[IMP] util/misc: new literal_replace

Avoid replacing as string.

closes #214

Signed-off-by: Christophe Simonis (chs) <[email protected]>

Author: aj-fuentes

src/base/tests/test_util.py

@@ -1609,6 +1609,24 @@ def test_SelfPrint_failure(self, value):
         with self.assertRaises(ValueError):
             safe_eval(value, util.SelfPrintEvalContext(), nocopy=True)
 
+    @parametrize(
+        [
+            ("[('company_id','in',allowed_company_ids)]", "[('company_id', 'in', companies.active_ids)]"),
+            (
+                "[('company_id','in',allowed_company_ids or [False])]",
+                "[('company_id', 'in', companies.active_ids or [False])]",
+            ),
+            (
+                "[('company_id','in', user.other.allowed_company_ids)]",
+                "[('company_id', 'in', user.other.allowed_company_ids)]",
+            ),
+        ]
+    )
+    @unittest.skipUnless(util.ast_unparse is not None, "`ast.unparse` available from Python3.9")
+    def test_literal_replace(self, orig, expected):
+        repl = util.literal_replace(orig, {"allowed_company_ids": "companies.active_ids"})
+        self.assertEqual(repl, expected)
+
 
 def not_doing_anything_converter(el):
     return True

src/util/misc.py

@@ -4,6 +4,7 @@
 import collections
 import datetime
 import functools
+import logging
 import os
 import re
 import uuid
@@ -35,6 +36,8 @@
     except ImportError:
         ast_unparse = None
 
+_logger = logging.getLogger(__name__)
+
 
 def _cached(func):
     sentinel = object()
@@ -510,3 +513,22 @@ def visit_UnaryOp(self, node):
         root = ast.parse(expr.strip(), mode="eval").body
         visited = replacer.visit(root)
         return (ast_unparse(visited).strip(), SelfPrintEvalContext(replacer.replaces))
+
+
+class _Replacer(ast.NodeTransformer):
+    """Replace literal nodes in an AST."""
+
+    def __init__(self, mapping):
+        self.mapping = mapping
+
+    def visit_Name(self, node):
+        return ast.Name(id=self.mapping[node.id], ctx=ast.Load()) if node.id in self.mapping else node
+
+
+def literal_replace(expr, mapping):
+    if ast_unparse is None:
+        _logger.critical("AST unparse unavailable")
+        return expr
+    root = ast.parse(expr.strip(), mode="eval").body
+    visited = _Replacer(mapping).visit(root)
+    return ast_unparse(visited).strip()