Struct TeardownRegistries 

pub struct TeardownRegistries<'a> {

    pub commands: &'a mut CommandRegistry,
    pub pickers: &'a mut PickerRegistry,
    pub provider_views: Option<&'a ProviderViewRegistry>,
    pub modes: &'a mut ModeRegistry,
    pub keymap: &'a KeymapHandle,
    pub config: &'a ConfigRegistry,
    pub bus: &'a EventBus,
    pub decorations: &'a mut GutterDecorationSourceRegistry,
    pub media: &'a mut MediaSourceRegistry,
    pub agenda: &'a mut ScannedExcerptSourceRegistry,
    pub contexts: &'a mut ContextSourceRegistry,
    pub theme: &'a dyn ThemeRegistry,
    pub signs: Option<&'a SignRegistryHandle>,
    pub modeline: Option<&'a ModelineServiceHandle>,
    pub parsers: &'a CompilationParserFactoriesHandle,
}

The host-owned registries a plugin’s contributions live in — the set PluginTeardown::unload reverses against. Grouped as a borrow struct so unload takes one argument instead of six, and so the caller passes exactly the registries a &mut Editor context already holds. All are required: a plugin can contribute to any surface, and passing the whole set is cheaper than threading option-ness through the driver (an unexercised surface’s reversal is already a no-op).

Fields

commands: &'a mut CommandRegistry

pickers: &'a mut PickerRegistry

provider_views: Option<&'a ProviderViewRegistry>

MV.1: where a plugin’s declared multibuffer views registered their openers. Option because a headless boot may not publish the seam, and a teardown must not require a service the load never used.

modes: &'a mut ModeRegistry

keymap: &'a KeymapHandle

config: &'a ConfigRegistry

bus: &'a EventBus

decorations: &'a mut GutterDecorationSourceRegistry

PL8.E: the decoration-producer registry (unregister by producer id).

media: &'a mut MediaSourceRegistry

IM.6b: the media-producer registry, for the same reversal.

agenda: &'a mut ScannedExcerptSourceRegistry

OM.A1: the agenda-producer registry, for the same reversal.

contexts: &'a mut ContextSourceRegistry

TC.2: the context-producer registry (unregister by producer id).

theme: &'a dyn ThemeRegistry

TC.4: the theme registry (unregister_element by namespaced name).

signs: Option<&'a SignRegistryHandle>

SG.3a: the sign registry (undefine by namespaced name).

Option, like modeline and for the same reason: the loader gates the whole reversal on one all-or-nothing tuple of handles, so making this required would turn every unload in a harness that has not wired a sign registry into a silent no-op — options, commands and all. A sign registry is not a precondition for reversing a config option.

modeline: Option<&'a ModelineServiceHandle>

OC.3 / ML.6: the modeline element registry (clear + remove by namespaced id). A handle, not a &mut — ModelineService is ArcSwap-backed interior-mutable, like theme above.

Option, unlike its neighbours, and the reason is a bug this field caused before it was one: the loader gates the whole reversal on a single all-or-nothing tuple of registry handles, so making the modeline a required member turned every unload in a harness that had not wired one into a silent no-op — options, commands and all. A modeline is not a precondition for reversing a config option. Wired-ness is still checked where it belongs, in WiredSeams::all(), which the boot pin asserts.

parsers: &'a CompilationParserFactoriesHandle

CM.6b: the compilation parser-factory registry (unregister_plugin by host-issued id, RCU’d like the other ArcSwap-held registries).