Add submit update message field for multi-selected commits

Summary:
Like previous diff, but add it when you have multiple commits selected.

This is slightly hairy, because we try to save your edited messages, and yet the keying is by hash. So if you change your selection at all (or a succession happens), you'd lose your message.

I really don't think it should be a big deal—these update messages are supposed to be brief and simply explain what you changed, unlike the summary/ test plan.

Reviewed By: quark-zju

Differential Revision: D49339371

fbshipit-source-id: 47113d097e5e672e85f61365aadd23b8cd7272ae

addons/isl/src/CommitInfoView/CommitInfoView.tsx

@@ -107,6 +107,12 @@ export function MultiCommitInfo({selectedCommits}: {selectedCommits: Array<Commi
   const provider = useRecoilValue(codeReviewProvider);
   const diffSummaries = useRecoilValue(allDiffSummaries);
   const shouldSubmitAsDraft = useRecoilValue(submitAsDraft);
+  const commitsWithDiffs = selectedCommits.filter(commit => commit.diffId != null);
+  const [updateMessage, setUpdateMessage] = useRecoilState(
+    // Combine hashes to key the typed update message.
+    // This is kind of volatile, since if you change your selection at all, the message will be cleared.
+    diffUpdateMessagesState(selectedCommits.map(commit => commit.hash).join(',')),
+  );
   const submittable =
     (diffSummaries.value != null
       ? provider?.getSubmittableDiffs(selectedCommits, diffSummaries.value)
@@ -129,6 +135,9 @@ export function MultiCommitInfo({selectedCommits}: {selectedCommits: Array<Commi
         ))}
       </div>
       <div className="commit-info-actions-bar">
+        {commitsWithDiffs.length === 0 ? null : (
+          <SubmitUpdateMessageInput commits={selectedCommits} />
+        )}
         <div className="commit-info-actions-bar-left">
           <SubmitAsDraftCheckbox commitsToBeSubmit={selectedCommits} />
         </div>
@@ -139,8 +148,11 @@ export function MultiCommitInfo({selectedCommits}: {selectedCommits: Array<Commi
                 contextKey={'submit-selected'}
                 appearance="secondary"
                 runOperation={() => {
+                  // clear update message on submit
+                  setUpdateMessage('');
                   return unwrap(provider).submitOperation(selectedCommits, {
                     draft: shouldSubmitAsDraft,
+                    updateMessage: updateMessage || undefined,
                   });
                 }}>
                 <T>Submit Selected Commits</T>

addons/isl/src/SubmitUpdateMessageInput.tsx

@@ -24,6 +24,7 @@ export function SubmitUpdateMessageInput({commits}: {commits: Array<CommitInfo>}
   }
   return (
     <VSCodeTextField
+      style={{width: '100%'}}
       value={message}
       onChange={e => setMessage((e.target as HTMLInputElement).value)}>
       <T>Update Message</T>