perf(push): parallelize blob creation within a batch commit

User reported push-all was still slow on GitHub after the one-
commit-per-run batching landed. Root cause: GitHubService/
GiteaService.pushBatch still created each file's blob with a
sequential for loop -- one POST .../git/blobs awaited fully before
the next started -- so wall-clock time was still O(N) round trips of
pure latency even though only one commit came out the other end.

- Add BaseGitService.mapWithConcurrency<T,R>: an order-preserving,
  bounded-concurrency mapper (worker-pool over a shared cursor).
- Add BLOB_CREATE_CONCURRENCY = 8 alongside MAX_BATCH_PUSH_SIZE.
- GitHubService/GiteaService.pushBatch now create blobs via
  mapWithConcurrency instead of a for loop; the tree/commit/ref
  sequence after it is unchanged since each step genuinely depends on
  the previous one's result.
- GitLab is unaffected -- its pushBatch already sends the whole batch
  in one Commits API request, no per-file blob step to parallelize.

Added a regression-guard test: deferred blob-response promises that
only resolve after every blob POST has been dispatched, so a
reintroduced sequential loop deadlocks the test instead of silently
passing.

Evidence: npx eslint . -> 0 errors; npm run build -> clean;
npx vitest run -> 340/340 passed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

feature_list.json

@@ -97,6 +97,14 @@
       "dependencies": ["feat-011"],
       "status": "done",
       "evidence": "npx eslint . -> 0 errors; npm run build -> clean; npx vitest run -> 339/339 passed; consolidated onto PR #51"
+    },
+    {
+      "id": "feat-013",
+      "name": "perf(push): parallelize blob creation within a batch commit",
+      "description": "User reported push-all was still slow on GitHub after feat-011's one-commit-per-run batching landed. Root cause: GitHubService/GiteaService.pushBatch still created each file's blob with a sequential `for` loop (N sequential POST .../git/blobs round trips before the single tree/commit/ref sequence), so wall-clock time was still O(N) latency-bound. Added a shared BaseGitService.mapWithConcurrency helper (order-preserving, bounded concurrency) and a BLOB_CREATE_CONCURRENCY=8 cap in git-service-base.ts; both services' pushBatch now creates blobs concurrently instead of one at a time. GitLab unaffected (its Commits API already sends the whole batch in one request, no per-file blob step)",
+      "dependencies": ["feat-011"],
+      "status": "done",
+      "evidence": "npx eslint . -> 0 errors; npm run build -> clean; npx vitest run -> 340/340 passed; consolidated onto PR #51"
     }
   ],
   "_evidenceStyle": "Keep evidence to one line: commit hash + short pointer (e.g. 'Commit abc1234 - added X, tests pass'). Debugging narrative and design discussion belong in the commit message, not this file."

progress.md

@@ -12,9 +12,9 @@ Completed work is archived in [archive/](./archive/), one file per calendar mont
 
 ## Current State
 
-**Last Updated:** 2026-07-14 10:30
+**Last Updated:** 2026-07-14 10:45
 **Session ID:** current
-**Active Feature:** feat-012 (perf: batch-commit remote-only file deletion) — done, lint/build/test all green. feat-011 (push-all batching) also done this session. Previous active item (issue #78 delete-remote-only-file fix) still awaiting user re-test after rebuild.
+**Active Feature:** feat-013 (perf: parallelize blob creation in batch push) — done, lint/build/test all green. feat-011/feat-012 (push-all + delete batching) also done this session. Previous active item (issue #78 delete-remote-only-file fix) still awaiting user re-test after rebuild.
 
 ## Status
 
@@ -54,6 +54,15 @@ Completed work is archived in [archive/](./archive/), one file per calendar mont
   - Evidence: `npx eslint .` → 0 errors; `npm run build` → clean; `npx vitest run` → 339/339 passed.
   - Not yet committed as of this note — pending commit onto `claude/fix-directory-symlink-pull-260713`.
 
+- [x] feat-013: perf(push): parallelize blob creation within a batch commit. User reported "batch push 還是很慢" (batch push is still slow) after feat-011/feat-012 landed; confirmed they were on GitHub with the latest build. Root cause found by re-reading `GitHubService.pushBatch`/`GiteaService.pushBatch`: the blob-creation step was still a sequential `for` loop — one `POST .../git/blobs` awaited fully before the next started — so wall-clock time for the batch was still O(N) network round trips of pure latency, even though only one commit was produced at the end. This was a known, called-out tradeoff from feat-011's plan ("sequential is fine... could be Promise.all'd for extra speed, but... note as a possible future optimization"); the user's report made it worth doing now.
+  - Added `BaseGitService.mapWithConcurrency<T,R>(items, concurrency, fn)` (`git-service-base.ts`): order-preserving, bounded-concurrency mapper (worker-pool pattern over a shared cursor, `Promise.all` over `Math.min(concurrency, items.length)` workers).
+  - Added `BLOB_CREATE_CONCURRENCY = 8` constant alongside `MAX_BATCH_PUSH_SIZE`.
+  - `GitHubService.pushBatch`/`GiteaService.pushBatch` now build blobs via `mapWithConcurrency` instead of a `for` loop; the tree/commit/ref sequence after it is unchanged (genuinely sequential — each step depends on the previous one's result).
+  - GitLab unaffected — its `pushBatch` already sends the whole batch in one Commits API request, no per-file blob step to parallelize.
+  - Added a regression-guard test (`github-service.test.ts`): deferred blob-response promises that only resolve after every blob POST has been dispatched — a reintroduced sequential loop would deadlock on this test (call 2 never fires until call 1's promise resolves, which it doesn't), so it fails loudly if someone reverts to sequential.
+  - Evidence: `npx eslint .` → 0 errors; `npm run build` → clean; `npx vitest run` → 340/340 passed.
+  - Not yet committed as of this note — pending commit onto `claude/fix-directory-symlink-pull-260713`.
+
 ### What's In Progress
 
 - Nothing else actively in progress.
@@ -61,7 +70,7 @@ Completed work is archived in [archive/](./archive/), one file per calendar mont
 ### What's Next
 
 1. Get user confirmation that delete now works (or a new detailed error message) after they rebuild/reload with the latest push (issue #78).
-2. Manually verify feat-011/feat-012 in Obsidian if possible: push-all and batch-delete on a mixed vault should each produce exactly one new commit.
+2. Manually verify feat-011/feat-012/feat-013 in Obsidian if possible: push-all and batch-delete on a mixed vault should each produce exactly one new commit, and push-all should now feel noticeably faster on GitHub/Gitea (blobs created concurrently, up to 8 in flight).
 3. Issue #37 (Bitbucket provider support, feat-010) — large, was deferred until #38 (i18n) landed. Now unblocked. Its `GitServiceInterface` implementation should simply omit `pushBatch`/`deleteBatch` and use the existing per-file fallbacks.
 4. Re-sync against `gh issue list --repo firstsun-dev/git-files-sync --state open`. Remaining genuinely-unstarted issues as of this session: #47 (regex ignore lists), #45 (SonarQube findings), #37 (Bitbucket), #28 (non-engineering: community visibility).
 5. PR #51 is large (8+ issues' worth of changes now). If the user wants to review/merge it before more work piles on, flag this rather than continuing to add commits indefinitely.

src/services/git-service-base.ts

@@ -59,6 +59,14 @@ export interface ConnectionTestResult {
  * bodies / provider payload limits when a vault has thousands of files. */
 export const MAX_BATCH_PUSH_SIZE = 200;
 
+/** How many blob-creation requests to have in flight at once when building a
+ * batch commit. Creating each file's blob is an independent request with no
+ * ordering dependency, so running them one-at-a-time (as opposed to the final
+ * tree/commit/ref sequence, which genuinely is sequential) just adds N
+ * round trips of pure latency. A moderate cap keeps this fast without
+ * bursting past a provider's abuse-detection/secondary rate limits. */
+export const BLOB_CREATE_CONCURRENCY = 8;
+
 export abstract class BaseGitService {
     protected token: string = '';
     protected rootPath: string = '';
@@ -320,6 +328,25 @@ export abstract class BaseGitService {
         return newCommitSha;
     }
 
+    /**
+     * Runs `fn` over `items` with at most `concurrency` calls in flight at
+     * once, preserving result order. Used to parallelize independent
+     * per-file requests (e.g. blob creation) that would otherwise pay N
+     * round trips of latency running one at a time.
+     */
+    protected async mapWithConcurrency<T, R>(items: T[], concurrency: number, fn: (item: T, index: number) => Promise<R>): Promise<R[]> {
+        const results = new Array<R>(items.length);
+        let nextIndex = 0;
+        const worker = async (): Promise<void> => {
+            while (nextIndex < items.length) {
+                const i = nextIndex++;
+                results[i] = await fn(items[i] as T, i);
+            }
+        };
+        await Promise.all(Array.from({ length: Math.min(concurrency, items.length) }, worker));
+        return results;
+    }
+
     async getRepoGitignores(branch: string): Promise<string[]> {
         try {
             const allFiles = await this.listFiles(branch, false); // Fetch ALL files to find gitignores

src/services/gitea-service.ts

@@ -1,5 +1,5 @@
 import { GitServiceInterface, GitTreeEntry, BatchPushItem, BatchPushResult } from './git-service-interface';
-import { BaseGitService, ConnectionTestResult, GitFile, GitHubContentResponse, GitHubTreeResponse, GIT_SYMLINK_MODE } from './git-service-base';
+import { BaseGitService, ConnectionTestResult, GitFile, GitHubContentResponse, GitHubTreeResponse, GIT_SYMLINK_MODE, BLOB_CREATE_CONCURRENCY } from './git-service-base';
 import { logger } from '../utils/logger';
 
 export class GiteaService extends BaseGitService implements GitServiceInterface {
@@ -80,14 +80,13 @@ export class GiteaService extends BaseGitService implements GitServiceInterface
         const base = this.getGitDataApiBase();
         const { latestCommitSha, baseTreeSha } = await this.resolveBaseTree(branch);
 
-        const blobShas: string[] = [];
-        for (const item of items) {
+        const blobShas = await this.mapWithConcurrency(items, BLOB_CREATE_CONCURRENCY, async item => {
             const blobResp = await this.safeRequest(`${base}/git/blobs`, 'POST', {
                 content: this.encodeContent(item.content),
                 encoding: 'base64',
             });
-            blobShas.push(this.parseJson<{ sha: string }>(blobResp).sha);
-        }
+            return this.parseJson<{ sha: string }>(blobResp).sha;
+        });
 
         const treeItems = items.map((item, i) => ({
             path: this.getFullPath(item.path),

src/services/github-service.ts

@@ -1,5 +1,5 @@
 import { GitServiceInterface, GitTreeEntry, BatchPushItem, BatchPushResult } from './git-service-interface';
-import { BaseGitService, ConnectionTestResult, GitFile, GitHubContentResponse, GitHubTreeResponse, GIT_SYMLINK_MODE } from './git-service-base';
+import { BaseGitService, ConnectionTestResult, GitFile, GitHubContentResponse, GitHubTreeResponse, GIT_SYMLINK_MODE, BLOB_CREATE_CONCURRENCY } from './git-service-base';
 import { logger } from '../utils/logger';
 
 export class GitHubService extends BaseGitService implements GitServiceInterface {
@@ -92,14 +92,13 @@ export class GitHubService extends BaseGitService implements GitServiceInterface
         const base = this.getGitDataApiBase();
         const { latestCommitSha, baseTreeSha } = await this.resolveGitHubStyleBaseTree(branch);
 
-        const blobShas: string[] = [];
-        for (const item of items) {
+        const blobShas = await this.mapWithConcurrency(items, BLOB_CREATE_CONCURRENCY, async item => {
             const blobResp = await this.safeRequest(`${base}/git/blobs`, 'POST', {
                 content: this.encodeContent(item.content),
                 encoding: 'base64',
             });
-            blobShas.push(this.parseJson<{ sha: string }>(blobResp).sha);
-        }
+            return this.parseJson<{ sha: string }>(blobResp).sha;
+        });
 
         const treeItems = items.map((item, i) => ({
             path: this.getFullPath(item.path),

tests/services/github-service.test.ts

@@ -144,6 +144,50 @@ describe('GitHubService', () => {
             expect(calls[6]?.method).toBe('PATCH');
             expect(JSON.parse(calls[6]?.body as string)).toEqual({ sha: 'commit2' });
         });
+
+        it('creates blobs concurrently, not one at a time (regression guard against a sequential loop)', async () => {
+            // Deferred blob responses: none of them resolve until every blob
+            // POST has already been dispatched. A sequential `for` loop would
+            // deadlock here since call N+1 never fires until call N resolves.
+            const blobDeferreds = Array.from({ length: 4 }, () => {
+                let resolve!: (v: RequestUrlResponse) => void;
+                const promise = new Promise<RequestUrlResponse>(r => { resolve = r; });
+                return { promise, resolve };
+            });
+            let blobCallCount = 0;
+
+            vi.mocked(requestUrl).mockImplementation(((param: string | RequestUrlParam) => {
+                const url = (param as RequestUrlParam).url;
+                if (url.endsWith('/git/ref/heads/main')) {
+                    return Promise.resolve({ status: 200, json: { object: { sha: 'commit1' } } } as unknown as RequestUrlResponse);
+                }
+                if (url.includes('/git/commits/commit1')) {
+                    return Promise.resolve({ status: 200, json: { tree: { sha: 'tree1' } } } as unknown as RequestUrlResponse);
+                }
+                if (url.endsWith('/git/blobs')) {
+                    return blobDeferreds[blobCallCount++]!.promise;
+                }
+                if (url.endsWith('/git/trees')) {
+                    return Promise.resolve({ status: 201, json: { sha: 'tree2' } } as unknown as RequestUrlResponse);
+                }
+                if (url.endsWith('/git/commits')) {
+                    return Promise.resolve({ status: 201, json: { sha: 'commit2' } } as unknown as RequestUrlResponse);
+                }
+                return Promise.resolve({ status: 200, json: {} } as unknown as RequestUrlResponse);
+            }) as unknown as typeof requestUrl);
+
+            const items = Array.from({ length: 4 }, (_, i) => ({ path: `f${i}.md`, content: `content${i}` }));
+            const resultPromise = service.pushBatch(items, 'main', 'push');
+
+            // Wait for every blob POST to have been dispatched — a sequential
+            // loop would never get past the first one, since its promise never resolves.
+            await vi.waitFor(() => expect(blobCallCount).toBe(4));
+
+            blobDeferreds.forEach((d, i) => d.resolve({ status: 201, json: { sha: `blob-${i}` } } as unknown as RequestUrlResponse));
+            const result = await resultPromise;
+
+            expect(result).toEqual(items.map((item, i) => ({ path: item.path, sha: `blob-${i}` })));
+        });
     });
 
     describe('pushFile', () => {