Disambiguate binary and lambda output. (pantsbuild#10735)

Previously we named them after the target name, which might
not be unique across the repo. Now we use the entire target
address. The new name is `path.to.target.dir/target_name.pex/zip`.
This seems like a good compromise between completely flat
and overstructured. It also preserves the existing filenames,
for less confusion.

[ci skip-rust]

build-support/bin/bootstrap_pants_pex.sh

@@ -15,4 +15,4 @@ source "${REPO_ROOT}/build-support/pants_venv"
 source "${REPO_ROOT}/build-support/bin/native/bootstrap_code.sh"
 
 ./pants binary src/python/pants/bin:pants_local_binary || exit 1
-mv dist/pants_local_binary.pex pants.pex
+mv dist/src.python.pants.bin/pants_local_binary.pex pants.pex

pants.toml

@@ -1,6 +1,8 @@
 [GLOBAL]
 print_exception_stacktrace = true
 
+pants_distdir_legacy_paths = false
+
 # Enable our custom loose-source plugins.
 pythonpath = ["%(buildroot)s/pants-plugins"]
 backend_packages.add = [

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

@@ -1,6 +1,8 @@
 # Copyright 2019 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
+import logging
+import os
 from dataclasses import dataclass
 
 from pants.backend.awslambda.common.awslambda_common_rules import (
@@ -30,8 +32,11 @@
 from pants.engine.process import ProcessResult
 from pants.engine.rules import Get, collect_rules, rule
 from pants.engine.unions import UnionRule
+from pants.option.global_options import GlobalOptions
 from pants.util.logging import LogLevel
 
+logger = logging.getLogger(__name__)
+
 
 @dataclass(frozen=True)
 class PythonAwsLambdaFieldSet(AWSLambdaFieldSet):
@@ -48,10 +53,23 @@ class LambdexSetup:
 
 @rule(desc="Create Python AWS Lambda", level=LogLevel.DEBUG)
 async def create_python_awslambda(
-    field_set: PythonAwsLambdaFieldSet, lambdex_setup: LambdexSetup
+    field_set: PythonAwsLambdaFieldSet, lambdex_setup: LambdexSetup, global_options: GlobalOptions
 ) -> CreatedAWSLambda:
     # Lambdas typically use the .zip suffix, so we use that instead of .pex.
-    pex_filename = f"{field_set.address.target_name}.zip"
+    disambiguated_pex_filename = os.path.join(
+        field_set.address.spec_path.replace(os.sep, "."), f"{field_set.address.target_name}.zip"
+    )
+    if global_options.options.pants_distdir_legacy_paths:
+        pex_filename = f"{field_set.address.target_name}.zip"
+        logger.warning(
+            f"Writing to the legacy subpath: {pex_filename}, which may not be unique. An "
+            f"upcoming version of Pants will switch to writing to the fully-qualified subpath: "
+            f"{disambiguated_pex_filename}. You can effect that switch now (and silence this "
+            f"warning) by setting `pants_distdir_legacy_paths = false` in the [GLOBAL] section of "
+            f"pants.toml."
+        )
+    else:
+        pex_filename = disambiguated_pex_filename
     # We hardcode the platform value to the appropriate one for each AWS Lambda runtime.
     # (Running the "hello world" lambda in the example code will report the platform, and can be
     # used to verify correctness of these platform strings.)

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

@@ -37,6 +37,7 @@ def create_python_awslambda(rule_runner: RuleRunner, addr: str) -> Tuple[str, by
         args=[
             "--backend-packages=pants.backend.awslambda.python",
             "--source-root-patterns=src/python",
+            "--pants-distdir-legacy-paths=false",
         ]
     )
     target = rule_runner.get_target(Address.parse(addr), bootstrapper)
@@ -83,7 +84,7 @@ def handler(event, context):
     zip_file_relpath, content = create_python_awslambda(
         rule_runner, "src/python/foo/bar:hello_world_lambda"
     )
-    assert "hello_world_lambda.zip" == zip_file_relpath
+    assert "src.python.foo.bar/hello_world_lambda.zip" == zip_file_relpath
     zipfile = ZipFile(BytesIO(content))
     names = set(zipfile.namelist())
     assert "lambdex_handler.py" in names

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

@@ -1,6 +1,8 @@
 # Copyright 2019 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
+import logging
+import os
 from dataclasses import dataclass
 from typing import Tuple
 
@@ -28,8 +30,11 @@
 from pants.engine.rules import Get, collect_rules, rule
 from pants.engine.target import HydratedSources, HydrateSourcesRequest
 from pants.engine.unions import UnionRule
+from pants.option.global_options import GlobalOptions
 from pants.util.logging import LogLevel
 
+logger = logging.getLogger(__name__)
+
 
 @dataclass(frozen=True)
 class PythonBinaryFieldSet(BinaryFieldSet, RunFieldSet):
@@ -67,7 +72,9 @@ def generate_additional_args(
 
 @rule(level=LogLevel.DEBUG)
 async def create_python_binary(
-    field_set: PythonBinaryFieldSet, python_binary_defaults: PythonBinaryDefaults
+    field_set: PythonBinaryFieldSet,
+    python_binary_defaults: PythonBinaryDefaults,
+    global_options: GlobalOptions,
 ) -> CreatedBinary:
     entry_point = field_set.entry_point.value
     if entry_point is None:
@@ -80,7 +87,21 @@ async def create_python_binary(
         entry_point = PythonBinarySources.translate_source_file_to_entry_point(
             stripped_binary_sources.snapshot.files
         )
-    output_filename = f"{field_set.address.target_name}.pex"
+
+    disambiguated_output_filename = os.path.join(
+        field_set.address.spec_path.replace(os.sep, "."), f"{field_set.address.target_name}.pex"
+    )
+    if global_options.options.pants_distdir_legacy_paths:
+        output_filename = f"{field_set.address.target_name}.pex"
+        logger.warning(
+            f"Writing to the legacy subpath: {output_filename}, which may not be unique. An "
+            f"upcoming version of Pants will switch to writing to the fully-qualified subpath: "
+            f"{disambiguated_output_filename}. You can effect that switch now (and silence this "
+            f"warning) by setting `pants_distdir_legacy_paths = false` in the [GLOBAL] section of "
+            f"pants.toml."
+        )
+    else:
+        output_filename = disambiguated_output_filename
     two_step_pex = await Get(
         TwoStepPex,
         TwoStepPexFromTargetsRequest(

src/python/pants/option/global_options.py

@@ -384,6 +384,17 @@ def register_bootstrap_options(cls, register):
             default=os.path.join(buildroot, "dist"),
             help="Write end-product artifacts to this dir.",
         )
+        # TODO: Change the default to false in 2.1, deprecate the option in 2.2 and remove in 2.3.
+        register(
+            "--pants-distdir-legacy-paths",
+            type=bool,
+            advanced=True,
+            default=True,
+            help="Whether to write binaries to the pre-2.0 paths under distdir. These legacy "
+            "paths are not qualified by target address, so may be ambiguous.  This option "
+            "is a temporary mechanism for easing transition to 2.0.  We recommemd switching "
+            "to the new, unambiguous paths ASAP, by setting this option to true.",
+        )
         register(
             "--pants-subprocessdir",
             advanced=True,