feat: queue screenshot comments offline (Closes #477)

README.md

@@ -20,8 +20,11 @@ list repository labels and open milestones, set or clear due dates on assigned i
 inspect/comment on assigned pull
 requests, merge assigned pull requests, and submit pull-request reviews.
 Assigned-issue comments can include one PNG, JPEG, or WebP screenshot up to 2 MB.
-The screenshot uploads before the comment is posted; validation or upload failures keep
-both the typed comment and removable preview available for retry. The mobile **New issue**
+For online delivery, the screenshot uploads before the comment is posted; validation or upload
+failures keep both the typed comment and removable preview available for retry. Offline screenshot comments
+admit their text and image bytes to IndexedDB before confirmation, keep only bounded metadata in
+localStorage, and use checkpointed upload/comment identities so reconnect retries cannot duplicate
+either stage. The mobile **New issue**
 sheet accepts the same image formats and stores the screenshot with its account-bound
 outbox capture. Durable admission writes the complete screenshot capture to IndexedDB
 before confirmation; localStorage keeps only bounded attachment metadata, avoiding base64

frontend/authored-outbox.js

@@ -74,6 +74,13 @@ function createAuthoredOutbox({ storage, fetchJson, coordinator, backgroundSync,
       ownerLogin,
       status: 'queued',
       queuedAt: Number(now()),
+      ...(message.kind === 'issue-comment' && message.attachment ? {
+        attachment: {
+          filename: String(message.attachment.filename || ''),
+          contentType: String(message.attachment.contentType || ''),
+          stored: true,
+        },
+      } : {}),
       ...(message.kind === 'pull-review' ? {
         decision: String(message.decision || 'comment'),
         expectedHeadSha: String(message.expectedHeadSha || ''),
@@ -94,8 +101,21 @@ function createAuthoredOutbox({ storage, fetchJson, coordinator, backgroundSync,
     if (!backgroundSync?.reconcile || !backgroundSync?.requestSync) {
       return { item, background: false, durability: 'foreground-only' };
     }
+    const durableItems = read().map(candidate => candidate.id === item.id && message.attachment ? {
+      ...candidate,
+      attachment: {
+        filename: String(message.attachment.filename || ''),
+        contentType: String(message.attachment.contentType || ''),
+        data: String(message.attachment.data || ''),
+      },
+    } : candidate);
+    try {
+      await backgroundSync.reconcile(durableItems, 'authored');
+    } catch (error) {
+      write(read().filter(candidate => candidate.id !== item.id), false);
+      throw error;
+    }
     try {
-      await backgroundSync.reconcile(read(), 'authored');
       await backgroundSync.requestSync();
       return { item, background: true, durability: 'background' };
     } catch (error) {

frontend/background-issue-sync.js

@@ -410,11 +410,53 @@ function createBackgroundIssueSync({
     return deliveredIssue;
   }
 
+  async function deliverScreenshotComment(item) {
+    const repository = String(item.repository || '').split('/').map(encodeURIComponent).join('/');
+    let attachmentMarkdown = item.attachmentMarkdown;
+    if (!attachmentMarkdown) {
+      const uploaded = await requestJson(
+        base + 'api/v1/repos/' + repository + '/issues/' + encodeURIComponent(item.number) + '/attachments',
+        {
+          method: 'POST',
+          headers: {
+            Accept: 'application/json', 'Content-Type': 'application/json',
+            'Idempotency-Key': stageOperationId(item.operationId, 'attachment'),
+          },
+          body: JSON.stringify({
+            filename: item.attachment.filename,
+            content_type: item.attachment.contentType,
+            data: item.attachment.data,
+          }),
+        },
+      );
+      attachmentMarkdown = String(uploaded?.markdown || '');
+      if (!attachmentMarkdown) {
+        const error = new Error('The server did not confirm the screenshot upload.');
+        error.status = 422;
+        throw error;
+      }
+      await store.update?.(item.id, current => ({ ...current, attachmentMarkdown }));
+    }
+    const text = String(item.body || '').trim();
+    return requestJson(
+      base + 'api/v1/repos/' + repository + '/issues/' + encodeURIComponent(item.number) + '/comments',
+      {
+        method: 'POST',
+        headers: {
+          Accept: 'application/json', 'Content-Type': 'application/json',
+          'Idempotency-Key': stageOperationId(item.operationId, 'comment'),
+        },
+        body: JSON.stringify({ body: text ? text + '\n\n' + attachmentMarkdown : attachmentMarkdown }),
+      },
+    );
+  }
+
   async function deliver(item) {
     const request = deliveryRequest(item);
     try {
-      const delivered = item.attachment && !item.kind ?
-        await deliverIssueCapture(item) : await requestJson(request.url, request.options);
+      const delivered = item.attachment && item.kind === 'issue-comment' ?
+        await deliverScreenshotComment(item) : item.attachment && !item.kind ?
+          await deliverIssueCapture(item) : await requestJson(request.url, request.options);
       if (item.kind === 'issue-close' && delivered?.state !== 'closed') {
         const error = new Error('Issue closure was not confirmed.');
         error.status = 422;

frontend/comment-next.js

@@ -1,6 +1,20 @@
 function createCommentNext({ post, queue, queueKind = '', canQueue, accept = () => undefined, complete }) {
   let inFlight = null;
 
+  async function admitQueued(item, message) {
+    const admission = await queue(message);
+    if (!admission || (!admission.item && admission.durable !== true)) {
+      throw new Error('Comment was not saved for delivery.');
+    }
+    accept(item, { delivery: admission.background ? 'queued' : 'saved' });
+    return {
+      accepted: true,
+      delivery: admission.background ? 'queued' : 'saved',
+      background: Boolean(admission.background),
+      completed: Boolean(complete(item)),
+    };
+  }
+
   function submit(item, body, operationId = '') {
     if (inFlight) return inFlight;
     inFlight = (async () => {
@@ -16,20 +30,10 @@ function createCommentNext({ post, queue, queueKind = '', canQueue, accept = ()
             kind: item.kind === 'pull' ? 'pull-comment' : 'issue-comment',
             repository: item.repository, number: item.number,
           };
-          const admission = await queue({
+          return admitQueued(item, {
             ...identity, body,
             operationId: typeof operationId === 'function' ? operationId() : operationId,
           });
-          if (!admission || (!admission.item && admission.durable !== true)) {
-            throw new Error('Comment was not saved for delivery.');
-          }
-          accept(item, { delivery: admission.background ? 'queued' : 'saved' });
-          return {
-            accepted: true,
-            delivery: admission.background ? 'queued' : 'saved',
-            background: Boolean(admission.background),
-            completed: Boolean(complete(item)),
-          };
         }
         accept(item, { delivery: 'posted', comment });
         return {
@@ -45,7 +49,13 @@ function createCommentNext({ post, queue, queueKind = '', canQueue, accept = ()
     return inFlight;
   }
 
-  return { submit, busy: () => Boolean(inFlight) };
+  function admit(item, message) {
+    if (inFlight) return inFlight;
+    inFlight = admitQueued(item, message).finally(() => { inFlight = null; });
+    return inFlight;
+  }
+
+  return { submit, admit, busy: () => Boolean(inFlight) };
 }
 
 if (typeof module !== 'undefined' && module.exports) module.exports = createCommentNext;

frontend/dashboard.js

@@ -3795,6 +3795,19 @@
       qs('#issue-milestone').disabled = false;
     }
   });
+  async function queueIssueScreenshotComment(item, body, operationId, advance = false) {
+    const message = {
+      kind: 'issue-comment', repository: item.repository, number: item.number, body,
+      operationId: operationId || globalThis.crypto?.randomUUID?.() || String(Date.now()),
+      attachment: await issueAttachmentController.serialize(),
+    };
+    if (advance) return await issueCommentNext.admit(item, message);
+    const admission = await authoredOutbox.enqueueDurably(message);
+    issueController.saveDraft(item, '');
+    if (selectedIssue === item) qs('#issue-comment').value = '';
+    return admission;
+  }
+
   async function submitCommentAndNext(kind) {
     const item = kind === 'issue' ? selectedIssue : selectedPull;
     if (!item || !workSession.checkpointed(item)) return;
@@ -3816,9 +3829,20 @@
     status.textContent = kind === 'issue' && issueAttachmentController.state() ?
       'Uploading screenshot before opening next…' : 'Posting comment and opening next…';
     try {
-      const preparedBody = kind === 'issue' ?
-        await issueAttachmentController.prepareComment(item, body) : body;
-      const result = await controller.submit(item, preparedBody, operationId);
+      let result;
+      if (kind === 'issue' && issueAttachmentController.state() && navigator.onLine === false) {
+        result = await queueIssueScreenshotComment(item, body, operationId(), true);
+      } else {
+        let preparedBody;
+        try {
+          preparedBody = kind === 'issue' ?
+            await issueAttachmentController.prepareComment(item, body) : body;
+        } catch (error) {
+          if (kind !== 'issue' || !issueAttachmentController.state() || !canQueueMessage(error)) throw error;
+          result = await queueIssueScreenshotComment(item, body, operationId(), true);
+        }
+        if (!result) result = await controller.submit(item, preparedBody, operationId);
+      }
       const stillOpen = kind === 'issue' ? selectedIssue === item : selectedPull === item;
       if (!stillOpen) return;
       if (kind === 'issue') issueAttachmentController.clear();
@@ -3850,8 +3874,34 @@
       'Uploading screenshot…' : 'Posting comment…';
     let preparedBody;
     try {
+      if (issueAttachmentController.state() && navigator.onLine === false) {
+        const operationId = localStorage.getItem('stackchain.issue-comment.v1:' + selectedIssue.repository + '#' + selectedIssue.number + ':operation');
+        const admission = await queueIssueScreenshotComment(selectedIssue, body, operationId);
+        refreshMyWorkView();
+        issueAttachmentController.clear();
+        qs('#issue-comment-status').textContent = admission.background ?
+          'Queued with screenshot for sync when the connection returns.' :
+          'Saved with screenshot for next launch; background delivery unavailable.';
+        button.disabled = false;
+        return;
+      }
       preparedBody = await issueAttachmentController.prepareComment(selectedIssue, body);
     } catch (error) {
+      if (issueAttachmentController.state() && canQueueMessage(error)) {
+        try {
+          const operationId = localStorage.getItem('stackchain.issue-comment.v1:' + selectedIssue.repository + '#' + selectedIssue.number + ':operation');
+          const admission = await queueIssueScreenshotComment(selectedIssue, body, operationId);
+          refreshMyWorkView();
+          issueAttachmentController.clear();
+          qs('#issue-comment-status').textContent = admission.background ?
+            'Queued with screenshot for sync when the connection returns.' :
+            'Saved with screenshot for next launch; background delivery unavailable.';
+          button.disabled = false;
+          return;
+        } catch (admissionError) {
+          error = admissionError;
+        }
+      }
       qs('#issue-comment-status').textContent = error.message + ' Your comment and screenshot are safe; retry.';
       qs('#issue-comment').focus();
       button.disabled = false;

tests/test_authored_outbox.py

@@ -425,3 +425,52 @@ async def test_mobile_dashboard_loads_and_operates_authored_message_outbox():
     assert "if (result?.queued)" in html
     assert "backgroundSync: backgroundIssueSync" in html
     assert "authoredOutbox.reconcileBackground(records)" in html
+
+
+def test_screenshot_comment_admits_bytes_to_indexeddb_without_putting_them_in_localstorage():
+    script = f"""
+const createAuthoredOutbox = require({json.dumps(str(OUTBOX))});
+const values = new Map(); const mirrors=[];
+const storage = {{getItem:k=>values.get(k)||null,setItem:(k,v)=>values.set(k,v),removeItem:k=>values.delete(k)}};
+const outbox=createAuthoredOutbox({{
+  storage,getOwnerLogin:()=>'timmy',
+  backgroundSync:{{reconcile:async(items,lane)=>mirrors.push({{items,lane}}),requestSync:async()=>{{}}}},
+}});
+(async()=>{{
+  const admission=await outbox.enqueueDurably({{
+    kind:'issue-comment',repository:'stackchain/dashboard',number:477,
+    body:'Broken at 320px',operationId:'comment-image-477',
+    attachment:{{filename:'phone.png',contentType:'image/png',data:'PRIVATE-IMAGE-BYTES'}},
+  }});
+  process.stdout.write(JSON.stringify({{admission,local:values.get('stackchain.authored-outbox.v1'),mirrored:mirrors[0]}}));
+}})();
+"""
+    output = run_node(script)
+
+    assert "PRIVATE-IMAGE-BYTES" not in output["local"]
+    local_item = json.loads(output["local"])["items"][0]
+    assert local_item["attachment"] == {
+        "filename": "phone.png", "contentType": "image/png", "stored": True
+    }
+    assert output["mirrored"]["lane"] == "authored"
+    assert output["mirrored"]["items"][0]["attachment"]["data"] == "PRIVATE-IMAGE-BYTES"
+    assert output["admission"]["durability"] == "background"
+
+
+def test_screenshot_comment_failed_indexeddb_admission_is_not_accepted_locally():
+    script = f"""
+const createAuthoredOutbox=require({json.dumps(str(OUTBOX))});
+const values=new Map();
+const storage={{getItem:k=>values.get(k)||null,setItem:(k,v)=>values.set(k,v),removeItem:k=>values.delete(k)}};
+const outbox=createAuthoredOutbox({{storage,getOwnerLogin:()=>'timmy',backgroundSync:{{
+  reconcile:async()=>{{throw new Error('IndexedDB unavailable');}},requestSync:async()=>{{}},
+}}}});
+(async()=>{{
+  let error='';try{{await outbox.enqueueDurably({{kind:'issue-comment',repository:'o/r',number:1,
+    body:'Keep me',operationId:'image-op',attachment:{{filename:'a.png',contentType:'image/png',data:'abc'}}}});}}
+  catch(caught){{error=caught.message;}}
+  process.stdout.write(JSON.stringify({{error,items:outbox.list()}}));
+}})();
+"""
+    output = run_node(script)
+    assert output == {"error": "IndexedDB unavailable", "items": []}

tests/test_background_issue_sync.py

@@ -129,6 +129,43 @@ createBackgroundIssueSync({{store,fetchJson}}).flush().then(()=>process.stdout.w
     assert all(len(key) <= 128 for key in keys)
 
 
+def test_screenshot_comment_retry_reuses_upload_checkpoint_and_posts_combined_body_once():
+    script = f"""
+const createBackgroundIssueSync=require({json.dumps(str(SYNC))});
+let item={{id:'message-image',operationId:'message-image',ownerLogin:'timmy',status:'queued',
+  kind:'issue-comment',repository:'stackchain/dashboard',number:477,body:'Broken at 320px',
+  attachment:{{filename:'phone.png',contentType:'image/png',data:'iVBORw0KGgo='}}}};
+const state={{calls:[],released:0,completed:0}};let commentAttempts=0;
+const store={{claimNext:async()=>item?{{...item}}:null,update:async(_id,transform)=>{{item=transform(item);}},
+  complete:async()=>{{state.completed++;item=null;}},release:async()=>{{state.released++;item={{...item,status:'queued'}};}},
+  fail:async()=>{{}},countBlocked:async()=>0}};
+const fetchJson=async(url,options={{}})=>{{
+  if(url==='api/v1/background-identity')return{{login:'timmy'}};
+  state.calls.push({{url,key:options.headers?.['Idempotency-Key'],body:options.body&&JSON.parse(options.body)}});
+  if(url.endsWith('/attachments'))return{{markdown:'![phone.png](https://forge.example/phone.png)'}};
+  if(commentAttempts++===0){{const error=new Error('Comment unavailable');error.status=503;throw error;}}
+  return{{id:91}};
+}};
+(async()=>{{const sync=createBackgroundIssueSync({{store,fetchJson}});let firstError='';
+  try{{await sync.flush();}}catch(error){{firstError=error.message;}}
+  const checkpoint={{...item}};const second=await sync.flush();
+  process.stdout.write(JSON.stringify({{state,firstError,checkpoint,second}}));
+}})();
+"""
+    output = run_node(script)
+
+    assert output["firstError"] == "Comment unavailable"
+    assert output["checkpoint"]["attachmentMarkdown"].startswith("![phone.png]")
+    assert sum(call["url"].endswith("/attachments") for call in output["state"]["calls"]) == 1
+    comments = [call for call in output["state"]["calls"] if call["url"].endswith("/comments")]
+    assert [call["key"] for call in comments] == ["message-image:comment"] * 2
+    assert comments[-1]["body"] == {
+        "body": "Broken at 320px\n\n![phone.png](https://forge.example/phone.png)"
+    }
+    assert output["state"]["completed"] == 1
+    assert output["second"]["confirmed"] == [{"id": 91}]
+
+
 def test_closed_app_sync_retains_created_issue_for_create_and_start_recovery():
     script = f"""
 const createBackgroundIssueSync = require({json.dumps(str(SYNC))});

tests/test_comment_next.py

@@ -254,6 +254,30 @@ process.stdout.write(JSON.stringify({{
     }
 
 
+def test_comment_and_next_can_admit_a_complete_screenshot_message_before_advancing():
+    script = f"""
+const createCommentNext=require({json.dumps(str(COMMENT_NEXT))});
+const calls=[];
+const controller=createCommentNext({{
+  post:()=>{{throw new Error('must not post');}},canQueue:()=>true,
+  queue:async message=>{{calls.push({{queue:message}});return{{item:{{id:'queued'}},background:true}};}},
+  accept:item=>calls.push({{accept:item.number}}),
+  complete:item=>{{calls.push({{complete:item.number}});return true;}},
+}});
+(async()=>{{const item={{kind:'issue',repository:'stackchain/dashboard',number:477}};
+  const result=await controller.admit(item,{{kind:'issue-comment',repository:item.repository,number:item.number,
+    body:'Mobile evidence',operationId:'image-op',attachment:{{filename:'phone.png',contentType:'image/png',data:'abc'}}}});
+  process.stdout.write(JSON.stringify({{result,calls}}));
+}})();
+"""
+    output = json.loads(run_node(script))
+    assert output["result"] == {
+        "accepted": True, "delivery": "queued", "background": True, "completed": True
+    }
+    assert output["calls"][0]["queue"]["attachment"]["data"] == "abc"
+    assert output["calls"][1:] == [{"accept": 477}, {"complete": 477}]
+
+
 @pytest.mark.anyio
 async def test_mobile_composers_offer_comment_and_next_only_for_today_checkpoint():
     html = await dashboard()

tests/test_issue_attachment_ui.py

@@ -252,3 +252,13 @@ def test_readme_documents_mobile_screenshot_limits_and_delivery_order():
     assert "uploads before the comment is posted" in readme
     assert "New issue" in readme
     assert "retry resumes with the confirmed issue" in readme
+
+
+def test_issue_screenshot_comments_queue_serialized_bytes_before_clearing_or_advancing():
+    source = DASHBOARD.read_text()
+
+    assert "async function queueIssueScreenshotComment" in source
+    assert "attachment: await issueAttachmentController.serialize()" in source
+    assert "await authoredOutbox.enqueueDurably(message)" in source
+    assert "await issueCommentNext.admit(item, message)" in source
+    assert "navigator.onLine === false" in source