gitbutlerapp/gitbutler · error

Hunk drop data must specify the source stackId and commitId

Error message

Hunk drop data must specify the source stackId and commitId

What it means

Thrown by ondropHunkData when a hunk drag-and-drop operation carries selection type 'commit' but the drop data lacks a source stackId or commitId. The handler needs both fields to locate the origin commit of the hunks being moved. This is a defensive check against malformed HunkDropDataV3 payloads constructed by the drag layer.

Solutions

1. Populate stackId and commitId in the HunkDropDataV3 payload at drag start (in the code that creates the drop data for 'commit' selections).
2. Check the drag source component to ensure it waits for the commit/stack to be resolved before enabling hunk dragging.
3. If the source stack/commit can genuinely be unknown, use the worktree selection type instead of 'commit' or restructure HunkDropDataV3 to make the fields required.

Example fix

// before
const dropData: HunkDropDataV3 = { selectionId: { type: 'commit' }, change, hunk };
// after
const dropData: HunkDropDataV3 = { selectionId: { type: 'commit' }, stackId, commitId, change, hunk };

if (data.selectionId.type === 'commit' && (!data.stackId || !data.commitId)) {
  throw new Error('Drop data missing stackId/commitId');
}

function hasCommitContext(d: HunkDropDataV3): d is HunkDropDataV3 & { stackId: string; commitId: string } {
  return d.selectionId.type !== 'commit' || Boolean(d.stackId && d.commitId);
}

When it happens

Trigger: Calling ondropHunkData with data.selectionId.type === 'commit' while data.stackId or data.commitId is undefined/null/empty string.

Common situations: A drag payload built before stack/commit resolution completed, stale drag data referencing a deleted commit or stack, or a UI path that forgot to fill in the commit context when assembling HunkDropDataV3.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• anchor is always present in the order at this point
• Can't receive a change without it's source or commit
• Change drop data must specify the source stackId
• Change to discard at
• commits cannot be moved to the merge base

AI-assisted analysis of gitbutlerapp/gitbutler@58e5313667 (2026-09-18). Data as JSON: /api/errors/0df3649a5f2429be. Report an issue: GitHub.

Appendix: source

Thrown at apps/desktop/src/lib/dragging/dropHandlers/stackDropHandler.ts:134

					)
					.map((h) => ({
						hunkHeader: h.hunkHeader,
						pathBytes: h.pathBytes,
						target: this.stackTarget(stack.id),
					}));
				await this.diffService.assignHunk({
					projectId: this.projectId,
					assignments,
				});
			}
		}
	}

	async ondropHunkData(data: HunkDropDataV3) {
		switch (data.selectionId.type) {
			case "commit": {
				if (!data.stackId || !data.commitId) {
					throw new Error("Hunk drop data must specify the source stackId and commitId");
				}

				const { stack, outcome, branchName } = await this.macros.createNewStackAndCommit();

				if (!outcome.newCommit) {
					throw new Error("Failed to create a new commit");
				}

				const previousPathBytes =
					data.change.status.type === "Rename"
						? data.change.status.subject.previousPathBytes
						: null;

				await this.macros.moveChangesToNewCommit(
					stack.id,
					outcome.newCommit,
					data.stackId,
					data.commitId,

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