diff --git a/_specifications/lsp/3.18/language/completion.md b/_specifications/lsp/3.18/language/completion.md
index 68fe55b3e..4ef2ccb48 100644
--- a/_specifications/lsp/3.18/language/completion.md
+++ b/_specifications/lsp/3.18/language/completion.md
@@ -166,6 +166,21 @@ export interface CompletionClientCapabilities {
* @since 3.17.0
*/
itemDefaults?: string[];
+
+ /**
+ * Specifies whether the client supports `CompletionList.applyKind` to
+ * indicate how supported values from `completionList.itemDefaults`
+ * and `completion` will be combined.
+ *
+ * If a client supports `applyKind` it must support it for all fields
+ * that it supports that are listed in `CompletionList.applyKind`. This
+ * means when clients add support for new/future fields in completion
+ * items the MUST also support merge for them if those fields are
+ * defined in `CompletionList.applyKind`.
+ *
+ * @since 3.18.0
+ */
+ applyKindSupport?: boolean;
}
}
```
@@ -338,7 +353,9 @@ export interface CompletionList {
* be used if a completion item itself doesn't specify the value.
*
* If a completion list specifies a default value and a completion item
- * also specifies a corresponding value, the one from the item is used.
+ * also specifies a corresponding value, the rules for combining these are
+ * defined by `applyKinds` (if the client supports it), defaulting to
+ * ApplyKind.Replace.
*
* Servers are only allowed to return default values if the client
* signals support for this via the `completionList.itemDefaults`
@@ -386,6 +403,73 @@ export interface CompletionList {
data?: LSPAny;
}
+ /**
+ * Specifies how fields from a completion item should be combined with those
+ * from `completionList.itemDefaults`.
+ *
+ * If unspecified, all fields will be treated as ApplyKind.Replace.
+ *
+ * If a field's value is ApplyKind.Replace, the value from a completion item
+ * (if provided and not `null`) will always be used instead of the value
+ * from `completionItem.itemDefaults`.
+ *
+ * If a field's value is ApplyKind.Merge, the values will be merged using
+ * the rules defined against each field below.
+ *
+ * Servers are only allowed to return `applyKind` if the client
+ * signals support for this via the `completionList.applyKindSupport`
+ * capability.
+ *
+ * @since 3.18.0
+ */
+ applyKind?: {
+ /**
+ * Specifies whether commitCharacters on a completion will replace or be
+ * merged with those in `completionList.itemDefaults.commitCharacters`.
+ *
+ * If ApplyKind.Replace, the commit characters from the completion item
+ * will always be used unless not provided, in which case those from
+ * `completionList.itemDefaults.commitCharacters` will be used. An
+ * empty list can be used if a completion item does not have any commit
+ * characters and also should not use those from
+ * `completionList.itemDefaults.commitCharacters`.
+ *
+ * If ApplyKind.Merge the commitCharacters for the completion will be
+ * the union of all values in both
+ * `completionList.itemDefaults.commitCharacters` and the completion's
+ * own `commitCharacters`.
+ *
+ * @since 3.18.0
+ */
+ commitCharacters?: ApplyKind;
+
+ /**
+ * Specifies whether the `data` field on a completion will replace or
+ * be merged with data from `completionList.itemDefaults.data`.
+ *
+ * If ApplyKind.Replace, the data from the completion item will be used
+ * if provided (and not `null`), otherwise
+ * `completionList.itemDefaults.data` will be used. An empty object can
+ * be used if a completion item does not have any data but also should
+ * not use the value from `completionList.itemDefaults.data`.
+ *
+ * If ApplyKind.Merge, a shallow merge will be performed between
+ * `completionList.itemDefaults.data` and the completion's own data
+ * using the following rules:
+ *
+ * - If a completion's `data` field is not provided (or `null`), the
+ * entire `data` field from `completionList.itemDefaults.data` will be
+ * used as-is.
+ * - If a completion's `data` field is provided, each field will
+ * overwrite the field of the same name in
+ * `completionList.itemDefaults.data` but no merging of nested fields
+ * within that value will occur.
+ *
+ * @since 3.18.0
+ */
+ data?: ApplyKind;
+ }
+
/**
* The completion items.
*/
@@ -525,6 +609,40 @@ export interface CompletionItemLabelDetails {
}
```
+
+
+```typescript
+/**
+ * Defines how values from a set of defaults and an individual item will be
+ * merged.
+ *
+ * @since 3.18.0
+ */
+export namespace ApplyKind {
+ /**
+ * The value from the individual item (if provided and not `null`) will be
+ * used instead of the default.
+ */
+ export const Replace: 1 = 1;
+
+ /**
+ * The value from the item will be merged with the default.
+ *
+ * The specific rules for mergeing values are defined against each field
+ * that supports merging.
+ */
+ export const Merge: 2 = 2;
+}
+
+/**
+ * Defines how values from a set of defaults and an individual item will be
+ * merged.
+ *
+ * @since 3.18.0
+ */
+export type ApplyKind = 1 | 2;
+```
+
```typescript
diff --git a/_specifications/lsp/3.18/specification.md b/_specifications/lsp/3.18/specification.md
index 0c6ffd51a..cec1e604b 100644
--- a/_specifications/lsp/3.18/specification.md
+++ b/_specifications/lsp/3.18/specification.md
@@ -737,6 +737,7 @@ Since 3.17 there is a meta model describing the LSP protocol:
* Support for snippets in text document edits.
* Support for debug message kind.
* Client capability to enumerate properties that can be resolved for code lenses.
+* Added support for `completionList.applyKind` to determine how values from `completionList.itemDefaults` and `completion` are combined.
#### 3.17.0 (05/10/2022)