Allow install under pypy

.github/workflows/test.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "pypy-3.7"]
         os: [ubuntu-latest, macOS-latest, windows-latest]
 
     steps:
@@ -41,9 +41,15 @@ jobs:
           python -m pip install --upgrade tox
 
       - name: Unit tests
+        if: "!startsWith(matrix.python-version, 'pypy')"
         run: |
           tox -e ci-py -- -v --color=yes
 
+      - name: Unit tests pypy
+        if: "startsWith(matrix.python-version, 'pypy')"
+        run: |
+          tox -e ci-pypy3 -- -v --color=yes
+
       - name: Publish coverage to Coveralls
         # If pushed / is a pull request against main repo AND
         # we're running on Linux (this action only supports Linux)

CHANGES.md

@@ -8,6 +8,7 @@
 - Add new `--workers` parameter (#2514)
 - Fixed feature detection for positional-only arguments in lambdas (#2532)
 - Bumped typed-ast version minimum to 1.4.3 for 3.10 compatiblity (#2519)
+- Add experimental pypy support (#2559)
 
 ### _Blackd_
 

docs/faq.md

@@ -88,3 +88,9 @@ influence their behavior. While Black does its best to recognize such comments a
 them in the right place, this detection is not and cannot be perfect. Therefore, you'll
 sometimes have to manually move these comments to the right place after you format your
 codebase with _Black_.
+
+## Can I run black with PyPy?
+
+Yes, there is _experimental_ support for PyPy 3.7 and higher. You cannot format Python 2
+files under PyPy, because PyPy's inbuilt ast module does not support this. For the most
+stable user-experience, we recommend using CPython if possible.

setup.py

@@ -75,7 +75,7 @@ def get_long_description() -> str:
         "click>=7.1.2",
         "platformdirs>=2",
         "tomli>=0.2.6,<2.0.0",
-        "typed-ast>=1.4.2; python_version < '3.8'",
+        "typed-ast>=1.4.2; python_version < '3.8' and implementation_name == 'cpython'",
         "regex>=2020.1.8",
         "pathspec>=0.9.0, <1",
         "dataclasses>=0.6; python_version < '3.7'",

src/black/cache.py

@@ -35,7 +35,7 @@ def read_cache(mode: Mode) -> Cache:
     with cache_file.open("rb") as fobj:
         try:
             cache: Cache = pickle.load(fobj)
-        except (pickle.UnpicklingError, ValueError):
+        except (pickle.UnpicklingError, ValueError, IndexError):
             return {}
 
     return cache

src/black/parsing.py

@@ -2,6 +2,7 @@
 Parse Python code and perform AST validation.
 """
 import ast
+import platform
 import sys
 from typing import Iterable, Iterator, List, Set, Union, Tuple
 
@@ -15,10 +16,13 @@
 from black.mode import TargetVersion, Feature, supports_feature
 from black.nodes import syms
 
+_IS_PYPY = platform.python_implementation() == "PyPy"
+
 try:
     from typed_ast import ast3, ast27
 except ImportError:
-    if sys.version_info < (3, 8):
+    # Either our python version is too low, or we're on pypy
+    if sys.version_info < (3, 7) or (sys.version_info < (3, 8) and not _IS_PYPY):
         print(
             "The typed_ast package is required but not installed.\n"
             "You can upgrade to Python 3.8+ or install typed_ast with\n"
@@ -114,7 +118,10 @@ def parse_single_version(
     if sys.version_info >= (3, 8) and version >= (3,):
         return ast.parse(src, filename, feature_version=version)
     elif version >= (3,):
-        return ast3.parse(src, filename, feature_version=version[1])
+        if _IS_PYPY:
+            return ast3.parse(src, filename)
+        else:
+            return ast3.parse(src, filename, feature_version=version[1])
     elif version == (2, 7):
         return ast27.parse(src)
     raise AssertionError("INTERNAL ERROR: Tried parsing unsupported Python version!")
@@ -148,12 +155,14 @@ def stringify_ast(
     yield f"{'  ' * depth}{node.__class__.__name__}("
 
     for field in sorted(node._fields):  # noqa: F402
-        # TypeIgnore has only one field 'lineno' which breaks this comparison
-        type_ignore_classes = (ast3.TypeIgnore, ast27.TypeIgnore)
-        if sys.version_info >= (3, 8):
-            type_ignore_classes += (ast.TypeIgnore,)
-        if isinstance(node, type_ignore_classes):
-            break
+        # TypeIgnore will not be present using pypy < 3.8, so need for this
+        if not (_IS_PYPY and sys.version_info < (3, 8)):
+            # TypeIgnore has only one field 'lineno' which breaks this comparison
+            type_ignore_classes = (ast3.TypeIgnore, ast27.TypeIgnore)
+            if sys.version_info >= (3, 8):
+                type_ignore_classes += (ast.TypeIgnore,)
+            if isinstance(node, type_ignore_classes):
+                break
 
         try:
             value = getattr(node, field)

tests/test_black.py

@@ -943,7 +943,7 @@ def test_broken_symlink(self) -> None:
             symlink = workspace / "broken_link.py"
             try:
                 symlink.symlink_to("nonexistent.py")
-            except OSError as e:
+            except (OSError, NotImplementedError) as e:
                 self.skipTest(f"Can't create symlinks: {e}")
             self.invokeBlack([str(workspace.resolve())])
 

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = {,ci-}py{36,37,38,39,310},fuzz
+envlist = {,ci-}py{36,37,38,39,310,py3},fuzz
 
 [testenv]
 setenv = PYTHONPATH = {toxinidir}/src
@@ -31,6 +31,31 @@ commands =
         --cov --cov-append {posargs}
     coverage report
 
+[testenv:{,ci-}pypy3]
+setenv = PYTHONPATH = {toxinidir}/src
+skip_install = True
+recreate = True
+deps =
+    -r{toxinidir}/test_requirements.txt
+; a separate worker is required in ci due to https://foss.heptapod.net/pypy/pypy/-/issues/3317
+; this seems to cause tox to wait forever
+; remove this when pypy releases the bugfix
+commands =
+    pip install -e .[d]
+    coverage erase
+    pytest tests --run-optional no_python2 \
+        --run-optional no_jupyter \
+        !ci: --numprocesses auto \
+        ci: --numprocesses 1 \
+        --cov {posargs}
+    pip install -e .[jupyter]
+    pytest tests --run-optional jupyter \
+        -m jupyter \
+        !ci: --numprocesses auto \
+        ci: --numprocesses 1 \
+        --cov --cov-append {posargs}
+    coverage report
+
 [testenv:fuzz]
 skip_install = True
 deps =