Crash in WrapAsAUV2::CopyClumpName

[SamWindell]

Got a crash report as follows.

Host: Live 12.1.11 (2025-04-08_ce4b7c22b0) (CLAP-as-AUv2)
OS: macOS 15.4.1
Reason: address not mapped to object

0   <unknown>                       0x7ff811cdcdf0      ???
1   <unknown>                       0x7ff81d7176a7      ???
2   <unknown>                       0x7ff81d71796c      ???
3   <unknown>                       0x7ff81d72c3ac      ???
4   <unknown>                       0x7ff814064768      ???
5   <unknown>                       0x7ff8140647b6      ???
6   <unknown>                       0x7ff81405c62e      ???
7   <unknown>                       0x7ff81405c45f      ???
8   <unknown>                       0x7ff811b3e7e5      ???
9   <unknown>                       0x7ff811b479fc      ???
10  <unknown>                       0x7ff814064907      ???
11  <unknown>                       0x7ff81405e6ea      ???
12  <unknown>                       0x7ff81406305d      ???
13  <unknown>                       0x7ff81411aaab      ???
14  <unknown>                       0x1116850fe         ausdk::AUMethodGetProperty
15  <unknown>                       0x11167e510         ausdk::AUBase::DispatchGetProperty
16  <unknown>                       0x11180db55         free_audio::auv2_wrapper::WrapAsAUV2::CopyClumpName
17  <unknown>                       0x7ff811d1525c      ???
18  <unknown>                       0x1116b1489         SignalHandler
19  <unknown>                       0x1117275f7         GlobalInit::lambda::__invoke
20  <unknown>                       0x1116cd007         CurrentStacktrace

Looking at our code, I can't see anything obvious.

Does anyone else notice a possible cause? Surely Live isn't sending is a nullptr for the output buffer?

clap-wrapper/src/wrapasauv2.cpp

Lines 524 to 537 in 5ba58f1

	OSStatus WrapAsAUV2::CopyClumpName(AudioUnitScope inScope, UInt32 inClumpID, UInt32 inDesiredNameLength,
	CFStringRef* outClumpName)
	{
	if (inScope == kAudioUnitScope_Global)
	{
	auto p = _clumps.getClump(inClumpID);
	if (p)
	{
	*outClumpName = CFStringCreateWithCString(NULL, p, kCFStringEncodingUTF8);
	return noErr;
	}
	}
	return kAudioUnitErr_InvalidProperty;
	}

Other musings:

I wonder what does clump name do? I don't see JUCE implementing it.

Is the string copying correct in our clump name code? I honestly have no idea if this is the cause but I've been bitten before by weird memory issues related to CFStrings. Is CFStringCreateWithCStringNoCopy a better option (again, really not sure but it's feasilbe)?

[baconpaul]

The clump name is how you group params in Logic. JUCE does implement it.

Create is correct here I think. https://stackoverflow.com/questions/5718415/corefoundation-ownership-follows-the-createrule

I agree a check for outClimpName being non-null may be warranted here. But also we may need to use inDesiredNameLength and truncate the string accordingly.

This is how the module name in clap gets through, by the way. If you have a super long module name wonder if that could do it.

[SamWindell]

Ahh ok that's what it's for.

Thanks for the insights, it could very well be a name length thing. I have some quite long module names - maybe around 50 characters.

I'll add some changes as mentioned and see if that means this crash can't trigger again.