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VST3/AUv2: ignore a param rescan requested from inside init() - #580
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defiantnerd merged 2 commits intoOct 8, 2026
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The plugin's init() runs inside Clap::Plugin::createInstance, before the wrapper has assigned _plugin. A plugin that calls params->rescan() from init() - after loading a default state, say - reached param_rescan with _plugin still empty and dereferenced it. There is nothing to rescan at that point: both wrappers set the parameters up as soon as createInstance returns, so the request is dropped.
baconpaul
approved these changes
Oct 8, 2026
defiantnerd
self-requested a review
October 8, 2026 15:58
defiantnerd
approved these changes
Oct 8, 2026
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Fixes a crash when a plugin calls
clap_host_params::rescan()from its owninit().Cause
Clap::Plugin::createInstancecalls the plugin'sinit()(inconnectClap) before it returns. The VST3 and AUv2 wrappers only assign_pluginfrom that return value. A rescan sent duringinit()therefore reachesClapAsVst3::param_rescanorWrapAsAUV2::param_rescanwhile_pluginis still empty. The first line of each,setupParameters(_plugin->_plugin, ...), then dereferences a nullshared_ptr.We hit this by loading a default preset in
init()and sending a rescan withCLAP_PARAM_RESCAN_VALUES | CLAP_PARAM_RESCAN_INFOafterwards. The CLAP build was fine; the VST3 and AUv2 builds segfaulted on instantiation.Fix
Both
param_rescanimplementations return early while_pluginis null. Nothing is lost:initialize()callssetupParametersas soon ascreateInstancereturns, so it reads the plugin's parameters as they stand afterinit().🤖 Generated with Claude Code