Fix use-after-move in console implementation #44297
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Summary: Changelog: [Internal] In the new CDP backend, calling any `console` method a second time involves a call to a moved-from `std::function`. This shouldn't work, and indeed results in an exception on some platforms, but isn't strictly an error according to the C++ standard: moving from a `std::function` leaves it in an [unspecified state](https://en.cppreference.com/w/cpp/utility/functional/function/function#:~:text=the%20call%20too.-,other,is%20in%20a%20valid%20but%20unspecified%20state%20right%20after%20the%20call.,-5), not necessarily an empty state, so (in particular) it's perfectly legal for the implementation to perform a copy instead of a move and leave the original variable intact. (See [Compiler Explorer](https://godbolt.org/z/qoo5Mnd68) for proof that libc++ and libstdc++ differ on this - the former performs a copy, while the latter actually performs a move, resulting in a `std::bad_function_call` exception later.) In the code in question, we're right to want to avoid a copy of the `body` function into the argument of `delegateExecutorSync` - only one copy of this function needs to exist at a time. But the correct way to avoid this copy is to capture `body` by reference, as we can do that repeatedly with no ill effects. (`delegateExecutorSync` is, as its name suggests, synchronous, so there are no lifetime issues.) Doing this also allows us to remove the use of `mutable` so the capturing is by *const* reference. Differential Revision: D56673529
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Summary:
Changelog: [Internal]
In the new CDP backend, calling any
consolemethod a second time involves a call to a moved-fromstd::function. This shouldn't work, but depending on the toolchain, sometimes it does - likely because moving from astd::functionleaves it in an unspecified state rather than a definitely empty state, andstd::functions are always copyable so falling back to a copy is technically legal.In the code in question, we're right to want to avoid a copy of the
bodyfunction into the argument ofdelegateExecutorSync- only one copy of this function needs to exist at a time. But the correct way to avoid this copy is to capturebodyby reference, as we can do that repeatedly with no ill effects. (delegateExecutorSyncis, as its name suggests, synchronous, so there are no lifetime issues.) Doing this also allows us to remove the use ofmutableso the capturing is by const reference.Differential Revision: D56673529