Handle deprecation/removal of pkg_resources.

Add `resource_string.py` that provides a compatibility layer between
versions of Python that do and don't have the `pkg_resources` library,
removed in version 3.12.

Author: rpgoldman

popper/gen2.py

@@ -5,11 +5,11 @@
 
 import clingo
 import clingo.script
-import pkg_resources
 from clingo import Function, Number, Tuple_
 
 from .util import Constraint, Literal, Settings
 from . abs_generate import Generator as AbstractGenerator
+from .resources import resource_string
 
 
 def arg_to_symbol(arg):
@@ -47,7 +47,7 @@ def __init__(self, settings: Settings, bkcons=[]):
         self.pruned_sizes = set()
 
         encoding = []
-        alan = pkg_resources.resource_string(__name__, "lp/alan.pl").decode()
+        alan = resource_string(__name__, "lp/alan.pl").decode()
         encoding.append(alan)
 
         with open(settings.bias_file) as f:

popper/gen3.py

@@ -7,10 +7,10 @@
 import operator
 import numbers
 import clingo.script
-import pkg_resources
 from collections import defaultdict
 from . util import rule_is_recursive, Constraint, Literal
 from . abs_generate import Generator as AbstractGenerator
+from .resources import resource_string
 
 clingo.script.enable_python()
 from clingo import Function, Number, Tuple_
@@ -56,7 +56,7 @@ def __init__(self, settings, bkcons=[]):
         self.new_ground_cons = set()
 
         encoding = []
-        alan = pkg_resources.resource_string(__name__, "lp/alan-old.pl").decode()
+        alan = resource_string(__name__, "lp/alan-old.pl").decode()
         encoding.append(alan)
 
         with open(settings.bias_file) as f:
@@ -717,4 +717,4 @@ def remap_variables(rule):
         new_atom = Literal(atom.predicate, tuple(new_args))
         new_body.add(new_atom)
 
-    return head, frozenset(new_body)
+    return head, frozenset(new_body)

popper/generate.py

@@ -9,7 +9,6 @@
 
 import clingo
 import clingo.script
-import pkg_resources
 
 from .util import rule_is_recursive, Constraint, Literal, remap_variables
 
@@ -19,6 +18,7 @@
 import dataclasses
 from . abs_generate import Generator as AbstractGenerator
 from . abs_generate import Rule, RuleBase
+from .resources import resource_string
 
 @dataclasses.dataclass(frozen=True)
 class Var:
@@ -109,7 +109,7 @@ def __init__(self, settings, bkcons=[]):
         self.new_ground_cons = set()
 
         encoding = []
-        alan = pkg_resources.resource_string(__name__, "lp/alan-old.pl").decode()
+        alan = resource_string(__name__, "lp/alan-old.pl").decode()
         # alan = pkg_resources.resource_string(__name__, "lp/alan.pl").decode()
         encoding.append(alan)
 
@@ -1204,4 +1204,4 @@ def gteq(a, b):
     return Literal('>=', (a,b))
 
 def body_size_literal(clause_var, body_size):
-    return Literal('body_size', (clause_var, body_size))
+    return Literal('body_size', (clause_var, body_size))

popper/resources.py

@@ -0,0 +1,26 @@
+from typing import Dict, Any
+
+
+try:
+    from pkg_resources import resource_string, resource_filename
+    def close_resource_file(ref: Any):
+        pass
+except:
+    import importlib.resources
+    from contextlib import ExitStack
+    from importlib.resources.abc import Traversable
+    def resource_string(package: str, path: str) -> bytes:
+        ref = importlib.resources.files(package).joinpath(path)
+        with ref.open('rb') as fp:
+            my_bytes = fp.read()
+        return my_bytes
+    managers: Dict[Traversable, ExitStack] = {}
+    def resource_filename(pkg: str, path: str) -> Traversable:
+        manager = ExitStack()
+        ref = manager.enter_context(importlib.resources.files(pkg) / path)
+        managers[ref] = manager
+        return ref
+    def close_resource_file(ref: Traversable):
+        if ref in managers:
+            managers[ref].close()
+            del managers[ref]

popper/tester.py

@@ -5,12 +5,12 @@
 from itertools import product
 from typing import Tuple
 
-import pkg_resources
 from bitarray import bitarray, frozenbitarray
 from bitarray.util import ones
 from janus_swi import consult, query_once
 
 from .util import Literal, calc_prog_size, calc_rule_size, format_rule, order_prog, prog_hash, prog_is_recursive
+from .resources import resource_string, resource_filename, close_resource_file
 
 
 def format_literal_janus(literal):
@@ -27,7 +27,7 @@ def __init__(self, settings):
 
         bk_pl_path = self.settings.bk_file
         exs_pl_path = self.settings.ex_file
-        test_pl_path = pkg_resources.resource_filename(__name__, "lp/test.pl")
+        test_pl_path = resource_filename(__name__, "lp/test.pl")
 
         if not settings.pi_enabled:
             consult('prog', f':- dynamic {settings.head_literal.predicate}/{len(settings.head_literal.arguments)}.')
@@ -36,6 +36,7 @@ def __init__(self, settings):
             if os.name == 'nt': # if on Windows, SWI requires escaped directory separators
                 x = x.replace('\\', '\\\\')
             consult(x)
+            close_resource_file(x)
 
         query_once('load_examples')
 
@@ -521,4 +522,4 @@ def deduce_neg_example_recalls(settings, atoms):
     return all_recalls
 
 def generate_binary_strings(bit_count):
-    return list(product((0,1), repeat=bit_count))[1:-1]
+    return list(product((0,1), repeat=bit_count))[1:-1]