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fix: support pygls v2 LanguageServer import #25

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Merged
dguido merged 1 commit into from
Jan 26, 2026
Merged

fix: support pygls v2 LanguageServer import #25

dguido merged 1 commit into from
Jan 26, 2026
+51 −49

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@nisedo
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@nisedo nisedo commented Jan 25, 2026

Context / Bug

slither-lsp imports LanguageServer from pygls.server.

In pygls>=2.0, LanguageServer was moved to pygls.lsp.server, so the import fails and the LSP crashes on startup with:

ImportError: cannot import name 'LanguageServer' from 'pygls.server'

Impact

Any environment that resolves pygls>=2 (e.g., uv tool installs) fails to start slither-lsp, causing the VSCode extension to repeatedly restart the server and never initialize.

Fix

Add a backward‑compatible import shim that tries the old path first and falls back to the new path:

try:
from pygls.server import LanguageServer
except ImportError:
from pygls.lsp.server import LanguageServer

Applied consistently in:

- slither_lsp/app/slither_server.py
- slither_lsp/app/logging/lsp_handler.py
- slither_lsp/app/request_handlers/analysis/get_detector_list.py
- slither_lsp/app/request_handlers/analysis/get_version.py
- slither_lsp/app/request_handlers/compilation/get_command_line_args.py

### Why this approach

- Preserves compatibility with pygls<2 without breaking existing environments.
- Unblocks pygls>=2 without pinning dependencies.
- Minimal, low‑risk change: only import paths, no behavior changes.

### Testing

Manual: verified that slither-lsp starts with pygls>=2 after the change (previously crashed).

@dguido @claude
Migrate to pygls v2 (drop v1 support)
97eb4ae 
- Update pygls dependency to >=2.0.0
- Update imports from pygls.server to pygls.lsp.server
- Update method calls to use v2 params-based API:
  - show_message() -> window_show_message(ShowMessageParams)
  - show_message_log() -> window_log_message(LogMessageParams)
  - publish_diagnostics() -> text_document_publish_diagnostics(PublishDiagnosticsParams)
- Update tests for new API

Co-Authored-By: Claude Opus 4.5 <[email protected]>
@dguido dguido force-pushed the fix/pygls-2-compat branch from 9c33bad to 97eb4ae Compare January 26, 2026 18:44
@dguido dguido merged commit 41156fb into main Jan 26, 2026
7 checks passed
@dguido dguido deleted the fix/pygls-2-compat branch January 26, 2026 18:48
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3 participants

@nisedo @dguido