feat(github): Post a stack comment on stacked pull requests

scripts/screenshot/specs/repository-settings-stack-comments.spec.tsx

@@ -0,0 +1,47 @@
+import * as React from "react";
+import { expect, it } from "vitest";
+import userEvent from "@testing-library/user-event";
+import { createTestRepo, openRepo } from "../../../test/utils";
+import { render, screen } from "../../../test/test-utils";
+import { Dashboard } from "../../../src/components/Dashboard";
+import { captureDocument } from "../capture";
+
+it("captures the stack comments toggle defaulting on and saving off", async () => {
+	const { repoPath } = createTestRepo(false);
+	openRepo(repoPath);
+
+	const user = userEvent.setup();
+	render(<Dashboard />);
+
+	await user.click(await screen.findByLabelText("Settings"));
+	await screen.findByRole("tab", { name: /repository/i, selected: true });
+
+	const toggle = await screen.findByRole("switch", {
+		name: /post stack comments on pull requests/i,
+	});
+	expect(toggle).toHaveAttribute("aria-checked", "true");
+
+	await captureDocument(document, {
+		name: "repository-settings-stack-comments-01-default-on",
+		viewport: { width: 1440, height: 1200 },
+		expectations: [
+			"The Repository tab shows a 'Post stack comments on pull requests' row below 'Ignore generated Treq paths'.",
+			"The row's description says the comment lists the merge order and is visible to everyone on GitHub.",
+			"The Post stack comments switch is in the on (checked) position.",
+		],
+	});
+
+	await user.click(toggle);
+	expect(toggle).toHaveAttribute("aria-checked", "false");
+	await user.click(screen.getByRole("button", { name: /save settings/i }));
+	await screen.findByText("Settings saved");
+
+	await captureDocument(document, {
+		name: "repository-settings-stack-comments-02-off-and-saved",
+		viewport: { width: 1440, height: 1200 },
+		expectations: [
+			"The Post stack comments switch is in the off (unchecked) position.",
+			"A 'Settings saved' toast is visible confirming the save.",
+		],
+	});
+}, 60000);

src-tauri/src/commands/github.rs

@@ -404,6 +404,31 @@ pub async fn gh_create_pr(
   .map_err(|e| format!("Failed to join gh_create_pr task: {}", e))?
 }
 
+/// Post or refresh the stack comment on every open PR in `head_branch`'s
+/// stack. The frontend calls this only after `gh_create_pr` has returned,
+/// so a failure here cannot fail PR creation.
+#[tauri::command]
+pub async fn gh_sync_stack_comments(
+  repo_path: String,
+  repo_full_name: String,
+  head_branch: String,
+) -> Result<crate::core::stack_comments::StackCommentOutcome, String> {
+  // A missing `gh` is only an error once the core finds a stack to comment on.
+  let gh = gh_bin().ok();
+  let extended_path = get_extended_path();
+  tauri::async_runtime::spawn_blocking(move || {
+    crate::core::stack_comments::sync_stack_comments(
+      &repo_path,
+      &repo_full_name,
+      &head_branch,
+      gh.as_deref(),
+      &extended_path,
+    )
+  })
+  .await
+  .map_err(|e| format!("Failed to join gh_sync_stack_comments task: {e}"))?
+}
+
 #[cfg(test)]
 mod tests {
   use std::fs;

src-tauri/src/core/mod.rs

@@ -27,6 +27,7 @@ pub mod repo;
 pub mod resolve;
 pub mod sessions;
 pub mod skills;
+pub mod stack_comments;
 pub mod stash;
 pub mod submodules;
 pub mod workspaces;