fix #4479: add fuzzy keyword search to title

Author: silkentrance

modules/indexer/internal/bleve/query.go

@@ -28,6 +28,14 @@ func MatchPhraseQuery(matchPhrase, field, analyzer string, fuzziness int) *query
 	return q
 }
 
+// FuzzyQuery generates a fuzzy query for the given phrase, field, and fuzziness
+func FuzzyQuery(matchPhrase, field string, fuzziness int) *query.FuzzyQuery {
+	q := bleve.NewFuzzyQuery(matchPhrase)
+	q.FieldVal = field
+	q.Fuzziness = fuzziness
+	return q
+}
+
 // BoolFieldQuery generates a bool field query for the given value and field
 func BoolFieldQuery(value bool, field string) *query.BoolFieldQuery {
 	q := bleve.NewBoolFieldQuery(value)

modules/indexer/internal/bleve/util.go

@@ -50,12 +50,14 @@ func openIndexer(path string, latestVersion int) (bleve.Index, int, error) {
 
 func GuessFuzzinessByKeyword(s string) int {
 	// according to https://github.com/blevesearch/bleve/issues/1563, the supported max fuzziness is 2
-	// magic number 4 was chosen to determine the levenshtein distance per each character of a keyword
-	// BUT, when using CJK (eg: `갃갃갃` `啊啊啊`), it mismatches a lot.
+	// BUT, when using CJK (eg: `갃갃갃` `啊啊啊`), it mismatches a lot
+	// which we need to live with, as we need to support not just ASCII
+	// in case of code points >= 128 we will increase the fuzziness to 2
+	// the standard is 1
 	for _, r := range s {
 		if r >= 128 {
-			return 0
+			return 2
 		}
 	}
-	return min(2, len(s)/4)
+	return 1
 }

modules/indexer/issues/bleve/bleve.go

@@ -162,7 +162,7 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		}
 
 		queries = append(queries, bleve.NewDisjunctionQuery([]query.Query{
-			inner_bleve.MatchPhraseQuery(options.Keyword, "title", issueIndexerAnalyzer, fuzziness),
+			inner_bleve.FuzzyQuery(options.Keyword, "title", fuzziness),
 			inner_bleve.MatchPhraseQuery(options.Keyword, "content", issueIndexerAnalyzer, fuzziness),
 			inner_bleve.MatchPhraseQuery(options.Keyword, "comments", issueIndexerAnalyzer, fuzziness),
 		}...))

modules/indexer/issues/indexer_test.go

@@ -209,13 +209,13 @@ func searchIssueIsPull(t *testing.T) {
 			SearchOptions{
 				IsPull: optional.Some(false),
 			},
-			[]int64{17, 16, 15, 14, 13, 6, 5, 18, 10, 7, 4, 1},
+			[]int64{25, 24, 23, 17, 16, 15, 14, 13, 6, 5, 18, 10, 7, 4, 1},
 		},
 		{
 			SearchOptions{
 				IsPull: optional.Some(true),
 			},
-			[]int64{22, 21, 12, 11, 20, 19, 9, 8, 3, 2},
+			[]int64{22, 21, 28, 27, 26, 12, 11, 20, 19, 9, 8, 3, 2},
 		},
 	}
 	for _, test := range tests {
@@ -236,7 +236,7 @@ func searchIssueIsClosed(t *testing.T) {
 			SearchOptions{
 				IsClosed: optional.Some(false),
 			},
-			[]int64{22, 21, 17, 16, 15, 14, 13, 12, 11, 20, 6, 19, 18, 10, 7, 9, 8, 3, 2, 1},
+			[]int64{25, 24, 23, 22, 21, 28, 27, 26, 17, 16, 15, 14, 13, 12, 11, 20, 6, 19, 18, 10, 7, 9, 8, 3, 2, 1},
 		},
 		{
 			SearchOptions{
@@ -302,7 +302,7 @@ func searchIssueByLabelID(t *testing.T) {
 			SearchOptions{
 				ExcludedLabelIDs: []int64{1},
 			},
-			[]int64{22, 21, 17, 16, 15, 14, 13, 12, 11, 20, 6, 5, 19, 18, 10, 7, 4, 9, 8, 3},
+			[]int64{25, 24, 23, 22, 21, 28, 27, 26, 17, 16, 15, 14, 13, 12, 11, 20, 6, 5, 19, 18, 10, 7, 4, 9, 8, 3},
 		},
 	}
 	for _, test := range tests {
@@ -323,7 +323,7 @@ func searchIssueByTime(t *testing.T) {
 			SearchOptions{
 				UpdatedAfterUnix: optional.Some(int64(0)),
 			},
-			[]int64{22, 21, 17, 16, 15, 14, 13, 12, 11, 20, 6, 5, 19, 18, 10, 7, 4, 9, 8, 3, 2, 1},
+			[]int64{25, 24, 23, 22, 21, 28, 27, 26, 17, 16, 15, 14, 13, 12, 11, 20, 6, 5, 19, 18, 10, 7, 4, 9, 8, 3, 2, 1},
 		},
 	}
 	for _, test := range tests {
@@ -344,7 +344,7 @@ func searchIssueWithOrder(t *testing.T) {
 			SearchOptions{
 				SortBy: internal.SortByCreatedAsc,
 			},
-			[]int64{1, 2, 3, 8, 9, 4, 7, 10, 18, 19, 5, 6, 20, 11, 12, 13, 14, 15, 16, 17, 21, 22},
+			[]int64{1, 2, 3, 8, 9, 4, 7, 10, 18, 19, 5, 6, 20, 11, 12, 13, 14, 15, 16, 17, 26, 27, 28, 21, 22, 23, 24, 25},
 		},
 	}
 	for _, test := range tests {
@@ -401,8 +401,8 @@ func searchIssueWithPaginator(t *testing.T) {
 					PageSize: 5,
 				},
 			},
-			[]int64{22, 21, 17, 16, 15},
-			22,
+			[]int64{25, 24, 23, 22, 21},
+			28,
 		},
 	}
 	for _, test := range tests {

routers/web/repo/issue.go

@@ -2677,6 +2677,7 @@ func SearchIssues(ctx *context.Context) {
 		MilestoneIDs:        includedMilestones,
 		ProjectID:           projectID,
 		SortBy:              issue_indexer.SortByCreatedDesc,
+		IsFuzzyKeyword:      true,
 	}
 
 	if since != 0 {