Deprecate --interpreter-constraints option where it no-ops (#10833)

There are several places now where `--interpreter-constraints` is never used, or it's exceedingly rare to be used so it's misleading to have as an option.

This also fixes Pylint to ensure that no matter what, the tool Pex uses the same constraints as the requirements Pex. It looks like this was happening in practice, but it's important to enforce to avoid a Pex runtime error about "Missing Wheels".

Finally, this fixes `setuptools` to have default constraints, which it needs.

[ci skip-build-wheels]
[ci skip-rust]

src/python/pants/backend/awslambda/python/lambdex.py

@@ -12,5 +12,6 @@ class Lambdex(PythonToolBase):
     # TODO(John Sirois): Remove when we can upgrade to a version of lambdex with
     # https://github.com/wickman/lambdex/issues/6 fixed.
     default_extra_requirements = ["setuptools>=50.3.0,<50.4"]
+    register_interpreter_constraints = True
     default_interpreter_constraints = ["CPython>=3.5"]
     default_entry_point = "lambdex.bin.lambdex"

src/python/pants/backend/python/goals/coverage_py.py

@@ -98,6 +98,7 @@ class CoverageSubsystem(PythonToolBase):
     options_scope = "coverage-py"
     default_version = "coverage>=5.0.3,<5.1"
     default_entry_point = "coverage"
+    register_interpreter_constraints = True
     default_interpreter_constraints = ["CPython>=3.6"]
 
     @classmethod

src/python/pants/backend/python/lint/bandit/rules.py

@@ -68,10 +68,7 @@ async def bandit_lint_partition(
             output_filename="bandit.pex",
             internal_only=True,
             requirements=PexRequirements(bandit.all_requirements),
-            interpreter_constraints=(
-                partition.interpreter_constraints
-                or PexInterpreterConstraints(bandit.interpreter_constraints)
-            ),
+            interpreter_constraints=partition.interpreter_constraints,
             entry_point=bandit.entry_point,
         ),
     )

src/python/pants/backend/python/lint/bandit/subsystem.py

@@ -15,7 +15,6 @@ class Bandit(PythonToolBase):
     # `setuptools<45` is for Python 2 support. `stevedore` is because the 3.0 release breaks Bandit.
     default_extra_requirements = ["setuptools<45", "stevedore<3"]
     default_entry_point = "bandit"
-    default_interpreter_constraints = ["CPython>=2.7,<3", "CPython>=3.5"]
 
     @classmethod
     def register_options(cls, register):

src/python/pants/backend/python/lint/black/subsystem.py

@@ -14,6 +14,7 @@ class Black(PythonToolBase):
     default_version = "black==20.8b1"
     default_extra_requirements = ["setuptools"]
     default_entry_point = "black:patched_main"
+    register_interpreter_constraints = True
     default_interpreter_constraints = ["CPython>=3.6"]
 
     @classmethod

src/python/pants/backend/python/lint/docformatter/subsystem.py

@@ -13,6 +13,8 @@ class Docformatter(PythonToolBase):
     options_scope = "docformatter"
     default_version = "docformatter>=1.3.1,<1.4"
     default_entry_point = "docformatter:main"
+    register_interpreter_constraints = True
+    default_interpreter_constraints = ["CPython==2.7.*", "CPython>=3.4,<3.9"]
 
     @classmethod
     def register_options(cls, register):

src/python/pants/backend/python/lint/flake8/rules.py

@@ -68,10 +68,7 @@ async def flake8_lint_partition(
             output_filename="flake8.pex",
             internal_only=True,
             requirements=PexRequirements(flake8.all_requirements),
-            interpreter_constraints=(
-                partition.interpreter_constraints
-                or PexInterpreterConstraints(flake8.interpreter_constraints)
-            ),
+            interpreter_constraints=partition.interpreter_constraints,
             entry_point=flake8.entry_point,
         ),
     )

src/python/pants/backend/python/lint/flake8/subsystem.py

@@ -14,7 +14,6 @@ class Flake8(PythonToolBase):
     default_version = "flake8>=3.7.9,<3.9"
     default_extra_requirements = ["setuptools<45"]  # NB: `<45` is for Python 2 support
     default_entry_point = "flake8"
-    default_interpreter_constraints = ["CPython>=2.7,<3", "CPython>=3.4"]
 
     @classmethod
     def register_options(cls, register):

src/python/pants/backend/python/lint/isort/subsystem.py

@@ -13,6 +13,7 @@ class Isort(PythonToolBase):
     options_scope = "isort"
     default_version = "isort[pyproject]>=5.5.1,<5.6"
     default_extra_requirements = ["setuptools"]
+    register_interpreter_constraints = True
     default_interpreter_constraints = ["CPython>=3.6"]
     default_entry_point = "isort.main"
 

src/python/pants/backend/python/lint/pylint/rules.py

@@ -131,6 +131,10 @@ async def pylint_lint_partition(partition: PylintPartition, pylint: Pylint) -> L
         PexFromTargetsRequest,
         PexFromTargetsRequest.for_requirements(
             (field_set.address for field_set in partition.field_sets),
+            # NB: These constraints must be identical to the other PEXes. Otherwise, we risk using
+            # a different version for the requirements than the other two PEXes, which can result
+            # in a PEX runtime error about missing dependencies.
+            hardcoded_interpreter_constraints=partition.interpreter_constraints,
             internal_only=True,
             direct_deps_only=True,
         ),
@@ -267,20 +271,23 @@ async def pylint_lint(
 
     # We batch targets by their interpreter constraints to ensure, for example, that all Python 2
     # targets run together and all Python 3 targets run together.
+    # Note that Pylint uses the AST of the interpreter that runs it. So, we include any plugin
+    # targets in this interpreter constraints calculation.
     interpreter_constraints_to_target_setup = defaultdict(set)
     for field_set, tgt, dependencies in zip(
         request.field_sets, linted_targets, per_target_dependencies
     ):
         target_setup = PylintTargetSetup(field_set, Targets([tgt, *dependencies]))
-        interpreter_constraints = (
-            PexInterpreterConstraints.create_from_compatibility_fields(
-                (
-                    *(tgt.get(PythonInterpreterCompatibility) for tgt in [tgt, *dependencies]),
-                    *plugin_targets_compatibility_fields,
+        interpreter_constraints = PexInterpreterConstraints.create_from_compatibility_fields(
+            (
+                *(
+                    tgt[PythonInterpreterCompatibility]
+                    for tgt in [tgt, *dependencies]
+                    if tgt.has_field(PythonInterpreterCompatibility)
                 ),
-                python_setup,
-            )
-            or PexInterpreterConstraints(pylint.interpreter_constraints)
+                *plugin_targets_compatibility_fields,
+            ),
+            python_setup,
         )
         interpreter_constraints_to_target_setup[interpreter_constraints].add(target_setup)
 

src/python/pants/backend/python/lint/pylint/subsystem.py

@@ -14,7 +14,6 @@ class Pylint(PythonToolBase):
     options_scope = "pylint"
     default_version = "pylint>=2.4.4,<2.5"
     default_entry_point = "pylint"
-    default_interpreter_constraints = ["CPython>=3.5"]
 
     @classmethod
     def register_options(cls, register):

src/python/pants/backend/python/subsystems/ipython.py

@@ -1,8 +1,6 @@
 # Copyright 2020 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-from typing import List
-
 from pants.backend.python.subsystems.python_tool_base import PythonToolBase
 
 
@@ -11,9 +9,7 @@ class IPython(PythonToolBase):
 
     options_scope = "ipython"
     default_version = "ipython==7.16.1"  # The last version to support Python 3.6.
-    default_extra_requirements: List[str] = []
     default_entry_point = "IPython:start_ipython"
-    default_interpreter_constraints = ["CPython>=3.6"]
 
     @classmethod
     def register_options(cls, register):

src/python/pants/backend/python/subsystems/python_tool_base.py

@@ -1,7 +1,7 @@
 # Copyright 2018 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-from typing import Optional, Sequence, Tuple, cast
+from typing import ClassVar, Optional, Sequence, Tuple, cast
 
 from pants.option.subsystem import Subsystem
 
@@ -10,11 +10,12 @@ class PythonToolBase(Subsystem):
     """Base class for subsystems that configure a python tool to be invoked out-of-process."""
 
     # Subclasses must set.
-    default_version: Optional[str] = None
-    default_entry_point: Optional[str] = None
+    default_version: ClassVar[Optional[str]] = None
+    default_entry_point: ClassVar[Optional[str]] = None
     # Subclasses do not need to override.
-    default_extra_requirements: Sequence[str] = []
-    default_interpreter_constraints: Sequence[str] = []
+    default_extra_requirements: ClassVar[Sequence[str]] = []
+    default_interpreter_constraints: ClassVar[Sequence[str]] = []
+    register_interpreter_constraints: ClassVar[bool] = False
 
     @classmethod
     def register_options(cls, register):
@@ -36,14 +37,6 @@ def register_options(cls, register):
             "tool allows you to install plugins or if you need to constrain a dependency to "
             "a certain version.",
         )
-        register(
-            "--interpreter-constraints",
-            type=list,
-            advanced=True,
-            default=cls.default_interpreter_constraints,
-            help="Python interpreter constraints for this tool. An empty list uses the default "
-            "interpreter constraints for the repo.",
-        )
         register(
             "--entry-point",
             type=str,
@@ -54,6 +47,40 @@ def register_options(cls, register):
             "library, invoked by a wrapper script.",
         )
 
+        if cls.default_interpreter_constraints and not cls.register_interpreter_constraints:
+            raise ValueError(
+                f"`default_interpreter_constraints` are configured for `{cls.options_scope}`, but "
+                "`register_interpreter_constraints` is not set to `True`, so the "
+                "`--interpreter-constraints` option will not be registered. Did you mean to set "
+                "this?"
+            )
+        interpreter_constraints_help = (
+            "Python interpreter constraints for this tool. An empty list uses the default "
+            "interpreter constraints for the repo."
+        )
+        if cls.register_interpreter_constraints:
+            register(
+                "--interpreter-constraints",
+                type=list,
+                advanced=True,
+                default=cls.default_interpreter_constraints,
+                help=interpreter_constraints_help,
+            )
+        else:
+            register(
+                "--interpreter-constraints",
+                type=list,
+                advanced=True,
+                default=[],
+                help=interpreter_constraints_help,
+                removal_version="2.1.0.dev0",
+                removal_hint=(
+                    "This option no longer does anything, as Pants auto-configures the interpreter "
+                    f"constraints for {cls.options_scope} based on your code's interpreter "
+                    "constraints."
+                ),
+            )
+
     @property
     def version(self) -> Optional[str]:
         return cast(Optional[str], self.options.version)

src/python/pants/backend/python/subsystems/setuptools.py

@@ -12,3 +12,5 @@ class Setuptools(PythonToolBase):
     options_scope = "setuptools"
     default_version = "setuptools>=50.3.0,<50.4"
     default_extra_requirements = ["wheel==0.35.1"]
+    register_interpreter_constraints = True
+    default_interpreter_constraints = ["CPython>=3.5"]

src/python/pants/backend/python/target_types.py

@@ -224,8 +224,7 @@ class PythonBinary(Target):
     """A Python target that can be converted into an executable PEX file.
 
     PEX files are self-contained executable files that contain a complete Python environment capable
-    of running the target. For more information about PEX files, see
-    https://www.pantsbuild.org/docs/pex-files.
+    of running the target. For more information, see https://www.pantsbuild.org/docs/pex-files.
     """
 
     alias = "python_binary"

src/python/pants/backend/python/typecheck/mypy/subsystem.py

@@ -15,6 +15,7 @@ class MyPy(PythonToolBase):
     default_version = "mypy==0.782"
     default_entry_point = "mypy"
     # See `mypy/rules.py`. We only use these default constraints in some situations.
+    register_interpreter_constraints = True
     default_interpreter_constraints = ["CPython>=3.5"]
 
     @classmethod

src/python/pants/backend/python/util_rules/pex_from_targets.py

@@ -59,6 +59,7 @@ class PexFromTargetsRequest:
     include_source_files: bool
     additional_sources: Optional[Digest]
     additional_inputs: Optional[Digest]
+    hardcoded_interpreter_constraints: Optional[PexInterpreterConstraints]
     direct_deps_only: bool
     # This field doesn't participate in comparison (and therefore hashing), as it doesn't affect
     # the result.
@@ -77,6 +78,7 @@ def __init__(
         include_source_files: bool = True,
         additional_sources: Optional[Digest] = None,
         additional_inputs: Optional[Digest] = None,
+        hardcoded_interpreter_constraints: Optional[PexInterpreterConstraints] = None,
         direct_deps_only: bool = False,
         description: Optional[str] = None,
     ) -> None:
@@ -105,6 +107,8 @@ def __init__(
         :param additional_sources: Any additional source files to include in the built Pex.
         :param additional_inputs: Any inputs that are not source files and should not be included
             directly in the Pex, but should be present in the environment when building the Pex.
+        :param hardcoded_interpreter_constraints: Use these constraints rather than resolving the
+            constraints from the input.
         :param direct_deps_only: Only consider the input addresses and their direct dependencies,
             rather than the transitive closure.
         :param description: A human-readable description to render in the dynamic UI when building
@@ -120,6 +124,7 @@ def __init__(
         self.include_source_files = include_source_files
         self.additional_sources = additional_sources
         self.additional_inputs = additional_inputs
+        self.hardcoded_interpreter_constraints = hardcoded_interpreter_constraints
         self.direct_deps_only = direct_deps_only
         self.description = description
 
@@ -129,6 +134,7 @@ def for_requirements(
         addresses: Iterable[Address],
         *,
         internal_only: bool,
+        hardcoded_interpreter_constraints: Optional[PexInterpreterConstraints] = None,
         zip_safe: bool = False,
         direct_deps_only: bool = False,
     ) -> "PexFromTargetsRequest":
@@ -148,6 +154,7 @@ def for_requirements(
             output_filename="requirements.pex",
             include_source_files=False,
             additional_args=() if zip_safe else ("--not-zip-safe",),
+            hardcoded_interpreter_constraints=hardcoded_interpreter_constraints,
             internal_only=internal_only,
             direct_deps_only=direct_deps_only,
         )
@@ -190,13 +197,17 @@ async def pex_from_targets(request: PexFromTargetsRequest, python_setup: PythonS
         input_digests.append(prepared_sources.stripped_source_files.snapshot.digest)
     merged_input_digest = await Get(Digest, MergeDigests(input_digests))
 
-    interpreter_constraints = PexInterpreterConstraints.create_from_compatibility_fields(
-        (
-            tgt[PythonInterpreterCompatibility]
-            for tgt in all_targets
-            if tgt.has_field(PythonInterpreterCompatibility)
-        ),
-        python_setup,
+    interpreter_constraints = (
+        request.hardcoded_interpreter_constraints
+        if request.hardcoded_interpreter_constraints
+        else PexInterpreterConstraints.create_from_compatibility_fields(
+            (
+                tgt[PythonInterpreterCompatibility]
+                for tgt in all_targets
+                if tgt.has_field(PythonInterpreterCompatibility)
+            ),
+            python_setup,
+        )
     )
 
     exact_reqs = PexRequirements.create_from_requirement_fields(