[v3] wails build/dev take indefinitely then crashes

[OpperDev]

Description

I'm programming an application with Wails 3 & React; with a few services (to handle multi-windows, to handle a firebird server connexion, and to manage files.)
Everything was building correctly until I added @mui/material to design my ui.
The build/dev command started to take indefinitely (around 20-30mins) where it was taking ~30 seconds juste before.
I did checked if it was from the package, or the react bundle size,
I built the frontend:

npm run build -- --debug
✓ 1200 modules transformed.
dist/index.html                   0.45 kB │ gzip:   0.30 kB
dist/assets/LOGO-CWprdyL7.png   100.71 kB
dist/assets/index-CsEdVz_A.css    0.14 kB │ gzip:   0.13 kB
dist/assets/mui-DpnXnvqI.js     466.54 kB │ gzip: 144.00 kB
dist/assets/index-C2TqKBoI.js   478.87 kB │ gzip: 148.11 kB
✓ built in 5.87s

And then I tried to compile the .exe by myself :

go clean -cache
go build -v -tags production -trimpath -buildvcs=false -ldflags="-w -s -H windowsgui" -o bin/application.exe

Its taking around 20 seconds,

So im facing a wall right now to understand why wails3 build is taking so much time, there is no verbose/debug parameter? or I didn't found it.

Thanks in advance.

To Reproduce

1. Init a wails3 application w/ react
2. Install few UI packages
3. Build

Expected behaviour

Manual / Automatic build should be the same thing?

Screenshots

No response

Attempted Fixes

No response

System Details

wails3 doctor
 Wails (v3.0.0-alpha.64)  Wails Doctor
                                                                                  # System

┌─────────────────────────────────────────────────────────────────────────────────────────┐
| Name              | Windows 10 Home                                                     |
| Version           | 2009 (Build: 22631)                                                 |
| ID                | 23H2                                                                |
| Branding          | Windows 11 Famille                                                  |
| Platform          | windows                                                             |
| Architecture      | amd64                                                               |
| Go WebView2Loader | true                                                                |
| WebView2 Version  | 144.0.3719.93                                                       |
| CPU               | 11th Gen Intel(R) Core(TM) i5-11400H @ 2.70GHz                      |
| GPU 1             | Intel(R) UHD Graphics (Intel Corporation) - Driver: 31.0.101.4502   |
| GPU 2             | NVIDIA GeForce RTX 3060 Laptop GPU (NVIDIA) - Driver: 32.0.15.8183  |
| Memory            | 16GB                                                                |
└─────────────────────────────────────────────────────────────────────────────────────────┘

# Build Environment

┌────────────────────────────────┐
| Wails CLI    | v3.0.0-alpha.64 |
| Go Version   | go1.25.6        |
| -buildmode   | exe             |
| -compiler    | gc              |
| CGO_CFLAGS   |                 |
| CGO_CPPFLAGS |                 |
| CGO_CXXFLAGS |                 |
| CGO_ENABLED  | 1               |
| CGO_LDFLAGS  |                 |
| GOAMD64      | v1              |
| GOARCH       | amd64           |
| GOOS         | windows         |
└────────────────────────────────┘

# Dependencies

┌─────────────────────────────────────────────────────────────────────────────────────────┐
| npm                        | 10.4.0                                                     |
| NSIS                       | Not Installed                                              |
| MakeAppx.exe (Windows SDK) | Not Installed                                              |
| MSIX Packaging Tool        | Not Installed                                              |
| SignTool.exe (Windows SDK) | Not Installed                                              |
| docker                     | *Docker version 29.1.0, build 360952c (daemon not running) |
|                                                                                         |
└──────────────────────────────── * - Optional Dependency ────────────────────────────────┘

# Checking for issues

 SUCCESS  No issues found

# Diagnosis

 SUCCESS  Your system is ready for Wails development

Additional context

No response

[leaanthony]

Root Cause Analysis

The issue is in the build:frontend task defined in the Taskfile template (v3/internal/commands/build_assets/Taskfile.tmpl.yml):

build:frontend:
    dir: frontend
    sources:
      - "**/*"       # <--- This is the problem
    generates:
      - dist/**/*

Go-task uses sources for up-to-date checking — before running the task, it recursively enumerates and checksums every file matching the glob. The **/* pattern in frontend/ includes frontend/node_modules/.

A typical React project has ~1,000 files in node_modules. But @mui/material plus its peer dependencies (@emotion/react, @emotion/styled, etc.) brings this to 50,000-100,000+ files. On Windows (where NTFS metadata operations are slower and Windows Defender may scan each file), statting and checksumming 100,000 files takes 20-30 minutes — which matches the reported behavior exactly.

Why npm run build is fast

Vite/Rollup resolves imports lazily through the module graph — it doesn't enumerate every file in node_modules.

Why go build is fast

It only processes .go files and doesn't touch the frontend at all.

Fix

Add a node_modules exclusion to the build:frontend sources (the exclude: pattern is already used elsewhere in the same file):

build:frontend:
    dir: frontend
    sources:
      - "**/*"
      - exclude: node_modules/**/*
    generates:
      - dist/**/*

Workaround

For existing projects, manually edit your project's Taskfile.yml and add - exclude: node_modules/**/* under build:frontend > sources.