fix: handle SyntaxError gracefully in ast_analyzer

backend/app/services/ast_analyzer.py

@@ -304,7 +304,20 @@ def walk(node, depth):
     return issues
 
 def analyze(source: str) -> list[dict]:
-    tree = ast.parse(source)
+    try:
+        tree = ast.parse(source)
+    except SyntaxError as exc:
+        return [
+            _make_issue(
+                "Syntax Error",
+                exc.lineno or 1,
+                f"Python syntax error: {exc.msg}",
+                "Fix the syntax error before running analysis.",
+                "error",
+                ""
+            )
+        ]
+
     issues = []
     issues += detect_unreachable_code(tree, source)
     issues += detect_unused_imports(tree, source)

backend/tests/test_ast_analyzer.py

@@ -230,3 +230,10 @@ def test_deep_nesting_exact_boundary():
     )
     issues = analyze(code)
     assert not any(i["type"] == "Deep Nesting" for i in issues)
+
+
+def test_analyze_handles_syntax_error():
+    result = analyze("def f(:\n    pass")
+
+    assert len(result) == 1
+    assert result[0]["type"] == "Syntax Error"