Merge #3742

3742: Compute split words derivations of terms that don't accept typos r=ManyTheFish a=loiclec

Allows looking for the split-word derivation for short words in the user's query (like `the -> "t he"` or `door -> do or`) as well as for 3grams.

Co-authored-by: Loïc Lecrenier <loic.lecrenier@me.com>

milli/src/search/new/query_term/compute_derivations.rs

@@ -28,11 +28,9 @@ pub enum ZeroOrOneTypo {
 impl Interned<QueryTerm> {
     pub fn compute_fully_if_needed(self, ctx: &mut SearchContext) -> Result<()> {
         let s = ctx.term_interner.get_mut(self);
-        if s.max_nbr_typos == 0 {
+        if s.max_nbr_typos <= 1 && s.one_typo.is_uninit() {
-            s.one_typo = Lazy::Init(OneTypoTerm::default());
-            s.two_typo = Lazy::Init(TwoTypoTerm::default());
-        } else if s.max_nbr_typos == 1 && s.one_typo.is_uninit() {
             assert!(s.two_typo.is_uninit());
+            // Initialize one_typo subterm even if max_nbr_typo is 0 because of split words
             self.initialize_one_typo_subterm(ctx)?;
             let s = ctx.term_interner.get_mut(self);
             assert!(s.one_typo.is_init());
@@ -277,7 +275,7 @@ fn find_split_words(ctx: &mut SearchContext, word: &str) -> Result<Option<Intern
 impl Interned<QueryTerm> {
     fn initialize_one_typo_subterm(self, ctx: &mut SearchContext) -> Result<()> {
         let self_mut = ctx.term_interner.get_mut(self);
-        let QueryTerm { original, is_prefix, one_typo, .. } = self_mut;
+        let QueryTerm { original, is_prefix, one_typo, max_nbr_typos, .. } = self_mut;
         let original = *original;
         let is_prefix = *is_prefix;
         // let original_str = ctx.word_interner.get(*original).to_owned();
@@ -286,6 +284,7 @@ impl Interned<QueryTerm> {
         }
         let mut one_typo_words = BTreeSet::new();
 
+        if *max_nbr_typos > 0 {
             find_zero_one_typo_derivations(ctx, original, is_prefix, |derived_word, nbr_typos| {
                 match nbr_typos {
                     ZeroOrOneTypo::Zero => {}
@@ -299,6 +298,8 @@ impl Interned<QueryTerm> {
                 }
                 Ok(ControlFlow::Continue(()))
             })?;
+        }
+
         let original_str = ctx.word_interner.get(original).to_owned();
         let split_words = find_split_words(ctx, original_str.as_str())?;
 
@@ -327,7 +328,7 @@ impl Interned<QueryTerm> {
     }
     fn initialize_one_and_two_typo_subterm(self, ctx: &mut SearchContext) -> Result<()> {
         let self_mut = ctx.term_interner.get_mut(self);
-        let QueryTerm { original, is_prefix, two_typo, .. } = self_mut;
+        let QueryTerm { original, is_prefix, two_typo, max_nbr_typos, .. } = self_mut;
         let original_str = ctx.word_interner.get(*original).to_owned();
         if two_typo.is_init() {
             return Ok(());
@@ -335,6 +336,7 @@ impl Interned<QueryTerm> {
         let mut one_typo_words = BTreeSet::new();
         let mut two_typo_words = BTreeSet::new();
 
+        if *max_nbr_typos > 0 {
             find_zero_one_two_typo_derivations(
                 *original,
                 *is_prefix,
@@ -363,6 +365,8 @@ impl Interned<QueryTerm> {
                     Ok(ControlFlow::Continue(()))
                 },
             )?;
+        }
+
         let split_words = find_split_words(ctx, original_str.as_str())?;
         let self_mut = ctx.term_interner.get_mut(self);
 

milli/src/search/new/tests/ngram_split_words.rs

@@ -3,9 +3,9 @@ This module tests the following properties:
 
 1. Two consecutive words from a query can be combined into a "2gram"
 2. Three consecutive words from a query can be combined into a "3gram"
-3. A word from the query can be split into two consecutive words (split words)
+3. A word from the query can be split into two consecutive words (split words), no matter how short it is
 4. A 2gram can be split into two words
-5. A 3gram cannot be split into two words
+5. A 3gram can be split into two words
 6. 2grams can contain up to 1 typo
 7. 3grams cannot have typos
 8. 2grams and 3grams can be prefix tolerant
@@ -14,6 +14,7 @@ This module tests the following properties:
 11. Disabling typo tolerance does not disable ngram tolerance
 12. Prefix tolerance is disabled for the last word if a space follows it
 13. Ngrams cannot be formed by combining a phrase and a word or two phrases
+14. Split words are not disabled by the `disableOnAttribute` or `disableOnWords` typo settings
 */
 
 use crate::index::tests::TempIndex;
@@ -56,6 +57,10 @@ fn create_index() -> TempIndex {
             {
                 "id": 5,
                 "text": "sunflowering is not a verb"
+            },
+            {
+                "id": 6,
+                "text": "xy z"
             }
         ]))
         .unwrap();
@@ -263,11 +268,12 @@ fn test_disable_split_words() {
     s.query("sunflower ");
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
     // no document containing `sun flower`
-    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[3]");
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[1, 3]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);
     insta::assert_debug_snapshot!(texts, @r###"
     [
         "\"the sun flower is tall\"",
+        "\"the sunflower is tall\"",
     ]
     "###);
 }
@@ -307,10 +313,11 @@ fn test_3gram_no_split_words() {
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
 
     // no document with `sun flower`
-    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[2, 3, 5]");
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[1, 2, 3, 5]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);
     insta::assert_debug_snapshot!(texts, @r###"
     [
+        "\"the sun flower is tall\"",
         "\"the sunflowers are pretty\"",
         "\"the sunflower is tall\"",
         "\"sunflowering is not a verb\"",
@@ -369,3 +376,50 @@ fn test_no_ngram_phrases() {
     ]
     "###);
 }
+
+#[test]
+fn test_short_split_words() {
+    let index = create_index();
+    let txn = index.read_txn().unwrap();
+
+    let mut s = Search::new(&txn, &index);
+    s.terms_matching_strategy(TermsMatchingStrategy::All);
+    s.query("xyz");
+    let SearchResult { documents_ids, .. } = s.execute().unwrap();
+
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[6]");
+    let texts = collect_field_values(&index, &txn, "text", &documents_ids);
+    insta::assert_debug_snapshot!(texts, @r###"
+    [
+        "\"xy z\"",
+    ]
+    "###);
+}
+
+#[test]
+fn test_split_words_never_disabled() {
+    let index = create_index();
+
+    index
+        .update_settings(|s| {
+            s.set_exact_words(["sunflower"].iter().map(ToString::to_string).collect());
+            s.set_exact_attributes(["text"].iter().map(ToString::to_string).collect());
+        })
+        .unwrap();
+
+    let txn = index.read_txn().unwrap();
+
+    let mut s = Search::new(&txn, &index);
+    s.terms_matching_strategy(TermsMatchingStrategy::All);
+    s.query("the sunflower is tall");
+    let SearchResult { documents_ids, .. } = s.execute().unwrap();
+
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[1, 3]");
+    let texts = collect_field_values(&index, &txn, "text", &documents_ids);
+    insta::assert_debug_snapshot!(texts, @r###"
+    [
+        "\"the sun flower is tall\"",
+        "\"the sunflower is tall\"",
+    ]
+    "###);
+}

milli/src/search/new/tests/typo.rs

@@ -9,7 +9,7 @@ This module tests the following properties:
 6. A typo on the first letter of a word counts as two typos
 7. Phrases are not typo tolerant
 8. 2grams can have 1 typo if they are larger than `min_word_len_two_typos`
-9. 3grams are not typo tolerant
+9. 3grams are not typo tolerant (but they can be split into two words)
 10. The `typo` ranking rule assumes the role of the `words` ranking rule implicitly
 if `words` doesn't exist before it.
 11. The `typo` ranking rule places documents with the same number of typos in the same bucket
@@ -287,15 +287,16 @@ fn test_typo_exact_word() {
     ]
     "###);
 
-    // exact words do not disable prefix (sunflowering OK, but no sunflowar or sun flower)
+    // exact words do not disable prefix (sunflowering OK, but no sunflowar)
     let mut s = Search::new(&txn, &index);
     s.terms_matching_strategy(TermsMatchingStrategy::All);
     s.query("network interconnection sunflower");
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
-    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[16, 18]");
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[16, 17, 18]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);
     insta::assert_debug_snapshot!(texts, @r###"
     [
+        "\"network interconnection sunflower\"",
         "\"network interconnection sun flower\"",
         "\"network interconnection sunflowering\"",
     ]