feat(pr): delete branches after merge or close

apps/mobile/src/features/pull-requests/PullRequestRouteScreen.tsx

@@ -104,6 +104,7 @@ import {
   PullRequestStatusMenu,
   PullRequestChecksRow,
   PullRequestBranchRow,
+  PullRequestDeleteBranchRow,
   PullRequestReviewersRow,
 } from "./PullRequestStatusRows";
 import { PullRequestMergeControls } from "./PullRequestMergeControls";
@@ -249,6 +250,7 @@ function PullRequestOverview(props: {
         <Animated.View layout={PR_ROW_LAYOUT}>
           <PullRequestMergeControls pr={pr} params={props.params} stack={props.stack} />
         </Animated.View>
+        <PullRequestDeleteBranchRow pr={pr} params={props.params} />
       </PullRequestCardGroup>
       {pr.labels.length ? (
         <Animated.View layout={PR_ROW_LAYOUT} className="flex-row flex-wrap gap-2">

apps/mobile/src/features/pull-requests/PullRequestStatusRows.tsx

@@ -14,7 +14,12 @@ import { PullRequestCardRow } from "./PullRequestControls";
 import { PullRequestAgentRow } from "./PullRequestAgentRow";
 import { composerPullRequests } from "../../state/pull-requests";
 import { useEnvironmentQuery } from "../../state/query";
-import { allowedUpdateMethods, PR_ACTION_ICONS, PR_ACTION_LABELS } from "./pullRequestActions";
+import {
+  allowedUpdateMethods,
+  canPerformPullRequestAction,
+  PR_ACTION_ICONS,
+  PR_ACTION_LABELS,
+} from "./pullRequestActions";
 import {
   checkStatus,
   pullRequestBranchSummary,
@@ -25,6 +30,7 @@ import {
 import { pullRequestTarget, type PullRequestParams } from "./usePullRequestDiff";
 import { usePullRequestAction } from "./usePullRequestAction";
 import { usePullRequestAgentActions } from "./usePullRequestAgentActions";
+import { usePullRequestPermissions } from "./usePullRequestPermissions";
 
 type RowProps = { readonly pr: PullRequestDetail; readonly params: PullRequestParams };
 const STATUS_ACTIONS: readonly PullRequestAction[] = [
@@ -226,6 +232,39 @@ export function PullRequestBranchRow(props: RowProps) {
   );
 }
 
+export function PullRequestDeleteBranchRow(props: RowProps) {
+  const action = usePullRequestAction(props.params, props.pr);
+  const { connected } = usePullRequestPermissions(props.params, props.pr);
+  if (!canPerformPullRequestAction(props.pr, "delete-branch")) return null;
+  const repository = props.pr.headRepositoryNameWithOwner ?? props.pr.repository;
+  return (
+    <Animated.View
+      layout={PR_ROW_LAYOUT}
+      exiting={PR_ROW_EXIT}
+      className="border-t border-border-subtle"
+    >
+      <PullRequestCardRow
+        title={PR_ACTION_LABELS["delete-branch"]}
+        icon={PR_ACTION_ICONS["delete-branch"]}
+        destructive={connected}
+        value={action.busy ? "Deleting…" : undefined}
+        detail={connected ? props.pr.headBranch : "Reconnect to delete this branch."}
+        last
+        onPress={
+          action.available("delete-branch")
+            ? () =>
+                action.confirm(
+                  "delete-branch",
+                  PR_ACTION_LABELS["delete-branch"],
+                  `Delete ${props.pr.headBranch} from ${repository}? Local branches and worktrees are not changed.`,
+                )
+            : undefined
+        }
+      />
+    </Animated.View>
+  );
+}
+
 export function PullRequestReviewersRow(props: RowProps) {
   const [expanded, setExpanded] = useState(false);
   const navigation = useNavigation();

apps/mobile/src/features/pull-requests/pullRequestActions.test.ts

@@ -112,6 +112,19 @@ describe("mobile pull request actions", () => {
     expect(mergeSummary(unknown, true)).toBe("Squash");
   });
 
+  it("offers deleting the source branch only once merged or closed on a host that supports it", () => {
+    const capabilities = { ...detail().capabilities, deleteBranch: true };
+    expect(canPerformPullRequestAction(detail({ capabilities }), "delete-branch")).toBe(false);
+    for (const state of ["merged", "closed"] as const) {
+      expect(canPerformPullRequestAction(detail({ state, capabilities }), "delete-branch")).toBe(
+        true,
+      );
+      expect(canPerformPullRequestAction(detail({ state }), "delete-branch")).toBe(false);
+    }
+    const refused = detail({ state: "merged", capabilities, viewerPermissions: { actions: [] } });
+    expect(canPerformPullRequestAction(refused, "delete-branch")).toBe(false);
+  });
+
   it("cannot merge when the repository has disabled every offered strategy", () => {
     const pr = detail({ mergeCapabilities: { merge: false, squash: false, rebase: false } });
     expect(canPerformPullRequestAction(pr, "merge")).toBe(false);

apps/mobile/src/features/pull-requests/pullRequestActions.ts

@@ -13,7 +13,7 @@ type ActionDetail = Pick<
 > & {
   readonly capabilities: Pick<
     PullRequestDetail["capabilities"],
-    "actions" | "mergeMethods" | "updateMethods"
+    "actions" | "mergeMethods" | "updateMethods" | "deleteBranch"
   >;
   readonly viewerPermissions: Pick<
     PullRequestDetail["viewerPermissions"],
@@ -41,6 +41,7 @@ export const PR_ACTION_LABELS = {
   "enable-auto-merge": "Enable auto-merge",
   "disable-auto-merge": "Disable auto-merge",
   revert: "Create revert pull request",
+  "delete-branch": "Delete branch",
   "approve-workflows": "Approve workflows",
 } as const satisfies Record<PullRequestAction, string>;
 
@@ -54,6 +55,7 @@ export const PR_ACTION_ICONS = {
   "enable-auto-merge": "clock",
   "disable-auto-merge": "xmark",
   revert: "arrow.uturn.backward",
+  "delete-branch": "trash",
   "approve-workflows": "checkmark",
 } as const satisfies Record<PullRequestAction, AppSymbolName>;
 
@@ -68,6 +70,7 @@ export const ALL_PR_ACTIONS: readonly PullRequestAction[] = [
   "close",
   "reopen",
   "revert",
+  "delete-branch",
 ];
 
 export function allowedMergeMethods(pr: ActionDetail) {
@@ -86,6 +89,8 @@ export function canPerformPullRequestAction(pr: ActionDetail, action: PullReques
     return false;
   if (action === "reopen") return pr.state === "closed";
   if (action === "revert") return pr.state === "merged";
+  if (action === "delete-branch")
+    return pr.state !== "open" && pr.capabilities.deleteBranch === true;
   if (pr.state !== "open") return false;
   switch (action) {
     case "update-branch":

apps/mobile/src/features/pull-requests/usePullRequestAction.ts

@@ -51,7 +51,7 @@ export function usePullRequestAction(params: PullRequestParams, pr: PullRequestD
       { text: "Cancel", style: "cancel" },
       {
         text: title,
-        style: action === "close" ? "destructive" : "default",
+        style: action === "close" || action === "delete-branch" ? "destructive" : "default",
         onPress: () => void perform(action),
       },
     ]);

apps/server/src/pullRequest/PullRequestService.test.ts

@@ -1573,6 +1573,76 @@ it.effect("refreshes every reader before a queued merge confirmation finishes",
   ),
 );
 
+it.effect("runs branch deletion only when the host and viewer support it, never for a stack", () =>
+  Effect.gen(function* () {
+    let actions = 0;
+    let supported = false;
+    let allowed = true;
+    const base = fakeProvider(SourceControlProviderKind.make("github"));
+    const service = yield* makeService({
+      projects: [project({ id: "p1", title: "web", workspaceRoot: "/a", repository: "acme/web" })],
+      providers: [
+        {
+          ...base,
+          capabilities: {
+            ...base.capabilities,
+            actions: ["delete-branch"],
+            stackActions: true,
+            get deleteBranch() {
+              return supported;
+            },
+          },
+          getViewerPermissions: () =>
+            Effect.succeed({
+              actions: allowed ? ["delete-branch"] : [],
+              comment: true,
+              resolve: true,
+              verdicts: [],
+              requestReviewers: false,
+            }),
+          runAction: (input) =>
+            Effect.sync(() => {
+              assert.strictEqual(input.action, "delete-branch");
+              actions++;
+            }),
+        },
+      ],
+    });
+    const input = {
+      projectId: "p1" as ProjectId,
+      repository: "acme/web",
+      number: 1,
+      action: "delete-branch" as const,
+    };
+    assert.strictEqual(
+      (yield* Effect.flip(service.runAction(input)))._tag,
+      "PullRequestOperationError",
+    );
+    assert.strictEqual(actions, 0);
+    supported = true;
+    assert.strictEqual(
+      (yield* Effect.flip(
+        service.runAction({
+          ...input,
+          stackNumber: 2,
+          expectedStackHeads: [{ number: 1, headSha: "abc123" }],
+        }),
+      ))._tag,
+      "PullRequestOperationError",
+    );
+    assert.strictEqual(actions, 0);
+    allowed = false;
+    assert.strictEqual(
+      (yield* Effect.flip(service.runAction(input)))._tag,
+      "PullRequestOperationError",
+    );
+    assert.strictEqual(actions, 0);
+    allowed = true;
+    yield* service.runAction(input);
+    assert.strictEqual(actions, 1);
+  }),
+);
+
 it.effect("refuses an action this viewer may not take, and says what access it takes", () =>
   Effect.gen(function* () {
     let ran: string | null = null;

apps/server/src/pullRequest/PullRequestService.ts

@@ -356,6 +356,7 @@ const ACTION_ACCESS_REFUSALS: Record<PullRequestAction, string> = {
   "disable-auto-merge":
     "You need write access on this repository to stop it being merged for you once it is ready.",
   revert: "You need write access on this repository to open a revert pull request.",
+  "delete-branch": "You need write access on the source repository to delete its branch.",
   "approve-workflows":
     "You need write access on this repository to approve workflows from a fork pull request.",
 };
@@ -2019,6 +2020,14 @@ export const make = Effect.gen(function* () {
   const runAction = (input: PullRequestActionInput): Effect.Effect<string, PullRequestError> =>
     requireProject(input).pipe(
       Effect.flatMap((project): Effect.Effect<string, PullRequestError> => {
+        if (input.action === "delete-branch" && project.api.capabilities.deleteBranch !== true) {
+          return Effect.fail(
+            new PullRequestOperationError({
+              operation: "runAction",
+              detail: "This host cannot delete a change request's source branch.",
+            }),
+          );
+        }
         if (
           input.stackNumber !== undefined &&
           (project.api.capabilities.stackActions !== true ||

apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx

@@ -45,6 +45,7 @@ import {
   PlayIcon,
   RotateCcwIcon,
   SparklesIcon,
+  Trash2Icon,
   TriangleAlertIcon,
 } from "lucide-react";
 import {
@@ -161,6 +162,7 @@ import {
   resolveDisplayedPullRequestDetail,
   resolvePullRequestPrimaryControl,
   allowsSinglePullRequestMerge,
+  canDeletePullRequestBranch,
   resolveBaseFreshness,
   resolvePullRequestMergeMethod,
   type PullRequestFinding,
@@ -204,6 +206,7 @@ const ACTION_FAILURE_LABELS: Record<PullRequestAction, string> = {
   "enable-auto-merge": "Could not turn on auto-merge",
   "disable-auto-merge": "Could not turn off auto-merge",
   revert: "Could not open a revert pull request",
+  "delete-branch": "Could not delete this branch",
   "approve-workflows": "Could not approve workflows",
 };
 
@@ -228,6 +231,8 @@ const ACTION_FAILURE_HINTS: Record<PullRequestAction, string> = {
     "The host refused it. Check that you have write access, and that the merge has not already happened.",
   revert:
     "The host refused it. Check that you have write access and that this pull request was merged on the host.",
+  "delete-branch":
+    "The host refused it. Check that you have write access to the source repository and that the branch has not moved since this page loaded.",
   "approve-workflows":
     "The host refused it. Check that you have Actions write access and that these workflow runs are still awaiting approval.",
 };
@@ -1030,6 +1035,9 @@ export function PullRequestDetailPanel({
     if (action === "revert") {
       toastManager.add({ type: "success", title: "Revert pull request opened" });
     }
+    if (action === "delete-branch") {
+      toastManager.add({ type: "success", title: "Branch deleted" });
+    }
     // A branch update moves the head commit, which leaves the diff atom pointed at a comparison
     // that no longer exists — the same staleness the manual refresh button fixes, so it goes
     // through that path rather than a second one. Every other action here only changes metadata;
@@ -1639,6 +1647,22 @@ export function PullRequestDetailPanel({
   const statePresentation = detail
     ? resolvePullRequestState({ state: detail.state, isDraft: detail.isDraft })
     : null;
+  const showsDeleteBranch = detail !== null && canDeletePullRequestBranch(detail);
+  const environmentConnected = environments.some(
+    (environment) =>
+      environment.environmentId === environmentId && environment.connection.phase === "connected",
+  );
+  const confirmDeleteBranch = async () => {
+    if (detail === null) return;
+    const confirmed = await readLocalApi()?.dialogs.confirm(
+      [
+        `Delete branch ${detail.headBranch}?`,
+        `This deletes ${detail.headBranch} from ${detail.headRepositoryNameWithOwner ?? detail.repository}. Local branches and worktrees are not changed.`,
+      ].join("\n"),
+      { variant: "destructive" },
+    );
+    if (confirmed) void perform("delete-branch");
+  };
   const showsApproveWorkflows =
     workflowApprovalsRequired > 0 && !checksStale && can("approve-workflows");
   const checksSummary = checksStale
@@ -2157,6 +2181,37 @@ export function PullRequestDetailPanel({
                   </span>
                 </Badge>
               ) : null}
+              {showsDeleteBranch ? (
+                <Tooltip>
+                  <TooltipTrigger
+                    render={
+                      <span className="inline-flex shrink-0">
+                        <Button
+                          size="xs"
+                          variant="destructive-outline"
+                          disabled={actionPending || !environmentConnected}
+                          onClick={() => void confirmDeleteBranch()}
+                          aria-label={
+                            pendingAction === "delete-branch"
+                              ? "Deleting branch..."
+                              : "Delete branch"
+                          }
+                        >
+                          <Trash2Icon aria-hidden className="size-3.5" />
+                          <span className="@max-[30rem]/pr-header:hidden">
+                            {pendingAction === "delete-branch" ? "Deleting..." : "Delete branch"}
+                          </span>
+                        </Button>
+                      </span>
+                    }
+                  />
+                  <TooltipPopup side="top">
+                    {environmentConnected
+                      ? `Delete ${detail.headBranch}`
+                      : "Reconnect to delete this branch"}
+                  </TooltipPopup>
+                </Tooltip>
+              ) : null}
               {/* Keep checkout beside the menu so host actions arriving on its left cannot
                   move a different action under the reader's pointer. */}
               {checkoutControl}