fix: preview works when alias can't resolve target

Author: machow

quartodoc/ast.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import warnings
+
 from enum import Enum
 from dataclasses import dataclass
 from griffe.docstrings import dataclasses as ds
@@ -179,7 +181,15 @@ def fields(el: dc.Object):
 
 @dispatch
 def fields(el: dc.ObjectAliasMixin):
-    return fields(el.target)
+    try:
+        return fields(el.target)
+    except dc.AliasResolutionError:
+        warnings.warn(
+            f"Could not resolve Alias target `{el.target_path}`."
+            " This often occurs because the module was not loaded (e.g. it is a"
+            " package outside of your package)."
+        )
+        return ["name", "target_path"]
 
 
 @dispatch

quartodoc/tests/test_ast.py

@@ -75,6 +75,17 @@ def test_preview_no_fail(capsys):
     assert "get_object" in res.out
 
 
+def test_preview_warn_alias_no_load():
+    # fetch an alias to pydantic.BaseModel, without loading pydantic
+    # attempting to get alias.target will fail, but preview should still work.
+    obj = get_object("quartodoc.ast.BaseModel", load_aliases=False)
+    with pytest.warns(UserWarning) as record:
+        qast.preview(obj)
+
+    msg = record[0].message.args[0]
+    assert "Could not resolve Alias target `pydantic.BaseModel`" in msg
+
+
 @pytest.mark.parametrize(
     "text, dst",
     [("One\n---\nab\n\nTwo\n---\n\ncd", [("One", "ab\n\n"), ("Two", "\ncd")])],