[FIX] makes sure that commit classification information is only retri…

…eved when using backend is optional or always

prospector/core/prospector.py

@@ -246,15 +246,26 @@ def prospector(  # noqa: C901
     ):
         save_or_update_processed_commits(backend_address, payload)
     else:
-        logger.warning("Preprocessed commits are not being sent to backend")
+        logger.warning(
+            "Preprocessed commits are not being sent to backend (after phase 1)"
+        )
 
     ranked_candidates = evaluate_commits(
-        preprocessed_commits, advisory_record, backend_address, enabled_rules
+        preprocessed_commits,
+        advisory_record,
+        use_backend,
+        backend_address,
+        enabled_rules,
     )
 
     # Save outcome of security relevance to DB (Phase 2 Rule)
     payload = [c.to_dict() for c in ranked_candidates[:NUM_COMMITS_PHASE_2]]
-    save_or_update_processed_commits(backend_address, payload)
+    if len(payload) > 0 and use_backend != USE_BACKEND_NEVER:
+        save_or_update_processed_commits(backend_address, payload)
+    else:
+        logger.warning(
+            "Preprocessed commits are not being sent to backend (after phase 2)"
+        )
 
     # ConsoleWriter.print("Commit ranking and aggregation...")
     ranked_candidates = remove_twins(ranked_candidates)
@@ -298,6 +309,7 @@ def filter(commits: Dict[str, RawCommit]) -> Dict[str, RawCommit]:
 def evaluate_commits(
     commits: List[Commit],
     advisory: AdvisoryRecord,
+    use_backend: str,
     backend_address: str,
     enabled_rules: List[str],
 ) -> List[Commit]:
@@ -318,8 +330,15 @@ def evaluate_commits(
     """
     with ExecutionTimer(core_statistics.sub_collection("candidates analysis")):
         with ConsoleWriter("Candidate analysis") as _:
+            # Pass True to the rules module if the backend is being used, False
+            # otherwise (needed to decide whether to update the database)
+            use_backend = use_backend != USE_BACKEND_NEVER
             ranked_commits = apply_rules(
-                commits, advisory, backend_address, enabled_rules=enabled_rules
+                commits,
+                advisory,
+                use_backend,
+                backend_address,
+                enabled_rules=enabled_rules,
             )
 
     return ranked_commits

prospector/rules/rules.py

@@ -57,6 +57,7 @@ def get_id(self):
 def apply_rules(
     candidates: List[Commit],
     advisory_record: AdvisoryRecord,
+    use_backend: bool,
     backend_address: str,
     enabled_rules: List[str] = [],
 ) -> List[Commit]:
@@ -95,7 +96,7 @@ def apply_rules(
 
         for candidate in candidates[:NUM_COMMITS_PHASE_2]:
             for rule in phase_2_rules:
-                if rule.apply(candidate, backend_address):
+                if rule.apply(candidate, use_backend, backend_address):
                     counter.increment("matches")
                     candidate.add_match(rule.as_dict())
             candidate.compute_relevance()
@@ -433,6 +434,7 @@ class CommitIsSecurityRelevant(Rule):
     def apply(
         self,
         candidate: Commit,
+        use_backend: bool,
         backend_address: str,
     ) -> bool:
 
@@ -441,27 +443,26 @@ def apply(
         ):
             # Check if this commit is already in the database
             try:
-                r = requests.get(
-                    f"{backend_address}/commits/{candidate.repository}",
-                    params={"commit_id": candidate.commit_id},
-                    timeout=10,
-                )
-                r.raise_for_status()
-                commit_data = r.json()[0]
-
-                is_security_relevant = commit_data.get("security_relevant")
-                if is_security_relevant is not None:
-                    candidate.security_relevant = is_security_relevant
-                    return is_security_relevant
+                if use_backend:
+                    r = requests.get(
+                        f"{backend_address}/commits/{candidate.repository}",
+                        params={"commit_id": candidate.commit_id},
+                        timeout=10,
+                    )
+                    r.raise_for_status()
+                    commit_data = r.json()[0]
+
+                    is_security_relevant = commit_data.get("security_relevant")
+                    if is_security_relevant is not None:
+                        candidate.security_relevant = is_security_relevant
+                        return is_security_relevant
 
                 candidate.security_relevant = LLMService().classify_commit(
                     candidate.diff, candidate.repository, candidate.message
                 )
 
                 return candidate.security_relevant
 
-                return candidate.security_relevant
-
             except requests.exceptions.RequestException as e:
                 error_type = type(e).__name__
                 print(