Ability to drag changes to start a commit

apps/desktop/src/components/BranchCard.svelte

@@ -8,7 +8,7 @@
 	import CreateReviewBox from '$components/CreateReviewBox.svelte';
 	import Dropzone from '$components/Dropzone.svelte';
 	import PrNumberUpdater from '$components/PrNumberUpdater.svelte';
-	import { BranchDropData } from '$lib/branches/dropHandler';
+	import { BranchDropData, StartCommitDzHandler } from '$lib/branches/dropHandler';
 	import { MoveCommitDzHandler } from '$lib/commits/dropHandler';
 	import { ReorderCommitDzHandler } from '$lib/dragging/stackingReorderDropzoneManager';
 	import { DEFAULT_FORGE_FACTORY } from '$lib/forge/forgeFactory.svelte';
@@ -150,6 +150,13 @@
 			});
 		}
 	}
+
+	function getCardOverlayLabel(handler: DropzoneHandler | undefined): string {
+		if (handler instanceof MoveCommitDzHandler) return 'Move here';
+		if (handler instanceof ReorderCommitDzHandler) return 'Reorder here';
+		if (handler instanceof StartCommitDzHandler) return 'Start commit';
+		return 'Drop here';
+	}
 </script>
 
 <div
@@ -171,12 +178,7 @@
 			handlers={args.first ? [moveHandler, ...args.dropzones].filter(isDefined) : args.dropzones}
 		>
 			{#snippet overlay({ hovered, activated, handler })}
-				{@const label =
-					handler instanceof MoveCommitDzHandler
-						? 'Move here'
-						: handler instanceof ReorderCommitDzHandler
-							? 'Reorder here'
-							: 'Start commit'}
+				{@const label = getCardOverlayLabel(handler)}
 				<CardOverlay {hovered} {activated} {label} />
 			{/snippet}
 

apps/desktop/src/components/BranchList.svelte

@@ -13,6 +13,7 @@
 	import ReduxResult from '$components/ReduxResult.svelte';
 	import { getColorFromCommitState, getIconFromCommitState } from '$components/lib';
 	import { BASE_BRANCH_SERVICE } from '$lib/baseBranch/baseBranchService.svelte';
+	import { StartCommitDzHandler } from '$lib/branches/dropHandler';
 	import { CLAUDE_CODE_SERVICE } from '$lib/codegen/claude';
 	import { focusClaudeInput } from '$lib/codegen/focusClaudeInput';
 	import { currentStatus } from '$lib/codegen/messages';
@@ -22,6 +23,7 @@
 	import { DEFAULT_FORGE_FACTORY } from '$lib/forge/forgeFactory.svelte';
 	import { MODE_SERVICE } from '$lib/mode/modeService';
 	import { createBranchSelection } from '$lib/selection/key';
+	import { UNCOMMITTED_SERVICE } from '$lib/selection/uncommittedService.svelte';
 	import { type BranchDetails } from '$lib/stacks/stack';
 	import { STACK_SERVICE } from '$lib/stacks/stackService.svelte';
 	import { combineResults } from '$lib/state/helpers';
@@ -53,6 +55,7 @@
 	const urlService = inject(URL_SERVICE);
 	const baseBranchService = inject(BASE_BRANCH_SERVICE);
 	const claudeCodeService = inject(CLAUDE_CODE_SERVICE);
+	const uncommittedService = inject(UNCOMMITTED_SERVICE);
 
 	// Component is read-only when stackId is undefined
 	const isReadOnly = $derived(!stackId);
@@ -159,7 +162,10 @@
 				commitQuery.result
 			)}
 		>
-			{#snippet children([localAndRemoteCommits, upstreamOnlyCommits, branchDetails, commit])}
+			{#snippet children(
+				[localAndRemoteCommits, upstreamOnlyCommits, branchDetails, commit],
+				{ projectId, stackId }
+			)}
 				{@const firstBranch = i === 0}
 				{@const lastBranch = i === branches.length - 1}
 				{@const iconName = getIconFromCommitState(commit?.id, commit?.state)}
@@ -190,6 +196,13 @@
 				{@const codegenQuery = stackId
 					? claudeCodeService.messages({ projectId, stackId })
 					: undefined}
+				{@const startCommittingDz = new StartCommitDzHandler(
+					uiState,
+					uncommittedService,
+					projectId,
+					stackId,
+					branchName
+				)}
 				{#if stackId}
 					<BranchInsertion
 						{projectId}
@@ -228,7 +241,7 @@
 					numberOfUpstreamCommits={upstreamOnlyCommits.length}
 					numberOfBranchesInStack={branches.length}
 					baseCommit={branchDetails.baseCommit}
-					dropzones={[stackingReorderDropzoneManager.top(branchName)]}
+					dropzones={[stackingReorderDropzoneManager.top(branchName), startCommittingDz]}
 					trackingBranch={branch.remoteTrackingBranch ?? undefined}
 					readonly={!!branch.remoteTrackingBranch}
 					onclick={() => {

apps/desktop/src/lib/branches/dropHandler.ts

@@ -1,7 +1,10 @@
+import { FileChangeDropData, FolderChangeDropData, HunkDropDataV3 } from '$lib/dragging/draggables';
 import { updateStackPrs } from '$lib/forge/shared/prFooter';
 import type { DropzoneHandler } from '$lib/dragging/handler';
 import type { ForgePrService } from '$lib/forge/interface/forgePrService';
+import type { UncommittedService } from '$lib/selection/uncommittedService.svelte';
 import type { StackService } from '$lib/stacks/stackService.svelte';
+import type { UiState } from '$lib/state/uiState.svelte';
 
 export class BranchDropData {
 	constructor(
@@ -62,3 +65,66 @@ export class MoveBranchDzHandler implements DropzoneHandler {
 		await updateStackPrs(this.prService, branchDetails, this.baseBranchName);
 	}
 }
+
+export class StartCommitDzHandler implements DropzoneHandler {
+	constructor(
+		private readonly uiState: UiState,
+		private readonly uncommittedService: UncommittedService,
+		private readonly projectId: string,
+		private readonly stackId: string | undefined,
+		private readonly branchName: string
+	) {}
+
+	print(): string {
+		return `StartCommitDzHandler(${this.projectId}, ${this.stackId}, ${this.branchName})`;
+	}
+
+	accepts(data: unknown): boolean {
+		if (data instanceof FileChangeDropData || data instanceof FolderChangeDropData) {
+			// Only accept uncomitted files/folders
+			if (data.isCommitted) return false;
+			// Only accept unassinged files/folders or those assigned to the same stack
+			if (data.stackId !== undefined && data.stackId !== this.stackId) return false;
+			return true;
+		}
+		if (data instanceof HunkDropDataV3) {
+			// Only accept uncommitted hunks
+			if (!data.uncommitted) return false;
+			if (data.selectionId.type !== 'worktree') return false;
+			// Only accept unassigned hunks or those assigned to the same stack
+			if (data.stackId !== undefined && data.stackId !== this.stackId) return false;
+			return true;
+		}
+		return false;
+	}
+
+	private startCommitting() {
+		const projectState = this.uiState.project(this.projectId);
+		projectState.exclusiveAction.set({
+			type: 'commit',
+			stackId: this.stackId,
+			branchName: this.branchName
+		});
+	}
+
+	private async checkDropData(
+		data: FileChangeDropData | FolderChangeDropData | HunkDropDataV3
+	): Promise<true> {
+		if (data instanceof FileChangeDropData || data instanceof FolderChangeDropData) {
+			const changes = await data.treeChanges();
+			const paths = changes.map((c) => c.path);
+			if (paths.length === 0) return true;
+			this.uncommittedService.checkFiles(data.stackId ?? null, paths);
+			return true;
+		}
+
+		// Handle hunk data
+		this.uncommittedService.checkHunk(data.stackId ?? null, data.change.path, data.hunk);
+		return true;
+	}
+
+	async ondrop(data: FileChangeDropData | FolderChangeDropData | HunkDropDataV3): Promise<void> {
+		this.startCommitting();
+		await this.checkDropData(data);
+	}
+}