Python 3.12 support

.github/workflows/test.yml

@@ -43,6 +43,7 @@ jobs:
           "windows-py39",
           "windows-py310",
           "windows-py311",
+          "windows-py312",
 
           "ubuntu-py37",
           "ubuntu-py37-pluggy",
@@ -51,12 +52,13 @@ jobs:
           "ubuntu-py39",
           "ubuntu-py310",
           "ubuntu-py311",
+          "ubuntu-py312",
           "ubuntu-pypy3",
 
           "macos-py37",
-          "macos-py38",
           "macos-py39",
           "macos-py310",
+          "macos-py312",
 
           "docs",
           "doctesting",
@@ -86,9 +88,13 @@ jobs:
             os: windows-latest
             tox_env: "py310-xdist"
           - name: "windows-py311"
-            python: "3.11-dev"
+            python: "3.11"
             os: windows-latest
             tox_env: "py311"
+          - name: "windows-py312"
+            python: "3.12-dev"
+            os: windows-latest
+            tox_env: "py312"
 
           - name: "ubuntu-py37"
             python: "3.7"
@@ -116,10 +122,15 @@ jobs:
             os: ubuntu-latest
             tox_env: "py310-xdist"
           - name: "ubuntu-py311"
-            python: "3.11-dev"
+            python: "3.11"
             os: ubuntu-latest
             tox_env: "py311"
             use_coverage: true
+          - name: "ubuntu-py312"
+            python: "3.12-dev"
+            os: ubuntu-latest
+            tox_env: "py312"
+            use_coverage: true
           - name: "ubuntu-pypy3"
             python: "pypy-3.7"
             os: ubuntu-latest
@@ -129,19 +140,19 @@ jobs:
             python: "3.7"
             os: macos-latest
             tox_env: "py37-xdist"
-          - name: "macos-py38"
-            python: "3.8"
-            os: macos-latest
-            tox_env: "py38-xdist"
-            use_coverage: true
           - name: "macos-py39"
             python: "3.9"
             os: macos-latest
             tox_env: "py39-xdist"
+            use_coverage: true
           - name: "macos-py310"
             python: "3.10"
             os: macos-latest
             tox_env: "py310-xdist"
+          - name: "macos-py312"
+            python: "3.12-dev"
+            os: macos-latest
+            tox_env: "py312-xdist"
 
           - name: "plugins"
             python: "3.9"
@@ -168,6 +179,7 @@ jobs:
       uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python }}
+        check-latest: ${{ endsWith(matrix.python, '-dev') }}
 
     - name: Install dependencies
       run: |

.pre-commit-config.yaml

@@ -50,7 +50,7 @@ repos:
     rev: v2.3.0
     hooks:
     -   id: setup-cfg-fmt
-        args: ["--max-py-version=3.11", "--include-version-classifiers"]
+        args: ["--max-py-version=3.12", "--include-version-classifiers"]
 -   repo: https://github.com/pre-commit/pygrep-hooks
     rev: v1.10.0
     hooks:

changelog/10894.bugfix.rst

@@ -0,0 +1 @@
+Support for Python 3.12 (beta at the time of writing).

setup.cfg

@@ -22,6 +22,7 @@ classifiers =
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3.11
+    Programming Language :: Python :: 3.12
     Topic :: Software Development :: Libraries
     Topic :: Software Development :: Testing
     Topic :: Utilities
@@ -73,6 +74,7 @@ testing =
     nose
     pygments>=2.7.2
     requests
+    setuptools
     xmlschema
 
 [options.package_data]

src/_pytest/assertion/rewrite.py

@@ -46,8 +46,14 @@
 
 if sys.version_info >= (3, 8):
     namedExpr = ast.NamedExpr
+    astNameConstant = ast.Constant
+    astStr = ast.Constant
+    astNum = ast.Constant
 else:
     namedExpr = ast.Expr
+    astNameConstant = ast.NameConstant
+    astStr = ast.Str
+    astNum = ast.Num
 
 
 assertstate_key = StashKey["AssertionState"]()
@@ -680,9 +686,12 @@
             if (
                 expect_docstring
                 and isinstance(item, ast.Expr)
-                and isinstance(item.value, ast.Str)
+                and isinstance(item.value, astStr)
             ):
-                doc = item.value.s
+                if sys.version_info >= (3, 8):
+                    doc = item.value.value
+                else:
+                    doc = item.value.s
                 if self.is_rewrite_disabled(doc):
                     return
                 expect_docstring = False
@@ -814,7 +823,7 @@
         current = self.stack.pop()
         if self.stack:
             self.explanation_specifiers = self.stack[-1]
-        keys = [ast.Str(key) for key in current.keys()]
+        keys = [astStr(key) for key in current.keys()]
         format_dict = ast.Dict(keys, list(current.values()))
         form = ast.BinOp(expl_expr, ast.Mod(), format_dict)
         name = "@py_format" + str(next(self.variable_counter))
@@ -868,16 +877,16 @@
         negation = ast.UnaryOp(ast.Not(), top_condition)
 
         if self.enable_assertion_pass_hook:  # Experimental pytest_assertion_pass hook
-            msg = self.pop_format_context(ast.Str(explanation))
+            msg = self.pop_format_context(astStr(explanation))
 
             # Failed
             if assert_.msg:
                 assertmsg = self.helper("_format_assertmsg", assert_.msg)
                 gluestr = "\n>assert "
             else:
-                assertmsg = ast.Str("")
+                assertmsg = astStr("")
                 gluestr = "assert "
-            err_explanation = ast.BinOp(ast.Str(gluestr), ast.Add(), msg)
+            err_explanation = ast.BinOp(astStr(gluestr), ast.Add(), msg)
             err_msg = ast.BinOp(assertmsg, ast.Add(), err_explanation)
             err_name = ast.Name("AssertionError", ast.Load())
             fmt = self.helper("_format_explanation", err_msg)
@@ -893,8 +902,8 @@
             hook_call_pass = ast.Expr(
                 self.helper(
                     "_call_assertion_pass",
-                    ast.Num(assert_.lineno),
-                    ast.Str(orig),
+                    astNum(assert_.lineno),
+                    astStr(orig),
                     fmt_pass,
                 )
             )
@@ -913,7 +922,7 @@
                 variables = [
                     ast.Name(name, ast.Store()) for name in self.format_variables
                 ]
-                clear_format = ast.Assign(variables, ast.NameConstant(None))
+                clear_format = ast.Assign(variables, astNameConstant(None))
                 self.statements.append(clear_format)
 
         else:  # Original assertion rewriting
@@ -924,9 +933,9 @@
                 assertmsg = self.helper("_format_assertmsg", assert_.msg)
                 explanation = "\n>assert " + explanation
             else:
-                assertmsg = ast.Str("")
+                assertmsg = astStr("")
                 explanation = "assert " + explanation
-            template = ast.BinOp(assertmsg, ast.Add(), ast.Str(explanation))
+            template = ast.BinOp(assertmsg, ast.Add(), astStr(explanation))
             msg = self.pop_format_context(template)
             fmt = self.helper("_format_explanation", msg)
             err_name = ast.Name("AssertionError", ast.Load())
@@ -938,7 +947,7 @@
         # Clear temporary variables by setting them to None.
         if self.variables:
             variables = [ast.Name(name, ast.Store()) for name in self.variables]
-            clear = ast.Assign(variables, ast.NameConstant(None))
+            clear = ast.Assign(variables, astNameConstant(None))
             self.statements.append(clear)
         # Fix locations (line numbers/column offsets).
         for stmt in self.statements:
@@ -952,20 +961,20 @@
         # thinks it's acceptable.
         locs = ast.Call(self.builtin("locals"), [], [])
         target_id = name.target.id  # type: ignore[attr-defined]
-        inlocs = ast.Compare(ast.Str(target_id), [ast.In()], [locs])
+        inlocs = ast.Compare(astStr(target_id), [ast.In()], [locs])
         dorepr = self.helper("_should_repr_global_name", name)
         test = ast.BoolOp(ast.Or(), [inlocs, dorepr])
-        expr = ast.IfExp(test, self.display(name), ast.Str(target_id))
+        expr = ast.IfExp(test, self.display(name), astStr(target_id))
         return name, self.explanation_param(expr)
 
     def visit_Name(self, name: ast.Name) -> Tuple[ast.Name, str]:
         # Display the repr of the name if it's a local variable or
         # _should_repr_global_name() thinks it's acceptable.
         locs = ast.Call(self.builtin("locals"), [], [])
-        inlocs = ast.Compare(ast.Str(name.id), [ast.In()], [locs])
+        inlocs = ast.Compare(astStr(name.id), [ast.In()], [locs])
         dorepr = self.helper("_should_repr_global_name", name)
         test = ast.BoolOp(ast.Or(), [inlocs, dorepr])
-        expr = ast.IfExp(test, self.display(name), ast.Str(name.id))
+        expr = ast.IfExp(test, self.display(name), astStr(name.id))
         return name, self.explanation_param(expr)
 
     def visit_BoolOp(self, boolop: ast.BoolOp) -> Tuple[ast.Name, str]:
@@ -1003,7 +1012,7 @@
             self.push_format_context()
             res, expl = self.visit(v)
             body.append(ast.Assign([ast.Name(res_var, ast.Store())], res))
-            expl_format = self.pop_format_context(ast.Str(expl))
+            expl_format = self.pop_format_context(astStr(expl))
             call = ast.Call(app, [expl_format], [])
             self.expl_stmts.append(ast.Expr(call))
             if i < levels:
@@ -1015,7 +1024,7 @@
                 self.statements = body = inner
         self.statements = save
         self.expl_stmts = fail_save
-        expl_template = self.helper("_format_boolop", expl_list, ast.Num(is_or))
+        expl_template = self.helper("_format_boolop", expl_list, astNum(is_or))
         expl = self.pop_format_context(expl_template)
         return ast.Name(res_var, ast.Load()), self.explanation_param(expl)
 
@@ -1118,9 +1127,9 @@
                 next_expl = f"({next_expl})"
             results.append(next_res)
             sym = BINOP_MAP[op.__class__]
-            syms.append(ast.Str(sym))
+            syms.append(astStr(sym))
             expl = f"{left_expl} {sym} {next_expl}"
-            expls.append(ast.Str(expl))
+            expls.append(astStr(expl))
             res_expr = ast.Compare(left_res, [op], [next_res])
             self.statements.append(ast.Assign([store_names[i]], res_expr))
             left_res, left_expl = next_res, next_expl

src/_pytest/mark/expression.py

@@ -18,6 +18,7 @@
 import dataclasses
 import enum
 import re
+import sys
 import types
 from typing import Callable
 from typing import Iterator
@@ -26,6 +27,11 @@
 from typing import Optional
 from typing import Sequence
 
+if sys.version_info >= (3, 8):
+    astNameConstant = ast.Constant
+else:
+    astNameConstant = ast.NameConstant
+
 
 __all__ = [
     "Expression",
@@ -132,7 +138,7 @@
 
 def expression(s: Scanner) -> ast.Expression:
     if s.accept(TokenType.EOF):
-        ret: ast.expr = ast.NameConstant(False)
+        ret: ast.expr = astNameConstant(False)
     else:
         ret = expr(s)
         s.accept(TokenType.EOF, reject=True)

testing/python/collect.py

@@ -897,25 +897,29 @@ def pytest_pycollect_makeitem(collector, name, obj):
     def test_issue2369_collect_module_fileext(self, pytester: Pytester) -> None:
         """Ensure we can collect files with weird file extensions as Python
         modules (#2369)"""
-        # We'll implement a little finder and loader to import files containing
+        # Implement a little meta path finder to import files containing
         # Python source code whose file extension is ".narf".
         pytester.makeconftest(
             """
-            import sys, os, imp
+            import sys
+            import os.path
+            from importlib.util import spec_from_loader
+            from importlib.machinery import SourceFileLoader
             from _pytest.python import Module
 
-            class Loader(object):
-                def load_module(self, name):
-                    return imp.load_source(name, name + ".narf")
-            class Finder(object):
-                def find_module(self, name, path=None):
-                    if os.path.exists(name + ".narf"):
-                        return Loader()
-            sys.meta_path.append(Finder())
+            class MetaPathFinder:
+                def find_spec(self, fullname, path, target=None):
+                    if os.path.exists(fullname + ".narf"):
+                        return spec_from_loader(
+                            fullname,
+                            SourceFileLoader(fullname, fullname + ".narf"),
+                        )
+            sys.meta_path.append(MetaPathFinder())
 
             def pytest_collect_file(file_path, parent):
                 if file_path.suffix == ".narf":
-                    return Module.from_parent(path=file_path, parent=parent)"""
+                    return Module.from_parent(path=file_path, parent=parent)
+            """
         )
         pytester.makefile(
             ".narf",