Problem with projects using different ruby versions opened in one workspace in VSC

[ToniShingly]

Description

Ruby LSP Information

VS Code Version

1.121.0

Ruby LSP Extension Version

0.10.4

Ruby LSP Server Version

0.26.9

Ruby LSP Add-ons

• Ruby LSP Rails (0.4.8)
• RuboCop (unknown)

Ruby Version

3.0.2

Ruby Version Manager

rbenv

Installed Extensions

Click to expand

• LiveServer (5.7.10)
• debugpy (2026.6.0)
• docker (0.18.0)
• es7-react-js-snippets (4.4.3)
• go (0.52.2)
• makefile-tools (0.12.17)
• markdown-preview-enhanced (0.8.27)
• prisma (31.11.0)
• python (2026.4.0)
• remote-containers (0.459.0)
• remote-wsl (0.104.3)
• ruby-lsp (0.10.4)
• todo-tree (0.0.226)
• vs-code-prettier-eslint (6.0.0)
• vscode-containers (2.4.4)
• vscode-docker (2.0.0)
• vscode-eslint (3.0.24)
• vscode-pylance (2026.2.1)
• vscode-tailwindcss (0.14.29)

Ruby LSP Settings

Click to expand

Workspace

{}

User

{
 "enabledFeatures": {
 "codeActions": true,
 "diagnostics": true,
 "documentHighlights": true,
 "documentLink": true,
 "documentSymbols": true,
 "foldingRanges": true,
 "formatting": true,
 "hover": true,
 "inlayHint": true,
 "onTypeFormatting": true,
 "selectionRanges": true,
 "semanticHighlighting": true,
 "completion": true,
 "codeLens": true,
 "definition": true,
 "workspaceSymbol": true,
 "signatureHelp": true,
 "typeHierarchy": true
 },
 "featuresConfiguration": {},
 "addonSettings": {},
 "rubyVersionManager": {
 "identifier": "rbenv"
 },
 "customRubyCommand": "",
 "formatter": "auto",
 "linters": null,
 "bundleGemfile": "",
 "testTimeout": 30,
 "pullDiagnosticsOn": "both",
 "useBundlerCompose": false,
 "bypassTypechecker": false,
 "rubyExecutablePath": "",
 "indexing": {},
 "erbSupport": true,
 "featureFlags": {},
 "sigOpacityLevel": "1"
}

Reproduction steps

1. Open VS Code.

2. Add two different Ruby projects to the same workspace (Multi-root Workspace).

3. Project A has .ruby-version set to 3.0.2.

4. Project B has .ruby-version set to 3.3.x (or any other version).

5. Ensure rubyLsp.rubyVersionManager is set to rbenv in User Settings.

6. Wait for the Ruby LSP server to initialize.

Expected behavior

Ruby LSP should spin up two separate language server processes, each using the Ruby version specified in the respective project's .ruby-version file (leveraging rbenv context).

Actual behavior

Ruby LSP attempts to initialize for both projects using only one Ruby version (usually the one from the first project opened).

• In the Output channel for Ruby LSP, I see that it tries to run bundle install or start the server for the second project using the wrong Ruby executable.
• Syntax highlighting and constant resonance work for one project but fail for the other with "index out of bounds" or "failed to spawn" errors because of the version mismatch.
• If I open these projects in separate VS Code windows, they work perfectly fine.

[hiSandog]

Multi-root workspaces need the Ruby runtime and bundle resolution to be keyed by workspace folder rather than by the first activated server. A useful compatibility test would open two folders with different .ruby-version and Gemfile.lock files, then confirm diagnostics, formatting, and indexing commands each run with the owning folder’s interpreter after either folder is added first.