Infer target version based on project metadata (#3219)

Co-authored-by: Richard Si <sichard26@gmail.com>

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 576f6405d6c73bbfba74a1737efbc82d9421e64b..a69fb6452384787c4eb0ee11092a018a4b6e61fe 100644 (file)
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -48,6 +48,7 @@ repos:
           - tomli >= 0.2.6, < 2.0.0
           - types-typed-ast >= 1.4.1
           - click >= 8.1.0
           - tomli >= 0.2.6, < 2.0.0
           - types-typed-ast >= 1.4.1
           - click >= 8.1.0

+          - packaging >= 22.0

           - platformdirs >= 2.1.0
           - pytest
           - hypothesis
           - platformdirs >= 2.1.0
           - pytest
           - hypothesis

diff --git a/CHANGES.md b/CHANGES.md
index ecc8a41f5054755a03230d87a9d74c869a122400..471567509d351a297438c27cd96c9b09648b5cbf 100644 (file)
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -77,6 +77,9 @@
 
 <!-- Changes to how Black can be configured -->
 
 
 <!-- Changes to how Black can be configured -->
 

+- Black now tries to infer its `--target-version` from the project metadata specified in
+  `pyproject.toml` (#3219)
+

 ### Packaging
 
 <!-- Changes to how Black is packaged, such as dependency requirements -->
 ### Packaging
 
 <!-- Changes to how Black is packaged, such as dependency requirements -->


@@ -86,6 +89,8 @@
 - Drop specific support for the `tomli` requirement on 3.11 alpha releases, working
   around a bug that would cause the requirement not to be installed on any non-final
   Python releases (#3448)
 - Drop specific support for the `tomli` requirement on 3.11 alpha releases, working
   around a bug that would cause the requirement not to be installed on any non-final
   Python releases (#3448)

+- Black now depends on `packaging` version `22.0` or later. This is required for new
+  functionality that needs to parse part of the project metadata (#3219)

 
 ### Parser
 
 
 ### Parser
 

diff --git a/pyproject.toml b/pyproject.toml
index ab38908ba15bb0721f0bd3b47b6d9f04a7727680..435626ac8f4dbccc6715aec8d3c0b74de4b4e994 100644 (file)
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,6 +65,7 @@ classifiers = [
 dependencies = [
   "click>=8.0.0",
   "mypy_extensions>=0.4.3",
 dependencies = [
   "click>=8.0.0",
   "mypy_extensions>=0.4.3",

+  "packaging>=22.0",

   "pathspec>=0.9.0",
   "platformdirs>=2",
   "tomli>=1.1.0; python_version < '3.11'",
   "pathspec>=0.9.0",
   "platformdirs>=2",
   "tomli>=1.1.0; python_version < '3.11'",

diff --git a/src/black/__init__.py b/src/black/__init__.py
index 42bdfc1a5ddd2fa57850a98ac68d0086afb43816..4ebf28821c39ca339b05f372de2695246f6fcc99 100644 (file)
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -219,8 +219,9 @@ def validate_regex(
     callback=target_version_option_callback,
     multiple=True,
     help=(
     callback=target_version_option_callback,
     multiple=True,
     help=(

-        "Python versions that should be supported by Black's output. [default: per-file"
-        " auto-detection]"
+        "Python versions that should be supported by Black's output. By default, Black"
+        " will try to infer this from the project metadata in pyproject.toml. If this"
+        " does not yield conclusive results, Black will use per-file auto-detection."

     ),
 )
 @click.option(
     ),
 )
 @click.option(

diff --git a/src/black/files.py b/src/black/files.py
index ea517f4ece9c2c2bbeaef35d2714ccdf50511992..8c0131126b7b29f418a17ca6651a7b2a0f79cbdb 100644 (file)
--- a/src/black/files.py
+++ b/src/black/files.py
@@ -18,6 +18,8 @@ from typing import (
 )
 
 from mypy_extensions import mypyc_attr
 )
 
 from mypy_extensions import mypyc_attr

+from packaging.specifiers import InvalidSpecifier, Specifier, SpecifierSet
+from packaging.version import InvalidVersion, Version

 from pathspec import PathSpec
 from pathspec.patterns.gitwildmatch import GitWildMatchPatternError
 
 from pathspec import PathSpec
 from pathspec.patterns.gitwildmatch import GitWildMatchPatternError
 


@@ -32,6 +34,7 @@ else:
     import tomli as tomllib
 
 from black.handle_ipynb_magics import jupyter_dependencies_are_installed
     import tomli as tomllib
 
 from black.handle_ipynb_magics import jupyter_dependencies_are_installed

+from black.mode import TargetVersion

 from black.output import err
 from black.report import Report
 
 from black.output import err
 from black.report import Report
 


@@ -108,14 +111,103 @@ def find_pyproject_toml(path_search_start: Tuple[str, ...]) -> Optional[str]:
 
 @mypyc_attr(patchable=True)
 def parse_pyproject_toml(path_config: str) -> Dict[str, Any]:
 
 @mypyc_attr(patchable=True)
 def parse_pyproject_toml(path_config: str) -> Dict[str, Any]:

-    """Parse a pyproject toml file, pulling out relevant parts for Black
+    """Parse a pyproject toml file, pulling out relevant parts for Black.

 
 

-    If parsing fails, will raise a tomllib.TOMLDecodeError
+    If parsing fails, will raise a tomllib.TOMLDecodeError.

     """
     with open(path_config, "rb") as f:
         pyproject_toml = tomllib.load(f)
     """
     with open(path_config, "rb") as f:
         pyproject_toml = tomllib.load(f)

-    config = pyproject_toml.get("tool", {}).get("black", {})
-    return {k.replace("--", "").replace("-", "_"): v for k, v in config.items()}
+    config: Dict[str, Any] = pyproject_toml.get("tool", {}).get("black", {})
+    config = {k.replace("--", "").replace("-", "_"): v for k, v in config.items()}
+
+    if "target_version" not in config:
+        inferred_target_version = infer_target_version(pyproject_toml)
+        if inferred_target_version is not None:
+            config["target_version"] = [v.name.lower() for v in inferred_target_version]
+
+    return config
+
+
+def infer_target_version(
+    pyproject_toml: Dict[str, Any]
+) -> Optional[List[TargetVersion]]:
+    """Infer Black's target version from the project metadata in pyproject.toml.
+
+    Supports the PyPA standard format (PEP 621):
+    https://packaging.python.org/en/latest/specifications/declaring-project-metadata/#requires-python
+
+    If the target version cannot be inferred, returns None.
+    """
+    project_metadata = pyproject_toml.get("project", {})
+    requires_python = project_metadata.get("requires-python", None)
+    if requires_python is not None:
+        try:
+            return parse_req_python_version(requires_python)
+        except InvalidVersion:
+            pass
+        try:
+            return parse_req_python_specifier(requires_python)
+        except (InvalidSpecifier, InvalidVersion):
+            pass
+
+    return None
+
+
+def parse_req_python_version(requires_python: str) -> Optional[List[TargetVersion]]:
+    """Parse a version string (i.e. ``"3.7"``) to a list of TargetVersion.
+
+    If parsing fails, will raise a packaging.version.InvalidVersion error.
+    If the parsed version cannot be mapped to a valid TargetVersion, returns None.
+    """
+    version = Version(requires_python)
+    if version.release[0] != 3:
+        return None
+    try:
+        return [TargetVersion(version.release[1])]
+    except (IndexError, ValueError):
+        return None
+
+
+def parse_req_python_specifier(requires_python: str) -> Optional[List[TargetVersion]]:
+    """Parse a specifier string (i.e. ``">=3.7,<3.10"``) to a list of TargetVersion.
+
+    If parsing fails, will raise a packaging.specifiers.InvalidSpecifier error.
+    If the parsed specifier cannot be mapped to a valid TargetVersion, returns None.
+    """
+    specifier_set = strip_specifier_set(SpecifierSet(requires_python))
+    if not specifier_set:
+        return None
+
+    target_version_map = {f"3.{v.value}": v for v in TargetVersion}
+    compatible_versions: List[str] = list(specifier_set.filter(target_version_map))
+    if compatible_versions:
+        return [target_version_map[v] for v in compatible_versions]
+    return None
+
+
+def strip_specifier_set(specifier_set: SpecifierSet) -> SpecifierSet:
+    """Strip minor versions for some specifiers in the specifier set.
+
+    For background on version specifiers, see PEP 440:
+    https://peps.python.org/pep-0440/#version-specifiers
+    """
+    specifiers = []
+    for s in specifier_set:
+        if "*" in str(s):
+            specifiers.append(s)
+        elif s.operator in ["~=", "==", ">=", "==="]:
+            version = Version(s.version)
+            stripped = Specifier(f"{s.operator}{version.major}.{version.minor}")
+            specifiers.append(stripped)
+        elif s.operator == ">":
+            version = Version(s.version)
+            if len(version.release) > 2:
+                s = Specifier(f">={version.major}.{version.minor}")
+            specifiers.append(s)
+        else:
+            specifiers.append(s)
+
+    return SpecifierSet(",".join(str(s) for s in specifiers))

 
 
 @lru_cache()
 
 
 @lru_cache()

diff --git a/src/black/parsing.py b/src/black/parsing.py
index c37c12b868d7f5e75e73e6f036ea7d7d5bae3604..ba474c5e047cabb0776abc139b96b204f3c58e77 100644 (file)
--- a/src/black/parsing.py
+++ b/src/black/parsing.py
@@ -11,7 +11,7 @@ if sys.version_info < (3, 8):
 else:
     from typing import Final
 
 else:
     from typing import Final
 

-from black.mode import Feature, TargetVersion, supports_feature
+from black.mode import VERSION_TO_FEATURES, Feature, TargetVersion, supports_feature

 from black.nodes import syms
 from blib2to3 import pygram
 from blib2to3.pgen2 import driver
 from black.nodes import syms
 from blib2to3 import pygram
 from blib2to3.pgen2 import driver


@@ -52,7 +52,7 @@ def get_grammars(target_versions: Set[TargetVersion]) -> List[Grammar]:
     if not target_versions:
         # No target_version specified, so try all grammars.
         return [
     if not target_versions:
         # No target_version specified, so try all grammars.
         return [

-            # Python 3.7+
+            # Python 3.7-3.9

             pygram.python_grammar_no_print_statement_no_exec_statement_async_keywords,
             # Python 3.0-3.6
             pygram.python_grammar_no_print_statement_no_exec_statement,
             pygram.python_grammar_no_print_statement_no_exec_statement_async_keywords,
             # Python 3.0-3.6
             pygram.python_grammar_no_print_statement_no_exec_statement,


@@ -72,7 +72,7 @@ def get_grammars(target_versions: Set[TargetVersion]) -> List[Grammar]:
     if not supports_feature(target_versions, Feature.ASYNC_KEYWORDS):
         # Python 3.0-3.6
         grammars.append(pygram.python_grammar_no_print_statement_no_exec_statement)
     if not supports_feature(target_versions, Feature.ASYNC_KEYWORDS):
         # Python 3.0-3.6
         grammars.append(pygram.python_grammar_no_print_statement_no_exec_statement)

-    if supports_feature(target_versions, Feature.PATTERN_MATCHING):
+    if any(Feature.PATTERN_MATCHING in VERSION_TO_FEATURES[v] for v in target_versions):

         # Python 3.10+
         grammars.append(pygram.python_grammar_soft_keywords)
 
         # Python 3.10+
         grammars.append(pygram.python_grammar_soft_keywords)
 

diff --git a/tests/data/project_metadata/both_pyproject.toml b/tests/data/project_metadata/both_pyproject.toml
new file mode 100644 (file)
index 0000000..cf8f148
--- /dev/null
+++ b/tests/data/project_metadata/both_pyproject.toml
@@ -0,0 +1,8 @@
+[project]
+name = "test"
+version = "1.0.0"
+requires-python = ">=3.7,<3.11"
+
+[tool.black]
+line-length = 79
+target-version = ["py310"]

diff --git a/tests/data/project_metadata/neither_pyproject.toml b/tests/data/project_metadata/neither_pyproject.toml
new file mode 100644 (file)
index 0000000..67623d2
--- /dev/null
+++ b/tests/data/project_metadata/neither_pyproject.toml
@@ -0,0 +1,6 @@
+[project]
+name = "test"
+version = "1.0.0"
+
+[tool.black]
+line-length = 79

diff --git a/tests/data/project_metadata/only_black_pyproject.toml b/tests/data/project_metadata/only_black_pyproject.toml
new file mode 100644 (file)
index 0000000..94058bb
--- /dev/null
+++ b/tests/data/project_metadata/only_black_pyproject.toml
@@ -0,0 +1,7 @@
+[project]
+name = "test"
+version = "1.0.0"
+
+[tool.black]
+line-length = 79
+target-version = ["py310"]

diff --git a/tests/data/project_metadata/only_metadata_pyproject.toml b/tests/data/project_metadata/only_metadata_pyproject.toml
new file mode 100644 (file)
index 0000000..1c8cdbb
--- /dev/null
+++ b/tests/data/project_metadata/only_metadata_pyproject.toml
@@ -0,0 +1,7 @@
+[project]
+name = "test"
+version = "1.0.0"
+requires-python = ">=3.7,<3.11"
+
+[tool.black]
+line-length = 79

diff --git a/tests/test_black.py b/tests/test_black.py
index d0e78b7dd926c4894e5bd3a6d57e7d9e8e9f0bb9..e5e1777771548f0ca3c6c6de59f926e83a99ef07 100644 (file)
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -1560,6 +1560,72 @@ class BlackTestCase(BlackBaseTestCase):
         self.assertEqual(config["exclude"], r"\.pyi?$")
         self.assertEqual(config["include"], r"\.py?$")
 
         self.assertEqual(config["exclude"], r"\.pyi?$")
         self.assertEqual(config["include"], r"\.py?$")
 

+    def test_parse_pyproject_toml_project_metadata(self) -> None:
+        for test_toml, expected in [
+            ("only_black_pyproject.toml", ["py310"]),
+            ("only_metadata_pyproject.toml", ["py37", "py38", "py39", "py310"]),
+            ("neither_pyproject.toml", None),
+            ("both_pyproject.toml", ["py310"]),
+        ]:
+            test_toml_file = THIS_DIR / "data" / "project_metadata" / test_toml
+            config = black.parse_pyproject_toml(str(test_toml_file))
+            self.assertEqual(config.get("target_version"), expected)
+
+    def test_infer_target_version(self) -> None:
+        for version, expected in [
+            ("3.6", [TargetVersion.PY36]),
+            ("3.11.0rc1", [TargetVersion.PY311]),
+            (">=3.10", [TargetVersion.PY310, TargetVersion.PY311]),
+            (">=3.10.6", [TargetVersion.PY310, TargetVersion.PY311]),
+            ("<3.6", [TargetVersion.PY33, TargetVersion.PY34, TargetVersion.PY35]),
+            (">3.7,<3.10", [TargetVersion.PY38, TargetVersion.PY39]),
+            (">3.7,!=3.8,!=3.9", [TargetVersion.PY310, TargetVersion.PY311]),
+            (
+                "> 3.9.4, != 3.10.3",
+                [TargetVersion.PY39, TargetVersion.PY310, TargetVersion.PY311],
+            ),
+            (
+                "!=3.3,!=3.4",
+                [
+                    TargetVersion.PY35,
+                    TargetVersion.PY36,
+                    TargetVersion.PY37,
+                    TargetVersion.PY38,
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                ],
+            ),
+            (
+                "==3.*",
+                [
+                    TargetVersion.PY33,
+                    TargetVersion.PY34,
+                    TargetVersion.PY35,
+                    TargetVersion.PY36,
+                    TargetVersion.PY37,
+                    TargetVersion.PY38,
+                    TargetVersion.PY39,
+                    TargetVersion.PY310,
+                    TargetVersion.PY311,
+                ],
+            ),
+            ("==3.8.*", [TargetVersion.PY38]),
+            (None, None),
+            ("", None),
+            ("invalid", None),
+            ("==invalid", None),
+            (">3.9,!=invalid", None),
+            ("3", None),
+            ("3.2", None),
+            ("2.7.18", None),
+            ("==2.7", None),
+            (">3.10,<3.11", None),
+        ]:
+            test_toml = {"project": {"requires-python": version}}
+            result = black.files.infer_target_version(test_toml)
+            self.assertEqual(result, expected)
+

     def test_read_pyproject_toml(self) -> None:
         test_toml_file = THIS_DIR / "test.toml"
         fake_ctx = FakeContext()
     def test_read_pyproject_toml(self) -> None:
         test_toml_file = THIS_DIR / "test.toml"
         fake_ctx = FakeContext()