Prune the query graph after executing a ranking rule

milli/src/search/new/graph_based_ranking_rule.rs

@@ -36,6 +36,7 @@ That is we find the documents where either:
 - OR: `pretty` is 2-close to `house` AND `house` is 1-close to `by`
 */
 
+use std::collections::HashSet;
 use std::ops::ControlFlow;
 
 use roaring::RoaringBitmap;
@@ -50,6 +51,7 @@ use super::ranking_rule_graph::{
 use super::small_bitmap::SmallBitmap;
 use super::{QueryGraph, RankingRule, RankingRuleOutput, SearchContext};
 use crate::search::new::interner::Interned;
+use crate::search::new::query_graph::QueryNodeData;
 use crate::Result;
 
 pub type Proximity = GraphBasedRankingRule<ProximityGraph>;
@@ -216,9 +218,8 @@ impl<'ctx, G: RankingRuleGraphTrait> RankingRule<'ctx, QueryGraph> for GraphBase
         let original_universe = universe;
         let mut universe = universe.clone();
 
-        // TODO: remove this unnecessary clone
         let original_graph = graph.clone();
-        // and this vector as well
+        let mut used_conditions = SmallBitmap::for_interned_values_in(&graph.conditions_interner);
         let mut paths = vec![];
 
         // For each path of the given cost, we will compute its associated
@@ -243,8 +244,8 @@ impl<'ctx, G: RankingRuleGraphTrait> RankingRule<'ctx, QueryGraph> for GraphBase
                 // We store the edges and their docids in vectors in case the path turns out to be
                 // empty and we need to figure out why it was empty.
                 let mut visited_conditions = vec![];
-                let mut cached_edge_docids =
-                    graph.conditions_interner.map(|_| RoaringBitmap::new());
+                let mut cached_edge_docids = vec![];
+                // graph.conditions_interner.map(|_| RoaringBitmap::new());
 
                 for &condition_interned_raw in path {
                     let condition = Interned::new(condition_interned_raw);
@@ -253,7 +254,7 @@ impl<'ctx, G: RankingRuleGraphTrait> RankingRule<'ctx, QueryGraph> for GraphBase
                     let edge_docids =
                         edge_docids_cache.get_edge_docids(ctx, condition, graph, &universe)?;
 
-                    *cached_edge_docids.get_mut(condition) = edge_docids.clone();
+                    cached_edge_docids.push((condition, edge_docids.clone())); // .get_mut(condition) = edge_docids.clone();
 
                     // If the edge is empty, then the path will be empty as well, we update the graph
                     // and caches accordingly and skip to the next candidate path.
@@ -279,12 +280,12 @@ impl<'ctx, G: RankingRuleGraphTrait> RankingRule<'ctx, QueryGraph> for GraphBase
                         // then we also know that any path containing the same couple of
                         // edges will also be empty.
                         for (past_condition, edge_docids2) in cached_edge_docids.iter() {
-                            if past_condition == condition {
+                            if *past_condition == condition {
                                 continue;
                             };
                             let intersection = edge_docids & edge_docids2;
                             if intersection.is_disjoint(&universe) {
-                                empty_paths_cache.add_condition_couple(past_condition, condition);
+                                empty_paths_cache.add_condition_couple(*past_condition, condition);
                             }
                         }
                         // We should maybe instead try to compute:
@@ -292,6 +293,10 @@ impl<'ctx, G: RankingRuleGraphTrait> RankingRule<'ctx, QueryGraph> for GraphBase
                         return Ok(ControlFlow::Continue(()));
                     }
                 }
+                assert!(!path_docids.is_empty());
+                for condition in path {
+                    used_conditions.insert(Interned::new(*condition));
+                }
                 bucket |= &path_docids;
                 // Reduce the size of the universe so that we can more optimistically discard candidate paths
                 universe -= path_docids;
@@ -307,16 +312,50 @@ impl<'ctx, G: RankingRuleGraphTrait> RankingRule<'ctx, QueryGraph> for GraphBase
         G::log_state(
             &original_graph,
             &paths,
-            &state.empty_paths_cache,
+            empty_paths_cache,
             original_universe,
-            &state.all_distances,
+            all_distances,
             cost,
             logger,
         );
 
-        // TODO: Graph-based ranking rules do not (yet) modify the query graph. We could, however,
-        // remove nodes and/or terms within nodes that weren't present in any of the paths.
-        let next_query_graph = state.graph.query_graph.clone();
+        // We modify the next query graph so that it only contains the subgraph
+        // that was used to compute this bucket
+        // But we only do it in case the bucket length is >1, because otherwise
+        // we know the child ranking rule won't be called anyway
+        let mut next_query_graph = original_graph.query_graph;
+        next_query_graph.simplify();
+        if bucket.len() > 1 {
+            // 1. Gather all the words and phrases used in the computation of this bucket
+            let mut used_words = HashSet::new();
+            let mut used_phrases = HashSet::new();
+            for condition in used_conditions.iter() {
+                let condition = graph.conditions_interner.get(condition);
+                used_words.extend(G::words_used_by_edge_condition(ctx, condition)?);
+                used_phrases.extend(G::phrases_used_by_edge_condition(ctx, condition)?);
+            }
+            // 2. Remove the unused words and phrases from all the nodes in the graph
+            let mut nodes_to_remove = vec![];
+            for (node_id, node) in next_query_graph.nodes.iter_mut() {
+                let term = match &mut node.data {
+                    QueryNodeData::Term(term) => term,
+                    QueryNodeData::Deleted | QueryNodeData::Start | QueryNodeData::End => continue,
+                };
+                if let Some(new_term) = ctx
+                    .term_interner
+                    .get(term.value)
+                    .removing_forbidden_terms(&used_words, &used_phrases)
+                {
+                    if new_term.is_empty() {
+                        nodes_to_remove.push(node_id);
+                    } else {
+                        term.value = ctx.term_interner.insert(new_term);
+                    }
+                }
+            }
+            // 3. Remove the empty nodes from the graph
+            next_query_graph.remove_nodes(&nodes_to_remove);
+        }
 
         self.state = Some(state);
 

milli/src/search/new/logger/detailed.rs

@@ -528,7 +528,7 @@ shape: class"
         ctx: &mut SearchContext,
         graph: &RankingRuleGraph<R>,
         paths: &[Vec<u16>],
-        _empty_paths_cache: &DeadEndPathCache<R>,
+        dead_end_paths_cache: &DeadEndPathCache<R>,
         distances: MappedInterner<Vec<(u16, SmallBitmap<R::EdgeCondition>)>, QueryNode>,
         file: &mut File,
     ) {
@@ -552,12 +552,11 @@ shape: class"
                         .unwrap();
                 }
                 EdgeCondition::Conditional(condition) => {
-                    let condition = graph.conditions_interner.get(*condition);
+                    // let condition = graph.conditions_interner.get(*condition);
                     writeln!(
                         file,
-                        "{source_node} -> {dest_node} : \"cost {cost} {edge_label}\"",
+                        "{source_node} -> {dest_node} : \"{condition} cost {cost}\"",
                         cost = edge.cost,
-                        edge_label = R::label_for_edge_condition(condition)
                     )
                     .unwrap();
                 }
@@ -569,28 +568,33 @@ shape: class"
         // Self::paths_d2_description(graph, paths, file);
         // writeln!(file, "}}").unwrap();
 
-        writeln!(file, "Shortest Paths {{").unwrap();
+        writeln!(file, "Paths {{").unwrap();
         Self::paths_d2_description(ctx, graph, paths, file);
         writeln!(file, "}}").unwrap();
 
-        // writeln!(file, "Empty Edge Couples {{").unwrap();
-        // for (i, (e1, e2)) in empty_paths_cache.empty_couple_edges.iter().enumerate() {
-        //     writeln!(file, "{i} : \"\" {{").unwrap();
-        //     Self::edge_d2_description(graph, *e1, file);
-        //     Self::edge_d2_description(graph, *e2, file);
-        //     writeln!(file, "{e1} -- {e2}").unwrap();
-        //     writeln!(file, "}}").unwrap();
-        // }
-        // writeln!(file, "}}").unwrap();
+        writeln!(file, "Dead-end couples of conditions {{").unwrap();
+        for (i, (e1, e2)) in dead_end_paths_cache.condition_couples.iter().enumerate() {
+            writeln!(file, "{i} : \"\" {{").unwrap();
+            Self::condition_d2_description(ctx, graph, e1, file);
+            for e2 in e2.iter() {
+                Self::condition_d2_description(ctx, graph, e2, file);
+                writeln!(file, "{e1} -- {e2}").unwrap();
+            }
+            writeln!(file, "}}").unwrap();
+        }
+        writeln!(file, "}}").unwrap();
 
-        // writeln!(file, "Removed Edges {{").unwrap();
-        // for edge_idx in empty_paths_cache.empty_edges.iter() {
-        //     writeln!(file, "{edge_idx}").unwrap();
-        // }
+        writeln!(file, "Dead-end edges {{").unwrap();
+        for condition in dead_end_paths_cache.conditions.iter() {
+            writeln!(file, "{condition}").unwrap();
+        }
+        writeln!(file, "}}").unwrap();
+
+        // writeln!(file, "Dead-end prefixes {{").unwrap();
         // writeln!(file, "}}").unwrap();
     }
     fn condition_d2_description<R: RankingRuleGraphTrait>(
-        _ctx: &mut SearchContext,
+        ctx: &mut SearchContext,
         graph: &RankingRuleGraph<R>,
         condition_id: Interned<R::EdgeCondition>,
         file: &mut File,
@@ -598,10 +602,11 @@ shape: class"
         let condition = graph.conditions_interner.get(condition_id);
         writeln!(
             file,
-            "{condition_id}: \"{}\" {{
-            shape: class
-        }}",
-            R::label_for_edge_condition(condition)
+            "{condition_id} {{
+shape: class
+{}
+}}",
+            R::label_for_edge_condition(ctx, condition).unwrap()
         )
         .unwrap();
     }

milli/src/search/new/mod.rs

@@ -303,7 +303,8 @@ mod tests {
             let mut ctx = SearchContext::new(&index, &txn);
             let results = execute_search(
                 &mut ctx,
-                "which a the releases from poison by the government",
+                "released from prison by the government",
+                // "which a the releases from poison by the government",
                 // "sun flower s are the best",
                 // "zero config",
                 TermsMatchingStrategy::Last,
@@ -338,7 +339,7 @@ mod tests {
 
             println!("{}us: {:?}", elapsed.as_micros(), results);
         }
-        // for (id, _document) in documents {
+        // for (id, document) in documents {
         //     println!("{id}:");
         //     // println!("{document}");
         // }
@@ -359,9 +360,13 @@ mod tests {
         let start = Instant::now();
 
         let mut s = Search::new(&txn, &index);
-        s.query("which a the releases from poison by the government");
+        s.query(
+            // "which a the releases from poison by the government",
+            // "sun flower s are the best",
+            "zero config",
+        );
         s.terms_matching_strategy(TermsMatchingStrategy::Last);
-        // s.criterion_implementation_strategy(crate::CriterionImplementationStrategy::OnlySetBased);
+        // s.criterion_implementation_strategy(crate::CriterionImplementationStrategy::OnlyIterative);
         let docs = s.execute().unwrap();
 
         let elapsed = start.elapsed();

milli/src/search/new/query_graph.rs

@@ -281,7 +281,7 @@ impl QueryGraph {
 
     /// Simplify the query graph by removing all nodes that are disconnected from
     /// the start or end nodes.
-    fn simplify(&mut self) {
+    pub fn simplify(&mut self) {
         loop {
             let mut nodes_to_remove = vec![];
             for (node_idx, node) in self.nodes.iter() {

milli/src/search/new/query_term.rs

@@ -1,3 +1,4 @@
+use std::collections::HashSet;
 use std::mem;
 use std::ops::RangeInclusive;
 
@@ -59,6 +60,111 @@ pub struct QueryTerm {
     pub use_prefix_db: Option<Interned<String>>,
 }
 impl QueryTerm {
+    pub fn removing_forbidden_terms(
+        &self,
+        allowed_words: &HashSet<Interned<String>>,
+        allowed_phrases: &HashSet<Interned<Phrase>>,
+    ) -> Option<Self> {
+        let QueryTerm {
+            original,
+            is_ngram,
+            is_prefix,
+            phrase,
+            zero_typo,
+            prefix_of,
+            synonyms,
+            split_words,
+            one_typo,
+            two_typos,
+            use_prefix_db,
+        } = self;
+
+        let mut changed = false;
+
+        let mut new_zero_typo = None;
+        if let Some(w) = zero_typo {
+            if allowed_words.contains(w) {
+                new_zero_typo = Some(*w);
+            } else {
+                changed = true;
+            }
+        }
+        // TODO: this is incorrect, prefix DB stuff should be treated separately
+        let mut new_use_prefix_db = None;
+        if let Some(w) = use_prefix_db {
+            if allowed_words.contains(w) {
+                new_use_prefix_db = Some(*w);
+            } else {
+                changed = true;
+            }
+        }
+        let mut new_prefix_of = vec![];
+        for w in prefix_of.iter() {
+            if allowed_words.contains(w) {
+                new_prefix_of.push(*w);
+            } else {
+                changed = true;
+            }
+        }
+        let mut new_one_typo = vec![];
+        for w in one_typo.iter() {
+            if allowed_words.contains(w) {
+                new_one_typo.push(*w);
+            } else {
+                changed = true;
+            }
+        }
+        let mut new_two_typos = vec![];
+        for w in two_typos.iter() {
+            if allowed_words.contains(w) {
+                new_two_typos.push(*w);
+            } else {
+                changed = true;
+            }
+        }
+        // TODO: this is incorrect, prefix DB stuff should be treated separately
+        let mut new_phrase = None;
+        if let Some(w) = phrase {
+            if !allowed_phrases.contains(w) {
+                new_phrase = Some(*w);
+            } else {
+                changed = true;
+            }
+        }
+        let mut new_split_words = None;
+        if let Some(w) = split_words {
+            if allowed_phrases.contains(w) {
+                new_split_words = Some(*w);
+            } else {
+                changed = true;
+            }
+        }
+        let mut new_synonyms = vec![];
+        for w in synonyms.iter() {
+            if allowed_phrases.contains(w) {
+                new_synonyms.push(*w);
+            } else {
+                changed = true;
+            }
+        }
+        if changed {
+            Some(QueryTerm {
+                original: *original,
+                is_ngram: *is_ngram,
+                is_prefix: *is_prefix,
+                phrase: new_phrase,
+                zero_typo: new_zero_typo,
+                prefix_of: new_prefix_of.into_boxed_slice(),
+                synonyms: new_synonyms.into_boxed_slice(),
+                split_words: new_split_words,
+                one_typo: new_one_typo.into_boxed_slice(),
+                two_typos: new_two_typos.into_boxed_slice(),
+                use_prefix_db: new_use_prefix_db,
+            })
+        } else {
+            None
+        }
+    }
     pub fn phrase(
         word_interner: &mut DedupInterner<String>,
         phrase_interner: &mut DedupInterner<Phrase>,

milli/src/search/new/ranking_rule_graph/cheapest_paths.rs

@@ -33,7 +33,7 @@ impl<G: RankingRuleGraphTrait> RankingRuleGraph<G> {
             empty_paths_cache,
             &mut visit,
             &mut vec![],
-            &mut SmallBitmap::new(self.edges_store.len()),
+            &mut SmallBitmap::for_interned_values_in(&self.conditions_interner),
             &mut empty_paths_cache.conditions.clone(),
         )?;
         Ok(())

milli/src/search/new/ranking_rule_graph/mod.rs

@@ -16,6 +16,7 @@ mod proximity;
 /// Implementation of the `typo` ranking rule
 mod typo;
 
+use std::collections::HashSet;
 use std::hash::Hash;
 
 pub use edge_docids_cache::EdgeConditionDocIdsCache;
@@ -26,6 +27,7 @@ pub use typo::{TypoEdge, TypoGraph};
 
 use super::interner::{DedupInterner, FixedSizeInterner, Interned, MappedInterner};
 use super::logger::SearchLogger;
+use super::query_term::Phrase;
 use super::small_bitmap::SmallBitmap;
 use super::{QueryGraph, QueryNode, SearchContext};
 use crate::Result;
@@ -82,7 +84,19 @@ pub trait RankingRuleGraphTrait: Sized {
 
     /// Return the label of the given edge condition, to be used when visualising
     /// the ranking rule graph.
-    fn label_for_edge_condition(edge: &Self::EdgeCondition) -> String;
+    fn label_for_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<String>;
+
+    fn words_used_by_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<HashSet<Interned<String>>>;
+    fn phrases_used_by_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<HashSet<Interned<Phrase>>>;
 
     /// Compute the document ids associated with the given edge condition,
     /// restricted to the given universe.

milli/src/search/new/ranking_rule_graph/proximity/mod.rs

@@ -1,6 +1,9 @@
 pub mod build;
 pub mod compute_docids;
 
+use std::collections::HashSet;
+use std::iter::FromIterator;
+
 use roaring::RoaringBitmap;
 
 use super::empty_paths_cache::DeadEndPathCache;
@@ -44,17 +47,6 @@ pub enum ProximityGraph {}
 impl RankingRuleGraphTrait for ProximityGraph {
     type EdgeCondition = ProximityCondition;
 
-    fn label_for_edge_condition(edge: &Self::EdgeCondition) -> String {
-        match edge {
-            ProximityCondition::Term { term } => {
-                format!("term {term}")
-            }
-            ProximityCondition::Pairs { pairs } => {
-                format!("pairs {}", pairs.len())
-            }
-        }
-    }
-
     fn resolve_edge_condition<'ctx>(
         ctx: &mut SearchContext<'ctx>,
         condition: &Self::EdgeCondition,
@@ -83,4 +75,113 @@ impl RankingRuleGraphTrait for ProximityGraph {
     ) {
         logger.log_proximity_state(graph, paths, empty_paths_cache, universe, distances, cost);
     }
+
+    fn label_for_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<String> {
+        match edge {
+            ProximityCondition::Term { term } => {
+                let term = ctx.term_interner.get(*term);
+                Ok(format!("{} : exists", ctx.word_interner.get(term.original)))
+            }
+            ProximityCondition::Pairs { pairs } => {
+                let mut s = String::new();
+                for pair in pairs.iter() {
+                    match pair {
+                        WordPair::Words { phrases, left, right, proximity } => {
+                            let left = ctx.word_interner.get(*left);
+                            let right = ctx.word_interner.get(*right);
+                            if !phrases.is_empty() {
+                                s.push_str(&format!("{} phrases + ", phrases.len()));
+                            }
+                            s.push_str(&format!("\"{left} {right}\": {proximity}\n"));
+                        }
+                        WordPair::WordPrefix { phrases, left, right_prefix, proximity } => {
+                            let left = ctx.word_interner.get(*left);
+                            let right = ctx.word_interner.get(*right_prefix);
+                            if !phrases.is_empty() {
+                                s.push_str(&format!("{} phrases + ", phrases.len()));
+                            }
+                            s.push_str(&format!("\"{left} {right}...\" : {proximity}\n"));
+                        }
+                        WordPair::WordPrefixSwapped { left_prefix, right, proximity } => {
+                            let left = ctx.word_interner.get(*left_prefix);
+                            let right = ctx.word_interner.get(*right);
+                            s.push_str(&format!("\"{left}... {right}\" : {proximity}\n"));
+                        }
+                    }
+                }
+                Ok(s)
+            }
+        }
+    }
+
+    fn words_used_by_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<HashSet<Interned<String>>> {
+        match edge {
+            ProximityCondition::Term { term } => {
+                let term = ctx.term_interner.get(*term);
+                Ok(HashSet::from_iter(term.all_single_words_except_prefix_db()))
+            }
+            ProximityCondition::Pairs { pairs } => {
+                let mut set = HashSet::new();
+                for pair in pairs.iter() {
+                    match pair {
+                        WordPair::Words { phrases: _, left, right, proximity: _ } => {
+                            set.insert(*left);
+                            set.insert(*right);
+                        }
+                        WordPair::WordPrefix { phrases: _, left, right_prefix, proximity: _ } => {
+                            set.insert(*left);
+                            // TODO: this is not correct, there should be another trait method for collecting the prefixes
+                            // to be used with the prefix DBs
+                            set.insert(*right_prefix);
+                        }
+                        WordPair::WordPrefixSwapped { left_prefix, right, proximity: _ } => {
+                            // TODO: this is not correct, there should be another trait method for collecting the prefixes
+                            // to be used with the prefix DBs
+                            set.insert(*left_prefix);
+                            set.insert(*right);
+                        }
+                    }
+                }
+                Ok(set)
+            }
+        }
+    }
+
+    fn phrases_used_by_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<HashSet<Interned<Phrase>>> {
+        match edge {
+            ProximityCondition::Term { term } => {
+                let term = ctx.term_interner.get(*term);
+                Ok(HashSet::from_iter(term.all_phrases()))
+            }
+            ProximityCondition::Pairs { pairs } => {
+                let mut set = HashSet::new();
+                for pair in pairs.iter() {
+                    match pair {
+                        WordPair::Words { phrases, left: _, right: _, proximity: _ } => {
+                            set.extend(phrases.iter().copied());
+                        }
+                        WordPair::WordPrefix {
+                            phrases,
+                            left: _,
+                            right_prefix: _,
+                            proximity: _,
+                        } => {
+                            set.extend(phrases.iter().copied());
+                        }
+                        WordPair::WordPrefixSwapped { left_prefix: _, right: _, proximity: _ } => {}
+                    }
+                }
+                Ok(set)
+            }
+        }
+    }
 }

milli/src/search/new/ranking_rule_graph/typo/mod.rs

@@ -5,10 +5,13 @@ use super::{EdgeCondition, RankingRuleGraph, RankingRuleGraphTrait};
 use crate::search::new::interner::{DedupInterner, Interned, MappedInterner};
 use crate::search::new::logger::SearchLogger;
 use crate::search::new::query_graph::QueryNodeData;
-use crate::search::new::query_term::{LocatedQueryTerm, QueryTerm};
+use crate::search::new::query_term::{LocatedQueryTerm, Phrase, QueryTerm};
 use crate::search::new::small_bitmap::SmallBitmap;
 use crate::search::new::{QueryGraph, QueryNode, SearchContext};
 use crate::Result;
+use std::collections::HashSet;
+use std::fmt::Write;
+use std::iter::FromIterator;
 
 #[derive(Clone, PartialEq, Eq, Hash)]
 pub struct TypoEdge {
@@ -21,10 +24,6 @@ pub enum TypoGraph {}
 impl RankingRuleGraphTrait for TypoGraph {
     type EdgeCondition = TypoEdge;
 
-    fn label_for_edge_condition(edge: &Self::EdgeCondition) -> String {
-        format!(", {} typos", edge.nbr_typos)
-    }
-
     fn resolve_edge_condition<'db_cache, 'ctx>(
         ctx: &mut SearchContext<'ctx>,
         edge: &Self::EdgeCondition,
@@ -147,4 +146,78 @@ impl RankingRuleGraphTrait for TypoGraph {
     ) {
         logger.log_typo_state(graph, paths, empty_paths_cache, universe, distances, cost);
     }
+
+    fn label_for_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<String> {
+        let TypoEdge { term, nbr_typos: _ } = edge;
+        let term = ctx.term_interner.get(*term);
+        let QueryTerm {
+            original: _,
+            is_ngram: _,
+            is_prefix: _,
+            phrase,
+            zero_typo,
+            prefix_of,
+            synonyms,
+            split_words,
+            one_typo,
+            two_typos,
+            use_prefix_db,
+        } = term;
+        let mut s = String::new();
+        if let Some(phrase) = phrase {
+            let phrase = ctx.phrase_interner.get(*phrase).description(&ctx.word_interner);
+            writeln!(&mut s, "\"{phrase}\" : phrase").unwrap();
+        }
+        if let Some(w) = zero_typo {
+            let w = ctx.word_interner.get(*w);
+            writeln!(&mut s, "\"{w}\" : 0 typo").unwrap();
+        }
+        for w in prefix_of.iter() {
+            let w = ctx.word_interner.get(*w);
+            writeln!(&mut s, "\"{w}\" : prefix").unwrap();
+        }
+        for w in one_typo.iter() {
+            let w = ctx.word_interner.get(*w);
+            writeln!(&mut s, "\"{w}\" : 1 typo").unwrap();
+        }
+        for w in two_typos.iter() {
+            let w = ctx.word_interner.get(*w);
+            writeln!(&mut s, "\"{w}\" : 2 typos").unwrap();
+        }
+        if let Some(phrase) = split_words {
+            let phrase = ctx.phrase_interner.get(*phrase).description(&ctx.word_interner);
+            writeln!(&mut s, "\"{phrase}\" : split words").unwrap();
+        }
+        for phrase in synonyms.iter() {
+            let phrase = ctx.phrase_interner.get(*phrase).description(&ctx.word_interner);
+            writeln!(&mut s, "\"{phrase}\" : synonym").unwrap();
+        }
+        if let Some(w) = use_prefix_db {
+            let w = ctx.word_interner.get(*w);
+            writeln!(&mut s, "\"{w}\" : use prefix db").unwrap();
+        }
+
+        Ok(s)
+    }
+
+    fn words_used_by_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<HashSet<Interned<String>>> {
+        let TypoEdge { term, .. } = edge;
+        let term = ctx.term_interner.get(*term);
+        Ok(HashSet::from_iter(term.all_single_words_except_prefix_db()))
+    }
+
+    fn phrases_used_by_edge_condition<'ctx>(
+        ctx: &mut SearchContext<'ctx>,
+        edge: &Self::EdgeCondition,
+    ) -> Result<HashSet<Interned<Phrase>>> {
+        let TypoEdge { term, .. } = edge;
+        let term = ctx.term_interner.get(*term);
+        Ok(HashSet::from_iter(term.all_phrases()))
+    }
 }