apertis-pkg-merge-upstream-to-downstreams: ensure merge request is created...

apertis-pkg-merge-upstream-to-downstreams: ensure merge request is created against the right project

In case of a forked project, like we are doing with the test of the rebase,
the GitLab API creates by default the MR against the original project
instead of the forked project.
To ensure the merge request is created against the forked project, we use
the push option merge_request.target_project to overwrite the default
behavior and to create the merge request against the forked project.

See:
https://docs.gitlab.com/ee/topics/git/commit.html#push-options-for-merge-requests



Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>

tools/apertis-pkg-merge-upstream-to-downstreams

@@ -183,6 +183,32 @@ def ensure_downstream_branch(project_url, downstream, dry_run):
         raise
 
 
+def get_path_with_namespace(project_url):
+    url = urllib.parse.urlsplit(project_url)
+    project_id = urllib.parse.quote(removesuffix(url.path.strip("/"), ".git"), safe="")
+    # drop the inline auth data as urllib does not like it
+    auth, netloc_no_auth = url.netloc.split("@", 1)
+    token = auth.split(":", 1)[-1]
+    url = url._replace(
+        path=f"/api/v4/projects/{project_id}",
+        netloc=netloc_no_auth,
+    )
+    project_metadata = url.geturl()
+    req_project_metadata = urllib.request.Request(
+        url=project_metadata,
+        headers={"PRIVATE-TOKEN": token},
+    )
+    try:
+        res = urllib.request.urlopen(req_project_metadata)
+        json_res = json.load(res)
+        path_with_namespace = json_res["path_with_namespace"]
+    except urllib.error.HTTPError as e:
+        print("ERROR:", e.read().decode())
+        raise
+
+    return path_with_namespace
+
+
 def push_merge_request(
     project_url, proposed_branch, upstream, downstream, auto_merge="", dry_run=False
 ):
@@ -213,8 +239,11 @@ def push_merge_request(
 
     ensure_downstream_branch(project_url, downstream, dry_run)
 
+    project_path = get_path_with_namespace(project_url)
+
     print(
-        f"Create merge request from '{proposed_branch}' to '{downstream}'", flush=True
+        f"Create merge request from '{proposed_branch}' to '{project_path}/{downstream}'",
+        flush=True,
     )
     git_push_custom(
         "-o",
@@ -224,6 +253,8 @@ def push_merge_request(
         "-o",
         f"merge_request.target={downstream}",
         "-o",
+        f"merge_request.target_project={project_path}",
+        "-o",
         f"merge_request.title={title}",
         project_url,
         f"{proposed_branch}:{proposed_branch}",