feat: take a platform's own libretro builds

A list naming retroarch now takes the libretro profiles whose built_by names the platform: ROCKNIX ships yabadabadoo with its RetroArch and named it nowhere, so its files never reached the ROCKNIX pack. Only change across the registry: rocknix + yabadabadoo. Also quotes the installer's current unproven-drive message.

scripts/common.py

@@ -2891,15 +2891,21 @@ def resolve_platform_cores(
     If target_cores is provided, result is intersected with it.
     """
     cores_config = config.get("cores")
+    platform_key = str(config.get("_key") or "")
 
     def every_libretro() -> set[str]:
-        # A build only some platforms compile (built_by) is reached by name:
-        # the buildbot RetroArch installs from does not publish it.
+        # A build only some platforms compile (built_by) is absent from the
+        # buildbot RetroArch installs from, so it is reached by name, or as one
+        # of the libretro cores of a platform that compiles it: ROCKNIX ships
+        # yabadabadoo with its RetroArch and names it nowhere else.
         return {
             name
             for name, p in profiles.items()
             if "libretro" in p.get("type", "") and p.get("type") != "alias"
-            and not p.get("built_by")
+            and (
+                not p.get("built_by")
+                or (platform_key and platform_key in p["built_by"])
+            )
         }
 
     if cores_config == "all_libretro":

tests/test_e2e.py

@@ -1183,6 +1183,23 @@ class TestE2E(unittest.TestCase):
         recalbox = {"cores": ["mame0278"], "systems": {}}
         self.assertEqual(resolve_platform_cores(recalbox, profiles), {"mame0278"})
 
+    def test_a_platform_s_own_libretro_build_comes_with_its_retroarch(self):
+        """ROCKNIX ships yabadabadoo with its RetroArch and names it nowhere
+        else: a list naming retroarch takes the libretro builds whose
+        built_by names that platform, and no other platform's."""
+        profiles = {
+            "yabause": {"type": "libretro", "systems": ["saturn"], "files": []},
+            "yabadabadoo": {"type": "libretro", "built_by": ["rocknix"],
+                            "systems": ["saturn"], "files": []},
+        }
+        rocknix = {"_key": "rocknix", "cores": ["retroarch"], "systems": {}}
+        self.assertEqual(resolve_platform_cores(rocknix, profiles),
+                         {"yabause", "yabadabadoo"})
+        other = {"_key": "batocera", "cores": ["retroarch"], "systems": {}}
+        self.assertEqual(resolve_platform_cores(other, profiles), {"yabause"})
+        everyone = {"_key": "retroarch", "cores": "all_libretro", "systems": {}}
+        self.assertEqual(resolve_platform_cores(everyone, profiles), {"yabause"})
+
     def test_resolve_cores_explicit_list(self):
         """Explicit cores list matches against profile dict keys."""
         config = {"cores": ["fbneo", "opera"], "systems": {"arcade": {"files": []}}}

wiki/adding-a-platform.md

@@ -198,7 +198,9 @@ resolved. Three strategies exist:
   platform, that profile answers for the name. Used by Batocera, Recalbox, RetroBat,
   RomM, KNULLI, AmberELEC, EmuELEC, MinUI, NextUI, MyMinUI, RetroPie, EmuDeck,
   RetroDECK, ROCKNIX. A list that names `retroarch` (the last
-  four) also takes every libretro profile, as `all_libretro` does. An empty list
+  four) also takes every libretro profile, as `all_libretro` does, plus the
+  libretro builds whose `built_by` names this platform (ROCKNIX's
+  `yabadabadoo`). An empty list
   (BizHawk, MiSTer FPGA) resolves no profile, and the pack holds the platform's own
   files.
 - **all_libretro**: `cores: all_libretro` - every profile whose `type` contains

wiki/installer.md

@@ -1323,7 +1323,7 @@ their systems`), and its `bios` folder comes first at the folder question,
 under Enter, before this computer's usual folder. A drive with a `bios` folder
 and none of those folders, a data drive or a stick, is numbered with a note
 (`DATA has a bios folder but no folder a handheld system writes. Pick it below
-if your files go there.`) and never taken under Enter. Another system's card or SHARE drive, and a
+if the BIOS files go there.`) and never taken under Enter. Another system's card or SHARE drive, and a
 drive two systems fit, are left out, and a line names them: each is reached
 through its own setup. A folder typed is read from the current
 one when it is not a full path, and named in full after. `q` quits there too