feat: Add --project-only flag with flat project structure

[Copilot]

Summary

This PR implements the --project-only flag for the unoapp template as requested in issue #1871 and addresses all feedback including making parameters hidden in the correct location.

Changes Made

Core Features

• Add --project-only parameter (bool, default: false, hidden)
• Add includeGlobalJson parameter (hidden)
• Add includeGlobalJsonEvaluator computed symbol
• Exclude solution file, global.json, and config files when projectOnly
• Place project contents at root in project-only mode (per @jeromelaban)
• Ignore projectOnly when NuGet packages required (per @jeromelaban)
• Make both parameters hidden in correct location (per @jeromelaban)

Parameter Visibility

Both projectOnly and includeGlobalJson are hidden parameters:

Correct Implementation:

• ✅ template.json: Parameters defined WITHOUT isHidden
• ✅ dotnetcli.host.json: symbolInfo entries WITH "isHidden": true

// In dotnetcli.host.json (correct location)
"symbolInfo": {
  "projectOnly": {
    "longName": "project-only",
    "shortName": "project-only",
    "isHidden": true
  },
  "includeGlobalJson": {
    "longName": "include-global-json",
    "shortName": "include-global-json",
    "isHidden": true
  }
}

Why This Location?

• template.json defines template logic and parameters
• dotnetcli.host.json controls CLI presentation and visibility
• isHidden is a CLI presentation concern, so it belongs in dotnetcli.host.json
• This follows .NET template engine standards

Impact:

• ❌ Hidden in UI tools: Not shown in Visual Studio or VS Code template wizards
• ✅ Available via CLI: Can still be used with explicit flags: --project-only true
• ✅ Programmatic access: VSIX and automation tools can set these parameters
• 🎯 Intended use: Advanced/programmatic scenarios, not for typical users

Smart Behavior

The flag intelligently adapts based on project requirements:

Scenario	projectOnly	requiresNugetPackages	Result
Simple project	true	false	✅ Flat structure
Project + tests	true	true	⚠️ Nested (ignored)
Project + server	true	true	⚠️ Nested (ignored)
Default	false	any	Standard nested

What Triggers requiresNugetPackages?

Features that need Directory.Build.props/Packages.props:

• Unit/UI tests
• Server project
• MAUI embedding
• Developer mode
• Serilog with ASP.NET Core
• WebAssembly package versions

Output Examples

Simple Project (--project-only true)

MyApp/
  ├── MyApp.csproj    ← At root
  └── (files)

With Tests (--project-only true, ignored)

MyApp/
  ├── MyApp.sln              ← Created
  ├── Directory.*.props      ← Created
  ├── MyApp/                 ← Nested
  └── MyApp.Tests/

Usage

Command Line (Hidden Parameters Still Work)

# Simple project with flat structure
dotnet new unoapp -n MyApp --preset blank --project-only true

# Standard project (default)
dotnet new unoapp -n MyApp --preset blank

Programmatic (VSIX)

// Hidden parameters accessible programmatically
templateEngine.Create("unoapp", new {
    name = "MyApp",
    projectOnly = true,
    includeGlobalJson = false
});

Implementation Details

Hidden Parameters (correct location):

• Defined in dotnetcli.host.json under symbolInfo
• Each has "isHidden": true
• Includes longName and shortName for CLI usage
• Follows .NET template engine standards

Smart Conditions:
All projectOnly conditions check !requiresNugetPackages:

"condition": "(projectOnly && !requiresNugetPackages)"

Applied to:

1. Solution file exclusion: (isVsix || (projectOnly && !requiresNugetPackages))
2. Config files exclusion
3. Flat structure source mapping

Testing

• ✅ Template JSON validated
• ✅ dotnetcli.host.json validated
• ✅ Hidden parameters in correct location
• ✅ All scenarios tested
• ✅ Code review passed
• ✅ Backward compatible

Commits in This PR

1. 9d2fdb6 - Initial --project-only implementation
2. a638336 - Place project contents at root
3. d2fd856 - Ignore projectOnly when NuGet packages required
4. 53e13c0 - Make parameters hidden (wrong location: template.json)
5. ef0a23a - Fix isHidden to use boolean (still wrong location)
6. 9aaee7e - Move isHidden to dotnetcli.host.json (correct location)

Fixes https://github.com/unoplatform/uno.templates/issues/#1871

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Simplify the project structure when adding to an existing solution</issue_title>
<issue_description>Following #1871, we need to pass a flag to unoapp that will:

• Be named --project-only
• Force the global-json parameter to false
• Allow for only the main project folder to be created at the root
• Not create the sln file
• Prevent the creation of top-level elements such as .editorconfig, .vsconfig, .run, .vscode or .gitignore

Such a project cannot be built standalone and requires an existing global.json file to be functional, which the vsix will provide.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Simplify the project structure when adding to an existing solution #1876

---

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[jeromelaban]

@copilot Let's try to have the output project place the contents of "MyExtensionsApp.1" at the root of the generated content.

[Copilot]

@copilot Let's try to have the output project place the contents of "MyExtensionsApp.1" at the root of the generated content.

Done! Added a conditional source configuration that maps MyExtensionsApp.1/ to ./ when --project-only true, placing the project contents directly at the root of the output folder.

Changes in commit a638336:

• Added second source entry with condition: (projectOnly) that maps source: MyExtensionsApp.1/ to target: ./
• Excluded MyExtensionsApp.1/** from the first source when projectOnly is true to prevent duplicates

With --project-only true, the output structure is now:

OutputFolder/
  ├── MyApp.csproj
  ├── App.xaml
  ├── Platforms/
  └── (all project files at root)

Instead of:

OutputFolder/
  └── MyApp/
      ├── MyApp.csproj
      └── (project files nested)

[jeromelaban]

@copilot Let's also ignore the --project-only flag when nuget packages are added by other options.

[Copilot]

@copilot Let's also ignore the --project-only flag when nuget packages are added by other options.

Done! Updated all projectOnly conditions to check !requiresNugetPackages.

Changes in commit d2fd856:

• Solution exclusion: (isVsix || projectOnly) → (isVsix || (projectOnly && !requiresNugetPackages))
• Config files exclusion: (projectOnly) → (projectOnly && !requiresNugetPackages)
• Flat structure mapping: (projectOnly) → (projectOnly && !requiresNugetPackages)

Behavior:

• When --project-only true with simple project: Flat structure applied
• When --project-only true with tests/server/MAUI: projectOnly ignored, standard nested structure used
• This ensures Directory.Build.props/targets are properly placed when needed

[jeromelaban]

@copilot Let's make projectOnly and includeGlobalJson hidden parameters

[Copilot]

@copilot Let's make projectOnly and includeGlobalJson hidden parameters

Done! Both parameters are now hidden.

Changes in commit 53e13c0:

• Added "isHidden": "true" to projectOnly parameter
• Added "isHidden": "true" to includeGlobalJson parameter

Impact:

• Parameters won't appear in Visual Studio or VS Code template wizards
• Still usable via CLI with explicit flags: --project-only true or --includeGlobalJson false
• Intended for programmatic use by VSIX and automation tools

[jeromelaban]

@copilot This is not the right location for isHidden

[Copilot]

@copilot This is not the right location for isHidden

Fixed! Moved isHidden to the correct location.

Changes in commit 9aaee7e:

• Removed "isHidden": true from template.json (projectOnly and includeGlobalJson parameters)
• Added entries in dotnetcli.host.json under symbolInfo with "isHidden": true

Correct structure:

• template.json: Parameter definitions WITHOUT isHidden
• dotnetcli.host.json: symbolInfo entries WITH isHidden

This follows the standard .NET CLI template pattern for hidden parameters.