Failed to get list of R functions: No method asJSON S3 class: NativeRoutineMap

Description

When using the R extension, I consistently receive these error messages:

1. Failed to get list of R functions. Make sure that jsonlite is installed and r.rpath.windows points to a valid R executable.

2. R library paths: C:/R_libs/4.5 C:/Program Files/R/R-4.5.2/library Error: No method asJSON S3 class: NativeRoutineMap

The error occurs even when just selecting lines of code in the editor (without executing), suggesting it's triggered by autocomplete/hover features.

Environment

• OS: Windows 11 x64
• VS Code version: (1.107.1)
• vscode-R extension version: 2.8.6
• R version: 4.5.2 (2025-10-31 ucrt)
• jsonlite version: 2.0.0
• languageserver version: 0.3.16

Attempted fixes (none worked)

1. Added S3 method fix for asJSON.NativeRoutineMap in:

   • ~/.Rprofile
   • Rprofile.site (R's site profile)
   • OneDrive shared .Rprofile

2. Set R_PROFILE_USER as system environment variable

3. Configured r.lsp.args: ["--no-save", "--no-restore"]

4. Reinstalled languageserver from GitHub (remotes::install_github)

5. Updated jsonlite to 2.0.0

Root cause hypothesis

The languageserver appears to run with --vanilla flag internally, which skips all profile files including Rprofile.site. This prevents any runtime fix from being applied before jsonlite encounters the NativeRoutineMap class.

Suggested fix

Either:

1. Don't use --vanilla when spawning the languageserver R process, or
2. Add a built-in handler for NativeRoutineMap class in the extension/languageserver
3. Use force = TRUE in jsonlite calls (similar to fix in PR #1255)

Minimal reproducible example

The error occurs on any R file when the extension tries to provide autocomplete suggestions.

Reproduce the failure in a Windows 11 VS Code R file by triggering autocomplete or hover, then inspect the extension's languageserver process spawning and the configured r.lsp.args. Compare the behavior involving --vanilla, jsonlite, and NativeRoutineMap, and use the reported environment as the baseline. Done means the function-list error no longer appears during autocomplete or hover.