Closed
Description
In SQLAlchemy's mypy plugin , we have custom attributes that are serialized, using code that is taken directly from Mypy's own dataclasses plugin:
class SQLAlchemyAttribute:
def __init__(
self,
name: str,
line: int,
column: int,
typ: Optional[Type],
info: TypeInfo,
) -> None:
self.name = name
self.line = line
self.column = column
self.type = typ
self.info = info
def serialize(self) -> JsonDict:
assert self.type
return {
"name": self.name,
"line": self.line,
"column": self.column,
"type": self.type.serialize(),
}
# ...as of mypy 1.11.0 we are getting this stack trace when an UnboundType is serialized:
File "mypy/api.py", line 71, in run
File "mypy/api.py", line 58, in _run
File "mypy/api.py", line 72, in <lambda>
File "mypy/main.py", line 103, in main
File "mypy/main.py", line 187, in run_build
File "mypy/build.py", line 193, in build
File "mypy/build.py", line 268, in _build
File "mypy/build.py", line 2950, in dispatch
File "mypy/build.py", line 3348, in process_graph
File "mypy/build.py", line 3443, in process_stale_scc
File "mypy/semanal_main.py", line 93, in semantic_analysis_for_scc
File "mypy/semanal_main.py", line 220, in process_top_levels
File "mypy/semanal_main.py", line 349, in semantic_analyze_target
File "mypy/semanal.py", line 619, in refresh_partial
File "mypy/semanal.py", line 630, in refresh_top_level
File "mypy/semanal.py", line 7094, in accept
File "mypy/errors.py", line 1269, in report_internal_error
File "mypy/semanal.py", line 7092, in accept
File "mypy/nodes.py", line 1183, in accept
File "mypy/semanal.py", line 1700, in visit_class_def
File "mypy/semanal.py", line 1891, in analyze_class
File "mypy/semanal.py", line 1925, in analyze_class_body_common
File "mypy/semanal.py", line 2010, in apply_class_plugin_hooks
File "/home/classic/dev/sqlalchemy/lib/sqlalchemy/ext/mypy/plugin.py", line 267, in _base_cls_hook
decl_class.scan_declarative_assignments_and_apply_types(ctx.cls, ctx.api)
File "/home/classic/dev/sqlalchemy/lib/sqlalchemy/ext/mypy/decl_class.py", line 114, in scan_declarative_assignments_and_apply_types
util.set_mapped_attributes(info, mapped_attributes)
File "/home/classic/dev/sqlalchemy/lib/sqlalchemy/ext/mypy/util.py", line 181, in set_mapped_attributes
[attribute.serialize() for attribute in attributes],
^^^^^^^^^^^^^^^^^^^^^
File "/home/classic/dev/sqlalchemy/lib/sqlalchemy/ext/mypy/util.py", line 77, in serialize
"type": self.type.serialize(),
^^^^^^^^^^^^^^^^^^^^^
File "mypy/types.py", line 960, in serialize
File "mypy/types.py", line 2726, in serialize
AssertionError: Synthetic types don't serialize
I looked at mypy's source to see if this was new, however, that assertion seems to be 6 years old.
pdbing, if I come into the place where this happens, the type that fails is:
(Pdb) self.type
List?[Address?]
(Pdb) type(self.type)
<class 'mypy.types.UnboundType'>
When using mypy 1.10.1, this type can be serialized:
(Pdb) self.type
List?[Address?]
(Pdb) type(self.type)
<class 'mypy.types.UnboundType'>
(Pdb) self.type.serialize()
{'.class': 'UnboundType', 'name': 'List', 'args': [{'.class': 'UnboundType', 'name': 'Address', 'args': [], 'expr': 'Address', 'expr_fallback': 'builtins.str'}], 'expr': None, 'expr_fallback': None}
so....I have no idea what to do here. Can this type just do what it used to do? I dont see how this is making things better to just throw an error for a serialization that has no reason it can't be serialized.