Enhance get_advisories to Handle Empty Advisories and Basis Version O…

…verrides

This commit updates the get_advisories function in http_requests.py. Changes include:
- Filtering out releases with empty advisories.
- Checking for 'advisories!' overrides not just in the current version, but also in each basis version while processing. This ensures that any empty or specific advisories from the basis versions are appropriately applied to the current version.

lib/http_requests.py

@@ -126,7 +126,7 @@ def process_version_advisories(version, yml_data, seen):
 def get_advisories(branch_name):
     """
     Gets the list of advisories from the releases.yml file of an OpenShift release.
-    Filters out releases with 'custom' assembly type.
+    Filters out releases with 'custom' assembly type or empty advisories.
     :param branch_name: OpenShift branch name in ocp-build-data. eg: openshift-4.10
     :returns: List of lists containing the advisories with the z-stream version. Eg:
                             [['4.11.6', {'extras': 102175, 'image': 102174, 'metadata': 102177, 'rpm': 102173}], ... ]
@@ -157,21 +157,33 @@ def get_advisories(branch_name):
         if not current_advisories:
             current_advisories = {}
 
+        override_applied = False
         while depth < MAX_DEPTH:
             depth += 1
             basis_version = yml_data[current_version].get('assembly', {}).get('basis', {}).get('assembly')
             if not basis_version or basis_version in seen:
                 break
 
+            # Check for 'advisories!' override in basis version
+            basis_override_advisories = yml_data[basis_version].get('assembly', {}).get('group', {}).get('advisories!', None)
+            if basis_override_advisories is not None:
+                if not basis_override_advisories:  # If basis version's override_advisories is empty
+                    current_advisories.clear()
+                    break  # No need to process further as the advisories are cleared
+                current_advisories.update(basis_override_advisories)
+
             basis_advisories, _ = process_version_advisories(basis_version, yml_data, seen)
             if basis_advisories:
                 current_advisories.update(basis_advisories)
             current_version = basis_version
 
-        # Apply override advisories specified with 'advisories!'
-        override_advisories = yml_data[version].get('assembly', {}).get('group', {}).get('advisories!', {})
-        if override_advisories:
-            current_advisories.update(override_advisories)
+        # Check for 'advisories!' override in the current version if not applied from basis
+        if not override_applied:
+            current_override_advisories = assembly_data.get('group', {}).get('advisories!', None)
+            if current_override_advisories is not None:
+                if not current_override_advisories:
+                    continue
+                current_advisories.update(current_override_advisories)
 
         if current_advisories:
             advisory_data.append([version, current_advisories, jira_link])