bug: Prisma generated files under generated/prisma are reformatted by Prettier, causing persistent git diff churn in fresh T3 scaffold

Provide environment information

• System:
  • OS: macOS 26.3
  • CPU: (20) arm64 Apple M1 Ultra
  • Memory: 777.50 MB / 64.00 GB
  • Shell: 5.9 - /bin/zsh
• Binaries:
  • Node: 22.22.0
  • npm: 10.9.4
  • bun: 1.3.5
• Packages:
  • Prettier: 3.8.1
  • Prisma CLI: 6.19.2
  • @prisma/client: 6.19.2
  • create-t3-app initVersion: 7.40.0
  • Database: SQLite (default scaffold)
  • Component:
    • package.json formatting scripts (format:check, format:write)
    • prisma/schema.prisma (generator client output = "../generated/prisma")

Describe the bug

Description

In a fresh T3 scaffold with Prisma output directed to generated/prisma, generated Prisma client files are included in broad Prettier globs. This causes repeated churn:

• prettier --write reformats generated files
• prisma generate rewrites them back
• git shows noisy diffs in generated/prisma/**

Current Behavior

• generated/prisma/** files are tracked and repeatedly modified by formatting/generation commands.
• prettier --check reports generated files as style violations.
• Running install/postinstall (which runs prisma generate) re-changes those files again.

Expected Behavior

Generated Prisma artifacts should not create formatting/diff churn in normal developer workflows.

Impact

• Large noisy diffs in PRs
• Confusing local state (AM / repeated modified generated files)
• Reduced signal-to-noise for code review

Proposed Solution

1. Add generated/prisma to .prettierignore (required to stop format churn).
2. Add generated/prisma to .gitignore (if the template intends not to track generated artifacts).
3. Optionally narrow formatting scripts to app/source files only (instead of **/*.{ts,tsx,js,jsx,mdx}).
4. If files were already tracked, untrack once:
   • git rm -r --cached generated/prisma

Reproduction repo

https://github.com/brucexu-eth/t3-prisma-issue

To reproduce

bun create t3-app@latest and select the following options

you will see a lot of changes in generated/ folder, which should be ignored.

Additional information

No response