Switch to bazel rule to filter extra opt parameters

Also remove some debug log messages and replace usage of static string
by switching to bazel variable equivalent.

Author: SebSparrowHawk

bazel/rules/rules_score/private/filter_execpath.bzl

@@ -0,0 +1,119 @@
+# *******************************************************************************
+# Copyright (c) 2026 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
+# *******************************************************************************
+"""Rule for resolving filtered execpaths at analysis time.
+This replaces the old string-encoding approach where filter_execpath() was a
+macro-time helper that encoded parameters into a delimited string for later
+processing inside the sphinx_module rule implementation.
+Now, filter_execpath is a proper Bazel rule that resolves the path at analysis
+time and provides the result via FilteredExecpathInfo.
+"""
+load("//bazel/rules/rules_score:providers.bzl", "FilteredExecpathInfo")
+def _filter_execpath_impl(ctx):
+    """Implementation of the filter_execpath rule.
+    Iterates over the output files of the target, finds the one matching
+    filter_pattern, and computes the resolved path suffix after /bin/.
+    """
+    target = ctx.attr.target
+    filter_pattern = ctx.attr.filter_pattern
+    flag = ctx.attr.flag
+    # Get all output files from the target
+    files = target[DefaultInfo].files.to_list()
+    # Filter for the path matching the filter pattern
+    matched_file = None
+    for f in files:
+        if filter_pattern in f.path:
+            matched_file = f
+            break
+    if not matched_file:
+        all_paths = [f.path for f in files]
+        fail("filter_execpath: no path matching '{}' found in outputs of {}. Available paths: {}".format(
+            filter_pattern,
+            target.label,
+            ", ".join(all_paths),
+        ))
+    # Strip the Bazel bin directory prefix from the matched path to get the path
+    # relative to the output base. Since _relocate() in sphinx_module symlinks
+    # source files under <source_prefix>/<original_path>, the relocated file lives
+    # at <source_dir>/<suffix_part> where source_dir is the Sphinx source directory.
+    # Breathe resolves breathe_projects paths relative to source_dir (app.srcdir),
+    # so we must return just the suffix_part.
+    matched_path = matched_file.path
+    bin_dir_prefix = ctx.bin_dir.path + "/"
+    if matched_path.startswith(bin_dir_prefix):
+        suffix_part = matched_path[len(bin_dir_prefix):]
+    else:
+        suffix_part = matched_path
+    resolved_arg = flag + "=" + suffix_part
+    return [
+        DefaultInfo(files = depset([matched_file])),
+        FilteredExecpathInfo(
+            flag = flag,
+            resolved_path = suffix_part,
+            arg = resolved_arg,
+            matched_file = matched_file,
+        ),
+    ]
+_filter_execpath_rule = rule(
+    implementation = _filter_execpath_impl,
+    attrs = {
+        "flag": attr.string(
+            mandatory = True,
+            doc = "The Sphinx -D flag prefix (e.g. '-Dbreathe_projects.com').",
+        ),
+        "target": attr.label(
+            mandatory = True,
+            allow_files = True,
+            doc = "The Bazel target whose output files to search.",
+        ),
+        "filter_pattern": attr.string(
+            mandatory = True,
+            doc = "Substring to match when filtering the target's output file paths (e.g. 'doxygen_build/xml').",
+        ),
+    },
+    doc = """Resolve and filter an execpath from a target's outputs at analysis time.
+    This rule finds the output file from `target` whose path contains
+    `filter_pattern`, strips the Bazel bin directory prefix, and provides
+    the result as a FilteredExecpathInfo for consumption by sphinx_module.
+    Example usage in BUILD:
+        load("@score_tooling//bazel/rules/rules_score:rules_score.bzl", "filter_execpath", "sphinx_module")
+        filter_execpath(
+            name = "breathe_doxygen_xml",
+            flag = "-Dbreathe_projects.doxygen_build",
+            target = "//docs/sphinx:doxygen_xml",
+            filter_pattern = "doxygen_build/xml",
+        )
+        sphinx_module(
+            name = "sphinx_doc",
+            extra_opts_targets = [":breathe_doxygen_xml"],
+            extra_opts = ["-Dbreathe_default_project=doxygen_build"],
+            ...
+        )
+    """,
+)
+def filter_execpath(name, flag, target, filter_pattern, **kwargs):
+    """Resolve and filter an execpath from a target's outputs at analysis time.
+    This is a macro wrapper around the _filter_execpath_rule.
+    Args:
+        name: Name for this target.
+        flag: The Sphinx -D flag prefix (e.g. "-Dbreathe_projects.doxygen_build").
+        target: The Bazel label whose output files to search.
+        filter_pattern: Substring to match when filtering the target's output file paths.
+        **kwargs: Additional keyword arguments passed to the underlying rule (e.g. visibility).
+    """
+    _filter_execpath_rule(
+        name = name,
+        flag = flag,
+        target = target,
+        filter_pattern = filter_pattern,
+        **kwargs
+    )