From b9c57fb78e8e0d80d786d8e1da433b6c7ebf2f1c Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Sat, 23 Mar 2024 16:45:13 +0100
Subject: Determine fuzziness of bleve indexer by keyword length (#29706)

also bleve did match on fuzzy search and the other way around. this also fix that bug.
---
 modules/indexer/code/bleve/bleve.go     | 15 +++++++--------
 modules/indexer/internal/bleve/query.go | 10 ++--------
 modules/indexer/issues/bleve/bleve.go   | 25 +++++++++++++------------
 3 files changed, 22 insertions(+), 28 deletions(-)

(limited to 'modules')

diff --git a/modules/indexer/code/bleve/bleve.go b/modules/indexer/code/bleve/bleve.go
index d7f735e957..c607d780ef 100644
--- a/modules/indexer/code/bleve/bleve.go
+++ b/modules/indexer/code/bleve/bleve.go
@@ -39,6 +39,8 @@ import (
 const (
 	unicodeNormalizeName = "unicodeNormalize"
 	maxBatchSize         = 16
+	// fuzzyDenominator determines the levenshtein distance per each character of a keyword
+	fuzzyDenominator = 4
 )
 
 func addUnicodeNormalizeTokenFilter(m *mapping.IndexMappingImpl) error {
@@ -239,15 +241,12 @@ func (b *Indexer) Search(ctx context.Context, opts *internal.SearchOptions) (int
 		keywordQuery query.Query
 	)
 
+	phraseQuery := bleve.NewMatchPhraseQuery(opts.Keyword)
+	phraseQuery.FieldVal = "Content"
+	phraseQuery.Analyzer = repoIndexerAnalyzer
+	keywordQuery = phraseQuery
 	if opts.IsKeywordFuzzy {
-		phraseQuery := bleve.NewMatchPhraseQuery(opts.Keyword)
-		phraseQuery.FieldVal = "Content"
-		phraseQuery.Analyzer = repoIndexerAnalyzer
-		keywordQuery = phraseQuery
-	} else {
-		prefixQuery := bleve.NewPrefixQuery(opts.Keyword)
-		prefixQuery.FieldVal = "Content"
-		keywordQuery = prefixQuery
+		phraseQuery.Fuzziness = len(opts.Keyword) / fuzzyDenominator
 	}
 
 	if len(opts.RepoIDs) > 0 {
diff --git a/modules/indexer/internal/bleve/query.go b/modules/indexer/internal/bleve/query.go
index b96875343e..21422b281c 100644
--- a/modules/indexer/internal/bleve/query.go
+++ b/modules/indexer/internal/bleve/query.go
@@ -20,17 +20,11 @@ func NumericEqualityQuery(value int64, field string) *query.NumericRangeQuery {
 }
 
 // MatchPhraseQuery generates a match phrase query for the given phrase, field and analyzer
-func MatchPhraseQuery(matchPhrase, field, analyzer string) *query.MatchPhraseQuery {
+func MatchPhraseQuery(matchPhrase, field, analyzer string, fuzziness int) *query.MatchPhraseQuery {
 	q := bleve.NewMatchPhraseQuery(matchPhrase)
 	q.FieldVal = field
 	q.Analyzer = analyzer
-	return q
-}
-
-// PrefixQuery generates a match prefix query for the given prefix and field
-func PrefixQuery(matchPrefix, field string) *query.PrefixQuery {
-	q := bleve.NewPrefixQuery(matchPrefix)
-	q.FieldVal = field
+	q.Fuzziness = fuzziness
 	return q
 }
 
diff --git a/modules/indexer/issues/bleve/bleve.go b/modules/indexer/issues/bleve/bleve.go
index 927ad58cd4..1f54be721b 100644
--- a/modules/indexer/issues/bleve/bleve.go
+++ b/modules/indexer/issues/bleve/bleve.go
@@ -35,7 +35,11 @@ func addUnicodeNormalizeTokenFilter(m *mapping.IndexMappingImpl) error {
 	})
 }
 
-const maxBatchSize = 16
+const (
+	maxBatchSize = 16
+	// fuzzyDenominator determines the levenshtein distance per each character of a keyword
+	fuzzyDenominator = 4
+)
 
 // IndexerData an update to the issue indexer
 type IndexerData internal.IndexerData
@@ -156,19 +160,16 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 	var queries []query.Query
 
 	if options.Keyword != "" {
+		fuzziness := 0
 		if options.IsFuzzyKeyword {
-			queries = append(queries, bleve.NewDisjunctionQuery([]query.Query{
-				inner_bleve.MatchPhraseQuery(options.Keyword, "title", issueIndexerAnalyzer),
-				inner_bleve.MatchPhraseQuery(options.Keyword, "content", issueIndexerAnalyzer),
-				inner_bleve.MatchPhraseQuery(options.Keyword, "comments", issueIndexerAnalyzer),
-			}...))
-		} else {
-			queries = append(queries, bleve.NewDisjunctionQuery([]query.Query{
-				inner_bleve.PrefixQuery(options.Keyword, "title"),
-				inner_bleve.PrefixQuery(options.Keyword, "content"),
-				inner_bleve.PrefixQuery(options.Keyword, "comments"),
-			}...))
+			fuzziness = len(options.Keyword) / fuzzyDenominator
 		}
+
+		queries = append(queries, bleve.NewDisjunctionQuery([]query.Query{
+			inner_bleve.MatchPhraseQuery(options.Keyword, "title", issueIndexerAnalyzer, fuzziness),
+			inner_bleve.MatchPhraseQuery(options.Keyword, "content", issueIndexerAnalyzer, fuzziness),
+			inner_bleve.MatchPhraseQuery(options.Keyword, "comments", issueIndexerAnalyzer, fuzziness),
+		}...))
 	}
 
 	if len(options.RepoIDs) > 0 || options.AllPublic {
-- 
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