DEVPROD-14354 avoid a division-by-zero when processing empty suites

CHANGELOG.md

@@ -1,4 +1,7 @@
 # Changelog
+## 0.7.22 - 2025-01-22
+* Avoid a division-by-zero when processing empty suites.
+
 ## 0.7.21 - 2025-01-16
 * Add additional logging for task generation that takes a long time.
 

Cargo.toml

@@ -2,7 +2,7 @@
 name = "mongo-task-generator"
 description = "Dynamically split evergreen tasks into subtasks for testing the mongodb/mongo project."
 license = "Apache-2.0"
-version = "0.7.21"
+version = "0.7.22"
 repository = "https://github.com/mongodb/mongo-task-generator"
 authors = ["Decision Automation Group <dev-prod-dag@mongodb.com>"]
 edition = "2018"

src/task_types/resmoke_tasks.rs

@@ -509,12 +509,16 @@ impl GenResmokeTaskServiceImpl {
         multiversion_name: Option<&str>,
         multiversion_tags: Option<String>,
     ) -> Result<Vec<SubSuite>> {
+        let mut sub_suites = vec![];
+
         let origin_suite = multiversion_name.unwrap_or(&params.suite_name);
         let test_list = self.get_test_list(params, multiversion_name)?;
+        if test_list.is_empty() {
+            return Ok(sub_suites);
+        }
         let n_suites = min(test_list.len(), self.config.n_suites);
         let tasks_per_suite = test_list.len() / n_suites;
 
-        let mut sub_suites = vec![];
         let mut current_tests = vec![];
         let mut i = 0;
         for test in test_list {
@@ -1306,6 +1310,28 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_split_task_fallback_empty_suite() {
+        let n_suites = 1;
+        let test_list = vec![];
+        let task_history = TaskRuntimeHistory {
+            task_name: "my task".to_string(),
+            test_map: hashmap! {},
+        };
+        let gen_resmoke_service =
+            build_mocked_service(test_list.clone(), task_history.clone(), n_suites);
+
+        let params = ResmokeGenParams {
+            ..Default::default()
+        };
+
+        let sub_suites = gen_resmoke_service
+            .split_task_fallback(&params, None, None)
+            .unwrap();
+
+        assert_eq!(sub_suites.len(), 0);
+    }
+
     // tests for get_test_list.
     #[rstest]
     #[case(true, 12)]