fix: name only the platform's cores as readers

install.ps1

@@ -16,7 +16,7 @@
     # and Invoke-WebRequest throws on a cut transfer before the hash is read:
     # the site's build rewrites this line there (scripts/sitebootstrap.py).
     $mismatchAdvice = "The download was most likely cut short: try again. Within minutes of an update of this project the two files can come from caches of different ages. Waiting five minutes settles that."
-    $defaultInstallSha256 = "3eb409c23f487f8b150c02591a33dbd2ea09343516daa388524c1dc66f860ebf"
+    $defaultInstallSha256 = "d3bfabb88e93d8ddf991965cd69929e73b0a254550f8f4c86a11ad34fe710a0b"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -11832,15 +11832,36 @@ def _copies(entry: dict) -> list[dict]:
             *entry.get("declared_choices", [])]
 
 
+# id(manifest) -> (manifest, the cores its entries name), read once per list.
+_LISTED_CORES: dict[int, tuple[dict, frozenset]] = {}
+
+
+def _listed_cores(manifest: dict) -> frozenset:
+    """Every core a copy of the list's entries names: the platform's own.
+
+    system_cores reaches every profile, the target rule needing the cores off
+    the platform too, and the "read by" line named Recalbox's mame0258 on
+    Batocera and BizHawk on RetroArch.
+    """
+    cached = _LISTED_CORES.get(id(manifest))
+    if cached is None or cached[0] is not manifest:
+        cores = frozenset(
+            core for entry in [*manifest.get("files", []), *manifest.get("omitted_files", [])]
+            for copy in _copies(entry) for core in copy.get("cores") or [])
+        cached = _LISTED_CORES[id(manifest)] = (manifest, cores)
+    return cached[1]
+
+
 def readers(entry: dict, manifest: dict) -> list[str]:
-    """The cores that open an entry: as its copies name them, else every core
-    the platform runs for its systems."""
+    """The cores that open an entry: as its copies name them, else the cores
+    of its systems that the platform's own list names."""
     named = sorted({core for copy in _copies(entry) for core in copy.get("cores") or []})
     if named:
         return named
     system_cores = manifest.get("system_cores") or {}
+    listed = _listed_cores(manifest)
     return sorted({core for system in entry_systems(entry)
-                   for core in system_cores.get(system, [])})
+                   for core in system_cores.get(system, []) if core in listed})
 
 
 def opened_line(entry: dict, manifest: dict, bios_path: Path) -> str:

install.sh

@@ -23,7 +23,7 @@ DEFAULT_INSTALL_URL="https://raw.githubusercontent.com/Abdess/retrobios/main/ins
 # curl or wget stop on a cut transfer before the hash is read: the site's
 # build rewrites this line there (scripts/sitebootstrap.py).
 MISMATCH_ADVICE="The download was most likely cut short: try again. Within minutes of an update of this project the two files can come from caches of different ages. Waiting five minutes settles that."
-DEFAULT_INSTALL_SHA256="3eb409c23f487f8b150c02591a33dbd2ea09343516daa388524c1dc66f860ebf"
+DEFAULT_INSTALL_SHA256="d3bfabb88e93d8ddf991965cd69929e73b0a254550f8f4c86a11ad34fe710a0b"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

install/launchers/index.json

@@ -27,8 +27,8 @@
         {
           "dest": "roms/ports/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 1085228,
-          "sha256": "3eb409c23f487f8b150c02591a33dbd2ea09343516daa388524c1dc66f860ebf",
+          "size": 1086137,
+          "sha256": "d3bfabb88e93d8ddf991965cd69929e73b0a254550f8f4c86a11ad34fe710a0b",
           "executable": false
         },
         {
@@ -71,8 +71,8 @@
     "muos": {
       "archive": {
         "dest": "ARCHIVE/RetroBIOS.muxapp",
-        "size": 1138855,
-        "sha256": "373aebd78e83ec88a29e4a14a13c6be8f77d40c2b2f8834543bb40a8c254ec95"
+        "size": 1139764,
+        "sha256": "f9b58890f89971a8c0b9850ece3d132955cbc4823230e59a9224f04305055fba"
       },
       "members": [
         {
@@ -92,8 +92,8 @@
         {
           "name": "RetroBIOS/install.py",
           "repo_path": "install.py",
-          "size": 1085228,
-          "sha256": "3eb409c23f487f8b150c02591a33dbd2ea09343516daa388524c1dc66f860ebf",
+          "size": 1086137,
+          "sha256": "d3bfabb88e93d8ddf991965cd69929e73b0a254550f8f4c86a11ad34fe710a0b",
           "executable": false
         },
         {
@@ -166,8 +166,8 @@
         {
           "dest": ".config/modules/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 1085228,
-          "sha256": "3eb409c23f487f8b150c02591a33dbd2ea09343516daa388524c1dc66f860ebf",
+          "size": 1086137,
+          "sha256": "d3bfabb88e93d8ddf991965cd69929e73b0a254550f8f4c86a11ad34fe710a0b",
           "executable": false
         },
         {

tests/test_install.py

@@ -4397,6 +4397,28 @@ class AQuestionLeftWithCtrlDOrCtrlCIsAStop(unittest.TestCase):
         self.assertIn("Stopped", out)
 
 
+class ReadersAreThePlatformsCores(unittest.TestCase):
+    """--check said bbcb.zip is "read by clk, mame, mame0258, mame0278" on
+    Batocera: system_cores reaches every profile, Recalbox's builds too."""
+
+    def test_an_off_platform_core_is_not_named(self):
+        manifest = {
+            "system_cores": {"bbc": ["clk", "mame", "mame0258"]},
+            "files": [{"dest": "bbcb.zip", "systems": ["bbc"], "cores": None},
+                      {"dest": "other.rom", "systems": ["x"], "cores": ["clk", "mame"]}],
+        }
+        self.assertEqual(install.readers(manifest["files"][0], manifest), ["clk", "mame"])
+
+    def test_on_the_real_lists(self):
+        for plat, dest, absent in (("batocera", "bbcb.zip", "mame0258"),
+                                   ("retroarch", "prboom.wad", "bizhawk")):
+            manifest = json.loads((REPO_ROOT / "install" / f"{plat}.json").read_text())
+            [entry] = [e for e in manifest["files"] + manifest["omitted_files"]
+                       if e["dest"] == dest]
+            with self.subTest(platform=plat):
+                self.assertNotIn(absent, install.readers(entry, manifest))
+
+
 class WhatTheCollectionLacksSaysForWhom(unittest.TestCase):
     """Required files the installer cannot supply were listed by bare name:
     DARK.GOB, Data.rsdk, ... and 69 more, with no system and no emulator."""