This PR fixes a potential panic that could occur when loading malformed
Wasm files.
We now use the `parse_wasm_extension_version` function that was
previously used just to extract the Zed extension API version from the
Wasm bytes as a pre-validation step. By parsing the entirety of the Wasm
file here instead of returning as soon as we find the version, the
invalid Wasm bytes are now surfaced as an `Err` instead of a panic.
We were able to replicate the panic using the following test:
```rs
#[gpui::test]
async fn test_bad_wasm(cx: &mut TestAppContext) {
init_test(cx);
let wasm_host = cx.update(|cx| {
WasmHost::new(
FakeFs::new(cx.background_executor().clone()),
FakeHttpClient::with_200_response(),
FakeNodeRuntime::new(),
Arc::new(LanguageRegistry::test(cx.background_executor().clone())),
PathBuf::from("/the/work/dir".to_string()),
cx,
)
});
let mut wasm_bytes = std::fs::read("/Users/maxdeviant/Library/Application Support/Zed/extensions/installed/dart/extension.wasm").unwrap();
// This is the error message we were seeing in the stack trace:
// range end index 267037 out of range for slice of length 253952
dbg!(&wasm_bytes.len());
// Truncate the bytes to the same point:
wasm_bytes.truncate(253952);
std::fs::write("/tmp/bad-extension.wasm", wasm_bytes.clone()).unwrap();
let manifest = Arc::new(ExtensionManifest {
id: "the-extension".into(),
name: "The Extension".into(),
version: "0.0.1".into(),
schema_version: SchemaVersion(1),
description: Default::default(),
repository: Default::default(),
authors: Default::default(),
lib: LibManifestEntry {
kind: None,
version: None,
},
themes: Default::default(),
languages: Default::default(),
grammars: Default::default(),
language_servers: Default::default(),
});
// 💥
let result = wasm_host
.load_extension(wasm_bytes, manifest, cx.executor())
.await;
dbg!(result.map(|_| ()));
```
Release Notes:
- Fixed a crash that could occur when loading malformed Wasm extensions
([#10352](https://github.com/zed-industries/zed/issues/10352)).
---------
Co-authored-by: Max <max@zed.dev>
081e9b9a60