[rules score] Add Rules_Score Aspect for simpler result CI-upload

Exports every dependable_element's doc/report artifacts as an opt-in
output group, so CI can collect them across a whole workspace without a
dedicated build step.

Author: Ehrja

bazel/aspects/rules_score/BUILD

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+exports_files(["dependable_element_export.bzl"])

bazel/aspects/rules_score/README.md

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+# `dependable_element_export` aspect
+
+Collects the doc/report artifacts of every `dependable_element()` (rules_score SEooC) reached by
+a build and republishes them under a uniform `_dependable_element_export/` path segment, as a
+dedicated, explicitly requestable output group.
+
+It is designed to be added to an **existing** build invocation without changing what that build
+produces for any other target: the aspect no-ops for every target that does not carry the
+`DependableElementInfo` provider, and its outputs are only built when you ask for the
+`dependable_element_export` output group.
+
+## Usage
+
+```sh
+bazel build //<your_target(s)> \
+    --aspects=@score_tooling//bazel/aspects/rules_score:dependable_element_export.bzl%dependable_element_export_aspect \
+    --output_groups=+dependable_element_export \
+    --remote_download_regex=".*/_dependable_element_export/.*"
+```
+
+The three flags are independent and all required:
+
+| Flag | Why |
+| --- | --- |
+| `--aspects=` | Attaches the aspect. Note the value is `<label of the .bzl file>%<aspect symbol>` — **not** a target label. |
+| `--output_groups=+dependable_element_export` | The leading `+` *adds* to the default output groups instead of replacing them, so the original build still produces everything it normally would. |
+| `--remote_download_regex=` | Only needed with remote execution (`--config=rbe`). Without it the exported artifacts stay on the remote worker and never materialize locally. |
+
+Safe to apply to a wide pattern such as `//...` — packages without a `dependable_element()` cost
+nothing.
+
+## Where the output lands
+
+```text
+bazel-bin/<package-path>/_dependable_element_export/
+```
+
+To find every exported element across a whole workspace after the build:
+
+```sh
+find -L bazel-bin -type d -name _dependable_element_export
+```
+
+## Why the artifacts are copied rather than just re-exposed
+
+A naive aspect would simply re-advertise each `dependable_element`'s existing default outputs.
+That is not enough for the CI use case, because those files live at unpredictable,
+rule-internal paths that differ per element, which makes them hard to glob, hard to filter with
+`--remote_download_regex`, and hard to upload under a stable directory structure.
+
+So the aspect declares new outputs under `_EXPORT_DIR` and populates them with explicit copy
+actions. Two details matter:
+
+- **Copies, not symlinks.** `ctx.actions.symlink()` was tried first and broke under remote
+  execution — the symlinks were not materialized usefully on the local side.
+- **Tree artifacts are handled separately.** Some `dependable_element` outputs are directories
+  (e.g. generated Sphinx HTML), so the implementation branches on `File.is_directory` and uses
+  `declare_directory()` + a recursive copy for those.
+
+The package prefix is stripped from each file's `short_path` before relocation, so paths are not
+redundantly nested inside themselves.
+

bazel/aspects/rules_score/dependable_element_export.bzl

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+# *******************************************************************************
+# Copyright (c) 2025 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+"""CLI-level aspect exporting dependable_element (rules_score SEooC) artifacts.
+
+The aspect exposes every dependable_element (rules_score SEooC)'s own doc/report
+artifacts as a dedicated output group. It no-ops for any target that isn't a
+dependable_element, so it is safe to apply unconditionally on //...
+Every `dependable_element`'s own doc/report artifacts become an explicitly requestable output group of that *same* build invocation - without changing what is built for any other target.
+
+Rather than merely re-exposing each dependable_element's existing output files as-is, this
+aspect *relocates/copies* them under a synthetic `_dependable_element_export/` path segment to simplify downloading it from remote-execution or uploading it in CI.
+
+Usage:
+
+bazel build //<your_target(s)> \
+    --aspects=@score_tooling//bazel/aspects/rules_score:dependable_element_export.bzl%dependable_element_export_aspect \
+    --output_groups=+dependable_element_export \
+    --remote_download_regex=".*/_dependable_element_export/.*"
+
+See README.md next to this file for details.
+"""
+
+load("@score_tooling//bazel/rules/rules_score:providers.bzl", "DependableElementInfo")
+
+_EXPORT_DIR = "_dependable_element_export"
+
+def _dependable_element_export_aspect_impl(target, ctx):
+    """Re-export a dependable_element's own default outputs under a uniform path segment.
+
+    No-ops for any target that isn't a dependable_element (identified via the
+    `DependableElementInfo` provider that `dependable_element()` forwards for exactly this kind
+    of cross-target lookup - see rules_score's own use of it for integrity-level checks).
+    """
+    if DependableElementInfo not in target:
+        return []
+
+    # Own package prefix of the file's short_path, if present, is stripped so the relocated
+    # path doesn't redundantly nest the package path inside itself a second time.
+    own_package_prefix = ctx.label.package + "/"
+
+    exported_files = []
+    for f in target[DefaultInfo].files.to_list():
+        short_path = f.short_path
+        if short_path.startswith("../"):
+            # Drop external repo prefix.
+            relative_path = short_path.split("/", 2)[2]
+        elif short_path.startswith(own_package_prefix):
+            relative_path = short_path[len(own_package_prefix):]
+        else:
+            relative_path = short_path
+
+        # Some dependable_element outputs are tree artifacts (e.g. a Sphinx HTML directory),
+        # not plain files - handled with a directory copy instead of a single-file one.
+        if f.is_directory:
+            exported = ctx.actions.declare_directory(_EXPORT_DIR + "/" + relative_path)
+            ctx.actions.run_shell(
+                inputs = [f],
+                outputs = [exported],
+                command = "mkdir -p \"$2\" && cp -r \"$1\"/. \"$2\"/",
+                arguments = [f.path, exported.path],
+                mnemonic = "DependableElementExportCopyDir",
+                progress_message = "Exporting dependable_element directory " + f.short_path,
+            )
+        else:
+            exported = ctx.actions.declare_file(_EXPORT_DIR + "/" + relative_path)
+            ctx.actions.run_shell(
+                inputs = [f],
+                outputs = [exported],
+                command = "mkdir -p \"$(dirname \"$2\")\" && cp \"$1\" \"$2\"",
+                arguments = [f.path, exported.path],
+                mnemonic = "DependableElementExportCopyFile",
+                progress_message = "Exporting dependable_element file " + f.short_path,
+            )
+        exported_files.append(exported)
+
+    return [
+        OutputGroupInfo(
+            dependable_element_export = depset(exported_files),
+        ),
+    ]
+
+dependable_element_export_aspect = aspect(
+    implementation = _dependable_element_export_aspect_impl,
+    doc = (
+        "Exports dependable_element (rules_score SEooC) default outputs (doc/report " +
+        "artifacts), relocated (via copy actions) under a uniform " +
+        "'_dependable_element_export/' path segment, as a dedicated " +
+        "'dependable_element_export' output group - for use as an additive `--aspects=` flag " +
+        "on an otherwise unrelated build."
+    ),
+)