From 93a8633f188150e2d13c7a2d5a3d6773f0c9d204 Mon Sep 17 00:00:00 2001
From: Kerollmops <clement@meilisearch.com>
Date: Wed, 9 Jun 2021 14:45:56 +0200
Subject: [PATCH] Remove the documents_merge method that must never be called

---
 milli/src/update/index_documents/merge_function.rs | 4 ----
 milli/src/update/index_documents/mod.rs            | 8 ++++----
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/milli/src/update/index_documents/merge_function.rs b/milli/src/update/index_documents/merge_function.rs
index c8424dc8c..904368fb0 100644
--- a/milli/src/update/index_documents/merge_function.rs
+++ b/milli/src/update/index_documents/merge_function.rs
@@ -26,10 +26,6 @@ pub fn keep_first(_key: &[u8], values: &[Cow<[u8]>]) -> anyhow::Result<Vec<u8>>
     Ok(values.first().unwrap().to_vec())
 }
 
-pub fn documents_merge(key: &[u8], _values: &[Cow<[u8]>]) -> anyhow::Result<Vec<u8>> {
-    bail!("merging documents is an error ({:?})", key.as_bstr())
-}
-
 pub fn merge_two_obkvs(base: obkv::KvReader, update: obkv::KvReader, buffer: &mut Vec<u8>) {
     use itertools::merge_join_by;
     use itertools::EitherOrBoth::{Both, Left, Right};
diff --git a/milli/src/update/index_documents/mod.rs b/milli/src/update/index_documents/mod.rs
index 2b790ce06..7fb47fa4a 100644
--- a/milli/src/update/index_documents/mod.rs
+++ b/milli/src/update/index_documents/mod.rs
@@ -26,7 +26,7 @@ use crate::update::{
 use self::store::{Store, Readers};
 pub use self::merge_function::{
     fst_merge, cbo_roaring_bitmap_merge, roaring_bitmap_merge,
-    docid_word_positions_merge, documents_merge, keep_first
+    docid_word_positions_merge, keep_first
 };
 pub use self::transform::{Transform, TransformOutput};
 
@@ -149,7 +149,7 @@ pub fn write_into_lmdb_database(
                 let mut iter = database.prefix_iter_mut::<_, ByteSlice, ByteSlice>(wtxn, k)?;
                 match iter.next().transpose()? {
                     Some((key, old_val)) if key == k => {
-                        let vals = vec![Cow::Borrowed(old_val), Cow::Borrowed(v)];
+                        let vals = &[Cow::Borrowed(old_val), Cow::Borrowed(v)][..];
                         let val = merge(k, &vals)?;
                         iter.put_current(k, &val)?;
                     },
@@ -634,12 +634,12 @@ impl<'t, 'u, 'i, 'a> IndexDocuments<'t, 'u, 'i, 'a> {
             total_databases,
         });
 
-        debug!("Writing the documents into LMDB on disk...");
+        debug!("Inserting the documents into LMDB on disk...");
         merge_into_lmdb_database(
             self.wtxn,
             *self.index.documents.as_polymorph(),
             documents_readers,
-            documents_merge,
+            keep_first,
             write_method
         )?;