nfpm: add get_package_field_sets_for_nfpm_content_file_deps rule

docs/notes/2.31.x.md

@@ -42,6 +42,10 @@ Go now compiles with trimpath to strip sandbox paths from output, allowing for r
 
 Pants no longer supports loading `pkg_resources`-style namespace packages for plugins. Instead, just use ["native namespace packages"](https://packaging.python.org/en/latest/guides/packaging-namespace-packages/#native-namespace-packages) as per [PEP 420](https://peps.python.org/pep-0420/).
 
+#### nFPM backend
+
+Added a new rule to help in-repo plugins implement the `inject_nfpm_package_fields(InjectNfpmPackageFieldsRequest) -> InjectedNfpmPackageFields` polymorphic rule. The `get_package_field_sets_for_nfpm_content_file_deps` rule (in the `pants.backend.nfpm.util_rules.contents` module) collects selected `PackageFieldSet`s from the contents of an `nfpm_*_package` so that the packages can be analyzed to inject things like package requirements.
+
 ## Full Changelog
 
 For the full changelog, see the individual GitHub Releases for this series: <https://github.com/pantsbuild/pants/releases>

src/python/pants/backend/nfpm/rules.py

@@ -3,6 +3,7 @@
 
 from __future__ import annotations
 
+from collections.abc import Iterable
 from dataclasses import dataclass
 
 from pants.backend.nfpm.field_sets import (
@@ -14,6 +15,7 @@
 )
 from pants.backend.nfpm.field_sets import rules as field_sets_rules
 from pants.backend.nfpm.subsystem import NfpmSubsystem
+from pants.backend.nfpm.util_rules.contents import rules as contents_rules
 from pants.backend.nfpm.util_rules.generate_config import (
     NfpmPackageConfigRequest,
     generate_nfpm_yaml,
@@ -34,7 +36,8 @@
 from pants.engine.intrinsics import create_digest, digest_to_snapshot, merge_digests, remove_prefix
 from pants.engine.platform import Platform
 from pants.engine.process import Process, execute_process_or_raise
-from pants.engine.rules import collect_rules, implicitly, rule
+from pants.engine.rules import Rule, collect_rules, implicitly, rule
+from pants.engine.unions import UnionRule
 from pants.util.logging import LogLevel
 
 
@@ -157,12 +160,13 @@ async def package_nfpm_rpm_package(field_set: NfpmRpmPackageFieldSet) -> BuiltPa
     return built_package
 
 
-def rules():
+def rules() -> Iterable[Rule | UnionRule]:
     return [
         *package.rules(),
         *field_sets_rules(),
         *inject_config_rules(),
         *generate_config_rules(),
         *sandbox_rules(),
+        *contents_rules(),
         *collect_rules(),
     ]

src/python/pants/backend/nfpm/util_rules/contents.py

@@ -0,0 +1,88 @@
+# Copyright 2025 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from __future__ import annotations
+
+from collections.abc import Iterable
+from dataclasses import dataclass
+
+from pants.backend.nfpm.field_sets import NfpmContentFileFieldSet
+from pants.core.goals.package import PackageFieldSet, TraverseIfNotPackageTarget
+from pants.engine.addresses import Address, Addresses
+from pants.engine.internals.graph import find_valid_field_sets
+from pants.engine.internals.graph import transitive_targets as get_transitive_targets
+from pants.engine.rules import Rule, collect_rules, implicitly, rule
+from pants.engine.target import (
+    FieldSetsPerTarget,
+    FieldSetsPerTargetRequest,
+    TransitiveTargets,
+    TransitiveTargetsRequest,
+)
+from pants.engine.unions import UnionMembership, UnionRule
+
+
+@dataclass(frozen=True)
+class GetPackageFieldSetsForNfpmContentFileDepsRequest:
+    addresses: Addresses
+    field_set_types: tuple[type[PackageFieldSet], ...]
+
+    def __init__(
+        self, addresses: Iterable[Address], field_set_types: Iterable[type[PackageFieldSet]]
+    ):
+        object.__setattr__(self, "addresses", Addresses(addresses))
+        object.__setattr__(self, "field_set_types", tuple(field_set_types))
+
+
+@dataclass(frozen=True)
+class PackageFieldSetsForNfpmContentFileDeps:
+    nfpm_content_file_targets: TransitiveTargets
+    package_field_sets: FieldSetsPerTarget
+
+
+@rule
+async def get_package_field_sets_for_nfpm_content_file_deps(
+    request: GetPackageFieldSetsForNfpmContentFileDepsRequest,
+    union_membership: UnionMembership,
+) -> PackageFieldSetsForNfpmContentFileDeps:
+    def transitive_targets_request(roots: Iterable[Address]):
+        return TransitiveTargetsRequest(
+            tuple(roots),
+            should_traverse_deps_predicate=TraverseIfNotPackageTarget(
+                roots=tuple(roots),
+                union_membership=union_membership,
+            ),
+        )
+
+    transitive_targets: TransitiveTargets = await get_transitive_targets(
+        transitive_targets_request(request.addresses), **implicitly()
+    )
+    content_file_transitive_targets: TransitiveTargets = await get_transitive_targets(
+        transitive_targets_request(
+            [
+                tgt.address
+                for tgt in transitive_targets.dependencies
+                if NfpmContentFileFieldSet.is_applicable(tgt)
+            ]
+        ),
+        **implicitly(),
+    )
+    package_field_sets: FieldSetsPerTarget = await find_valid_field_sets(
+        FieldSetsPerTargetRequest(
+            PackageFieldSet,  # has to be a union parent
+            [
+                tgt
+                for tgt in content_file_transitive_targets.dependencies
+                if any(
+                    field_set_type.is_applicable(tgt) for field_set_type in request.field_set_types
+                )
+            ],
+        ),
+        **implicitly(),
+    )
+    return PackageFieldSetsForNfpmContentFileDeps(
+        content_file_transitive_targets, package_field_sets
+    )
+
+
+def rules() -> Iterable[Rule | UnionRule]:
+    return collect_rules()

src/python/pants/backend/nfpm/util_rules/contents_test.py

@@ -0,0 +1,219 @@
+# Copyright 2025 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from __future__ import annotations
+
+from textwrap import dedent
+
+import pytest
+
+from pants.backend.nfpm.dependency_inference import rules as nfpm_dependency_inference_rules
+from pants.backend.nfpm.field_sets import NFPM_CONTENT_FIELD_SET_TYPES, NfpmContentFieldSet
+from pants.backend.nfpm.target_types import target_types as nfpm_target_types
+from pants.backend.nfpm.target_types_rules import rules as nfpm_target_types_rules
+from pants.backend.nfpm.util_rules.contents import (
+    GetPackageFieldSetsForNfpmContentFileDepsRequest,
+    PackageFieldSetsForNfpmContentFileDeps,
+)
+from pants.backend.nfpm.util_rules.contents import rules as nfpm_contents_rules
+from pants.backend.nfpm.util_rules.generate_config import rules as nfpm_generate_config_rules
+from pants.backend.nfpm.util_rules.inject_config import rules as nfpm_inject_config_rules
+from pants.core.target_types import ArchiveFieldSet, ArchiveTarget, FilesGeneratorTarget, FileTarget
+from pants.core.target_types import rules as core_target_type_rules
+from pants.engine.addresses import Address
+from pants.engine.rules import QueryRule
+from pants.engine.unions import UnionRule
+from pants.testutil.rule_runner import RuleRunner
+
+_PKG_NAME = "pkg"
+_PKG_VERSION = "3.2.1"
+
+
+@pytest.fixture
+def rule_runner() -> RuleRunner:
+    rule_runner = RuleRunner(
+        target_types=[
+            ArchiveTarget,
+            FileTarget,
+            FilesGeneratorTarget,
+            *nfpm_target_types(),
+        ],
+        rules=[
+            *core_target_type_rules(),
+            *nfpm_target_types_rules(),
+            *nfpm_dependency_inference_rules(),
+            *nfpm_generate_config_rules(),
+            *nfpm_inject_config_rules(),
+            *nfpm_contents_rules(),
+            *(
+                UnionRule(NfpmContentFieldSet, field_set_type)
+                for field_set_type in NFPM_CONTENT_FIELD_SET_TYPES
+            ),
+            QueryRule(
+                PackageFieldSetsForNfpmContentFileDeps,
+                (GetPackageFieldSetsForNfpmContentFileDepsRequest,),
+            ),
+        ],
+    )
+    rule_runner.set_options([], env_inherit={"PATH", "PYENV_ROOT", "HOME"})
+    return rule_runner
+
+
+@pytest.mark.parametrize(
+    ("packager",),
+    (
+        ("apk",),
+        ("archlinux",),
+        ("deb",),
+        ("rpm",),
+    ),
+)
+def test_get_package_field_sets_for_nfpm_content_file_deps(rule_runner: RuleRunner, packager: str):
+    description = f"A {packager} package"
+    rule_runner.write_files(
+        {
+            "BUILD": dedent(
+                f"""
+                nfpm_{packager}_package(
+                    name="{_PKG_NAME}",
+                    description="{description}",
+                    package_name="{_PKG_NAME}",
+                    version="{_PKG_VERSION}",
+                    {"" if packager != "deb" else 'maintainer="Foo Bar <[email protected]>",'}
+                    dependencies=[
+                        "contents:files",
+                        "contents:file",
+                        "package:package",
+                        "package:output_path_package",
+                    ],
+                )
+                """
+            ),
+            "package/BUILD": dedent(
+                """
+                file(
+                    name="file",
+                    source="archive-contents.txt",
+                )
+                archive(
+                    name="archive",
+                    format="tar",
+                    files=[":file"],
+                )
+                nfpm_content_file(
+                    name="package",
+                    src="archive.tar",
+                    dst="/opt/foo/archive.tar",
+                    dependencies=[":archive"],
+                )
+                archive(
+                    name="output_path_archive",
+                    format="tar",
+                    output_path="relative_to_build_root.tar",
+                    files=[":file"],
+                )
+                nfpm_content_file(
+                    name="output_path_package",
+                    src="relative_to_build_root.tar",
+                    dst="/opt/foo/relative_to_build_root.tar",
+                    dependencies=[":output_path_archive"],
+                )
+                """
+            ),
+            "package/archive-contents.txt": "",
+            "contents/BUILD": dedent(
+                f"""
+                file(
+                    name="unrelated_file",
+                    source="should.not.be.in.digest.txt",
+                )
+                file(
+                    name="sandbox_file",
+                    source="sandbox-file.txt",
+                )
+                nfpm_content_files(
+                    name="files",
+                    files=[
+                        ("sandbox-file.txt", "/usr/share/{_PKG_NAME}/{_PKG_NAME}.{_PKG_VERSION}/installed-file.txt"),
+                        ("sandbox-file.txt", "/etc/{_PKG_NAME}/installed-file.txt"),
+                    ],
+                    dependencies=[":sandbox_file"],
+                )
+                nfpm_content_file(
+                    name="file",
+                    source="some-executable",
+                    dst="/usr/bin/some-executable",
+                )
+                nfpm_content_symlinks(
+                    name="symlinks",
+                    symlinks=(
+                        ("some-executable", "/usr/bin/new-relative-symlinked-exe"),
+                        ("/usr/bin/some-executable", "/usr/bin/new-absolute-symlinked-exe"),
+                    ),
+                    overrides={{
+                        "/usr/bin/new-relative-symlinked-exe": dict(file_group="special-group"),
+                    }},
+                )
+                nfpm_content_symlink(
+                    name="symlink",
+                    src="/usr/bin/some-executable",
+                    dst="/usr/sbin/sbin-executable",
+                )
+                nfpm_content_dirs(
+                    name="dirs",
+                    dirs=["/usr/share/{_PKG_NAME}"],
+                    overrides={{
+                        "/usr/share/{_PKG_NAME}": dict(file_group="special-group"),
+                    }},
+                )
+                nfpm_content_dir(
+                    name="dir",
+                    dst="/etc/{_PKG_NAME}",
+                    file_mode=0o700,
+                )
+                """
+            ),
+            "contents/sandbox-file.txt": "",
+            "contents/some-executable": "",
+        }
+    )
+    address = Address("", target_name=_PKG_NAME)
+
+    result = rule_runner.request(
+        PackageFieldSetsForNfpmContentFileDeps,
+        [
+            GetPackageFieldSetsForNfpmContentFileDepsRequest([address], [ArchiveFieldSet]),
+        ],
+    )
+
+    content_file_tgts = result.nfpm_content_file_targets.roots
+    assert len(content_file_tgts) == 5
+    assert {tgt.address for tgt in content_file_tgts} == {
+        Address("package", target_name="package"),
+        Address("package", target_name="output_path_package"),
+        Address("contents", target_name="file"),
+        Address("contents", target_name="files", generated_name="/etc/pkg/installed-file.txt"),
+        Address(
+            "contents",
+            target_name="files",
+            generated_name="/usr/share/pkg/pkg.3.2.1/installed-file.txt",
+        ),
+    }
+
+    content_file_deps = result.nfpm_content_file_targets.dependencies
+    assert len(content_file_deps) == 3
+    assert {tgt.address for tgt in content_file_deps} == {
+        Address("package", target_name="archive"),
+        Address("package", target_name="output_path_archive"),
+        Address("contents", target_name="sandbox_file"),
+    }
+
+    pkg_field_sets = result.package_field_sets
+    assert len(pkg_field_sets.collection) == 2
+    assert [len(collection) for collection in pkg_field_sets.collection] == [1, 1]
+
+    assert len(pkg_field_sets.field_sets) == 2
+    assert {tgt.address for tgt in pkg_field_sets.field_sets} == {
+        Address("package", target_name="archive"),
+        Address("package", target_name="output_path_archive"),
+    }