Fail more gracefully if clangd is not installed

src/chatdbg/chatdbg_lldb.py

@@ -474,7 +474,7 @@ def find_definition(filename: str, lineno: int, character: int) -> str:
         if "result" not in definition or not definition["result"]:
             return "No definition found."
 
-        path = clangd_lsp_integration._uri_to_path(definition["result"][0]["uri"])
+        path = clangd_lsp_integration.uri_to_path(definition["result"][0]["uri"])
         start_lineno = definition["result"][0]["range"]["start"]["line"] + 1
         end_lineno = definition["result"][0]["range"]["end"]["line"] + 1
         (lines, first) = llm_utils.read_lines(path, start_lineno - 5, end_lineno + 5)
@@ -495,7 +495,13 @@ def find_definition(filename: str, lineno: int, character: int) -> str:
 
     assistant.add_function(lldb)
     assistant.add_function(get_code_surrounding)
-    assistant.add_function(find_definition)
+
+    if not clangd_lsp_integration.is_available():
+        print("[WARNING] clangd is not available.")
+        print("[WARNING] The `find_definition` function will not be made available.")
+    else:
+        assistant.add_function(find_definition)
+
     return assistant
 
 

src/chatdbg/clangd_lsp_integration.py

@@ -46,7 +46,7 @@ def _path_to_uri(path):
     return "file://" + os.path.abspath(path)
 
 
-def _uri_to_path(uri):
+def uri_to_path(uri):
     data = urllib.parse.urlparse(uri)
 
     assert data.scheme == "file"
@@ -61,6 +61,19 @@ def _uri_to_path(uri):
     return urllib.parse.unquote(path)  # clangd seems to escape paths.
 
 
+def is_available():
+    try:
+        clangd = subprocess.Popen(
+            ["clangd", "--version"],
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            text=True,
+        )
+        return clangd.returncode == 0
+    except FileNotFoundError:
+        return False
+
+
 class clangd:
     def __init__(
         self,