Fix clippy warnings: deprecated gen_range, manual div_ceil, legacy import (#2860)

- Replace deprecated rand::Rng::gen_range with random_range in benchmarks
- Use usize::div_ceil instead of manual (len + size - 1) / size
- Remove unused legacy std::i64 import
- Replace 'if let Some(_)' with '.is_some()'

Author: Charlie Tonneslan

benches/str_search_and_get.rs

@@ -45,7 +45,7 @@ fn build_shared_indices(num_docs: usize, distribution: &str) -> BenchIndex {
         match distribution {
             "dense_random" => {
                 for _doc_id in 0..num_docs {
-                    let suffix = rng.gen_range(0u64..1000u64);
+                    let suffix = rng.random_range(0u64..1000u64);
                     let str_val = format!("str_{:03}", suffix);
 
                     writer
@@ -71,7 +71,7 @@ fn build_shared_indices(num_docs: usize, distribution: &str) -> BenchIndex {
             }
             "sparse_random" => {
                 for _doc_id in 0..num_docs {
-                    let suffix = rng.gen_range(0u64..1000000u64);
+                    let suffix = rng.random_range(0u64..1000000u64);
                     let str_val = format!("str_{:07}", suffix);
 
                     writer

src/aggregation/bucket/composite/calendar_interval.rs

@@ -54,8 +54,6 @@ fn month_bucket_using_time_crate(timestamp_ns: i64) -> Result<i64, time::Error>
 
 #[cfg(test)]
 mod tests {
-    use std::i64;
-
     use time::format_description::well_known::Iso8601;
     use time::UtcDateTime;
 

src/aggregation/bucket/composite/mod.rs

@@ -533,7 +533,7 @@ mod tests {
         let expected_buckets_vec = expected_buckets.as_array().unwrap();
 
         for page_size in 1..=expected_buckets_vec.len() {
-            let page_count = (expected_buckets_vec.len() + page_size - 1) / page_size;
+            let page_count = expected_buckets_vec.len().div_ceil(page_size);
             let mut after_key = None;
             for page_idx in 0..page_count {
                 let mut agg_req_json = json!({
@@ -565,7 +565,7 @@ mod tests {
                         "expected after_key on all but last page"
                     );
                     after_key = Some(res["my_composite"]["after_key"].clone());
-                } else if let Some(_) = res["my_composite"].get("after_key") {
+                } else if res["my_composite"].get("after_key").is_some() {
                     // currently we sometime have an after_key on the last page,
                     // check that the next "page" is empty
                     let agg_req_json = json!({