Monorepo.Tool 3.0.0

Monorepo.Tool

A .NET global CLI that stitches many sibling git repos into a synthetic monorepo by rewriting NuGet PackageReference entries to ProjectReference at MSBuild evaluation time — without modifying any leaf repo. Fully reversible: one sentinel file toggles the whole thing on or off.

Install

dotnet pack -c Release
dotnet tool install -g --add-source ./nupkg Monorepo.Tool

Layout

backend/                              ← your existing backend root
├── <leaf-repo>/.git/…                ← many sibling repos, each with their own csprojs
└── synthetic-monorepo/               ← this tool's home (a sibling, NOT committed to any leaf repo)
    ├── monorepo.json                 ← generated config — edit Enabled=false to opt out selectively
    ├── Monorepo.sln                  ← generated VS solution spanning every leaf
    └── overlay/
        ├── Directory.Build.props
        └── Directory.Build.targets   ← generated MSBuild overlay that does the rewriting

After init also drops:

backend/Directory.Build.props         ← shim that imports overlay (sentinel-gated)
backend/Directory.Build.targets       ← shim that imports overlay (sentinel-gated)
backend/.monorepo-active              ← sentinel file — delete this and the overlay goes dark

Commands

# First run: discover repos and generate everything
monorepo init --backend path\to\backend --overlay .

# Re-scan after adding or removing a repo (preserves Enabled=false overrides)
monorepo generate --refresh

# Regenerate from existing monorepo.json without re-scanning
monorepo generate

# Opt a single package out of the rewrite
monorepo disable MyComp.MyProj
monorepo generate

# Opt back in
monorepo enable MyComp.MyProj
monorepo generate

# Toggle the whole overlay off/on without touching any config
monorepo off
monorepo on

# Show current state (configured mappings, drift, sentinel status)
monorepo status

Exit codes

How it works

Directory.Build.targets in the overlay uses three static ItemGroups:

1. Snapshot — copies the current @(PackageReference) into a private item type before anything is removed.
2. Remove — strips every mapped PackageReference so NuGet restore never sees them (skipped for net7/net6/netstandard, which stay on the original packages).
3. Inject — for each mapping, probes the snapshot and conditionally adds a <ProjectReference> at evaluation time. Because it happens at evaluation (not in a Target), the reference lands in project.assets.json and NuGet propagates transitive packages correctly.

The .monorepo-active sentinel is the master kill-switch — the shim Directory.Build.* files at the backend root only import the overlay when it exists.

Troubleshooting

• "monorepo.json not found" — cd into the overlay directory or a subdirectory of it, or pass --config.
• Drift warning from status — a csproj that used to produce a mapped package has been moved or deleted. Run monorepo generate --refresh.
• A project I depend on wasn't rewritten — check monorepo status for ✗ markers; run monorepo enable <packageId> if it's disabled.
• An older-TFM project is complaining — net7/net6/netstandard projects are intentionally skipped; they keep their original packages.