feat(web): add pull request merge defaults

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

@@ -50,7 +50,12 @@ import {
 
 import { type DraftId, useComposerDraftStore } from "~/composerDraftStore";
 import { useNewThreadHandler } from "~/hooks/useHandleNewThread";
+import { useClientSettings } from "~/hooks/useSettings";
 import { useCopyToClipboard, writeTextToClipboard } from "~/hooks/useCopyToClipboard";
+import {
+  deriveLogicalProjectKeyFromSettings,
+  selectProjectGroupingSettings,
+} from "~/logicalProject";
 import { changeRequestRepositoryUrl } from "~/lib/openPullRequestLink";
 import { usePreparePullRequestThreadAction } from "~/lib/sourceControlActions";
 import { cn } from "~/lib/utils";
@@ -64,6 +69,7 @@ import { pullRequestEnvironment } from "~/state/pullRequests";
 import { useAtomCommand } from "~/state/use-atom-command";
 import { vcsEnvironment } from "~/state/vcs";
 import { formatRelativeTimeLabel } from "~/timestampFormat";
+import { useUiStateStore } from "~/uiStateStore";
 
 import {
   AlertDialog,
@@ -114,8 +120,10 @@ import {
   pullRequestComposerTarget,
   pullRequestFindingKey,
   pullRequestHandoffLabels,
+  PULL_REQUEST_MERGE_METHOD_LABELS,
   readableFailure,
   resolveBaseFreshness,
+  resolvePullRequestMergeMethod,
   type PullRequestFinding,
   shouldRefreshPullRequestActivity,
 } from "./pullRequestDetail.logic";
@@ -153,12 +161,6 @@ const ACTION_SUCCESS_LABELS: Record<PullRequestAction, string> = {
   "disable-auto-merge": "Auto-merge turned off",
 };
 
-const MERGE_METHOD_LABELS: Record<PullRequestMergeMethod, string> = {
-  merge: "Merge",
-  squash: "Squash",
-  rebase: "Rebase",
-};
-
 /** Said as the thing that did not happen, rather than as the operation that returned an error. */
 const ACTION_FAILURE_LABELS: Record<PullRequestAction, string> = {
   merge: "Could not merge this pull request",
@@ -453,7 +455,16 @@ export function PullRequestDetailPanel({
     compensationRef.current = null;
     if (scroller) scroller.scrollTop = Math.max(0, scroller.scrollTop + delta);
   }, [condensed]);
-  const [mergeMethod, setMergeMethod] = useState<PullRequestMergeMethod>("merge");
+  const lastSelectedMergeMethod = useUiStateStore((state) => state.pullRequestMergeMethod);
+  const setLastSelectedMergeMethod = useUiStateStore((state) => state.setPullRequestMergeMethod);
+  const mergeMethodOverrides = useClientSettings(
+    (settings) => settings.pullRequestMergeMethodOverrides,
+  );
+  const projectGroupingSettings = useClientSettings(selectProjectGroupingSettings);
+  const [mergeMethodScope, setMergeMethodScope] = useState<{
+    pullRequestKey: string;
+    method: PullRequestMergeMethod;
+  } | null>(null);
   const [confirmation, setConfirmation] = useState<{
     readonly open: boolean;
     readonly action: "merge" | "close" | "enable-auto-merge";
@@ -590,6 +601,15 @@ export function PullRequestDetailPanel({
   const newThread = useNewThreadHandler();
   const { environments } = useEnvironments();
   const projects = useProjects();
+  const mergeMethodProject = projects.find(
+    (project) => project.environmentId === environmentId && project.id === reference.projectId,
+  );
+  const mergeMethodProjectKey = mergeMethodProject
+    ? deriveLogicalProjectKeyFromSettings(mergeMethodProject, projectGroupingSettings)
+    : null;
+  const projectDefaultMergeMethod = mergeMethodProjectKey
+    ? mergeMethodOverrides[mergeMethodProjectKey]
+    : undefined;
   // Beside a thread there is nothing to pick: the hand-offs land in that thread's composer, and
   // the thread is already on one server's copy of the branch.
   const pickableEnvironments = useMemo(
@@ -1022,10 +1042,15 @@ export function PullRequestDetailPanel({
   const allowedMergeMethods = detail
     ? detail.capabilities.mergeMethods.filter((method) => detail.mergeCapabilities[method])
     : [];
-  const selectedMergeMethod = allowedMergeMethods.includes(mergeMethod)
-    ? mergeMethod
-    : (allowedMergeMethods[0] ?? "merge");
-  const selectedMergeMethodLabel = MERGE_METHOD_LABELS[selectedMergeMethod];
+  const currentMergeMethod =
+    mergeMethodScope?.pullRequestKey === pullRequestKey ? mergeMethodScope.method : null;
+  const selectedMergeMethod = resolvePullRequestMergeMethod(
+    allowedMergeMethods,
+    currentMergeMethod,
+    projectDefaultMergeMethod,
+    lastSelectedMergeMethod,
+  );
+  const selectedMergeMethodLabel = PULL_REQUEST_MERGE_METHOD_LABELS[selectedMergeMethod];
   const conflicting = detail?.state === "open" && detail.mergeability === "conflicting";
   // Only an outright yes arms it. A host that reports nothing has not said the merge is already
   // spoken for, and an off switch for something that may not be on says the wrong thing twice.
@@ -1418,17 +1443,24 @@ export function PullRequestDetailPanel({
                           {showsDraftToggle ? <MenuSeparator /> : null}
                           <MenuRadioGroup
                             value={selectedMergeMethod}
-                            onValueChange={(method) =>
-                              setMergeMethod(method as PullRequestMergeMethod)
-                            }
+                            onValueChange={(method) => {
+                              const selectedMethod = method as PullRequestMergeMethod;
+                              setMergeMethodScope({ pullRequestKey, method: selectedMethod });
+                              setLastSelectedMergeMethod(selectedMethod);
+                            }}
                           >
                             {allowedMergeMethods.map((method) => (
-                              <MenuRadioItem key={method} value={method} disabled={actionPending}>
+                              <MenuRadioItem
+                                key={method}
+                                value={method}
+                                disabled={actionPending}
+                                closeOnClick
+                              >
                                 {/* The radio item lays its children out as one block, so the
                                     icon and the label need their own row to share a line. */}
                                 <span className="flex min-w-0 items-center gap-2">
                                   <GitMergeIcon className="size-3.5" />
-                                  <span>{MERGE_METHOD_LABELS[method]}</span>
+                                  <span>{PULL_REQUEST_MERGE_METHOD_LABELS[method]}</span>
                                 </span>
                               </MenuRadioItem>
                             ))}

apps/web/src/components/pullRequest/pullRequestDetail.logic.test.ts

@@ -32,6 +32,7 @@ import {
   readableFailure,
   shouldRefreshPullRequestActivity,
   resolveBaseFreshness,
+  resolvePullRequestMergeMethod,
   buildPullRequestTimeline,
   describePullRequestState,
   editPullRequestThreadComment,
@@ -63,6 +64,21 @@ const TIMELINE_SOURCE: Pick<
   closedAt: null,
 };
 
+describe("pull request merge method", () => {
+  it("uses the current choice, then the project default, then the last choice", () => {
+    expect(
+      resolvePullRequestMergeMethod(["merge", "squash", "rebase"], null, "squash", "rebase"),
+    ).toBe("squash");
+    expect(
+      resolvePullRequestMergeMethod(["merge", "squash", "rebase"], "rebase", "squash", "merge"),
+    ).toBe("rebase");
+    expect(resolvePullRequestMergeMethod(["merge", "rebase"], null, "squash", "rebase")).toBe(
+      "rebase",
+    );
+    expect(resolvePullRequestMergeMethod(["squash"], null, "merge", "rebase")).toBe("squash");
+  });
+});
+
 describe("pull request activity refresh", () => {
   const first = {
     key: "project:acme/web#7",

apps/web/src/components/pullRequest/pullRequestDetail.logic.ts

@@ -7,6 +7,7 @@ import type {
   PullRequestCommit,
   PullRequestDetailView,
   PullRequestMergeability,
+  PullRequestMergeMethod,
   PullRequestReaction,
   PullRequestReviewThread,
   PullRequestState,
@@ -16,6 +17,24 @@ import type {
 
 import { inferReviewCommentFenceLanguage, type ReviewCommentContext } from "~/reviewCommentContext";
 
+export const PULL_REQUEST_MERGE_METHOD_LABELS: Record<PullRequestMergeMethod, string> = {
+  merge: "Merge",
+  squash: "Squash and merge",
+  rebase: "Rebase and merge",
+};
+
+export function resolvePullRequestMergeMethod(
+  allowed: ReadonlyArray<PullRequestMergeMethod>,
+  current: PullRequestMergeMethod | null,
+  projectDefault: PullRequestMergeMethod | undefined,
+  lastSelected: PullRequestMergeMethod,
+): PullRequestMergeMethod {
+  for (const method of [current, projectDefault, lastSelected]) {
+    if (method && allowed.includes(method)) return method;
+  }
+  return allowed[0] ?? "merge";
+}
+
 /** Activity changes only when the same host resource reports a newer revision. */
 export function shouldRefreshPullRequestActivity(
   previous: { readonly key: string; readonly updatedAt: string } | null,

apps/web/src/components/settings/ProjectSettingsPanel.tsx

@@ -16,6 +16,7 @@ import type {
   ContextMenuItem,
   ModelSelection,
   ProviderDriverKind,
+  PullRequestMergeMethod,
   SidebarProjectGroupingMode,
   T3ProjectFileScript,
   ThreadEnvMode,
@@ -74,6 +75,7 @@ import { useAtomCommand } from "../../state/use-atom-command";
 import { ProviderModelPicker } from "../chat/ProviderModelPicker";
 import { TraitsPicker } from "../chat/TraitsPicker";
 import { ProjectFavicon } from "../ProjectFavicon";
+import { PULL_REQUEST_MERGE_METHOD_LABELS } from "../pullRequest/pullRequestDetail.logic";
 import {
   EMPTY_PROJECT_SCRIPT_INPUT,
   editorRequestForScript,
@@ -294,6 +296,9 @@ function ProjectDetail({ group }: { group: SidebarProjectSnapshot }) {
   const settings = usePrimarySettings();
   const updateClientSettings = useUpdateClientSettings();
   const projectGroupingSettings = useClientSettings(selectProjectGroupingSettings);
+  const mergeMethodOverrides = useClientSettings(
+    (settings) => settings.pullRequestMergeMethodOverrides,
+  );
   const serverProviders = useAtomValue(primaryServerProvidersAtom);
   const threads = useThreadShells();
   const updateProject = useAtomCommand(projectEnvironment.update, { reportFailure: false });
@@ -323,6 +328,20 @@ function ProjectDetail({ group }: { group: SidebarProjectSnapshot }) {
     group.memberProjects.find(
       (member) => member.environmentId === group.environmentId && member.id === group.id,
     ) ?? group.memberProjects[0]!;
+  const projectMergeMethod = mergeMethodOverrides[group.projectKey];
+  const setProjectMergeMethod = useCallback(
+    (method: PullRequestMergeMethod | null) => {
+      const nextOverrides = { ...mergeMethodOverrides };
+      if (method === null) {
+        delete nextOverrides[group.projectKey];
+      } else {
+        nextOverrides[group.projectKey] = method;
+      }
+      updateClientSettings({ pullRequestMergeMethodOverrides: nextOverrides });
+    },
+    [group.projectKey, mergeMethodOverrides, updateClientSettings],
+  );
+
   const faviconPath = representative.faviconPath ?? null;
   const pickProjectFavicon =
     typeof window !== "undefined" &&
@@ -809,6 +828,44 @@ function ProjectDetail({ group }: { group: SidebarProjectSnapshot }) {
               </div>
             }
           />
+          <SettingsRow
+            title="Default merge method"
+            description="Pull requests in this project start with this method. It overrides the last method selected."
+            resetAction={
+              projectMergeMethod !== undefined ? (
+                <SettingResetButton
+                  label="project merge method"
+                  onClick={() => setProjectMergeMethod(null)}
+                />
+              ) : null
+            }
+            control={
+              <Select
+                value={projectMergeMethod ?? "inherit"}
+                onValueChange={(value) => {
+                  if (value === "merge" || value === "squash" || value === "rebase") {
+                    setProjectMergeMethod(value);
+                  } else if (value === "inherit") {
+                    setProjectMergeMethod(null);
+                  }
+                }}
+              >
+                <SelectTrigger aria-label="Default pull request merge method">
+                  <SelectValue>
+                    {projectMergeMethod === undefined
+                      ? "Last selected"
+                      : PULL_REQUEST_MERGE_METHOD_LABELS[projectMergeMethod]}
+                  </SelectValue>
+                </SelectTrigger>
+                <SelectPopup align="end" alignItemWithTrigger={false}>
+                  <SelectItem value="inherit">Last selected</SelectItem>
+                  <SelectItem value="merge">{PULL_REQUEST_MERGE_METHOD_LABELS.merge}</SelectItem>
+                  <SelectItem value="squash">{PULL_REQUEST_MERGE_METHOD_LABELS.squash}</SelectItem>
+                  <SelectItem value="rebase">{PULL_REQUEST_MERGE_METHOD_LABELS.rebase}</SelectItem>
+                </SelectPopup>
+              </Select>
+            }
+          />
         </SettingsSection>
 
         <SettingsSection title="New threads">

apps/web/src/uiStateStore.test.ts

@@ -24,6 +24,7 @@ function makeUiState(overrides: Partial<UiState> = {}): UiState {
     threadLastVisitedAtById: {},
     threadChangedFilesExpandedById: {},
     defaultAdvertisedEndpointKey: null,
+    pullRequestMergeMethod: "merge",
     ...overrides,
   };
 }
@@ -147,6 +148,18 @@ describe("uiStateStore pure functions", () => {
 });
 
 describe("parsePersistedState", () => {
+  it("hydrates the last selected pull request merge method", () => {
+    const parsed = parsePersistedState({
+      pullRequestMergeMethod: "squash",
+    });
+    const invalid = parsePersistedState({
+      pullRequestMergeMethod: "fast-forward",
+    });
+
+    expect(parsed.pullRequestMergeMethod).toBe("squash");
+    expect(invalid.pullRequestMergeMethod).toBe("merge");
+  });
+
   it("hydrates raw UI-owned state without server entities", () => {
     const parsed = parsePersistedState({
       projectExpandedById: {
@@ -177,6 +190,7 @@ describe("parsePersistedState", () => {
         "environment:thread-1": "2026-02-25T12:35:00.000Z",
       },
       defaultAdvertisedEndpointKey: "desktop-core:lan:http",
+      pullRequestMergeMethod: "merge",
       threadChangedFilesExpandedById: {
         "environment:thread-1": {
           "turn-1": false,
@@ -303,6 +317,7 @@ describe("uiStateStore persistence", () => {
           "turn-2": true,
         },
       },
+      pullRequestMergeMethod: "merge",
     });
     expect(parsePersistedState(persisted)).toEqual({
       ...state,