my.config: catch possible nested config errors

my/core/error.py

@@ -4,7 +4,7 @@ See https://beepb00p.xyz/mypy-error-handling.html#kiss for more detail
 """
 
 from itertools import tee
-from typing import Union, TypeVar, Iterable, List, Tuple, Type, Optional, Callable, Any
+from typing import Union, TypeVar, Iterable, List, Tuple, Type, Optional, Callable, Any, cast
 
 
 T = TypeVar('T')
@@ -150,23 +150,43 @@ def error_to_json(e: Exception) -> Json:
     return {'error': estr}
 
 
-def warn_my_config_import_error(err: ImportError) -> None:
+MODULE_SETUP_URL = 'https://github.com/karlicoss/HPI/blob/master/doc/SETUP.org#private-configuration-myconfig'
+
+def warn_my_config_import_error(err: Union[ImportError, AttributeError]) -> bool:
     """
     If the user tried to import something from my.config but it failed,
     possibly due to missing the config block in my.config?
+
+    Returns True if it matched a possible config error
     """
     import re
     import click
-    if err.name != 'my.config':
-        return
-    # parse name that user attempted to import
-    em = re.match(r"cannot import name '(\w+)' from 'my.config'", str(err))
-    if em is not None:
-        section_name = em.group(1)
-        click.echo(click.style(f"""\
-   You may be missing the '{section_name}' section from your config.
-   See https://github.com/karlicoss/HPI/blob/master/doc/SETUP.org#private-configuration-myconfig\
+    if type(err) == ImportError:
+        if err.name != 'my.config':
+            return False
+        # parse name that user attempted to import
+        em = re.match(r"cannot import name '(\w+)' from 'my.config'", str(err))
+        if em is not None:
+            section_name = em.group(1)
+            click.echo(click.style(f"""\
+You may be missing the '{section_name}' section from your config.
+See {MODULE_SETUP_URL}\
 """, fg='yellow'), err=True)
+            return True
+    elif type(err) == AttributeError:
+        # test if user had a nested config block missing
+        # https://github.com/karlicoss/HPI/issues/223
+        if hasattr(err, 'obj') and hasattr(err, "name"):
+            config_obj = cast(object, getattr(err, 'obj'))  # the object that caused the attribute error
+            # e.g. active_browser for my.browser
+            nested_block_name = err.name  # type: ignore[attr-defined]
+            if config_obj.__module__ == 'my.config':
+                click.secho(f"You're likely missing the nested config block for '{getattr(config_obj, '__name__', str(config_obj))}.{nested_block_name}'.\nSee {MODULE_SETUP_URL} or check the module.py file for an example", fg='yellow', err=True)
+                return True
+    else:
+        click.echo(f"Unexpected error... {err}", err=True)
+    return False
+
 
 
 def test_datetime_errors() -> None: