--- name: IncrementalPatchBuilder last_updated: 2026-10-19T18:06:25Z inherits: - Instance - Object type: class memory_category: Instances tags: - NotCreatable - Service - NotReplicated summary: "Builds signed incremental patches for hot-reloading a running client from script changes detected by a separate file watcher." --- # Class: IncrementalPatchBuilder > Builds signed incremental patches for hot-reloading a running client from > script changes detected by a separate file watcher. ## Description Internal tooling service, not for creator game scripts. A separate file-watcher system detects changes in a mapped subtree of scripts; this service rebuilds an in-memory patch tree and serializes that tree into a signed binary patch that can be delivered to a running client for hot-reload. Builds are debounced so rapid successive edits coalesce into a single patch build. When [SerializePatch](/docs/reference/engine/classes/IncrementalPatchBuilder.md) is `true`, the resulting patch is delivered through [AssetDeliveryProxy](/docs/reference/engine/classes/AssetDeliveryProxy.md) and written to the configured output path. ## Properties ### Property: IncrementalPatchBuilder.AddPathsToBundle ```json { "type": "boolean", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Data" } ``` Defaults to `false`. When `true`, and the builder is running alongside a `CoreScriptSyncService`, each script instance added to the patch is given a `FilePath` attribute set to the on-disk path of the file it was synced from. When `false`, no path attributes are written. ### Property: IncrementalPatchBuilder.BuildDebouncePeriod ```json { "type": "double", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Data" } ``` Defaults to `0.1` (100 milliseconds). When the separate file watcher reports a script change, the builder waits this interval before rebuilding, and any additional changes that arrive during the window are batched into the same build. Larger values reduce redundant rebuilds during bursts of edits, at the cost of added latency before the patch updates. ### Property: IncrementalPatchBuilder.HighCompression ```json { "type": "boolean", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Data" } ``` Defaults to `false`. When `true`, the builder writes the binary patch with high-compression settings, trading additional build time for a smaller patch. ### Property: IncrementalPatchBuilder.SerializePatch ```json { "type": "boolean", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Data" } ``` Defaults to `true`. When `true`, each successful build is serialized into a signed binary patch, delivered through [AssetDeliveryProxy](/docs/reference/engine/classes/AssetDeliveryProxy.md), and written to the configured output path. When `false`, the builder still produces the in-memory patch tree but skips serialization, so no patch file is emitted. ### Property: IncrementalPatchBuilder.UseFileLevelCompressionInsteadOfChunk ```json { "type": "boolean", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Data" } ``` Defaults to `false`. When `true`, the builder disables the serializer's per-chunk compression, storing the patch's chunks uncompressed so that compression can be applied at the file level instead. This property takes precedence over [ZstdCompression](/docs/reference/engine/classes/IncrementalPatchBuilder.md): when it is `true`, the Zstandard setting has no effect. ### Property: IncrementalPatchBuilder.ZstdCompression ```json { "type": "boolean", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Data" } ``` Defaults to `false`. When `true`, the builder compresses the patch's chunks with the Zstandard algorithm. This applies only while [UseFileLevelCompressionInsteadOfChunk](/docs/reference/engine/classes/IncrementalPatchBuilder.md) is at its default of `false`, because that property takes precedence and disables per-chunk compression entirely. ## Inherited Members ### From [Instance](/docs/reference/engine/classes/Instance.md) - **Property `Archivable`** (`boolean`): Determines if an Instance and its descendants can be cloned using - **Property `archivable`** (`boolean`): *(deprecated, hidden)* - **Property `Capabilities`** (`SecurityCapabilities`): The set of capabilities allowed to be used for scripts inside this - **Property `IsInSandbox`** (`boolean`): Indicates whether the instance is inside a sandboxed container. - **Property `Name`** (`string`): A non-unique identifier of the Instance. - **Property `Parent`** (`Instance`): Determines the hierarchical parent of the Instance. - **Property `PredictionMode`** (`PredictionMode`): Reflects the client-side prediction mode applied to the instance under - **Property `RobloxLocked`** (`boolean`): A deprecated property that used to protect CoreGui objects. *(hidden)* - **Property `Sandboxed`** (`boolean`): When enabled, the instance can only access abilities in its `Capabilities` - **Property `UniqueId`** (`UniqueId`): A unique identifier for the instance. - **Method `AddTag(tag: string): ()`**: Applies a tag to the instance. - **Method `children(): Instances`**: Returns an array of the object's children. *(deprecated)* - **Method `ClearAllChildren(): ()`**: This method destroys all of an instance's children. - **Method `Clone(): Instance`**: Create a copy of an instance and all its descendants, ignoring instances - **Method `clone(): Instance`**: *(deprecated)* - **Method `Destroy(): ()`**: Sets the Instance.Parent property to `nil`, locks the - **Method `destroy(): ()`**: *(deprecated)* - **Method `FindFirstAncestor(name: string): Instance?`**: Returns the first ancestor of the Instance whose - **Method `FindFirstAncestorOfClass(className: string): Instance?`**: Returns the first ancestor of the Instance whose - **Method `FindFirstAncestorWhichIsA(className: string): Instance?`**: Returns the first ancestor of the Instance for whom - **Method `FindFirstChild(name: string, recursive?: boolean): Instance?`**: Returns the first child of the Instance found with the given name. - **Method `findFirstChild(name: string, recursive?: boolean): Instance`**: *(deprecated)* - **Method `FindFirstChildOfClass(className: string): Instance?`**: Returns the first child of the Instance whose - **Method `FindFirstChildWhichIsA(className: string, recursive?: boolean): Instance?`**: Returns the first child of the Instance for whom - **Method `FindFirstDescendant(name: string): Instance?`**: Returns the first descendant found with the given Instance.Name. - **Method `GetActor(): Actor?`**: Returns the Actor associated with the Instance, if any. - **Method `GetAttribute(attribute: string): Variant`**: Returns the value which has been assigned to the given attribute name. - **Method `GetAttributeChangedSignal(attribute: string): RBXScriptSignal`**: Returns an event that fires when the given attribute changes. - **Method `GetAttributes(): Dictionary`**: Returns a dictionary of the instance's attributes. - **Method `GetChildren(): Instances`**: Returns an array containing all of the instance's children. - **Method `getChildren(): Instances`**: *(deprecated)* - **Method `GetDebugId(scopeLength?: int): string`**: Returns a coded string of the debug ID used internally by Roblox. - **Method `GetDescendants(): Instances`**: Returns an array containing all of the descendants of the instance. - **Method `GetFullName(): string`**: Returns a string describing the instance's ancestry. - **Method `GetStyled(name: string, selector: string?): Variant`**: Returns the styled or explicitly modified value of the specified property, - **Method `GetStyledPropertyChangedSignal(property: string): RBXScriptSignal`**: Returns an event that fires when the given style property changes on the - **Method `GetTags(): Array`**: Gets an array of all tags applied to the instance. - **Method `HasTag(tag: string): boolean`**: Check whether the instance has a given tag. - **Method `IsAncestorOf(descendant: Instance): boolean`**: Returns true if an Instance is an ancestor of the given - **Method `IsDescendantOf(ancestor: Instance): boolean`**: Returns `true` if an Instance is a descendant of the given - **Method `isDescendantOf(ancestor: Instance): boolean`**: *(deprecated)* - **Method `IsPropertyModified(property: string): boolean`**: Returns `true` if the value stored in the specified property is not equal - **Method `QueryDescendants(selector: string): Instances`**: Returns an array containing all descendants of the instance that match the - **Method `Remove(): ()`**: Sets the object's `Parent` to `nil`, and does the same for all its *(deprecated)* - **Method `remove(): ()`**: *(deprecated)* - **Method `RemoveTag(tag: string): ()`**: Removes a tag from the instance. - **Method `ResetPropertyToDefault(property: string): ()`**: Resets a property to its default value. - **Method `SetAttribute(attribute: string, value: Variant): ()`**: Sets the attribute with the given name to the given value. - **Method `WaitForChild(childName: string, timeOut: double): Instance`**: Returns the child of the Instance with the given name. If the - **Event `AncestryChanged`**: Fires when the Instance.Parent property of this object or one of - **Event `AttributeChanged`**: Fires whenever an attribute is changed on the Instance. - **Event `ChildAdded`**: Fires after an object is parented to this Instance. - **Event `childAdded`**: *(deprecated)* - **Event `ChildRemoved`**: Fires after a child is removed from this Instance. - **Event `DescendantAdded`**: Fires after a descendant is added to the Instance. - **Event `DescendantRemoving`**: Fires immediately before a descendant of the Instance is removed. - **Event `Destroying`**: Fires immediately before (or is deferred until after) the instance is - **Event `StyledPropertiesChanged`**: Fires whenever any style property is changed on the instance, including ### From [Object](/docs/reference/engine/classes/Object.md) - **Property `ClassName`** (`string`): A read-only string representing the class this Object belongs to. - **Property `className`** (`string`): *(deprecated)* - **Method `GetPropertyChangedSignal(property: string): RBXScriptSignal`**: Get an event that fires when a given property of the object changes. - **Method `IsA(className: string): boolean`**: Returns true if an object's class matches or inherits from a given class. - **Method `isA(className: string): boolean`**: *(deprecated)* - **Event `Changed`**: Fires immediately after a property of the object changes, with some