fix(pack): output_root & doc update

[fireairforce]

Summary

output_root cause project chunk load error: #2582 (comment)

Doc config cause build error like:

Test Plan

[gemini-code-assist]

Summary of Changes

Hello @fireairforce, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses critical issues related to project build configurations and documentation accuracy. It corrects a bug where client-side chunk loading failed due to an incorrect output root path, ensuring proper asset resolution. Additionally, it updates the pack package's README.md to reflect the current API for build and dev functions, preventing configuration-related build errors for users following the documentation.

Highlights

• Output Root Fix: Resolved an issue where output_root was incorrectly using dist_root(), leading to project chunk load errors, by switching to client_root().
• Documentation Update: Updated the README.md examples for build and dev functions to correctly pass configuration parameters within a config object, addressing build errors caused by outdated documentation.

Changelog

• crates/pack-api/src/project.rs
  • Changed the source for output_root from self.dist_root().owned().await? to self.client_root().owned().await? within get_client_chunking_context.
• packages/pack/README.md
  • Wrapped the configuration object passed to the build function call within a config property.
  • Wrapped the configuration object passed to the dev function call within a config property.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request addresses two separate issues. First, it fixes a chunk loading error by correctly setting the output_root to client_root in the client chunking context. This ensures that in-memory assets are correctly handled, which is a solid improvement. Second, it updates the usage examples in the README.md to align with a recent API change, where configuration options are now nested under a config object. I've made one minor suggestion to fix an indentation issue in a code example in the README for better readability.

[github-actions]

📊 Performance Benchmark Report (with-antd)

Utoopack Performance Report

Report ID: utoopack_performance_report_20260224_073927
Generated: 2026-02-24 07:39:27
Trace File: trace_antd.json (0.5GB, 3.18M events)
Test Project: examples/with-antd

---

Executive Summary

Key Findings

Metric	Value	Assessment
Total Wall Time	8,081.1 ms	Baseline
Total Thread Work (de-duped)	25,247.2 ms	Non-overlapping busy time
Effective Parallelism	3.1x	thread_work / wall_time
Working Threads	5	Threads with actual spans
Thread Utilization	62.5%	🆗 Average
Total Spans	1,589,288	All B/E + X events
Meaningful Spans (>= 10us)	521,157	(32.8% of total)
Tracing Noise (< 10us)	1,068,131	(67.2% of total)

Note on Thread Work: Thread work is computed by merging overlapping intervals
per thread, eliminating double-counting from nested spans. This gives the true
wall-clock busy time across all threads.

Workload Distribution by Tier

Category	Tasks	Total Time (ms)	% of Thread Work
P0: Runtime/Resolution	0	0.0	0.0%
P1: I/O & Heavy Tasks	38,764	3,529.9	14.0%
P3: Asset Pipeline	28,871	3,302.9	13.1%
P4: Bridge/Interop	0	0.0	0.0%
Other	453,522	21,541.2	85.3%

Note: Percentages may sum to >100% because task durations include nesting
while thread work is de-duplicated. This is intentional for hotspot attribution.

---

Parallelization Analysis

Thread Utilization

Metric	Value
Working Threads	5
Total Thread Work (de-duped)	25,247.2 ms
Avg Work per Thread	5,049.4 ms
Effective Parallelism	3.12x
Thread Utilization	62.5%

Assessment: With 5 working threads, achieving 3.1x parallelism indicates significant loss of potential parallelism.

---

Top 20 Tasks by Total Duration

Total (ms)	Count	Avg (us)	Max (ms)	% Work	Task Name
8,235.6	187,658	43.9	8.7	32.6%	module
3,965.8	72,373	54.8	162.0	15.7%	process module
3,444.4	35,895	96.0	162.0	13.6%	analyze ecmascript module
2,813.7	24,455	115.1	59.4	11.1%	code generation
1,846.8	63,847	28.9	8.4	7.3%	internal resolving
1,772.9	59,106	30.0	8.7	7.0%	resolving
1,369.9	30,040	45.6	7.4	5.4%	precompute code generation
1,361.7	14,095	96.6	49.5	5.4%	chunking
1,214.1	12,848	94.5	113.5	4.8%	compute async module info
1,063.3	8,045	132.2	41.0	4.2%	parse ecmascript
496.2	4,691	105.8	49.0	2.0%	compute async chunks
311.6	1,936	160.9	17.8	1.2%	generate source map
73.7	2,169	34.0	3.3	0.3%	read file
67.6	649	104.1	18.9	0.3%	compute binding usage info
64.7	1,870	34.6	13.3	0.3%	collect mergeable modules
54.2	98	553.2	15.5	0.2%	make production chunks
46.1	560	82.4	8.3	0.2%	async reference
38.6	14	2758.1	15.3	0.2%	apply effects
37.9	13	2916.7	15.2	0.2%	write file
30.3	6	5053.0	15.5	0.1%	compute merged modules

---

Deep Dive by Tier

Tier 1: Runtime & Resolution (P0)

Focus: Task scheduling and dependency resolution.

Metric	Value	Status
Total Scheduling Time	0.0 ms	✅ Normal
Resolution Hotspots	0 distinct task types	Check Top Tasks

Potential P0 Issues:

• Thread utilization at 62.5% suggests critical path serialization or lock contention.
• 1,068,131 spans < 10us (67.2%) contribute to scheduler pressure.

Tier 2: Physical & Resource Barriers (P1)

Focus: Hardware utilization, I/O, and heavy monoliths.

Metric	Value	Status
I/O Work (Estimated)	3,529.9 ms	✅ Healthy
Large Tasks (> 100ms)	3	Minimal

Tier 3: Architecture & Asset Pipeline (P2-P3)

Focus: Global state and transformation pipeline.

Metric	Value	Status
Asset Processing (P3)	3,302.9 ms	13.1% of work
Bridge Overhead (P4)	0.0 ms	✅ Low

---

Duration Distribution

Range	Count	Percentage
< 10us (noise)	1,068,131	67.2%
10us - 100us	494,968	31.1%
100us - 1ms	22,164	1.4%
1ms - 10ms	3,952	0.2%
10ms - 100ms	70	0.0%
> 100ms	3	0.0%

---

Diagnostic Signal Summary

Signal	Status	Finding
Tracing Noise (P0)	⚠️ Significant	67.2% of spans < 10us
Thread Utilization (P0)	🆗 Average	62.5% utilization
Heavy Monoliths (P1)	✅ Minimal	3 tasks > 100ms
Asset Pipeline (P3)	Review	3,302.9 ms total
Bridge/Interop (P4)	Low	0.0 ms total

---

Action Items (P0-P4)

1. [P0] Profile lock contention to address 37% lost parallelism
2. [P1] Breakdown heavy monolith tasks (>100ms) to improve granularity
3. [P1] Review I/O patterns for potential batching opportunities
4. [P3] Optimize asset transformation pipeline hot-spots
5. [P4] Reduce "chatty" bridge operations if interop overhead is significant

---

Report generated by Utoopack Performance Analysis Agent on 2026-02-24
Following: Utoopack Performance Analysis Agent Protocol