Add Co-authored-by trailers to Merge's squash commit

web/src/api.gen.ts

@@ -160,6 +160,25 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/tasks/{taskId}/co-authors": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                taskId: string;
+            };
+            cookie?: never;
+        };
+        /** @description The humans other than the caller with a message in the task's transcript (sent its agent a message, or had an inbox answer delivered under their name), in order of their first message. A merge by the caller gives each one with a git identity a Co-authored-by trailer. */
+        get: operations["getCoAuthors"];
+        put?: never;
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/api/tasks/{taskId}/merge": {
         parameters: {
             query?: never;
@@ -171,7 +190,7 @@ export interface paths {
         };
         get?: never;
         put?: never;
-        /** @description Starts the same agent turn as merge-in. When that turn ends normally, byre squashes the task's worktree into one commit titled with the task's merge_title on the project's default branch, fast-forwards the project's checkout to it, then removes the worktree and branch and marks the task merged. Nothing is pushed. Refused while a turn is running or queued. */
+        /** @description Starts the same agent turn as merge-in. When that turn ends normally, byre squashes the task's worktree into one commit titled with the task's merge_title on the project's default branch, authored by the caller with a Co-authored-by trailer for each of the task's co-authors, pushes it to origin, fast-forwards the project's checkout to it, then removes the worktree and branch and marks the task merged. Refused while a turn is running or queued. */
         post: operations["mergeTask"];
         delete?: never;
         options?: never;
@@ -595,6 +614,13 @@ export interface components {
             /** @description Paths with uncommitted changes in the worktree. */
             uncommitted: number;
         };
+        Participant: {
+            login: string;
+            display_name: string;
+            /** @description Empty when the user hasn't set a git identity; they then get no trailer. */
+            git_name: string;
+            git_email: string;
+        };
         TaskCreate: {
             title: string;
         };
@@ -1163,6 +1189,29 @@ export interface operations {
             409: components["responses"]["Error"];
         };
     };
+    getCoAuthors: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                taskId: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description The co-authors. */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["Participant"][];
+                };
+            };
+            404: components["responses"]["Error"];
+        };
+    };
     mergeTask: {
         parameters: {
             query?: never;

web/src/api.ts

@@ -17,6 +17,7 @@ export type AgentProcess = Schemas["AgentProcess"];
 export type Zombie = Schemas["Zombie"];
 export type ProtocolErrors = Schemas["ProtocolErrors"];
 export type Snapshot = Schemas["Snapshot"];
+export type Participant = Schemas["Participant"];
 
 type Method = "get" | "post" | "put" | "delete";
 

web/src/task.ts

@@ -1,4 +1,4 @@
-import { get, post, type ByreEvent, type Snapshot } from "./api.js";
+import { get, post, type ByreEvent, type Participant, type Snapshot } from "./api.js";
 import { ago, errorText, h, replace, showAlert, showConfirm } from "./dom.js";
 import { markdown } from "./markdown.js";
 import { openChanges } from "./panes.js";
@@ -161,10 +161,18 @@ export function mountTranscript(root: HTMLElement): () => void {
       { disabled: busy || unmerged?.taskId !== task.id || !unmerged.has, title: `The agent merges ${target} in, then byre squashes into one commit on ${target} and pushes it to origin` },
       "Merge",
     );
-    merge.onclick = () =>
-      confirmThen(`Merge "${task.title}" into ${target}?`, "Merge", false, async () => {
+    merge.onclick = async () => {
+      let coAuthors;
+      try {
+        coAuthors = await get("/api/tasks/{taskId}/co-authors", { path: { taskId: task.id } });
+      } catch (err) {
+        void showAlert(errorText(err));
+        return;
+      }
+      await confirmThen(mergeQuestion(task.merge_title, target, coAuthors), "Merge", false, async () => {
         await post("/api/tasks/{taskId}/merge", { path: { taskId: task.id } });
       });
+    };
     const mergeIn = h("button", { disabled: busy, title: `Ask the agent to bring ${target} into this branch and resolve any conflicts` }, `Sync from ${target}`);
     mergeIn.onclick = async () => {
       mergeIn.disabled = true;
@@ -881,6 +889,19 @@ function messageImages(ids: unknown): HTMLElement | null {
   );
 }
 
+function mergeQuestion(title: string, target: string, coAuthors: Participant[]): string {
+  const lines = [`Merge "${title}" into ${target}?`];
+  const credited = coAuthors.filter((p) => p.git_name && p.git_email);
+  const missing = coAuthors.filter((p) => !p.git_name || !p.git_email);
+  if (credited.length > 0) {
+    lines.push("", "Co-authored-by:", ...credited.map((p) => `  ${p.git_name} <${p.git_email}>`));
+  }
+  if (missing.length > 0) {
+    lines.push("", "No git identity, so no trailer:", ...missing.map((p) => `  ${p.display_name} (${p.login})`));
+  }
+  return lines.join("\n");
+}
+
 async function confirmThen(question: string, action: string, danger: boolean, act: () => Promise<void>) {
   if (!(await showConfirm(question, action, danger))) {
     return;