fix(web): extract shared checkout error handler and update thread branch on stash & switch

Addresses bot review: the "Stash & Switch" onClick handler was missing
the onSetThreadBranch call, leaving the UI stale after a successful
stash-and-checkout. Extracts the duplicated error handling into a shared
handleCheckoutError function used by both selectBranch and createBranch.

Author: Marve10s

apps/web/src/components/BranchToolbarBranchSelector.tsx

@@ -1,5 +1,5 @@
-import type { GitBranch } from "@t3tools/contracts";
-import { useInfiniteQuery, useQueryClient } from "@tanstack/react-query";
+import type { GitBranch, NativeApi } from "@t3tools/contracts";
+import { type QueryClient, useInfiniteQuery, useQueryClient } from "@tanstack/react-query";
 import { useVirtualizer } from "@tanstack/react-virtual";
 import { ChevronDownIcon } from "lucide-react";
 import {
@@ -92,6 +92,83 @@ function formatDirtyWorktreeDescription(files: string[]): string {
   return `${basenames.slice(0, 2).join(", ")} and ${basenames.length - 2} other file${basenames.length - 2 === 1 ? "" : "s"} have uncommitted changes. Commit or stash before switching.`;
 }
 
+function handleCheckoutError(
+  error: unknown,
+  ctx: {
+    api: NativeApi;
+    cwd: string;
+    branch: string;
+    queryClient: QueryClient;
+    onSuccess: () => void;
+    fallbackTitle: string;
+  },
+): void {
+  const dirtyWorktree = parseDirtyWorktreeError(error);
+  if (dirtyWorktree) {
+    toastManager.add({
+      type: "warning",
+      title: "Uncommitted changes block checkout.",
+      description: formatDirtyWorktreeDescription(dirtyWorktree.files),
+      actionProps: {
+        children: "Stash & Switch",
+        onClick: async () => {
+          try {
+            await ctx.api.git.stashAndCheckout({ cwd: ctx.cwd, branch: ctx.branch });
+            await invalidateGitQueries(ctx.queryClient);
+            ctx.onSuccess();
+          } catch (stashError) {
+            if (isStashConflictError(stashError)) {
+              toastManager.add({
+                type: "warning",
+                title: "Stash could not be applied.",
+                description: toBranchActionErrorMessage(stashError),
+                actionProps: {
+                  children: "Discard stash",
+                  onClick: async () => {
+                    const confirmed = await readNativeApi()?.dialogs.confirm(
+                      "Drop the most recent stash entry? This cannot be undone.",
+                    );
+                    if (!confirmed) return;
+                    try {
+                      await ctx.api.git.stashDrop({ cwd: ctx.cwd });
+                    } catch (dropError) {
+                      toastManager.add({
+                        type: "error",
+                        title: "Failed to drop stash.",
+                        description: toBranchActionErrorMessage(dropError),
+                      });
+                    }
+                  },
+                },
+              });
+            } else {
+              toastManager.add({
+                type: "error",
+                title: "Failed to stash and switch.",
+                description: toBranchActionErrorMessage(stashError),
+              });
+            }
+          }
+        },
+      },
+    });
+    return;
+  }
+  if (isUnresolvedIndexError(error)) {
+    toastManager.add({
+      type: "error",
+      title: "Unresolved conflicts in the repository.",
+      description: toBranchActionErrorMessage(error),
+    });
+    return;
+  }
+  toastManager.add({
+    type: "error",
+    title: ctx.fallbackTitle,
+    description: toBranchActionErrorMessage(error),
+  });
+}
+
 function getBranchTriggerLabel(input: {
   activeWorktreePath: string | null;
   effectiveEnvMode: EnvMode;
@@ -275,71 +352,16 @@ export function BranchToolbarBranchSelector({
         onSetThreadBranch(nextBranchName, selectionTarget.nextWorktreePath);
       } catch (error) {
         setOptimisticBranch(previousBranch);
-        const dirtyWorktree = parseDirtyWorktreeError(error);
-        if (dirtyWorktree) {
-          toastManager.add({
-            type: "warning",
-            title: "Uncommitted changes block checkout.",
-            description: formatDirtyWorktreeDescription(dirtyWorktree.files),
-            actionProps: {
-              children: "Stash & Switch",
-              onClick: async () => {
-                try {
-                  await api.git.stashAndCheckout({
-                    cwd: selectionTarget.checkoutCwd,
-                    branch: branch.name,
-                  });
-                  await invalidateGitQueries(queryClient);
-                } catch (stashError) {
-                  if (isStashConflictError(stashError)) {
-                    toastManager.add({
-                      type: "warning",
-                      title: "Stash could not be applied.",
-                      description: toBranchActionErrorMessage(stashError),
-                      actionProps: {
-                        children: "Discard stash",
-                        onClick: async () => {
-                          const confirmed = await readNativeApi()?.dialogs.confirm(
-                            "Drop the most recent stash entry? This cannot be undone.",
-                          );
-                          if (!confirmed) return;
-                          try {
-                            await api.git.stashDrop({ cwd: selectionTarget.checkoutCwd });
-                          } catch (dropError) {
-                            toastManager.add({
-                              type: "error",
-                              title: "Failed to drop stash.",
-                              description: toBranchActionErrorMessage(dropError),
-                            });
-                          }
-                        },
-                      },
-                    });
-                  } else {
-                    toastManager.add({
-                      type: "error",
-                      title: "Failed to stash and switch.",
-                      description: toBranchActionErrorMessage(stashError),
-                    });
-                  }
-                }
-              },
-            },
-          });
-          return;
-        }
-        if (isUnresolvedIndexError(error)) {
-          toastManager.add({
-            type: "error",
-            title: "Unresolved conflicts in the repository.",
-            description: toBranchActionErrorMessage(error),
-          });
-          return;
-        }
-        toastManager.add({
-          type: "error",
-          title: "Failed to checkout branch.",
-          description: toBranchActionErrorMessage(error),
+        handleCheckoutError(error, {
+          api,
+          cwd: selectionTarget.checkoutCwd,
+          branch: branch.name,
+          queryClient,
+          onSuccess: () => {
+            setOptimisticBranch(selectedBranchName);
+            onSetThreadBranch(selectedBranchName, selectionTarget.nextWorktreePath);
+          },
+          fallbackTitle: "Failed to checkout branch.",
         });
       }
     });
@@ -366,68 +388,16 @@ export function BranchToolbarBranchSelector({
         onSetThreadBranch(createBranchResult.branch, activeWorktreePath);
       } catch (error) {
         setOptimisticBranch(previousBranch);
-        const dirtyWorktree = parseDirtyWorktreeError(error);
-        if (dirtyWorktree) {
-          toastManager.add({
-            type: "warning",
-            title: "Uncommitted changes block checkout.",
-            description: formatDirtyWorktreeDescription(dirtyWorktree.files),
-            actionProps: {
-              children: "Stash & Switch",
-              onClick: async () => {
-                try {
-                  await api.git.stashAndCheckout({ cwd: branchCwd, branch: name });
-                  await invalidateGitQueries(queryClient);
-                } catch (stashError) {
-                  if (isStashConflictError(stashError)) {
-                    toastManager.add({
-                      type: "warning",
-                      title: "Stash could not be applied.",
-                      description: toBranchActionErrorMessage(stashError),
-                      actionProps: {
-                        children: "Discard stash",
-                        onClick: async () => {
-                          const confirmed = await readNativeApi()?.dialogs.confirm(
-                            "Drop the most recent stash entry? This cannot be undone.",
-                          );
-                          if (!confirmed) return;
-                          try {
-                            await api.git.stashDrop({ cwd: branchCwd });
-                          } catch (dropError) {
-                            toastManager.add({
-                              type: "error",
-                              title: "Failed to drop stash.",
-                              description: toBranchActionErrorMessage(dropError),
-                            });
-                          }
-                        },
-                      },
-                    });
-                  } else {
-                    toastManager.add({
-                      type: "error",
-                      title: "Failed to stash and switch.",
-                      description: toBranchActionErrorMessage(stashError),
-                    });
-                  }
-                }
-              },
-            },
-          });
-          return;
-        }
-        if (isUnresolvedIndexError(error)) {
-          toastManager.add({
-            type: "error",
-            title: "Unresolved conflicts in the repository.",
-            description: toBranchActionErrorMessage(error),
-          });
-          return;
-        }
-        toastManager.add({
-          type: "error",
-          title: "Failed to create and checkout branch.",
-          description: toBranchActionErrorMessage(error),
+        handleCheckoutError(error, {
+          api,
+          cwd: branchCwd,
+          branch: name,
+          queryClient,
+          onSuccess: () => {
+            setOptimisticBranch(name);
+            onSetThreadBranch(name, activeWorktreePath);
+          },
+          fallbackTitle: "Failed to create and checkout branch.",
         });
       }
     });