fix(analyzer): resolve LSP CALLS edges on repos without a venv

The Python analyzer hardcoded `environment_path={path}/venv` when starting
jedi-language-server via multilspy. When the repo had no venv (the common
case for cloned codebases like sphinx, sympy, anything from SWE-bench),
jedi raised `InvalidPythonEnvironment` on every `request_definition()`
call. analyzer.resolve() then swallowed the exception silently and the
indexer produced a graph with DEFINES edges only — zero CALLS, zero
EXTENDS. Benchmark validation showed sphinx (5K functions) and sympy
(41K functions) had no resolved cross-references at all.

Fix:
- source_analyzer.py: prefer {repo}/venv, then {repo}/.venv, then fall
  back to the host interpreter's environment (sys.executable's prefix)
  so jedi always has a valid Python to introspect.
- analyzer.py: log resolve() failures at WARN with file/line context
  instead of swallowing them silently, so the next regression is loud.

Verified: re-indexed sphinx-doc/sphinx-9230 with the fix:
  DEFINES: 5640, CALLS: 4931, EXTENDS: 484 (was DEFINES-only).

Fixes #685.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: dvirdukhan

api/analyzers/analyzer.py

@@ -56,7 +56,12 @@ def resolve(self, files: dict[Path, File], lsp: SyncLanguageServer, file_path: P
         try:
             locations = lsp.request_definition(str(file_path), node.start_point.row, node.start_point.column)
             return [(files[Path(self.resolve_path(location['absolutePath'], path))], files[Path(self.resolve_path(location['absolutePath'], path))].tree.root_node.descendant_for_point_range(Point(location['range']['start']['line'], location['range']['start']['character']), Point(location['range']['end']['line'], location['range']['end']['character']))) for location in locations if location and Path(self.resolve_path(location['absolutePath'], path)) in files]
-        except Exception:
+        except Exception as e:
+            import logging
+            logging.getLogger(__name__).warning(
+                "resolve() failed for %s @%d:%d: %s",
+                file_path, node.start_point.row, node.start_point.column, e,
+            )
             return []
 
     @abstractmethod

api/analyzers/source_analyzer.py

@@ -139,7 +139,27 @@ def second_pass(self, graph: Graph, files: list[Path], path: Path) -> None:
         else:
             lsps[".java"] = NullLanguageServer()
         if any(path.rglob('*.py')):
-            config = MultilspyConfig.from_dict({"code_language": "python", "environment_path": f"{path}/venv"})
+            import sys
+            py_venv = path / "venv"
+            py_dotvenv = path / ".venv"
+            if py_venv.is_dir() and (py_venv / "bin" / "python").exists():
+                env_path = str(py_venv)
+            elif py_dotvenv.is_dir() and (py_dotvenv / "bin" / "python").exists():
+                env_path = str(py_dotvenv)
+            else:
+                # Fall back to the host's Python environment so jedi has a
+                # valid interpreter to introspect; otherwise every
+                # request_definition() raises InvalidPythonEnvironment and
+                # we'd silently produce a graph with zero CALLS edges.
+                env_path = str(Path(sys.executable).resolve().parent.parent)
+                logging.info(
+                    "No venv at %s; falling back to host env %s for jedi LSP",
+                    path, env_path,
+                )
+            config = MultilspyConfig.from_dict({
+                "code_language": "python",
+                "environment_path": env_path,
+            })
             lsps[".py"] = SyncLanguageServer.create(config, logger, str(path))
         else:
             lsps[".py"] = NullLanguageServer()