Merge pull request #8274 from dolthub/fulghum/dolt-8254

Allow duplicate indexes, to match MySQL behavior

Author: fulghum

Diff for: go/go.mod

@@ -57,7 +57,7 @@ require (
 	github.com/cespare/xxhash/v2 v2.2.0
 	github.com/creasty/defaults v1.6.0
 	github.com/dolthub/flatbuffers/v23 v23.3.3-dh.2
-	github.com/dolthub/go-mysql-server v0.18.2-0.20240815142344-761713e36043
+	github.com/dolthub/go-mysql-server v0.18.2-0.20240816004605-0fd0947fb3d8
 	github.com/dolthub/gozstd v0.0.0-20240423170813-23a2903bca63
 	github.com/dolthub/swiss v0.1.0
 	github.com/goccy/go-json v0.10.2

Diff for: go/go.sum

@@ -183,8 +183,8 @@ github.com/dolthub/fslock v0.0.3 h1:iLMpUIvJKMKm92+N1fmHVdxJP5NdyDK5bK7z7Ba2s2U=
 github.com/dolthub/fslock v0.0.3/go.mod h1:QWql+P17oAAMLnL4HGB5tiovtDuAjdDTPbuqx7bYfa0=
 github.com/dolthub/go-icu-regex v0.0.0-20230524105445-af7e7991c97e h1:kPsT4a47cw1+y/N5SSCkma7FhAPw7KeGmD6c9PBZW9Y=
 github.com/dolthub/go-icu-regex v0.0.0-20230524105445-af7e7991c97e/go.mod h1:KPUcpx070QOfJK1gNe0zx4pA5sicIK1GMikIGLKC168=
-github.com/dolthub/go-mysql-server v0.18.2-0.20240815142344-761713e36043 h1:KgrDVE4o4Y04XLnAs5BGv6I6z+Rd82FWntCbQEmbTKs=
-github.com/dolthub/go-mysql-server v0.18.2-0.20240815142344-761713e36043/go.mod h1:nbdOzd0ceWONE80vbfwoRBjut7z3CIj69ZgDF/cKuaA=
+github.com/dolthub/go-mysql-server v0.18.2-0.20240816004605-0fd0947fb3d8 h1:IMlS4ycXRhjRmYTgXCLX1jVSzeKlPCUpO5RHREzbCKY=
+github.com/dolthub/go-mysql-server v0.18.2-0.20240816004605-0fd0947fb3d8/go.mod h1:nbdOzd0ceWONE80vbfwoRBjut7z3CIj69ZgDF/cKuaA=
 github.com/dolthub/gozstd v0.0.0-20240423170813-23a2903bca63 h1:OAsXLAPL4du6tfbBgK0xXHZkOlos63RdKYS3Sgw/dfI=
 github.com/dolthub/gozstd v0.0.0-20240423170813-23a2903bca63/go.mod h1:lV7lUeuDhH5thVGDCKXbatwKy2KW80L4rMT46n+Y2/Q=
 github.com/dolthub/ishell v0.0.0-20240701202509-2b217167d718 h1:lT7hE5k+0nkBdj/1UOSFwjWpNxf+LCApbRHgnCA17XE=

Diff for: go/libraries/doltcore/schema/index_coll.go

@@ -41,7 +41,7 @@ type IndexCollection interface {
 	Equals(other IndexCollection) bool
 	// GetByName returns the index with the given name, or nil if it does not exist.
 	GetByName(indexName string) Index
-	// GetByName returns the index with a matching case-insensitive name, the bool return value indicates if a match was found.
+	// GetByNameCaseInsensitive returns the index with a matching case-insensitive name, the bool return value indicates if a match was found.
 	GetByNameCaseInsensitive(indexName string) (Index, bool)
 	// GetIndexByColumnNames returns whether the collection contains an index that has this exact collection and ordering of columns.
 	GetIndexByColumnNames(cols ...string) (Index, bool)
@@ -173,10 +173,6 @@ func (ixc *indexCollectionImpl) AddIndex(indexes ...Index) {
 		if ok {
 			ixc.removeIndex(oldNamedIndex)
 		}
-		oldTaggedIndex := ixc.containsColumnTagCollection(index.tags...)
-		if oldTaggedIndex != nil {
-			ixc.removeIndex(oldTaggedIndex)
-		}
 		ixc.indexes[lowerName] = index
 		for _, tag := range index.tags {
 			ixc.colTagToIndex[tag] = append(ixc.colTagToIndex[tag], index)

Diff for: go/libraries/doltcore/schema/index_test.go

@@ -84,56 +84,30 @@ func TestIndexCollectionAddIndex(t *testing.T) {
 		indexColl.clear(t)
 	}
 
-	const prefix = "new_"
-
-	t.Run("Tag Overwrites", func(t *testing.T) {
+	t.Run("Duplicate column set", func(t *testing.T) {
 		for _, testIndex := range testIndexes {
 			indexColl.AddIndex(testIndex)
 			newIndex := testIndex.copy()
-			newIndex.name = prefix + testIndex.name
+			newIndex.name = "dupe_" + testIndex.name
 			indexColl.AddIndex(newIndex)
 			assert.Equal(t, newIndex, indexColl.GetByName(newIndex.Name()))
-			assert.Nil(t, indexColl.GetByName(testIndex.Name()))
+			assert.Equal(t, testIndex, indexColl.GetByName(testIndex.Name()))
 			assert.Contains(t, indexColl.AllIndexes(), newIndex)
-			assert.NotContains(t, indexColl.AllIndexes(), testIndex)
+			assert.Contains(t, indexColl.AllIndexes(), testIndex)
 			for _, tag := range newIndex.IndexedColumnTags() {
 				assert.Contains(t, indexColl.IndexesWithTag(tag), newIndex)
-				assert.NotContains(t, indexColl.IndexesWithTag(tag), testIndex)
+				assert.Contains(t, indexColl.IndexesWithTag(tag), testIndex)
 			}
 			for _, col := range newIndex.ColumnNames() {
 				assert.Contains(t, indexColl.IndexesWithColumn(col), newIndex)
-				assert.NotContains(t, indexColl.IndexesWithColumn(col), testIndex)
+				assert.Contains(t, indexColl.IndexesWithColumn(col), testIndex)
 			}
 			assert.True(t, indexColl.Contains(newIndex.Name()))
-			assert.False(t, indexColl.Contains(testIndex.Name()))
+			assert.True(t, indexColl.Contains(testIndex.Name()))
 			assert.True(t, indexColl.hasIndexOnColumns(newIndex.ColumnNames()...))
 			assert.True(t, indexColl.hasIndexOnTags(newIndex.IndexedColumnTags()...))
 		}
 	})
-
-	t.Run("Name Overwrites", func(t *testing.T) {
-		// should be able to reduce collection to one index
-		lastStanding := &indexImpl{
-			name:      "none",
-			tags:      []uint64{4},
-			allTags:   []uint64{4, 1, 2},
-			indexColl: indexColl,
-		}
-
-		for _, testIndex := range testIndexes {
-			lastStanding.name = prefix + testIndex.name
-			indexColl.AddIndex(lastStanding)
-		}
-
-		assert.Equal(t, map[string]*indexImpl{lastStanding.name: lastStanding}, indexColl.indexes)
-		for tag, indexes := range indexColl.colTagToIndex {
-			if tag == 4 {
-				assert.Equal(t, indexes, []*indexImpl{lastStanding})
-			} else {
-				assert.Empty(t, indexes)
-			}
-		}
-	})
 }
 
 func TestIndexCollectionAddIndexByColNames(t *testing.T) {