Make facet indexation and storage optional

Added a FacetOptions for HierarchicalFacet which add indexed and stored flags to it.
Propagate change and update tests accordingly
Added a test to ensure that a not indexed flag was taken care of.
Added on Value implem the `path()` function to return the stored facet.

examples/faceted_search.rs

@@ -23,7 +23,7 @@ fn main() -> tantivy::Result<()> {
 
     let name = schema_builder.add_text_field("felin_name", TEXT | STORED);
     // this is our faceted field: its scientific classification
-    let classification = schema_builder.add_facet_field("classification");
+    let classification = schema_builder.add_facet_field("classification", INDEXED);
 
     let schema = schema_builder.build();
     let index = Index::create_in_ram(schema);

examples/faceted_search_with_tweaked_score.rs

@@ -9,7 +9,7 @@ fn main() -> tantivy::Result<()> {
     let mut schema_builder = Schema::builder();
 
     let title = schema_builder.add_text_field("title", STORED);
-    let ingredient = schema_builder.add_facet_field("ingredient");
+    let ingredient = schema_builder.add_facet_field("ingredient", INDEXED);
 
     let schema = schema_builder.build();
     let index = Index::create_in_ram(schema.clone());

src/collector/facet_collector.rs

@@ -80,7 +80,7 @@ fn facet_depth(facet_bytes: &[u8]) -> usize {
 /// ```rust
 /// use tantivy::collector::FacetCollector;
 /// use tantivy::query::AllQuery;
-/// use tantivy::schema::{Facet, Schema, TEXT};
+/// use tantivy::schema::{Facet, Schema, INDEXED, TEXT};
 /// use tantivy::{doc, Index};
 ///
 /// fn example() -> tantivy::Result<()> {
@@ -89,7 +89,7 @@ fn facet_depth(facet_bytes: &[u8]) -> usize {
 ///     // Facet have their own specific type.
 ///     // It is not a bad practise to put all of your
 ///     // facet information in the same field.
-///     let facet = schema_builder.add_facet_field("facet");
+///     let facet = schema_builder.add_facet_field("facet", INDEXED);
 ///     let title = schema_builder.add_text_field("title", TEXT);
 ///     let schema = schema_builder.build();
 ///     let index = Index::create_in_ram(schema);
@@ -461,7 +461,7 @@ mod tests {
     use crate::collector::Count;
     use crate::core::Index;
     use crate::query::{AllQuery, QueryParser, TermQuery};
-    use crate::schema::{Document, Facet, Field, IndexRecordOption, Schema};
+    use crate::schema::{Document, Facet, Field, IndexRecordOption, Schema, INDEXED};
     use crate::Term;
     use rand::distributions::Uniform;
     use rand::prelude::SliceRandom;
@@ -471,7 +471,7 @@ mod tests {
     #[test]
     fn test_facet_collector_drilldown() {
         let mut schema_builder = Schema::builder();
-        let facet_field = schema_builder.add_facet_field("facet");
+        let facet_field = schema_builder.add_facet_field("facet", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
 
@@ -531,7 +531,7 @@ mod tests {
     #[test]
     fn test_doc_unsorted_multifacet() {
         let mut schema_builder = Schema::builder();
-        let facet_field = schema_builder.add_facet_field("facets");
+        let facet_field = schema_builder.add_facet_field("facets", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut index_writer = index.writer_for_tests().unwrap();
@@ -555,7 +555,7 @@ mod tests {
     #[test]
     fn test_doc_search_by_facet() -> crate::Result<()> {
         let mut schema_builder = Schema::builder();
-        let facet_field = schema_builder.add_facet_field("facet");
+        let facet_field = schema_builder.add_facet_field("facet", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut index_writer = index.writer_for_tests()?;
@@ -612,7 +612,7 @@ mod tests {
     #[test]
     fn test_facet_collector_topk() {
         let mut schema_builder = Schema::builder();
-        let facet_field = schema_builder.add_facet_field("facet");
+        let facet_field = schema_builder.add_facet_field("facet", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
 
@@ -664,7 +664,7 @@ mod bench {
 
     use crate::collector::FacetCollector;
     use crate::query::AllQuery;
-    use crate::schema::{Facet, Schema};
+    use crate::schema::{Facet, Schema, INDEXED};
     use crate::Index;
     use rand::seq::SliceRandom;
     use rand::thread_rng;
@@ -673,7 +673,7 @@ mod bench {
     #[bench]
     fn bench_facet_collector(b: &mut Bencher) {
         let mut schema_builder = Schema::builder();
-        let facet_field = schema_builder.add_facet_field("facet");
+        let facet_field = schema_builder.add_facet_field("facet", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
 

src/core/segment_reader.rs

@@ -108,19 +108,22 @@ impl SegmentReader {
     /// Accessor to the `FacetReader` associated to a given `Field`.
     pub fn facet_reader(&self, field: Field) -> crate::Result<FacetReader> {
         let field_entry = self.schema.get_field_entry(field);
-        if field_entry.field_type() != &FieldType::HierarchicalFacet {
-            return Err(crate::TantivyError::InvalidArgument(format!(
+
+        match field_entry.field_type() {
+            FieldType::HierarchicalFacet(_) => {
+                let term_ords_reader = self.fast_fields().u64s(field)?;
+                let termdict = self
+                    .termdict_composite
+                    .open_read(field)
+                    .map(TermDictionary::open)
+                    .unwrap_or_else(|| Ok(TermDictionary::empty()))?;
+                Ok(FacetReader::new(term_ords_reader, termdict))
+            }
+            _ => Err(crate::TantivyError::InvalidArgument(format!(
                 "Field {:?} is not a facet field.",
                 field_entry.name()
-            )));
+            ))),
         }
-        let term_ords_reader = self.fast_fields().u64s(field)?;
-        let termdict = self
-            .termdict_composite
-            .open_read(field)
-            .map(TermDictionary::open)
-            .unwrap_or_else(|| Ok(TermDictionary::empty()))?;
-        Ok(FacetReader::new(term_ords_reader, termdict))
     }
 
     /// Accessor to the segment's `Field norms`'s reader.

src/fastfield/facet_reader.rs

@@ -84,14 +84,40 @@ impl FacetReader {
 mod tests {
     use crate::Index;
     use crate::{
-        schema::{Facet, SchemaBuilder},
-        Document,
+        schema::{Facet, SchemaBuilder, Value, INDEXED, STORED},
+        DocAddress, Document,
     };
 
+    #[test]
+    fn test_facet_not_indexed_for_all_docs() -> crate::Result<()> {
+        let mut schema_builder = SchemaBuilder::default();
+        let facet_field = schema_builder.add_facet_field("facet", STORED);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer = index.writer_for_tests()?;
+        index_writer.add_document(doc!(facet_field=>Facet::from_text("/a/b")));
+        index_writer.add_document(Document::default());
+        index_writer.commit()?;
+        let searcher = index.reader()?.searcher();
+        let facet_reader = searcher
+            .segment_reader(0u32)
+            .facet_reader(facet_field)
+            .unwrap();
+        let mut facet_ords = Vec::new();
+        facet_reader.facet_ords(0u32, &mut facet_ords);
+        assert!(facet_ords.is_empty());
+        let doc = searcher.doc(DocAddress(0u32, 0u32))?;
+        let value = doc.get_first(facet_field).and_then(Value::path).unwrap();
+        assert_eq!(value, "/a/b".to_string());
+        facet_reader.facet_ords(1u32, &mut facet_ords);
+        assert!(facet_ords.is_empty());
+        Ok(())
+    }
+
     #[test]
     fn test_facet_not_populated_for_all_docs() -> crate::Result<()> {
         let mut schema_builder = SchemaBuilder::default();
-        let facet_field = schema_builder.add_facet_field("facet");
+        let facet_field = schema_builder.add_facet_field("facet", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut index_writer = index.writer_for_tests()?;
@@ -113,7 +139,7 @@ mod tests {
     #[test]
     fn test_facet_not_populated_for_any_docs() -> crate::Result<()> {
         let mut schema_builder = SchemaBuilder::default();
-        let facet_field = schema_builder.add_facet_field("facet");
+        let facet_field = schema_builder.add_facet_field("facet", STORED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut index_writer = index.writer_for_tests()?;

src/fastfield/mod.rs

@@ -96,7 +96,7 @@ impl FastValue for u64 {
     fn fast_field_cardinality(field_type: &FieldType) -> Option<Cardinality> {
         match *field_type {
             FieldType::U64(ref integer_options) => integer_options.get_fastfield_cardinality(),
-            FieldType::HierarchicalFacet => Some(Cardinality::MultiValues),
+            FieldType::HierarchicalFacet(_) => Some(Cardinality::MultiValues),
             _ => None,
         }
     }

src/fastfield/multivalued/mod.rs

@@ -13,6 +13,7 @@ mod tests {
     use crate::schema::Facet;
     use crate::schema::IntOptions;
     use crate::schema::Schema;
+    use crate::schema::INDEXED;
     use crate::Index;
     use chrono::Duration;
 
@@ -212,7 +213,7 @@ mod tests {
     #[ignore]
     fn test_many_facets() {
         let mut schema_builder = Schema::builder();
-        let field = schema_builder.add_facet_field("facetfield");
+        let field = schema_builder.add_facet_field("facetfield", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut index_writer = index.writer_for_tests().unwrap();

src/fastfield/multivalued/reader.rs

@@ -60,12 +60,12 @@ impl<Item: FastValue> MultiValuedFastFieldReader<Item> {
 mod tests {
 
     use crate::core::Index;
-    use crate::schema::{Facet, Schema};
+    use crate::schema::{Facet, Schema, INDEXED};
 
     #[test]
     fn test_multifastfield_reader() {
         let mut schema_builder = Schema::builder();
-        let facet_field = schema_builder.add_facet_field("facets");
+        let facet_field = schema_builder.add_facet_field("facets", INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut index_writer = index

src/fastfield/readers.rs

@@ -38,7 +38,7 @@ fn type_and_cardinality(field_type: &FieldType) -> Option<(FastType, Cardinality
         FieldType::Date(options) => options
             .get_fastfield_cardinality()
             .map(|cardinality| (FastType::Date, cardinality)),
-        FieldType::HierarchicalFacet => Some((FastType::U64, Cardinality::MultiValues)),
+        FieldType::HierarchicalFacet(_) => Some((FastType::U64, Cardinality::MultiValues)),
         _ => None,
     }
 }

src/fastfield/writer.rs

@@ -52,7 +52,7 @@ impl FastFieldsWriter {
                         None => {}
                     }
                 }
-                FieldType::HierarchicalFacet => {
+                FieldType::HierarchicalFacet(_) => {
                     let fast_field_writer = MultiValuedFastFieldWriter::new(field, true);
                     multi_values_writers.push(fast_field_writer);
                 }

src/indexer/merger.rs

@@ -195,7 +195,7 @@ impl IndexMerger {
         for (field, field_entry) in self.schema.fields() {
             let field_type = field_entry.field_type();
             match field_type {
-                FieldType::HierarchicalFacet => {
+                FieldType::HierarchicalFacet(_) => {
                     let term_ordinal_mapping = term_ord_mappings
                         .remove(&field)
                         .expect("Logic Error in Tantivy (Please report). HierarchicalFact field should have required a\
@@ -515,10 +515,9 @@ impl IndexMerger {
             max_term_ords.push(terms.num_terms() as u64);
         }
 
-        let mut term_ord_mapping_opt = if *field_type == FieldType::HierarchicalFacet {
-            Some(TermOrdinalMapping::new(max_term_ords))
-        } else {
-            None
+        let mut term_ord_mapping_opt = match field_type {
+            FieldType::HierarchicalFacet(_) => Some(TermOrdinalMapping::new(max_term_ords)),
+            _ => None,
         };
 
         let mut merged_terms = TermMerger::new(field_term_streams);
@@ -1179,7 +1178,7 @@ mod tests {
     #[test]
     fn test_merge_facets() {
         let mut schema_builder = schema::Schema::builder();
-        let facet_field = schema_builder.add_facet_field("facet");
+        let facet_field = schema_builder.add_facet_field("facet", INDEXED);
         let index = Index::create_in_ram(schema_builder.build());
         let reader = index.reader().unwrap();
         {

src/indexer/segment_writer.rs

@@ -142,7 +142,7 @@ impl SegmentWriter {
             let (term_buffer, multifield_postings) =
                 (&mut self.term_buffer, &mut self.multifield_postings);
             match *field_entry.field_type() {
-                FieldType::HierarchicalFacet => {
+                FieldType::HierarchicalFacet(_) => {
                     term_buffer.set_field(field);
                     let facets =
                         field_values

src/postings/postings_writer.rs

@@ -39,7 +39,9 @@ fn posting_from_field_entry(field_entry: &FieldEntry) -> Box<dyn PostingsWriter>
         | FieldType::F64(_)
         | FieldType::Date(_)
         | FieldType::Bytes(_)
-        | FieldType::HierarchicalFacet => SpecializedPostingsWriter::<NothingRecorder>::new_boxed(),
+        | FieldType::HierarchicalFacet(_) => {
+            SpecializedPostingsWriter::<NothingRecorder>::new_boxed()
+        }
     }
 }
 
@@ -142,7 +144,7 @@ impl MultiFieldPostingsWriter {
             let field_entry = self.schema.get_field_entry(field);
 
             match *field_entry.field_type() {
-                FieldType::Str(_) | FieldType::HierarchicalFacet => {
+                FieldType::Str(_) | FieldType::HierarchicalFacet(_) => {
                     // populating the (unordered term ord) -> (ordered term ord) mapping
                     // for the field.
                     let unordered_term_ids = term_offsets[byte_offsets.clone()]

src/query/query_parser/query_parser.rs

@@ -357,7 +357,7 @@ impl QueryParser {
                     ))
                 }
             }
-            FieldType::HierarchicalFacet => {
+            FieldType::HierarchicalFacet(_) => {
                 let facet = Facet::from_text(phrase);
                 Ok(vec![(0, Term::from_field_text(field, facet.encoded_str()))])
             }
@@ -605,7 +605,8 @@ mod test {
         schema_builder.add_text_field("with_stop_words", text_options);
         schema_builder.add_date_field("date", INDEXED);
         schema_builder.add_f64_field("float", INDEXED);
-        schema_builder.add_facet_field("facet");
+        schema_builder.add_facet_field("facet", INDEXED);
+        schema_builder.add_facet_field("facet_not_indexed", STORED);
         schema_builder.add_bytes_field("bytes", INDEXED);
         schema_builder.add_bytes_field("bytes_not_indexed", STORED);
         schema_builder.build()
@@ -658,6 +659,13 @@ mod test {
         );
     }
 
+    #[test]
+    fn test_parse_query_facet_not_indexed() {
+        let error =
+            parse_query_to_logical_ast("facet_not_indexed:/root/branch/leaf", false).unwrap_err();
+        assert!(matches!(error, QueryParserError::FieldNotIndexed(_)));
+    }
+
     #[test]
     pub fn test_parse_query_with_boost() {
         let mut query_parser = make_query_parser();
@@ -799,7 +807,7 @@ mod test {
     fn test_parse_bytes() {
         test_parse_query_to_logical_ast_helper(
             "bytes:YnVidQ==",
-            "Term(field=12,bytes=[98, 117, 98, 117])",
+            "Term(field=13,bytes=[98, 117, 98, 117])",
             false,
         );
     }
@@ -814,7 +822,7 @@ mod test {
     fn test_parse_bytes_phrase() {
         test_parse_query_to_logical_ast_helper(
             "bytes:\"YnVidQ==\"",
-            "Term(field=12,bytes=[98, 117, 98, 117])",
+            "Term(field=13,bytes=[98, 117, 98, 117])",
             false,
         );
     }