sceNetAdhocMatching: Put the game workarounds behind compat flags

CancelTarget on a MAC that isn't a peer, and Start on a context ID that
doesn't exist, faked success for every game. On the PSP they fail with
UNKNOWN_TARGET and INVALID_ID (pspautotests net/adhoc/matching). Only
the games they were added for keep them now:
MatchingCancelUnknownTargetSucceeds for Soulcalibur: Broken Destiny, and
MatchingStartUnknownIdSucceeds for GTA: Vice City Stories.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Core/Compatibility.cpp

@@ -171,6 +171,8 @@ void Compatibility::CheckSettings(IniFile &iniFile, const std::string &gameID) {
 	CheckSetting(iniFile, gameID, "ColorPickingDrawSyncReadback", &flags_.ColorPickingDrawSyncReadback);
 	CheckSetting(iniFile, gameID, "SeparateLogicOpDraws", &flags_.SeparateLogicOpDraws);
 	CheckSetting(iniFile, gameID, "SnapHalfPixelSprites", &flags_.SnapHalfPixelSprites);
+	CheckSetting(iniFile, gameID, "MatchingCancelUnknownTargetSucceeds", &flags_.MatchingCancelUnknownTargetSucceeds);
+	CheckSetting(iniFile, gameID, "MatchingStartUnknownIdSucceeds", &flags_.MatchingStartUnknownIdSucceeds);
 	CheckSetting(iniFile, gameID, "FixedFramebuffer", &flags_.FixedFramebuffer);
 	CheckSetting(iniFile, gameID, "NativeResolutionFramebuffer", &flags_.NativeResolutionFramebuffer);
 }

Core/Compatibility.h

@@ -137,6 +137,8 @@ struct CompatFlags {
 	bool ColorPickingDrawSyncReadback;
 	bool SeparateLogicOpDraws;
 	bool SnapHalfPixelSprites;
+	bool MatchingCancelUnknownTargetSucceeds;
+	bool MatchingStartUnknownIdSucceeds;
 	CompatFramebuffer FixedFramebuffer;
 	uint32_t NativeResolutionFramebuffer;
 };

Core/HLE/sceNetAdhocMatching.cpp

@@ -17,6 +17,7 @@
 
 
 #include "Core/HLE/sceNetAdhocMatching.h"
+#include "Core/System.h"
 #include "Core/HLE/sceNetAdhoc.h"
 #include "Core/HLE/NetAdhocCommon.h"
 
@@ -1882,8 +1883,11 @@ int NetAdhocMatching_Start(int matchingId, int evthPri, int evthPartitionId, int
 	SceNetAdhocMatchingContext* item = findMatchingContext(matchingId);
 
 	if (item == NULL) {
-		// return SCE_NET_ADHOC_MATCHING_ERROR_INVALID_ID; //Faking success to prevent GTA:VCS from stuck unable to choose host/join menu
-		return hleLogDebug(Log::sceNet, 0);
+		// GTA: VCS gets stuck unable to choose host/join otherwise.
+		if (PSP_CoreParameter().compat.flags().MatchingStartUnknownIdSucceeds) {
+			return hleLogDebug(Log::sceNet, 0, "faking success");
+		}
+		return hleLogError(Log::sceNet, SCE_NET_ADHOC_MATCHING_ERROR_INVALID_ID, "invalid id");
 	}
 
 	if (item->running) {
@@ -2132,10 +2136,11 @@ int NetAdhocMatching_CancelTargetWithOpt(int matchingId, const char* macAddress,
 	SceNetAdhocMatchingMemberInternal* peer = findPeer(context, (SceNetEtherAddr*)target);
 
 	if (peer == NULL) {
-		// Peer not found
-		//return hleLogError(Log::sceNet, SCE_NET_ADHOC_MATCHING_ERROR_UNKNOWN_TARGET, "adhocmatching unknown target");
-		// Faking success to prevent the game (ie. Soul Calibur) to repeatedly calling this function when the other player is disconnected
-		return hleLogDebug(Log::sceNet, 0);
+		// Soulcalibur: Broken Destiny calls this over and over when the other player has gone, unless it succeeds.
+		if (PSP_CoreParameter().compat.flags().MatchingCancelUnknownTargetSucceeds) {
+			return hleLogDebug(Log::sceNet, 0, "faking success");
+		}
+		return hleLogError(Log::sceNet, SCE_NET_ADHOC_MATCHING_ERROR_UNKNOWN_TARGET, "adhocmatching unknown target");
 	}
 
 	// Valid Peer Mode

assets/compat.ini

@@ -2276,3 +2276,23 @@ POPS00000 = true
 # are moved back half a pixel, which draws the same at 1x. Above 1x they otherwise cover half a pixel more
 # and read their neighbours' texels: seams between tiles. The PS1 emulator draws its sprites like that.
 POPS00000 = true
+
+[MatchingCancelUnknownTargetSucceeds]
+# sceNetAdhocMatchingCancelTarget(WithOpt) on a MAC that isn't a peer succeeds instead of failing with
+# UNKNOWN_TARGET, as the PSP does. Soulcalibur: Broken Destiny calls it over and over once the other
+# player has gone, unless it succeeds.
+ULUS10457 = true
+ULES01298 = true
+ULJS00202 = true
+
+[MatchingStartUnknownIdSucceeds]
+# sceNetAdhocMatchingStart on a context ID that doesn't exist succeeds instead of failing with INVALID_ID,
+# as the PSP does. GTA: Vice City Stories gets stuck unable to choose host or join otherwise.
+ULUS10160 = true
+ULES00502 = true
+ULES00503 = true
+ULJM05297 = true
+ULJM05395 = true
+ULJM05884 = true
+NPJH50827 = true
+ULET00417 = true