Version incompatibility with new Pymbolic release 2024.1

[mlange05]

What happened?

Following the upstream update to Pymbolic v2024.1 ecWAM regression triggers an issue in the Loki expression layer during the confirgure/plan stage.

What are the steps to reproduce the bug?

With latest Pymbolic run py.test -vs loki/transformations/ -k ecwam

Version

main

Platform (OS and architecture)

Linux, Python 3.11

Relevant log output

11-Nov-2024 06:37:39    File "/lus/h2resw01/scratch/rdci/CI/LOKI-H24RAPS-NV2211GPU-30/source/loki/loki/expression/operations.py", line 63, in <module>
11-Nov-2024 06:37:39      class StringConcat(pmbl._MultiChildExpression):
11-Nov-2024 06:37:39                         ^^^^^^^^^^^^^^^^^^^^^^^^^^
11-Nov-2024 06:37:39  AttributeError: module 'pymbolic.primitives' has no attribute '_MultiChildExpression'

Accompanying data

No response

Organisation

No response

[quepas]

I have solved this problem by adding manually the children field (in the spirit of what has been done in pymbolic):

diff --git a/loki/expression/operations.py b/loki/expression/operations.py                                                                                                    
index 03a67753..1cf4d7f6 100644
--- a/loki/expression/operations.py
+++ b/loki/expression/operations.py
@@ -13,6 +13,7 @@ nevertheless change code results.
  
 from sys import intern
 import pymbolic.primitives as pmbl
+from pymbolic.typing import ExpressionT
  
 from loki.expression.symbols import (
     StringLiteral, Sum, Product, Quotient, Power,
@@ -60,10 +61,11 @@ class ParenthesisedPow(Power):
     make_stringifier = loki_make_stringifier
  
  
-class StringConcat(pmbl._MultiChildExpression):
+class StringConcat(pmbl.Expression):
     """
     Implements string concatenation in a way similar to :class:`Sum`.
     """
+    children: tuple[ExpressionT, ...]
  
     def __add__(self, other):
         if isinstance(other, (StringConcat, StringLiteral, pmbl.Variable)):

However, this is only the beginning of problems! In pymbolic, all has started with this commit: inducer/pymbolic@1dcc9c5#diff-a27cda1a4fd5316514a9277c4733b3a23cc10fcef61c6b3f847c25085ee73863 where they removed _MultiChildExpression and converted every symbol class to a dataclass. Fields in pymbolic dataclasses are by default frozen (inducer/pymbolic@1dcc9c5#diff-768f1abbde39f5f7efff7c209a95315a87e28e0ba4f42e7a468903203aba8ffcR900), and thus, another errors are produced:

  File "/home/loki/loki/frontend/regex.py", line 873, in match                                                                                                                
    symbols += [sym.Variable(name=s[0], type=type_, scope=scope)]                                                                                                             
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                                                                                              
  File "/home/loki/loki/expression/symbols.py", line 883, in __new__                                                                                                          
    return DeferredTypeSymbol(**kwargs)                                                                                                                                       
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                                                                                                                       
  File "/home/loki/loki/expression/symbols.py", line 401, in __init__                                                                                                         
    super().__init__(name=name, scope=scope, **kwargs)
  File "/home/loki/loki/expression/symbols.py", line 130, in __init__
    self.name = kwargs['name']
    ^^^^^^^^^                              
  File "<string>", line 4, in __setattr__
dataclasses.FrozenInstanceError: cannot assign to field 'name'

I think this requires further analysis and probably some architectural changes. I might be of use in the future, but I would need to know the direction to take :P