparable(a: str, b: str) -> bool:
-    return a == b or _REGION_PARENT.get(a) == b or _REGION_PARENT.get(b) == a
+    return (
+        a == b
+        or _REGION_PARENT.get(a) == b
+        or _REGION_PARENT.get(b) == a
+        or a in AREA_TERRITORIES.get(b, ())
+        or b in AREA_TERRITORIES.get(a, ())
+    )
 
 
 def _region_rank(file_regions: set[str], requested: list[str]) -> int:

install.sh

@@ -18,7 +18,7 @@ esac
 TEMP_INSTALLER=""
 TEMP_DIRECTORY=""
 DEFAULT_INSTALL_URL="https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-DEFAULT_INSTALL_SHA256="22737fbb470a63a8d3630f52ffee1535e57f96a2f1fea969e58368e06ca35f06"
+DEFAULT_INSTALL_SHA256="c1f70fb54ba84b75f434a04cdb41998e342210bb804276dda286a333efd80733"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

scripts/region.py

@@ -47,6 +47,17 @@ REGION_TREE: dict[str, frozenset[str]] = {
     "oceania": frozenset({"australia", "new-zealand"}),
 }
 
+# Hardware areas that fuse territory and signal standard, with the territories
+# the code serves through them. Mednafen's Saturn SMPC area 0x2 is "For TAIWAN
+# and PHILIPINES" and its area option offers it as "Taiwan", area 0xA as
+# "China" (mednafen/ss/ss.cpp:1119, 2363-2364 in the mednafen_stv port).
+# kronos tags the ST-V BIOS epr-19854.ic8 taiwan and mednafen_stv tags it
+# asia-ntsc: a request in either spelling has to reach the other.
+AREA_TERRITORIES: dict[str, frozenset[str]] = {
+    "asia-ntsc": frozenset({"taiwan"}),
+    "asia-pal": frozenset({"china"}),
+}
+
 _PARENT: dict[str, str] = {
     member: parent for parent, members in REGION_TREE.items() for member in members
 }
@@ -96,8 +107,15 @@ def _canonical(raw: str) -> str:
 
 
 def comparable(a: str, b: str) -> bool:
-    """True when two regions are equal or in a parent/child relation."""
-    return a == b or _PARENT.get(a) == b or _PARENT.get(b) == a
+    """True when two regions are equal, parent and child, or an area and a
+    territory it serves."""
+    return (
+        a == b
+        or _PARENT.get(a) == b
+        or _PARENT.get(b) == a
+        or a in AREA_TERRITORIES.get(b, ())
+        or b in AREA_TERRITORIES.get(a, ())
+    )
 
 
 def normalize_declared(raw: str | list | None) -> set[str]:

tests/test_install_selection.py

@@ -40,6 +40,7 @@ class OneRegionVocabulary(unittest.TestCase):
 
     def test_the_copy_matches(self):
         self.assertEqual(install.REGION_TREE, dict(region.REGION_TREE))
+        self.assertEqual(install.AREA_TERRITORIES, dict(region.AREA_TERRITORIES))
         self.assertEqual(install.REGION_ALIASES, region.ALIASES)
         self.assertEqual(install.WORLD_REGION, region.WORLD)
         self.assertEqual(install.REGIONS, region.REGIONS)
@@ -49,7 +50,8 @@ class TheRegionRuleIsTheBuilders(unittest.TestCase):
     """Random groups, both implementations, one answer."""
 
     POOL = ["north-america", "europe", "japan", "uk", "canada", "brazil",
-            "south-korea", "world", "asia", "oceania"]
+            "south-korea", "world", "asia", "oceania", "taiwan", "asia-ntsc",
+            "china", "asia-pal"]
 
     def _case(self, rng: random.Random):
         groups: dict[str, list[tuple[str, str]]] = {}
@@ -79,7 +81,8 @@ class TheRegionRuleIsTheBuilders(unittest.TestCase):
             if not entry["regions"]:
                 del entry["regions"], entry["region_groups"]
                 entry.pop("priority", None)
-        requested = rng.sample(["north-america", "europe", "japan", "uk", "canada"],
+        requested = rng.sample(["north-america", "europe", "japan", "uk", "canada",
+                                "taiwan", "asia-ntsc", "china", "asia-pal"],
                                rng.randint(1, 3))
         return groups, index, list(entries.values()), requested
 

tests/test_region.py

@@ -58,6 +58,17 @@ class TestComparable(unittest.TestCase):
     def test_saturn_fused_slug_is_under_asia(self):
         self.assertTrue(region.comparable("asia", "asia-ntsc"))
 
+    def test_an_area_matches_the_territory_it_serves(self):
+        """kronos tags the ST-V BIOS epr-19854.ic8 taiwan, mednafen_stv tags
+        it asia-ntsc, the SMPC area Mednafen names for Taiwan."""
+        self.assertTrue(region.comparable("taiwan", "asia-ntsc"))
+        self.assertTrue(region.comparable("asia-ntsc", "taiwan"))
+        self.assertTrue(region.comparable("china", "asia-pal"))
+
+    def test_an_area_does_not_match_other_territories(self):
+        self.assertFalse(region.comparable("japan", "asia-ntsc"))
+        self.assertFalse(region.comparable("taiwan", "asia-pal"))
+
 
 class TestNormalizeDeclared(unittest.TestCase):
     def test_none_is_empty(self):
@@ -889,6 +900,9 @@ class RegionalRequestsKeepWhatTheCodeLoads(unittest.TestCase):
         ("ace-dl", ["france"], "private/firmware/Amstrad_s4.cpr"),
         ("duckstation", ["brazil"], "scph5501.bin"),
         ("duckstation", ["south-korea"], "scph5500.bin"),
+        ("mednafen_stv", ["taiwan", "north-america"], "epr-19854.ic8"),
+        ("kronos", ["asia-ntsc", "north-america"], "epr-19854.ic8"),
+        ("beetle_saturn", ["taiwan", "north-america"], "sega_101.bin"),
         ("pcsx_rearmed", ["brazil", "japan"], "scph5501.bin"),
         ("pcsx_rearmed", ["brazil", "japan"], "scph1001.bin"),
         ("blastem", ["australia", "north-america"], "bios_CD_E.bin"),

wiki/profiling.md

@@ -186,7 +186,10 @@ What does not, and why each trap is easy to fall into:
   `env.Loader.ReqSpec == "PAL"`, a video specification, and the Atari 2600 has
   no region lock. There is no signal field: drop `region:` rather than map it.
   The exception is hardware that fuses both axes in one register, such as the
-  Saturn SMPC area codes behind `asia-ntsc` and `asia-pal`.
+  Saturn SMPC area codes behind `asia-ntsc` and `asia-pal`. Mednafen names
+  them for Taiwan and China, so a `--region taiwan` request reaches an
+  `asia-ntsc` file and a `--region china` request an `asia-pal` one, and the
+  other way round (`AREA_TERRITORIES` in `scripts/region.py`).
 - **A single-region system.** When every file of a system shares one region,
   the pack filter keeps them all anyway, so annotating adds nothing.
 - **A language without a territory.** Arabic MSX variants, CJK fonts. The