Fix Plugin::build detection
#8103
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crates/bevy_app/src/app.rs
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| @@ -765,9 +765,9 @@ impl App { | |||
| plugin_name: plugin.name().to_string(), | |||
| })?; | |||
| } | |||
| self.is_building_plugin = true; | |||
| self.building_plugin_counter += 1; | |||
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It's unlikely, but these should always be checked adds and subtractions. If this overflows (highly unlikely, though still incorrect), it can result in missing the check.
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I have to disagree, it's not highly unlikely, it's impossible. usize is large enough to store every memory address and for each recursion depth, we need to at least keep track of Box<dyn Plugin>. We will run out of memory addresses much sooner than we will reach usize::MAX.
james7132
added
C-Bug
crates/bevy_app/src/app.rs
Outdated
| @@ -765,9 +765,9 @@ impl App { | |||
| plugin_name: plugin.name().to_string(), | |||
| })?; | |||
| } | |||
| self.is_building_plugin = true; | |||
| self.building_plugin_counter += 1; | |||
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Probably not something we need to fix in this PR, but this leaves App in an incorrect state if the plugin build panics. We may want to use bevy_utils::CallOnDrop here.
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OnDrop does not work here because we pass self to Plugin::build. I've used catch_unwind and unwind_resume instead. I am not sure if using AssertUnwindSafe here is incorrect, but I think this shouldn't be an issue because we are resuming the unwind before we can observe any broken invariants.
Objective
App::runinsidePlugin::buildfails if that plugin adds another plugin before callingrun, because we don't keep track of recursive build calls.Solution
cant_call_app_run_from_plugin_buildtest to add another plugin before callingrun.