fixed "SCR_UpdateScreen: recursively called" false positives (e.g. after being kicked twice)

changelog.txt

@@ -1,6 +1,9 @@
 
 DD Mmm 17 - 1.49
 
+fix: false positives of the "SCR_UpdateScreen: recursively called" fatal error
+  repro: connect, get kicked, connect, get kicked
+
 fix: crash when the number of shader stages was wrong (would happen with the "brandon" player model)
 
 fix: the release of a key bound to "+vstr a b" would execute "b" even though the key press didn't execute "a"

code/client/cl_scrn.cpp

@@ -391,6 +391,13 @@ void SCR_UpdateScreen()
 		Com_Error( ERR_FATAL, "SCR_UpdateScreen: recursively called" );
 	}
 
+	// Why set to 1 and 0 explicitly?
+	// Because the increment/decrement approach doesn't work.
+	// One of the calls below might invoke Com_Error, which will in turn
+	// call longjmp and "abort" the current frame, meaning the end of this
+	// function (or any function for that matter) is not always reached.
+	recursive = 1;
+
 	SCR_DrawScreenField( STEREO_CENTER );
 
 	if ( com_speeds->integer ) {
@@ -406,6 +413,6 @@ void SCR_UpdateScreen()
 		re.EndFrame( NULL, NULL, NULL );
 	}
 
-	--recursive;
+	recursive = 0;
 }