Fix main-snapshot DRA alias lookup in minor-freeze wait

dev-tools/unittest/test_wait_version_bump_dra.py

@@ -74,6 +74,27 @@ def meta_side_effect(key: str) -> str | None:
     assert "still waiting: staging=None, snapshot=None" in out
 
 
+def test_wait_minor_polls_master_alias_for_main_snapshot() -> None:
+    """release-manager's project-configs dir for main is "master", not "main"; the DRA
+    "latest" snapshot alias it publishes is .../latest/master.json. _wait_minor must poll
+    that alias, not a .../latest/main.json that release-manager never creates."""
+    mod = _load_wait_module()
+    captured: list[tuple[str, str, str]] = []
+
+    def fake_wait_for_checks(checks: list[tuple[str, str, str]]) -> int:
+        captured.extend(checks)
+        return 0
+
+    with patch.object(mod, "_wait_for_checks", side_effect=fake_wait_for_checks):
+        assert mod._wait_minor("9.5", "9.5.0", "9.6.0") == 0
+
+    main_snapshot = next(c for c in captured if c[0] == "main snapshot")
+    _, url, expected = main_snapshot
+    assert url == "https://storage.googleapis.com/elastic-artifacts-snapshot/ml-cpp/latest/master.json"
+    assert "latest/main.json" not in url
+    assert expected == "9.6.0-SNAPSHOT"
+
+
 def test_main_skips_dra_wait_for_sandbox_branch(capsys) -> None:
     mod = _load_wait_module()
     with patch.dict(

dev-tools/wait_version_bump_dra.py

@@ -45,6 +45,10 @@
 STAGING_TMPL = "https://artifacts-staging.elastic.co/ml-cpp/latest/{branch}.json"
 SNAPSHOT_TMPL = "https://storage.googleapis.com/elastic-artifacts-snapshot/ml-cpp/latest/{branch}.json"
 
+# release-manager's project-configs dir for main is named "master", not "main", so the
+# DRA "latest" snapshot alias it publishes is .../latest/master.json, never .../latest/main.json.
+MAIN_BRANCH_DRA_ALIAS = "master"
+
 
 def _meta_get(key: str) -> str | None:
     """Read Buildkite meta-data. Returns None when not on Buildkite or key is unset."""
@@ -145,7 +149,7 @@ def _wait_patch(branch: str, new_version: str) -> int:
 
 
 def _wait_minor(branch: str, new_version: str, main_new_version: str) -> int:
-    main_snapshot_url = SNAPSHOT_TMPL.format(branch="main")
+    main_snapshot_url = SNAPSHOT_TMPL.format(branch=MAIN_BRANCH_DRA_ALIAS)
     branch_staging_url = STAGING_TMPL.format(branch=branch)
     branch_snapshot_url = SNAPSHOT_TMPL.format(branch=branch)
     checks = [