GT-138 Add missing deduplicate param to PersistentIndex (#411)

Author: jwierzbo

CHANGELOG.md

@@ -4,6 +4,7 @@
 - Fix `lastValue` field type
 - Setup Go-lang linter with minimal configuration 
 - Use Go 1.17.6
+- Add missing `deduplicate` param to PersistentIndex
 
 ## [1.3.2](https://github.com/arangodb/go-driver/tree/v1.3.2) (2022-05-16)
 - Fix selectivityEstimate Index field type

collection_indexes.go

@@ -103,6 +103,7 @@ type EnsureGeoIndexOptions struct {
 }
 
 // EnsureHashIndexOptions contains specific options for creating a hash index.
+// Note: "hash" and "skiplist" are only aliases for "persistent" with the RocksDB storage engine which is only storage engine since 3.7
 type EnsureHashIndexOptions struct {
 	// If true, then create a unique index.
 	Unique bool
@@ -121,11 +122,16 @@ type EnsureHashIndexOptions struct {
 }
 
 // EnsurePersistentIndexOptions contains specific options for creating a persistent index.
+// Note: "hash" and "skiplist" are only aliases for "persistent" with the RocksDB storage engine which is only storage engine since 3.7
 type EnsurePersistentIndexOptions struct {
 	// If true, then create a unique index.
 	Unique bool
 	// If true, then create a sparse index.
 	Sparse bool
+	// If true, de-duplication of array-values, before being added to the index, will be turned off.
+	// This flag requires ArangoDB 3.2.
+	// Note: this setting is only relevant for indexes with array fields (e.g. "fieldName[*]")
+	NoDeduplicate bool
 	// InBackground if true will not hold an exclusive collection lock for the entire index creation period (rocksdb only).
 	InBackground bool
 	// Name optional user defined name used for hints in AQL queries
@@ -135,6 +141,7 @@ type EnsurePersistentIndexOptions struct {
 }
 
 // EnsureSkipListIndexOptions contains specific options for creating a skip-list index.
+// Note: "hash" and "skiplist" are only aliases for "persistent" with the RocksDB storage engine which is only storage engine since 3.7
 type EnsureSkipListIndexOptions struct {
 	// If true, then create a unique index.
 	Unique bool

collection_indexes_impl.go

@@ -213,12 +213,16 @@ func (c *collection) EnsurePersistentIndex(ctx context.Context, fields []string,
 		Type:   string(PersistentIndex),
 		Fields: fields,
 	}
+	off := false
 	if options != nil {
 		input.InBackground = &options.InBackground
 		input.Name = options.Name
 		input.Unique = &options.Unique
 		input.Sparse = &options.Sparse
 		input.Estimates = options.Estimates
+		if options.NoDeduplicate {
+			input.Deduplicate = &off
+		}
 	}
 	idx, created, err := c.ensureIndex(ctx, input)
 	if err != nil {