ipex additional fixes for PEX-INFO interpreter constraints

add an integration test!!

src/python/pants/python/BUILD

@@ -15,3 +15,33 @@ python_library(
     'src/python/pants/util:memo',
   ]
 )
+
+
+python_tests(
+  name='tests',
+  sources=['*_test.py', '!*_integration.py'],
+  dependencies=[
+    '3rdparty/python:pex',
+    ':python',
+    'src/python/pants/backend/python/targets',
+    'src/python/pants/build_graph',
+    'src/python/pants/util:contextutil',
+    'src/python/pants/testutil/subsystem',
+    'src/python/pants/testutil:pexrc_util',
+    'src/python/pants/testutil:test_base',
+  ],
+  tags = {'partially_type_checked'},
+)
+
+
+python_tests(
+  name='integration',
+  sources=['*_integration.py'],
+  dependencies=[
+    '3rdparty/python:pex',
+    'src/python/pants/util:contextutil',
+    'src/python/pants/testutil:int-test',
+    'testprojects/src/python:python_targets_directory',
+  ],
+  tags = {'integration', 'partially_type_checked'},
+)

src/python/pants/python/pex_build_util.py

@@ -8,8 +8,8 @@
 from pathlib import Path
 from typing import Callable, Dict, List, Optional, Sequence, Set, Tuple
 
-from pex.fetcher import PyPIFetcher, Fetcher
-from pex.interpreter import PythonInterpreter
+from pex.fetcher import Fetcher, PyPIFetcher
+from pex.interpreter import PythonIdentity, PythonInterpreter
 from pex.pex_builder import PEXBuilder
 from pex.pex_info import PexInfo
 from pex.platforms import Platform
@@ -30,9 +30,9 @@
 from pants.build_graph.files import Files
 from pants.build_graph.target import Target
 from pants.option.custom_types import UnsetBool
-from pants.backend.python.subsystems.python_repos import PythonRepos
 from pants.backend.python.python_requirement import PythonRequirement
 from pants.backend.python.subsystems.python_setup import PythonSetup
+from pants.python.python_repos import PythonRepos
 from pants.subsystem.subsystem import Subsystem
 from pants.util.collections import assert_single_element
 from pants.util.contextutil import temporary_file
@@ -293,8 +293,8 @@ def add_resolved_requirements(
             )
           else:
             self._log.debug(
-              f"  Dumping distribution: .../{os.path.basename(dist.location)}"
-            )
+              f"  Dumping distribution: .../{os.path.basename(dist.location)}")
+
             self.add_distribution(dist)
         locations.add(dist.location)
     # In addition to the top-level requirements, we add all the requirements matching the resolved
@@ -435,22 +435,37 @@ def _prepare_inits(self) -> Set[str]:
   def set_emit_warnings(self, emit_warnings):
     self._builder.info.emit_warnings = emit_warnings
 
+  def _set_major_minor_interpreter_constraint_for_ipex(
+    self,
+    info: PexInfo,
+    identity: PythonIdentity,
+  ) -> PexInfo:
+    interpreter_name = identity.requirement.name
+    major, minor, _patch = identity.version
+    major_minor_only_constraint = f'{interpreter_name}=={major}.{minor}.*'
+    return ipex_launcher.modify_pex_info(
+      info,
+      interpreter_constraints=[str(major_minor_only_constraint)]
+    )
+
   def _shuffle_underlying_pex_builder(self) -> Tuple[PexInfo, Path]:
     """Replace the original builder with a new one, and just pull files from the old chroot."""
     # Ensure that (the interpreter selected to resolve requirements when the ipex is first run) is
     # (the exact same interpreter we used to resolve those requirements here). This is the only (?)
     # way to ensure that the ipex bootstrap uses the *exact* same interpreter version.
-    self._builder.info = ipex_launcher.modify_pex_info(
+    self._builder.info = self._set_major_minor_interpreter_constraint_for_ipex(
       self._builder.info,
-      interpreter_constraints=[str(self._builder.interpreter.identity.requirement)],
-    )
+      self._builder.interpreter.identity)
 
     orig_info = self._builder.info.copy()
 
     orig_chroot = self._builder.chroot()
 
     # Mutate the PexBuilder object which is manipulated by this subsystem.
     self._builder = PEXBuilder(interpreter=self._builder.interpreter)
+    self._builder.info = self._set_major_minor_interpreter_constraint_for_ipex(
+      self._builder.info,
+      self._builder.interpreter.identity)
 
     return (orig_info, Path(orig_chroot.path()))
 

src/python/pants/python/pex_build_util_test_integration.py

@@ -0,0 +1,46 @@
+# Copyright 2020 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+import json
+import os
+import subprocess
+
+from pex.interpreter import PythonInterpreter
+
+from pants.testutil.pants_run_integration_test import PantsRunIntegrationTest
+from pants.util.collections import assert_single_element
+from pants.util.contextutil import open_zip, temporary_dir
+
+
+class PexBuildUtilIntegrationTest(PantsRunIntegrationTest):
+
+  binary_target_address = "testprojects/src/python/python_targets:test"
+
+  def test_multiplatform_python_binary(self):
+    cur_interpreter_id = PythonInterpreter.get().identity
+    interpreter_name = cur_interpreter_id.requirement.name
+    major, minor, patch = cur_interpreter_id.version
+    cur_interpreter_constraint = f"{interpreter_name}=={major}.{minor}.{patch}"
+
+    imprecise_constraint = f"{interpreter_name}=={major}.{minor}.*"
+
+    with temporary_dir() as tmp_dir:
+      self.do_command(
+        "--binary-py-generate-ipex",
+        "binary",
+        self.binary_target_address,
+        config={
+          "GLOBAL": {"pants_distdir": tmp_dir},
+          "python-setup": {"interpreter_constraints": [cur_interpreter_constraint],},
+        },
+      )
+
+      pex_path = os.path.join(tmp_dir, "test.ipex")
+      assert os.path.isfile(pex_path)
+      pex_execution_result = subprocess.run([pex_path], stdout=subprocess.PIPE, check=True)
+      assert pex_execution_result.stdout.decode() == "test!\n"
+
+      with open_zip(pex_path) as zf:
+        info = json.loads(zf.read("PEX-INFO"))
+        constraint = assert_single_element(info["interpreter_constraints"])
+        assert constraint == imprecise_constraint

tests/python/pants_test/backend/codegen/thrift/python/test_apache_thrift_py_gen.py

@@ -12,9 +12,9 @@
 from pants.backend.codegen.thrift.python.apache_thrift_py_gen import ApacheThriftPyGen
 from pants.backend.codegen.thrift.python.python_thrift_library import PythonThriftLibrary
 from pants.backend.python.interpreter_cache import PythonInterpreterCache
+from pants.python.python_repos import PythonRepos
 from pants.backend.python.targets.python_library import PythonLibrary
 from pants.base.build_environment import get_buildroot
-from pants.backend.python.subsystems.python_repos import PythonRepos
 from pants.testutil.subsystem.util import global_subsystem_instance
 from pants.testutil.task_test_base import TaskTestBase
 

tests/python/pants_test/backend/python/tasks/util/build_local_dists_test_base.py

@@ -8,12 +8,12 @@
 from pants.backend.native.register import rules as native_backend_rules
 from pants.backend.native.subsystems.libc_dev import LibcDev
 from pants.backend.native.subsystems.native_build_step import ToolchainVariant
+from pants.python.python_repos import PythonRepos
 from pants.backend.python.tasks.build_local_python_distributions import (
   BuildLocalPythonDistributions,
 )
 from pants.backend.python.tasks.resolve_requirements import ResolveRequirements
 from pants.backend.python.tasks.select_interpreter import SelectInterpreter
-from pants.backend.python.subsystems.python_repos import PythonRepos
 from pants.testutil.task_test_base import DeclarativeTaskTestMixin
 from pants.util.collections import assert_single_element
 from pants.util.enums import match