fix(clojure): declare didChangeWatchedFiles client capability (#1884)

Serena notifies language servers about files changed outside its own edit tools (a git checkout, another editor, a build step) by sending workspace/didChangeWatchedFiles from LanguageServerManager.poll_and_notify, whose docstring names this exact case: such edits are 'otherwise invisible to a warm language server, causing symbolic queries to answer from a stale index'.

ClojureLSP never declared the corresponding client capability, so clojure-lsp was not told those notifications are sent and need not treat them as a reason to invalidate its analysis. DefaultInitializeParamsBuilder does not supply a default capabilities block, so nothing filled this in on the server's behalf.

Relates to #1593, where find_symbol returned a body from a comment mentioning the symbol rather than its definition, at a position the symbol had previously occupied.

CHANGELOG.md

@@ -8,6 +8,10 @@ Status of the `main` branch. Changes prior to the next official version change w
 
 * Language Servers:
   - Fix: Dart's `$/analyzerStatus` notifications were logged as unhandled-method warnings during analysis (#1855)
+  - Fix: clojure-lsp was not told that Serena sends `workspace/didChangeWatchedFiles`, so changes made
+    outside Serena's own edit tools (a git checkout, another editor, a build step) need not invalidate
+    its analysis; symbol queries could then answer from a stale index, e.g. `find_symbol` returning a
+    body from the position the symbol used to occupy (#1593)
   - Fix: Scala cross-file queries waited a fixed 5s after the first file was opened, which on a cold
     Metals is long before its build import, indexing and compilation have finished; the first
     `find_referencing_symbols` of a session could return a fraction of the references with nothing to

src/solidlsp/language_servers/clojure_lsp.py

@@ -325,6 +325,12 @@ class ClojureLSP(SolidLanguageServer):
                 "workspace": {
                     "applyEdit": True,
                     "workspaceEdit": {"documentChanges": True},
+                    # Serena notifies language servers about files changed outside its own
+                    # edit tools (git checkout, another editor, a build step) via
+                    # workspace/didChangeWatchedFiles; see LanguageServerManager.poll_and_notify.
+                    # Without declaring the capability, clojure-lsp is not told the client
+                    # sends those notifications and may keep answering from its stale analysis.
+                    "didChangeWatchedFiles": {"dynamicRegistration": True},
                     "symbol": {"symbolKind": {"valueSet": list(range(1, 27))}},
                     "workspaceFolders": True,
                 },

test/solidlsp/clojure/test_clojure_initialize_params.py

@@ -0,0 +1,42 @@
+import pytest
+
+from solidlsp.language_servers.clojure_lsp import ClojureLSP
+
+pytestmark = pytest.mark.clojure
+
+
+def _make_server(monkeypatch: pytest.MonkeyPatch) -> ClojureLSP:
+    """Build a ClojureLSP without running __init__ (no clojure-lsp binary needed)."""
+    server = object.__new__(ClojureLSP)
+    monkeypatch.setattr(ClojureLSP, "_resolve_source_paths", lambda _self: None)
+    return server
+
+
+def test_declares_did_change_watched_files_capability(monkeypatch: pytest.MonkeyPatch) -> None:
+    """clojure-lsp must announce that the client sends workspace/didChangeWatchedFiles.
+
+    Serena notifies language servers about files changed outside its own edit tools
+    (git checkout, another editor, a build step) via that notification
+    (LanguageServerManager.poll_and_notify). A server that was never told the client
+    supports it may keep answering symbol queries from its own stale analysis, which
+    surfaces as find_symbol returning a body from the wrong location.
+    """
+    params = _make_server(monkeypatch)._create_base_initialize_params()
+
+    workspace = params["capabilities"]["workspace"]
+    assert "didChangeWatchedFiles" in workspace, (
+        "clojure-lsp does not declare the didChangeWatchedFiles client capability, so external file changes may not invalidate its analysis"
+    )
+    assert workspace["didChangeWatchedFiles"]["dynamicRegistration"] is True
+
+
+def test_base_initialize_params_keep_existing_workspace_capabilities(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """The added capability must not displace the ones already relied upon."""
+    workspace = _make_server(monkeypatch)._create_base_initialize_params()["capabilities"]["workspace"]
+
+    assert workspace["applyEdit"] is True
+    assert workspace["workspaceEdit"] == {"documentChanges": True}
+    assert workspace["workspaceFolders"] is True
+    assert workspace["symbol"]["symbolKind"]["valueSet"] == list(range(1, 27))