[alex09x]

Problem

prod-code lsp served an editor from prod-code's own engines, not from the server the editor would run locally (#332). For Rust that was the in-memory engine; for the other languages, a server the gateway had initialised for itself. The editor's settings never reached the server, and neither did the server's requests. Nothing ran cargo check on save, and rust-analyzer's protocol extensions were refused. Run with a scripted editor session on a one-file crate that moves v twice (rustc's E0382), prod-code 0.3.8 with #320 deployed:

initialize 0.74s serverInfo={'name': 'prod-code', 'version': '0.3.8'}
rust-analyzer/expandMacro -> ERROR {"code": -32601, "message": "rust-analyzer/expandMacro is not supported by prod-code for Rust"}
notify textDocument/didSave
diagnostics after 15 s: {"src/lib.rs": []}

Two more gaps stood in the way of an editor:

• Definitions in the standard library, a dependency or a generated file came back as paths that exist only on the node, so the editor could not open them (Go to definition into std or a dependency opens a path that exists only on the node #333).
• There was no Zed extension (No Zed extension: prod-code cannot serve Zed as a language server #334).

Change

• Gateway, editor_proxy. A session whose handshake says purpose: "editor" gets a language server process of its own, started in the node's copy of the checkout.
  • The server is the language's own: rust-analyzer, gopls, clangd (for_cpp), basedpyright, the TypeScript server or sourcekit-lsp.
  • Every message is carried both ways with its paths translated, and nothing else is changed except processId in initialize, which is dropped. That id names a process on the editor's machine, and basedpyright exited 4 s after it found no such process on the node (measured below; rust-analyzer, gopls and clangd kept running).
  • The server ends with the session.
  • After a sync, the editors' servers are told which files changed (workspace/didChangeWatchedFiles, registry EditorServers).
  • Without the server on the node, or with PROD_CODE_EDITOR_SERVERS=off, the session is served by the shared engines as before.
• Client, prod-code lsp.
  • --language <lang> asks for one language's server, and places a language other than the root's under a key of its own, e.g. Swift on a macOS node.
  • textDocument/didSave and workspace/didChangeWatchedFiles wait for a push of the checkout, so that check on save checks what was saved. The push and the background syncs take turns.
  • editor_files::RemoteFiles copies a file the server names that the editor cannot open into a read-only mirror under the user's cache directory, and names the copy. The editor's messages about a copy name the node's path again. Toolchain and registry files are fetched once; others are fetched each time.
  • Frames are read with every header, case-insensitively.
  • PROD_CODE_LSP_TRACE=<file> logs every message.
• editors/zed. A Zed extension (zed_extension_api 0.7.0, builds to a 304 KB wasm32-wasip2 component). It has one server per language (prod-code-rust, -go, -cpp, -python, -typescript, -swift), each running prod-code lsp --language <lang>. The user's settings for the local server a prod-code server stands in for (lsp.rust-analyzer.* and so on) are passed on. Its README also shows how to point Zed's own rust-analyzer at prod-code lsp, which keeps every Rust feature Zed wires to rust-analyzer by name.
• The rust-analyzer component was installed on the two Linux nodes that lacked it (rustup component add rust-analyzer).

Reproduce and verify

The live tests run a real gateway and real servers on a Linux build node:

an_editor_gets_rust_analyzer_itself_on_the_node          ok
  serverInfo "rust-analyzer"; rust-analyzer/expandMacro expands format!;
  didSave -> cargo check on the node -> publishDiagnostics with code E0382
an_editors_python_server_does_not_watch_the_editors_process   ok
  initialize with a processId that names nothing on the node; 8 s later hover still answers
an_editor_session_gets_what_an_editor_needs_for_rust          ok   (PROD_CODE_EDITOR_SERVERS=off: the in-memory engine, as in #320)

In the CLI test lsp_asks_for_its_language_pushes_a_save_first_and_mirrors_node_files:

• the handshake carries engine=go;
• a sync lands between initialize and the didSave it precedes;
• a definition at /srv/toolchains/std/vec.rs reaches the editor as file://<cache>/prod-code/remote/<node>/srv/toolchains/std/vec.rs, read-only, with the node's content.

Each new test fails without its piece:

• Python process id. With processId passed through, an_editors_python_server_does_not_watch_the_editors_process fails after 8.75 s: the session ended.
• Save order. With the push before didSave removed, the CLI test fails. Its log shows no sync between initialize and didSave.

Which servers exit when processId names no process on the node (initialize with processId: 2147483000, 20 s):

rust-analyzer: still running after 20s
basedpyright-langserver: exited after 4s with 1
gopls: still running after 20s
clangd: still running after 20s

Checks (Linux build node)

• cargo fmt --all -- --check: fmt=0 (after cargo fmt --all on the node)
• cargo clippy -p prod-code-gateway -p prod-code-client --all-targets -- -D warnings: clippy=0
• cargo llvm-cov -p prod-code-gateway -p prod-code-client: passed=177 failed=0
• coverage (regions), by file:
  • editor_proxy.rs 89.60% (new)
  • editor_files.rs 96.54% (new)
  • gateway lib.rs 84.48%
  • workspace.rs 81.97%
  • client main.rs 80.91%
• editors/zed: cargo build --release --target wasm32-wasip2 ok; cargo clippy --target wasm32-wasip2 -- -D warnings clean; cargo fmt --check clean.
• In Zed itself. A second, isolated Zed cannot run next to a running one (zed is already running, whatever --user-data-dir says). The check in Zed follows the deploy, in a project that selects the servers in its .zed/settings.json.

Closes #332
Closes #333
Closes #334

[chatgpt-codex-connector]

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-25T08:02:34.935822Z	9c95a93	PR opened

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[chatgpt-codex-connector]

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Reviewed commit: 9c95a930eb

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[chatgpt-codex-connector]

Preserve the TypeScript server initialization options

When the node selects typescript-language-server and the checkout does not contain its own node_modules/typescript, GenericLspConfig::for_typescript() supplies the global tsserver.path needed by that server, but this conversion discards initialization_options. The dedicated editor process therefore starts successfully but cannot locate TypeScript unless the editor happens to provide a node-valid path itself; carry these defaults into the forwarded initialize request and merge them with the editor's options.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Stop forwarding saves when their sync fails

If the separate sync connection transiently fails while the main LSP session remains alive, this branch only logs the error and immediately forwards textDocument/didSave. Rust-analyzer then runs its check-on-save against the previous on-disk contents even though the editor has just saved newer text, producing stale or misleading diagnostics; retry the sync or surface/terminate the session instead of delivering the save before its contents reach the node.

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[chatgpt-codex-connector]

Encode the mirror root before matching file URIs

When HOME or XDG_CACHE_HOME contains a space, #, or another URL-escaped character, copy() returns a percent-encoded URI from Url::from_file_path, while mirror_uri and the early raw.contains(mirror) check use the unencoded filesystem string. Messages about an opened mirrored definition then bypass to_node, so the remote language server receives the client's cache path instead of the original node path and requests such as hover or references fail; construct and match the mirror prefix as a proper file URL.

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[alex09x]

Live output after the deploy (gateway a70c8bd on a Linux build node; checked again on v0.3.9). A scripted editor session drives prod-code lsp in a one-file crate whose function moves v twice:

initialize 0.11s serverInfo={'name': 'rust-analyzer', 'version': '1.98.1 (48a229c 2026-09-01)'} sync={'openClose': True, 'change': 2, 'save': {}}
open src/lib.rs
hover src/lib.rs:0:20 0.24s -> {"kind": "plaintext", "value": "alloc::string\n\npub struct String {\n    vec: Vec<u8>,\n}\n\n\nA UTF-8–encoded, growable string. ..."}
rust-analyzer/expandMacro 0.01s -> {"name": "format!", "expansion": "alloc::__export::must_use({ alloc::fmt::format(alloc::__export::format_args!(\"{s:?}{t:?}\")) })\n"}
definition src/lib.rs:0:17 0.06s -> [{"range": {"end": {"character": 14, "line": 435}, "start": {"character": 11, "line": 435}}, "uri": "file:///Users/<you>/Library/Caches/prod-code/remote/<node>/home/<user>/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/vec/mod.rs"}]
notify textDocument/didSave
diagnostics: {"src/lib.rs": [[2, "use of moved value: `v`\nvalue used here after move"], [1, "value moved here"], [0, "move occurs because `v` has type `Vec<String>`, which does not implement the `Co"], [1, "consider cloning the value if the performance cost is acceptable: `.clone()`"]]}
server messages: {'textDocument/publishDiagnostics': 3, 'workspace/diagnostic/refresh': 2}

The home directories and the node's address in the mirror path are replaced by <you>, <user> and <node>. The mirrored copy is read-only (-r--r--r--, 168,574 bytes).