From 2554072e8f48817003b73eba97fa96957e930da8 Mon Sep 17 00:00:00 2001
From: Luca Cominardi <luca.cominardi@datadoghq.com>
Date: Wed, 22 Jul 2026 14:50:29 +0200
Subject: [PATCH] fix: address manual mapping review comments

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 src/indexer/doc_id_mapping.rs              |  4 ++--
 src/indexer/single_segment_index_writer.rs | 26 ++++++++++------------
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/src/indexer/doc_id_mapping.rs b/src/indexer/doc_id_mapping.rs
index e15714a29..b78223d53 100644
--- a/src/indexer/doc_id_mapping.rs
+++ b/src/indexer/doc_id_mapping.rs
@@ -100,7 +100,7 @@ impl DocIdMapping {
 
     fn from_new_id_to_old_id_inner<E: Error>(
         new_doc_id_to_old: Vec<DocId>,
-        mut check: impl FnMut(DocId) -> Result<(), E>,
+        mut validate: impl FnMut(DocId) -> Result<(), E>,
     ) -> Result<Self, E> {
         let max_doc = new_doc_id_to_old.len();
         let old_max_doc = new_doc_id_to_old
@@ -111,7 +111,7 @@ impl DocIdMapping {
             .unwrap_or(0);
         let mut old_doc_id_to_new = vec![0; old_max_doc as usize];
         for i in 0..max_doc {
-            (check)(new_doc_id_to_old[i])?;
+            (validate)(new_doc_id_to_old[i])?;
             old_doc_id_to_new[new_doc_id_to_old[i] as usize] = i as DocId;
         }
         Ok(DocIdMapping {
diff --git a/src/indexer/single_segment_index_writer.rs b/src/indexer/single_segment_index_writer.rs
index c2a6a1b7e..7f07d4680 100644
--- a/src/indexer/single_segment_index_writer.rs
+++ b/src/indexer/single_segment_index_writer.rs
@@ -4,7 +4,7 @@ use crate::indexer::operation::AddOperation;
 use crate::indexer::segment_updater::save_metas;
 use crate::indexer::{DocIdMapping, SegmentWriter};
 use crate::schema::document::Document;
-use crate::{Directory, Index, IndexMeta, IndexSettings, Opstamp, Segment, TantivyDocument};
+use crate::{Directory, Index, IndexMeta, Opstamp, Segment, TantivyDocument};
 
 #[doc(hidden)]
 pub struct SingleSegmentIndexWriter<D: Document = TantivyDocument> {
@@ -45,9 +45,8 @@ impl<D: Document> SingleSegmentIndexWriter<D> {
         } = self;
         let max_doc = segment_writer.max_doc();
         segment_writer.finalize()?;
-        let remapping_required = segment.index().settings().sort_by_field.is_some();
-        let index_settings = segment.index().settings().clone();
-        Self::finalize_inner(segment, max_doc, remapping_required, index_settings)
+        let did_remapping = segment.index().settings().sort_by_field.is_some();
+        Self::finalize_inner(segment, max_doc, did_remapping, false)
     }
 
     pub fn finalize_with_doc_id_mapping(self, mapping: &DocIdMapping) -> crate::Result<Index> {
@@ -58,30 +57,29 @@ impl<D: Document> SingleSegmentIndexWriter<D> {
         } = self;
         let max_doc = segment_writer.max_doc();
         segment_writer.finalize_with_doc_id_mapping(mapping)?;
-        let mut index_settings = segment.index().settings().clone();
-        index_settings.manual_doc_id_mapping = false;
-        let mut index = Self::finalize_inner(segment, max_doc, true, index_settings)?;
-        index.settings_mut().manual_doc_id_mapping = false;
-        Ok(index)
+        Self::finalize_inner(segment, max_doc, true, true)
     }
 
     fn finalize_inner(
         segment: Segment,
         max_doc: u32,
-        remapping_required: bool,
-        index_settings: IndexSettings,
+        did_remapping: bool,
+        clear_manual_doc_id_mapping: bool,
     ) -> crate::Result<Index> {
         let segment: Segment = segment.with_max_doc(max_doc);
         let segment_meta = segment.meta();
         let mut index = segment.index().clone();
+        if clear_manual_doc_id_mapping {
+            index.settings_mut().manual_doc_id_mapping = false;
+        }
 
-        if remapping_required {
+        if did_remapping {
             // Untrack the temp docstore file from the segment metadata.
             segment_meta.untrack_temp_docstore();
         }
 
         let index_meta = IndexMeta {
-            index_settings,
+            index_settings: index.settings().clone(),
             segments: vec![segment_meta.clone()],
             schema: index.schema(),
             opstamp: 0,
@@ -90,7 +88,7 @@ impl<D: Document> SingleSegmentIndexWriter<D> {
         save_metas(&index_meta, index.directory())?;
         index.directory().sync_directory()?;
 
-        if remapping_required {
+        if did_remapping {
             // Run the garbage collector to remove the temp docstore file from the directory.
             let mut living_files = segment_meta.list_files();
             living_files.insert(crate::core::META_FILEPATH.to_path_buf());