[SP/MP] Fix mangling of non-dynamic background music file path from pointer overlap

[TwelveEyes]

Non-dynamic background music (such as in JO's yavin_temple map) is unable to loop after playing once due to file path mangling.

sMusic_BackgroundLoop is passed to S_StartBackgroundTrack_Actual as argument loop (fourth arg) here (line 4815):

OpenJK/code/client/snd_dma.cpp

Lines 4813 to 4816 in 8cce3ea

	if (S_FileExists( sTestName ))
	{
	S_StartBackgroundTrack_Actual( pMusicInfo, qfalse, sMusic_BackgroundLoop, sMusic_BackgroundLoop );
	}

This causes a pointer overlap (sMusic_BackgroundLoop and loop point to the same memory address) in Q_Strncpyz in S_StartBackgroundTrack_Actual here (line 4088):

OpenJK/code/client/snd_dma.cpp

Lines 4082 to 4088 in 8cce3ea

	static qboolean S_StartBackgroundTrack_Actual( MusicInfo_t *pMusicInfo, qboolean qbDynamic, const char *intro, const char *loop )
	{
	int len;
	char dump[16];
	char name[MAX_QPATH];
	Q_strncpyz( sMusic_BackgroundLoop, loop, sizeof( sMusic_BackgroundLoop ));

This mangles the path and prevents the music file from being looped (as it can't be found). Adding a pointer comparison stops the overlap operation from mangling the path.

[taysta]

Noticed this caused a crash on mac when debugging events logging, I think the CI just failed due to a github outage and will pass if re-ran

[TwelveEyes]

Noticed this caused a crash on mac when debugging events logging, I think the CI just failed due to a github outage and will pass if re-ran

From the log, it failed at the repo checkout step (it couldn't resolve github.com lol). As you said, just a GitHub hiccup that caused it to fail.