fix annotation evaluation error backtrace

sx/core/util.py

@@ -1,7 +1,8 @@
 import os
-import math
+import inspect
+import ast
 import collections
-from typing import BinaryIO, Generator, Callable, Union as U, Any, cast
+from typing import BinaryIO, Generator, Callable, Union as U, Tuple, Mapping, Any, cast
 from contextlib import contextmanager
 
 
@@ -65,3 +66,24 @@ def format_value(value: Any, formatter: Callable[[Any], str], indentation: int =
         fmt = '{}'
         values = [formatter(value)]
     return indent(fmt.format(*values), indentation)
+
+
+def get_annot_locations(cls: type) -> Tuple[str, Mapping[str, int]]:
+    """ why """
+    fn = inspect.getsourcefile(cls)
+    slines, start = inspect.getsourcelines(cls)
+    mdef = ast.parse(''.join(slines))
+
+    lines = {}
+    for b in mdef.body[0].body:
+        if isinstance(b, ast.Assign):
+            ts = b.targets
+        elif isinstance(b, (ast.AnnAssign, ast.AugAssign)):
+            ts = [b.target]
+        else:
+            continue
+        for t in ts:
+            if isinstance(t, ast.Name):
+                lines[t.id] = start + b.lineno - 2
+
+    return fn, lines

sx/types/struct.py

@@ -12,7 +12,7 @@ import sx
 from ..core import to_type
 from ..core.base import Context, Type, PathElement
 from ..core.io import Stream, Pos, add_sizes
-from ..core.util import indent, format_value
+from ..core.util import indent, format_value, get_annot_locations
 from ..core.meta import Generic
 from ..core.expr import IndirectExpr, TypeSource
 
@@ -227,8 +227,16 @@ class Struct:
         annots = {}
         localns = {'Self': cls}
         for c in reversed(cls.__mro__):
+            try:
+                fn, lines = get_annot_locations(c)
+            except:
+                fn = None
+                lines = {}
             globalns = sys.modules[c.__module__].__dict__
-            annots.update({k: (globalns, v) for k, v in getattr(c, '__annotations__', {}).items()})
+            annots.update({
+                k: (fn or f'<annotation:{k}>', lines.get(k, 0), globalns, v)
+                for k, v in getattr(c, '__annotations__', {}).items()
+            })
             localns[c.__name__] = c
         if inject:
             localns.update({x: getattr(sx, x) for x in sx.__all__})
@@ -238,8 +246,9 @@ class Struct:
         proxy = StructProxy()
         localns['self'] = proxy
         fields = {}
-        for name, (globalns, value) in annots.items():
-            val = eval(value, globalns, localns)
+        for name, (fn, line, globalns, value) in annots.items():
+            code = compile('\n' * line + value, fn, 'eval')
+            val = eval(code, globalns, localns)
             if isinstance(val, Annotated):
                 val = next(v for v in val.__metadata__ if isinstance(v, Type))
             fields[name] = val