fixed read-only CVar registration keeping the existing value

changelog.txt

@@ -77,6 +77,8 @@ chg: with r_backend GL3, depth fade with MSAA now requires GLSL 4.00 at a minimu
 
 chg: with r_backend GL3, alpha to coverage now requires GLSL 4.00 at a minimum
 
+fix: registration of a read-only CVar would keep the existing value
+
 fix: the Direct3D projection transform didn't perfectly match the OpenGL version
 
 fix: /video was writing incorrect audio stream lengths to the .avi file headers

code/qcommon/common.cpp

@@ -452,7 +452,7 @@ void Com_StartupVariable( const char *match )
 		if ( !match || !strcmp( s, match ) ) {
 			Cvar_Set( s, Cmd_Argv(2) );
 			cvar_t* cv = Cvar_Get( s, "", 0 );
-			cv->flags |= CVAR_USER_CREATED;
+			cv->flags |= CVAR_USER_CREATED | CVAR_CMDLINE_CREATED;
 		}
 	}
 }

code/qcommon/cvar.cpp

@@ -422,7 +422,10 @@ cvar_t* Cvar_Get( const char *var_name, const char *var_value, int flags )
 			cvar_modifiedFlags |= flags;
 		}
 
+		const qbool cmdLineCreated = (var->flags & CVAR_CMDLINE_CREATED) != 0;
 		var->flags |= flags;
+		var->flags &= ~CVAR_CMDLINE_CREATED;
+
 		// only allow one non-empty reset string without a warning
 		// KHB 071110  no, that's wrong for several reasons, notably vm changes caused by pure
 		if ((flags & CVAR_ROM) || !var->resetString[0]) {
@@ -443,6 +446,12 @@ cvar_t* Cvar_Get( const char *var_name, const char *var_value, int flags )
 			Z_Free( s );
 		}
 
+		// CVAR_INIT doesn't allow CVar registration to override the command-line value
+		// (even if CVAR_ROM is also set)
+		if (cmdLineCreated && (flags & CVAR_INIT) != 0) {
+			return var;
+		}
+
 /* KHB  note that this is #if 0'd in the 132 code, but is actually REQUIRED for correctness
 	consider a cgame that sets a CVAR_ROM client version:
 	you connect to a v1 server, load the v1 cgame, and set the ROM version to v1
@@ -452,11 +461,13 @@ cvar_t* Cvar_Get( const char *var_name, const char *var_value, int flags )
 i'm preserving this incorrect behavior FOR NOW for compatability, because
 game\ai_main.c(1352): trap_Cvar_Register( &mapname, "mapname", "", CVAR_SERVERINFO | CVAR_ROM );
 breaks every single mod except CPMA otherwise, but it IS wrong, and critically so
+myT: we don't care about other mods and keeping it broken is not acceptable at all
+*/
 		// CVAR_ROM always overrides
 		if (flags & CVAR_ROM) {
 			Cvar_Set2( var_name, var_value, qtrue );
 		}
-*/
+
 		return var;
 	}
 

code/qcommon/q_shared.h

@@ -662,7 +662,9 @@ default values.
 #define CVAR_CHEAT			512	// can not be changed if cheats are disabled
 #define CVAR_NORESTART		1024	// do not clear when a cvar_restart is issued
 
-#define CVAR_SERVER_CREATED	2048	// cvar was created by a server the client connected to.
+#define CVAR_SERVER_CREATED		2048	// cvar was created by a server the client connected to
+#define CVAR_CMDLINE_CREATED	4096	// cvar was created through the command-line (+set)
+
 #define CVAR_NONEXISTENT	0xFFFFFFFF	// Cvar doesn't exist.
 
 #define	MAX_CVAR_VALUE_STRING	256

code/server/sv_init.cpp

@@ -547,7 +547,7 @@ static const cvarTableItem_t sv_cvars[] =
 	// systeminfo vars
 	{ NULL, "sv_cheats", "0", CVAR_SYSTEMINFO | CVAR_ROM, CVART_BOOL, NULL, NULL, "enables cheat commands and changing cheat cvars" },
 	{ &sv_serverid, "sv_serverid", "0", CVAR_SYSTEMINFO | CVAR_ROM, CVART_INTEGER, NULL, NULL, "server session identifier" },
-	{ &sv_pure, "sv_pure", SV_PURE_DEFAULT, CVAR_SYSTEMINFO | CVAR_ROM, CVART_BOOL, NULL, NULL, "disables native code and forces client pk3s to match the server's" },
+	{ &sv_pure, "sv_pure", SV_PURE_DEFAULT, CVAR_SYSTEMINFO | CVAR_ROM | CVAR_INIT, CVART_BOOL, NULL, NULL, "disables native code and forces client pk3s to match the server's" },
 	{ NULL, "sv_paks", "", CVAR_SYSTEMINFO | CVAR_ROM, CVART_STRING, NULL, NULL, "checksums of the paks you're allowed to load data from" },
 	{ NULL, "sv_pakNames", "", CVAR_SYSTEMINFO | CVAR_ROM, CVART_STRING, NULL, NULL, "names of the paks you're allowed to load data from" },
 	{ NULL, "sv_referencedPaks", "", CVAR_SYSTEMINFO | CVAR_ROM, CVART_STRING, NULL, NULL, "checksums of the paks you might need to download" },