[yeonwooson]

Summary

Contributor motivation

Expose existing helpers so that the WASI host can apply unsaved document edits, track versions, and manage query transactions. Moving them into shared state lets the WASI integration reuse the native implementation instead of maintaining a duplicate, helping keep editing behavior consistent across both hosts.

AI-assisted implementation summary

• Extract document opening, UTF-16 text edits, language-ID preservation, and version bookkeeping into shared state, and have the native server call those helpers.
• Move TransactionManager, including its existing cancellation/restoration regression, without changing its implementation.
• Preserve existing native import paths through re-exports.

URI resolution, backwards-version warnings, rechecking, and notebook-specific handling stay in the native layer. This does not add a WASI guest or transport, or change TSP messages, analysis, dependencies, or lockfiles.

Follow-up to #5436. No issue auto-close is requested.

• I am a human, and I fully understand the code I am submitting.

Test Plan

AI-assisted test report: refreshed against current upstream on Windows ARM64 with Rust 1.99.1 and WASI SDK 34.

• PASS, 150 tests; 1 pre-existing ignored test: cargo test -p pyrefly --lib --locked --offline -- state::document::tests state::transaction_manager::tests test::tsp:: test::lsp::lsp_interaction::did_change:: test::lsp::lsp_interaction::notebook_sync:: test::lsp::lsp_interaction::io:: test::lsp::lsp_interaction::diagnostic::test_open_file_during_recheck test::lsp::lsp_interaction::diagnostic::test_edit_file_during_recheck --test-threads=2
• PASS: cargo check -p pyrefly --lib --target wasm32-wasip1 --locked --offline
• PASS: python test.py --mode cargo --no-test --no-tensor-shapes --no-conformance --no-jsonschema --no-extension

The tests cover whole-document and sequential UTF-16/CRLF edits, language IDs, backwards versions, reopening, missing-file and notebook rejection, and the existing transaction cancellation/restoration behavior. The native TSP, document-change, notebook-sync, and edit-during-recheck regressions also pass.

An additional local, out-of-tree Rust consumer was rebuilt for WASIp1 and executed using the public WASI shim. It exercised the shared public APIs for document edits, version/error state, and transaction creation. This smoke harness is not part of the PR.

The edit algorithm and transaction manager were mechanically checked against their original implementations. Full formatting left all six candidate files unchanged. Existing warnings remain; the upstream CI-flaky test_open_file_during_recheck stays ignored and is not counted as passed. The full native suite and Linux/macOS execution were not run.

[meta-codesync]

This pull request has been imported. If you are a Meta employee, you can view this in D128390074. (Because this pull request was imported automatically, there will not be any future comments.)

[kinto0]

thanks! some nits about where things go / abstractions

feel free to add parallel PRs that branch off of this if this merge process is going too slowly. I can figure out how to review them like that

[kinto0]

should openfiles just be an alias to the hashmap? and any user of this can put it in a rwlock? even better, if we want to abstract this, we should make a real data structure with its own apis

[yeonwooson]

Sounds good, applied the changes

[kinto0]

is there a reason we don't remove this file entirely?

[yeonwooson]

Removed it and updated so that shared transaction manager is imported directly

[kinto0]

can this go in lsp/wasm/document.rs instead?

[kinto0]

I made that naming convention a long time ago. I guess at the end of your work everything should be in wasm and nothing will be in non_wasm and we can remove non_wasm?

[kinto0]

this is what my agent proposes instead:

pub struct OpenFile {
    pub contents: Arc<LspFile>,
    pub version: i32,
}

#[derive(Default)]
pub struct OpenFiles(RwLock<HashMap<PathBuf, OpenFile>>);

impl OpenFiles {
    pub fn open(&self, path: PathBuf, version: i32, contents: Arc<LspFile>);
    pub fn close(&self, path: &Path) -> Option<OpenFile>;
    pub fn get(&self, path: &Path) -> Option<Arc<LspFile>>;
    pub fn versions(&self) -> HashMap<PathBuf, i32>;
    /// Replaces an open file's contents. The new version is stored only if `f` succeeds,
    /// and contents and version change under one lock.
    pub fn update(
        &self,
        path: &Path,
        version: i32,
        f: impl FnOnce(&OpenFile) -> anyhow::Result<LspFile>,
    ) -> anyhow::Result<()>;
}

impl LspFile {
    /// Applies text edits and keeps the language ID. Returns an error for a notebook.
    pub fn apply_text_changes(&self, changes: Vec<TextDocumentContentChangeEvent>) -> anyhow::Result<LspFile>;
}

[kinto0]

then the callsite becomes:

// textDocument/didChange
self.open_files.update(&path, version, |old| {
    if version < old.version { warn!("version went backwards ..."); }
    old.contents.apply_text_changes(params.content_changes)
})?;

// notebookDocument/didChange: same shape, but returns an error on a backwards version

[yeonwooson]

Implemented this structure and updated the callsites as well

[github-actions]

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅