Next major release 3.0.0-rc.0 by randy3k · Pull Request #1684 · REditorSupport/vscode-R

randy3k · 2026-03-14T21:46:02Z

The sess package is now bundled with the VSCode extension, we might move it to its own repository in the future.

Everything below this sentence was generated automatically.

🚀 Feature: Migrate Session Watcher to WebSockets & JSON-RPC 2.0

📝 Overview

This PR introduces a major architectural upgrade to vscode-R by replacing the legacy, file-based session watcher with a high-performance, token-authenticated IPC (Inter-Process Communication) mechanism.

The new system operates over a pure WebSocket architecture using JSON-RPC 2.0, enabling reliable, bidirectional communication between the R session and the VS Code extension.

✨ Key Changes

1. New `sess` R Package

Introduced the sess package to handle the server-side IPC.
Provides token-authenticated WebSocket connections instead of writing state to local temporary files.
Includes comprehensive hooks for the R environment (sess::register_hooks) and rstudioapi emulation.

2. Client Session Manager Modernization

src/session.ts refactored: Heavily refactored the extension's session manager to act as a JSON-RPC client/server.
Added bidirectional RPC dispatching and handling, allowing the extension to actively query the R session instead of just reacting to file system changes.

3. Viewer Architecture Overhaul

Plot Viewer: Refactored into a modular architecture (httpgdViewer.ts and standardViewer.ts).
Help & Web Viewers: Modernized helpViewer and webViewer implementations to cleanly integrate with the new IPC layer.

4. Comprehensive Testing & CI Modernization

Integration Tests: Added new integration test suites specifically for the modernized session (session.test.ts) and terminal (terminal.test.ts).
CI Pipelines: Updated GitHub Actions (main.yml, pre-release.yml, release.yml) to support the new testing architecture and package building steps.

💡 Motivation & Background

The previous file-based session watcher (writing state to .vscode-R directories) was prone to race conditions, slow I/O, and was strictly one-way (R -> VS Code).

By migrating to WebSockets and JSON-RPC 2.0:

Reliability: Communication is synchronous and direct, eliminating I/O bottlenecks.
Security: Sessions are now authenticated via random tokens upon initialization.
Extensibility: The bidirectional protocol lays the foundation for more complex features (e.g., interactive data viewing, precise plotting queries, advanced RStudio API emulation).

🧪 Testing Performed

Validated new integration test suite.
Tested plotting via httpgd and standard viewers.
Confirmed rstudioapi emulation and global environment variable syncing.

Note: Ensure to check any new dependencies introduced in package.json and package-lock.json are properly installed before building.

Introduce the 'sess' R package for WebSocket IPC, implement terminal orchestration, and modernize the session watcher architecture for improved reliability and performance.

renkun-ken · 2026-03-29T09:53:09Z

Thanks for the good work! I'm wondering how to make it work with self-managed R sessions, e.g. a radian console started in a tmux window?

renkun-ken · 2026-03-29T10:00:30Z

I'm also wondering if the dependencies of sess could be somehow reduced so that it is more self-contained and could work with more restrictive environments where more limits of package installation are imposed.

[sess] Connected to VS Code

> sessionInfo()
R version 4.5.1 (2025-06-13)
Platform: aarch64-apple-darwin20
Running under: macOS Tahoe 26.4

Matrix products: default
BLAS:   /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libRblas.0.dylib 
LAPACK: /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libRlapack.dylib;  LAPACK version 3.12.1

locale:
[1] C.UTF-8/en_US.UTF-8/C.UTF-8/C/C.UTF-8/C.UTF-8

time zone: Asia/Hong_Kong
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
 [1] websocket_1.4.4   compiler_4.5.1    R6_2.6.1          cli_3.6.5        
 [5] later_1.4.5       tools_4.5.1       Rcpp_1.1.1        httpgd_2.0.4     
 [9] unigd_0.1.3       jsonlite_2.0.0    sess_0.1.0        lifecycle_1.0.5  
[13] rlang_1.1.7       systemfonts_1.3.1

randy3k · 2026-03-30T16:29:41Z

Thanks for the good work! I'm wondering how to make it work with self-managed R sessions, e.g. a radian console started in a tmux window?

If you run R: Connect to R Session, it will copy a websocket address. You can then paste it in R (with sess installed) inside sess_app`. E.g.,

sess::sess_app("ws://......")

(at the moment of writing, it may be more convenient to copy the whoe command with sess::sess_app(....).

Theorietically, we could replace websocket with base R socketConnect but it is not very efficient. I beleive most users will also install languageserver, I guess it is also possible to absorb the package into langugeserver which is kind of bloated already.

renkun-ken · 2026-03-31T12:06:02Z

Yes, that's true. languageserver has many dependencies already. One difference is that languageserver is not loaded in the user session while sess is. For me, less packages loaded in user session could be cleaner :)

randy3k · 2026-05-02T04:43:47Z

Yes, that's true. languageserver has many dependencies already. One difference is that languageserver is not loaded in the user session while sess is. For me, less packages loaded in user session could be cleaner :)

Sorry for the late reply. sess requires

websocket,
later,
jsonlite,
rstudioapi,
svglite

I think minimally we will need websocket, later and jsonlite. It shouldn't be that bad. AFAIK, rstudio and positron have way more dependencies.

Add end-to-end integration tests for the session watcher and terminal, refactor existing unit tests, and update GitHub Action workflows for improved CI reliability.

Apply session watcher stability fixes, swap R IPC client/server roles for reliability, perform final linting, and bump the version to 3.0.0-rc.0.

Ported changes from PR #1693 to dev branch. Prepend params command when running selection or chunks from Rmd files with params in YAML frontmatter. Co-authored-by: tomtom <[email protected]>

- Added tests for getRmdParamsCommand in rmdParams.test.ts - Exported getRmdParamsCommand in rTerminal.ts for testing - Renamed sesson.test.ts to workspaceViewer.test.ts to fix typo - Deleted duplicate workspace.ts file

- Added version comparison between bundled and installed sess package. - Added unit tests in sessInstall.test.ts. - Used exports workaround in util.ts to enable stubbing of local functions in tests.

… hooks for sess compatibility

randy3k · 2026-05-02T21:46:44Z

I have spent sometime to make live share to work without success, finally realized that we need to whitelite our publisher id: #1218

But It seems that microsoft is not being very active there, we might have to drop the Live share functionality here.

…ndows

… logs

Close #1845 The development build already requires sess IPC protocol 2 and is incompatible with past releases. Use this compatibility break to remove the old R API compatibility layer and helpers whose roles have ended. - **`use_httpgd`, `use_jgd`, and their compatibility helpers:** `use_httpgd` was introduced in #1684, and `use_jgd` in #1706. #1817 replaced them with `plot_backend`, retaining the old arguments through `.warn_deprecated_plot_args()` and `.legacy_plot_backend()`. Extension callers already use `plot_backend`; removing the old arguments now also removes the need for these helpers. - **`register_hooks()`:** Introduced in #1684 for standalone hook registration and re-registration. It now delegates to `runtime_start()`, which `connect()` already calls directly, and has no extension callers. Re-registering also resets runtime-owned devices and viewer state without updating reconnect options, so this wrapper no longer provides a coherent independent configuration API. Keep the internal runtime lifecycle and use `connect()` as the public integration entry point. - **`rebind()`:** Introduced in #1684. #1739 migrated all callers to `.runtime_rebind()`, which records bindings for restoration when the runtime stops. Only the unused old definition remained. - **`json_rpc_response()` and `json_rpc_error()`:** Included in [#1684](#1684), but the upstream `sess` branch history shows they served the earlier HTTP `/rpc` implementation. [The WebSocket conversion](41b298a) removed their callers before sess reached main. Delete these unused HTTP response builders; the active `"json_rpc_error"` condition class remains. Update documentation, installer export checks, and test fixtures to match. Backend selection, fallback, and reconnect behavior remain unchanged, and the IPC protocol stays at version 2. Breaking API change: `connect()` no longer accepts `use_httpgd` or `use_jgd`, and `register_hooks()` is no longer exported. Use `plot_backend` and `connect()` instead.

randy3k changed the title ~~Modernize R Session IPC with WebSocket and JSON-RPC 2.0 (WIP_~~ Modernize R Session IPC with WebSocket and JSON-RPC 2.0 (WIP) Mar 14, 2026

randy3k force-pushed the dev branch 6 times, most recently from a4e988b to f5f38f2 Compare March 15, 2026 03:03

randy3k changed the title ~~Modernize R Session IPC with WebSocket and JSON-RPC 2.0 (WIP)~~ Next major release 3.0.0-rc.0 Mar 15, 2026

randy3k force-pushed the dev branch 2 times, most recently from 4ea0953 to b13558e Compare March 16, 2026 04:25

randy3k force-pushed the dev branch 3 times, most recently from 9cd3d26 to 979897b Compare March 23, 2026 23:02

feat(sess): migrate session watcher to WebSockets/JSON-RPC 2.0

4e1ca8b

Introduce the 'sess' R package for WebSocket IPC, implement terminal orchestration, and modernize the session watcher architecture for improved reliability and performance.

randy3k force-pushed the dev branch 2 times, most recently from 485bcbd to 1a247cc Compare March 26, 2026 01:09

BerriJ mentioned this pull request Apr 16, 2026

Add r.rterm.preferredConsoles for R console selection from PATH #1625

Merged

eitsupi mentioned this pull request Apr 22, 2026

.First() and .First.sys() are bypassed during the startup sequence eitsupi/arf#158

Closed

randy3k force-pushed the dev branch from abf1205 to 3b78701 Compare May 2, 2026 16:13

randy3k mentioned this pull request May 2, 2026

implement rstudioapi::showPrompt() and rstudioapi::askForPassword() #1694

Closed

randy3k force-pushed the dev branch 2 times, most recently from 49fb1f1 to d20d532 Compare May 2, 2026 17:03

randy3k mentioned this pull request May 2, 2026

In Rmd files: Evaluate params from a Yaml metadata header before evaluating any R code #1693

Closed

randy3k added 2 commits May 2, 2026 10:23

test: implement comprehensive integration test suite and modernize CI

e1fa7b5

Add end-to-end integration tests for the session watcher and terminal, refactor existing unit tests, and update GitHub Action workflows for improved CI reliability.

chore: final refinements and maintenance

7cf272e

Apply session watcher stability fixes, swap R IPC client/server roles for reliability, perform final linting, and bump the version to 3.0.0-rc.0.

randy3k and others added 5 commits May 2, 2026 10:23

style: fix line length lint error in sess/R/rstudioapi.R

310defe

feat: evaluate params from YAML header in Rmd files before running code

75d315a

Ported changes from PR #1693 to dev branch. Prepend params command when running selection or chunks from Rmd files with params in YAML frontmatter. Co-authored-by: tomtom <[email protected]>

test: add Rmd params tests and cleanup test files

e14dbdd

- Added tests for getRmdParamsCommand in rmdParams.test.ts - Exported getRmdParamsCommand in rTerminal.ts for testing - Renamed sesson.test.ts to workspaceViewer.test.ts to fix typo - Deleted duplicate workspace.ts file

perf: optimize package monitoring in helpServer.R

180d528

feat: check sess package version and prompt for update

978e8f6

- Added version comparison between bundled and installed sess package. - Added unit tests in sessInstall.test.ts. - Used exports workaround in util.ts to enable stubbing of local functions in tests.

randy3k force-pushed the dev branch from d20d532 to 978e8f6 Compare May 2, 2026 17:23

fix(liveshare): resolve activation errors, file reading bugs, and add…

6af9e16

… hooks for sess compatibility

randy3k force-pushed the dev branch from b3835a2 to 6af9e16 Compare May 2, 2026 20:31

randy3k added 3 commits May 2, 2026 14:52

chore(liveshare): remove all live share related code and documentation

b9fb9c2

test(session): add retry logic for plot tests to avoid timeouts on Wi…

5aac0f1

…ndows

test(session): add version check, retry logic, and fix lint warnings

a0edd8e

randy3k force-pushed the dev branch 3 times, most recently from d905392 to 16675e1 Compare May 2, 2026 22:57

feat(session): implement file-based reconnection and suppress verbose…

5e7e3ea

… logs

randy3k force-pushed the dev branch from 16675e1 to 5e7e3ea Compare May 2, 2026 23:05

docs: update READMEs and CHANGELOG

84132cd

randy3k merged commit 84132cd into master May 2, 2026
5 checks passed

eitsupi mentioned this pull request May 3, 2026

IPC mechanism / lightweight background server in the event loop for external editor support eitsupi/arf#112

Closed

renkun-ken mentioned this pull request May 9, 2026

3.0.0-rc for unmanaged R terminals #1701

Closed

grantmcdermott mentioned this pull request Sep 19, 2026

Provide better vsc.dev.args defaults #1657

Closed

This was referenced Sep 22, 2026

factor out init.R and other R API stuff to R package #372

Closed

Is live share still working? #1609

Closed

grantmcdermott mentioned this pull request Sep 28, 2026

Is VS Code v1.110.0 a necessary requirement? #1800

Closed

This was referenced Oct 6, 2026

vscode version constraint may need bumping #1477

Closed

Unit and integration tests #990

Closed

R session background connections #440

Closed

eitsupi mentioned this pull request Oct 7, 2026

refactor(sess!): remove legacy APIs and unused helpers #1847

Merged

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Next major release 3.0.0-rc.0 - #1684

Next major release 3.0.0-rc.0#1684
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🚀 Feature: Migrate Session Watcher to WebSockets & JSON-RPC 2.0

📝 Overview

✨ Key Changes

1. New sess R Package

2. Client Session Manager Modernization

3. Viewer Architecture Overhaul

4. Comprehensive Testing & CI Modernization

💡 Motivation & Background

🧪 Testing Performed

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randy3k commented Mar 14, 2026 •

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1. New `sess` R Package

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