Prepare groundwork for 0.5 dev post

Author: Yarwin

website/content/dev/05-update-wip/index.md

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+# Copyright (c) godot-rust; Bromeon and contributors.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+title = "0.5 dev update WIP"
+authors = ["Bromeon", "godot-rust contributors"]
+
+[extra]
+summary = "v0.5 WIP"
+tags = ["dev-update"]
++++
+
+This is WIP for **0.5** update! 
+
+Existence of this PR doesn't mean that we want to release 0.5 anytime soon – it just makes documenting changes easier and less taxing.
+
+
+# Performance
+
+## The Paranoid, The Balanced and Very Unsafe
+
+Godot-rust now supports three tiers that differ in the amount of runtime checks and validations that are performed:
+
+### 🛡️ **Strict**
+
+Default for dev builds. Performs lots of additional, sometimes expensive checks, but allows to detect many bugs during development.
+
+- Gd::bind/bind_mut() provides extensive diagnostics to locate runtime borrow errors.
+- Array safe conversion checks (for types like Array<i8>).
+- RTTI checks on object access (protect against type mismatch edge cases).
+- Geometric invariants (e.g. normalized quaternions).
+- Access to engine APIs outside valid scope.
+
+### ⚖️ Balanced
+
+Default for release builds. Performs basic validity and invariant checks, reasonably fast. 
+Within this level you should not be able to encounter undefined behavior (UB) in safe Rust code. 
+Invariant violations may however cause panics and logic errors.
+
+- Object liveness checks.
+- Gd::bind/bind_mut() cause panics on borrow errors.
+
+### ☣️ Disengaged
+
+Disables most checks, sacrificing safety for raw speed. 
+This renders a large part of the godot-rust API `unsafe` without polluting the code; you opt in via `unsafe impl ExtensionLibrary`.
+
+Before using this, measure to ensure you truly need the last bit of performance (balanced should be fast enough for most cases; if not, consider bringing it up). 
+Also test your code thoroughly using the other levels first. Undefined behavior and crashes arising from using this level are your full responsibility. 
+When reporting a bug, make sure you can reproduce it under the balanced level.
+
+- Unchecked object access -> instant UB if an object is dead.
+- Gd::bind/bind_mut() are unchecked -> UB if mutable aliasing occurs.
+
+### Cargo features
+
+You can downgrade 1 level in each `dev` (Debug) and `release` Cargo profiles, with following features:
+
+- `safeguards-dev-balanced`: for `dev`, use ⚖️ **balanced** instead of the default strict level.
+- `safeguards-release-disengaged`: for `release`, use ☣️ **disengaged** instead of the default balanced level.
+
+Thanks to @beicause for making bulk work for this feature! [#1278]
+
+[#1278]: https://github.com/godot-rust/gdext/pull/1278
+
+## Faster calls for Callables
+
+Thanks to @lyonbeckers Rust Callables received significant improvement – making calling `Callable::from_fn` twice as fast as it was in `0.4`!
+
+[#1331]: https://github.com/godot-rust/gdext/pull/1331
+
+## Simple API to cache and fetch Autoloads
+
+Godot [autoloads][godot-docs-autoload] can be now fetched and cached using higher-level convenience function – `get_autoload_by_name`.
+Thanks to it Godot autoloads can be easily accessed anywhere in the scope, even outside the scene tree – including calls from Callables and Objects.
+
+To create rust autoload firstly create a scene with your rust Node in it and add it as an autoload in project settings.
+Afterward it can be accessed via its name and will be cached on the very first use.
+
+```rust
+pub fn stage() -> Gd<Stage> {
+    get_autoload_by_name("StageAutoload")
+}
+
+#[derive(GodotClass)]
+#[class(init, base = Node)]
+pub struct Stage {
+    #[var]
+    level: Option<Gd<Level>>,
+}
+```
+
+Thanks to @bromeon for implementing this feature and @ValorZard for testing it! ([#1381])
+
+
+[#1381]: https://github.com/godot-rust/gdext/pull/1381
+
+## Improvements for macro-generated signatures
+
+Multiple improvements for macro-generated signatures has been implemented:
+
+- Docs for signals are now being preserved, allowing to inspect them in IDEs ([#1353]).
+- Docs in `#[godot_api(secondary)]` blocks are now properly preserved and registered ([#1355]).
+- Compile errors caused by wrong signature in `InterfaceTraits` now properly point to user code ([#1370], [#1373], [#1382]).
+
+[#1353]: https://github.com/godot-rust/gdext/pull/1353
+[#1355]: https://github.com/godot-rust/gdext/pull/1355
+[#1370]: https://github.com/godot-rust/gdext/pull/1370
+[#1373]: https://github.com/godot-rust/gdext/pull/1373
+[#1382]: https://github.com/godot-rust/gdext/pull/1382
+
+[godot-docs-autoload]: https://docs.godotengine.org/en/latest/tutorials/scripting/singletons_autoload.html