fix: use explicit refs/tags/ in GitHub raw package.xml URLs

vinca/distro.py

@@ -543,12 +543,26 @@ def _construct_raw_url_github(self, pkg_info):
         # Extract owner/repo
         owner_repo = raw_url_base.split("github.com/")[-1]
         # Use rev if available, otherwise fallback to tag
-        ref = pkg_info.get("rev") or pkg_info.get("tag")
+        rev = pkg_info.get("rev")
+        tag = pkg_info.get("tag")
         xml_name = pkg_info.get("package_xml_name", "package.xml")
         additional_folder = pkg_info.get("additional_folder", "")
         if additional_folder != "":
             additional_folder = additional_folder + "/"
-        raw_url = f"https://raw.githubusercontent.com/{owner_repo}/{ref}/{additional_folder}{xml_name}"
+        if rev:
+            # A commit hash is unambiguous as-is.
+            ref_path = rev
+        else:
+            # ros2-gbp release tags look like "release/jazzy/foo_pkg/1.2.3-1" --
+            # raw.githubusercontent.com's short <owner>/<repo>/<ref>/<path> form
+            # has to guess where a slash-containing ref ends and the path
+            # begins, and that guess is inconsistently cached across CDN edges:
+            # the same URL can 404 from some vantage points (including GitHub
+            # Actions runners) while resolving fine from others. The explicit
+            # refs/tags/<name> form removes the ambiguity and resolves
+            # reliably everywhere.
+            ref_path = f"refs/tags/{tag}"
+        raw_url = f"https://raw.githubusercontent.com/{owner_repo}/{ref_path}/{additional_folder}{xml_name}"
         return raw_url
 
     # format (checked against GitLab 19.x): https://gitlab.com/<NAMESPACE>/-/raw/<REV>/<PATH>

vinca/test_github_raw_url.py

@@ -0,0 +1,59 @@
+from typing import Any
+
+from vinca.distro import Distro
+
+
+def _distro() -> Any:
+    return Distro.__new__(Distro)
+
+
+def test_tag_ref_uses_explicit_refs_tags_prefix():
+    # ros2-gbp release tags look like "release/jazzy/foo_pkg/1.2.3-1" -- the
+    # short <owner>/<repo>/<ref>/<path> raw.githubusercontent.com form has to
+    # guess where a slash-containing ref ends and the path begins, and that
+    # guess is inconsistently cached across CDN edges (the same URL 404s from
+    # some vantage points, including GitHub Actions runners, while resolving
+    # fine from others). The explicit refs/tags/<name> form is unambiguous.
+    pkg_info = {
+        "url": "https://github.com/ros2-gbp/ros2_control-release.git",
+        "tag": "release/jazzy/controller_interface/4.47.0-1",
+    }
+
+    url = _distro()._construct_raw_url_github(pkg_info)
+
+    assert url == (
+        "https://raw.githubusercontent.com/ros2-gbp/ros2_control-release/"
+        "refs/tags/release/jazzy/controller_interface/4.47.0-1/package.xml"
+    )
+
+
+def test_rev_ref_is_used_as_is():
+    # A commit hash is already unambiguous -- it must not get the refs/tags/
+    # prefix, since it isn't a tag name.
+    pkg_info = {
+        "url": "https://github.com/ros2-gbp/ros2_control-release.git",
+        "rev": "abc123def456",
+    }
+
+    url = _distro()._construct_raw_url_github(pkg_info)
+
+    assert url == (
+        "https://raw.githubusercontent.com/ros2-gbp/ros2_control-release/"
+        "abc123def456/package.xml"
+    )
+
+
+def test_tag_ref_with_additional_folder_and_custom_xml_name():
+    pkg_info = {
+        "url": "https://github.com/example/some-release.git",
+        "tag": "release/rolling/some_pkg/1.0.0-1",
+        "additional_folder": "some_pkg",
+        "package_xml_name": "package.xml",
+    }
+
+    url = _distro()._construct_raw_url_github(pkg_info)
+
+    assert url == (
+        "https://raw.githubusercontent.com/example/some-release/"
+        "refs/tags/release/rolling/some_pkg/1.0.0-1/some_pkg/package.xml"
+    )

vinca/test_snapshot_metadata.py

@@ -61,9 +61,11 @@ def make_snapshot_distro(monkeypatch):
     distro._distro = Mock()
     snapshot_xml_by_url = {
         "https://raw.githubusercontent.com/example/snapshot-package-release/"
-        "release/rolling/snapshot_package/1.0.0-1/package.xml": (SNAPSHOT_PACKAGE_XML),
+        "refs/tags/release/rolling/snapshot_package/1.0.0-1/package.xml": (
+            SNAPSHOT_PACKAGE_XML
+        ),
         "https://raw.githubusercontent.com/example/snapshot-dependency-release/"
-        "release/rolling/snapshot_dependency/1.0.0-1/package.xml": (
+        "refs/tags/release/rolling/snapshot_dependency/1.0.0-1/package.xml": (
             SNAPSHOT_DEPENDENCY_XML
         ),
     }