dotnet new results in exception "maximumNumberOfValues must be greater than or equal to minimumNumberOfValues"

[markcandelora]

Product

dotnet CLI (dotnet new)

Describe The Bug

Using dotnet new on custom project template results in following error.
Full error below:

maximumNumberOfValues must be greater than or equal to minimumNumberOfValues
   at System.CommandLine.ArgumentArity..ctor(Int32 minimumNumberOfValues, Int32 maximumNumberOfValues)
   at Microsoft.TemplateEngine.Cli.ChoiceTemplateParameter.GetBaseOption(IReadOnlySet`1 aliases)
   at Microsoft.TemplateEngine.Cli.CliTemplateParameter.GetOption(IReadOnlySet`1 aliases)
   at Microsoft.TemplateEngine.Cli.Commands.TemplateCommand.AddTemplateOptionsToCommand(CliTemplateInfo templateInfo)
   at Microsoft.TemplateEngine.Cli.Commands.TemplateCommand..ctor(BaseCommand instantiateCommand, IEngineEnvironmentSettings environmentSettings, TemplatePackageManager templatePackageManager, TemplateGroup templateGroup, CliTemplateInfo template, Boolean buildDefaultLanguageValidation)
   at Microsoft.TemplateEngine.Cli.Commands.InstantiateCommand.ReparseForTemplate(InstantiateCommandArgs args, IEngineEnvironmentSettings environmentSettings, TemplatePackageManager templatePackageManager, TemplateGroup templateGroup, CliTemplateInfo template, Boolean validateDefaultLanguage)
   at Microsoft.TemplateEngine.Cli.Commands.InstantiateCommand.ReparseForTemplate(InstantiateCommandArgs args, IEngineEnvironmentSettings environmentSettings, TemplatePackageManager templatePackageManager, TemplateGroup templateGroup, IEnumerable`1 templatesToReparse, Boolean& languageOptionSpecified)
   at Microsoft.TemplateEngine.Cli.Commands.InstantiateCommand.GetTemplateCommand(InstantiateCommandArgs args, IEngineEnvironmentSettings environmentSettings, TemplatePackageManager templatePackageManager, TemplateGroup templateGroup)
   at Microsoft.TemplateEngine.Cli.Commands.InstantiateCommand.HandleTemplateInstantationAsync(InstantiateCommandArgs args, IEngineEnvironmentSettings environmentSettings, TemplatePackageManager templatePackageManager, TemplateGroup templateGroup, CancellationToken cancellationToken)
   at Microsoft.TemplateEngine.Cli.Commands.InstantiateCommand.ExecuteIntAsync(InstantiateCommandArgs instantiateArgs, IEngineEnvironmentSettings environmentSettings, TemplatePackageManager templatePackageManager, InvocationContext context)
   at Microsoft.TemplateEngine.Cli.Commands.BaseCommand`1.InvokeAsync(InvocationContext context)

template.json:

{
    "$schema": "http://json.schemastore.org/template",
    "author": "Mark Candelora",
    "classifications": [ "Sample", "WebApi", "Common" ],
    "identity": "Sample.WebApi.Common",
    "name": "Sample WebApi Common",
    "shortName": "SampleWebApi",
    "tags": {
        "language": "C#",
        "type": "project"
    },
    "sourceName": "SampleWebApi",
    "symbols": {
        "Auth": { "datatype": "choice", "choices": [ "None", "AAD", "ApiKey" ], "type": "parameter", "allowMultipleValues": true, "defaultValue": "AAD|ApiKey" }
    }
}

projtemplate.csproj:

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
      <PackageType>Template</PackageType>
      <PackageVersion>1.0</PackageVersion>
      <PackageId>Sample.WebApi</PackageId>
      <Title>Sample WebApi Project Template</Title>
      <Authors>Mark Candelora</Authors>
      <Description>Project Template</Description>
      <PackageTags>dotnet-new;Template;Sample</PackageTags>
      <TargetFramework>net7.0</TargetFramework>
      <IncludeContentInPack>true</IncludeContentInPack>
      <IncludeBuildOutput>false</IncludeBuildOutput>
      <ContentTargetFolders>content</ContentTargetFolders>
      <SuppressDependenciesWhenPacking>true</SuppressDependenciesWhenPacking>
    </PropertyGroup>
  
    <ItemGroup>
      <Content Include="**\*" Exclude="**\bin\**;**\obj\**;projTemplate.csproj" />
      <Compile Remove="**\*" />
    </ItemGroup>

  </Project>

Commenting out the symbols node in the template.json prevents the error.

To Reproduce

Steps:

1. create ./src folder
2. dotnet new webapi -n Sample.WebApi -o ./src/Sample.WebApi
3. dotnet new mstest -n Sample.WebApi.Test -o ./src/Sample.WebApi.Test
4. place template.json in ./src/.template.config/
5. place projtemplate.csproj in ./src/
6. dotnet pack -c packRelease ./src
7. dotnet new install ./src/bin/packRelease/Sample.WebApi.1.0.0.nupkg
8. dotnet new SampleWebApi -n ThisProducesAnError -o ./test

dotnet Info

output

.NET SDK:
Version: 7.0.102
Commit: 4bbdd14480

Runtime Environment:
OS Name: debian
OS Version: 11
OS Platform: Linux
RID: debian.11-x64
Base Path: /usr/share/dotnet/sdk/7.0.102/

Host:
Version: 7.0.2
Architecture: x64
Commit: d037e070eb

.NET SDKs installed:
7.0.102 [/usr/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 7.0.2 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 7.0.2 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
None

Environment variables:
Not set

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Visual Studio Version

Using VS Code devContainer

Additional context

devcontainer.json

{
	"name": "C# (.NET)",
	"build": {
		"dockerfile": "Dockerfile"
	},
	"features": {
		"ghcr.io/devcontainers/features/docker-in-docker:2": {},
		"ghcr.io/devcontainers/features/powershell:1": {}
	},
	"customizations": {
		"vscode": {
			"extensions": [
				"ms-vscode.powershell",
				"pspester.pester-test",
				"formulahendry.dotnet-test-explorer",
				"DotJoshJohnson.xml",
				"k--kato.docomment"
			],
			"settings": {
				"[csharp]": {
					"editor.maxTokenizationLineLength": 2500,
					"editor.formatOnSave": true,
					"editor.formatOnSaveMode": "file"
				}
			}
		}
	},
	"postCreateCommand": [
		"sudo pwsh -Command 'Install-Module Pester -Force -Scope AllUsers;'"
	]
	// Use 'forwardPorts' to make a list of ports inside the container available locally.
	// "forwardPorts": [5000, 5001],
	// "portsAttributes": {
	//		"5001": {
	//			"protocol": "https"
	//		}
	// }
	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
	// "remoteUser": "root"
}

Dockerfile

FROM mcr.microsoft.com/devcontainers/dotnet:0-7.0

[YuliiaKovalova]

Hi @markcandelora ,

Thank you for reporting the issue and providing details.
We are investigating it and when more information is available we will return back to you.

[GangWang01]

Root cause is wrong definition of choices in the symbol auth in template.json. It should be an array of the elements:

• choice: possible value of the symbol.
• description: human readable text describing the meaning of the choice. This has no effect on template generation.

Correct one looks like below.

    "symbols": {
        "Auth": {
            "datatype": "choice",
            "choices": [
                {
                    "choice": "None",
                    "description": "No Authentication"
                },
                {
                    "choice": "AAD",
                    "description": "Azure Active Directory"
                },
                {
                    "choice": "ApiKey",
                    "description": "API Key"
                }
            ],
            "type": "parameter",
            "allowMultipleValues": true,
            "defaultValue": "AAD|ApiKey"
        }
    }

Parameter symbol has more details and an example for Multi-choice symbols specifics

[vlada-shubina]

@markcandelora please confirm if suggestion provided by @GangWang01 works at your end.

I know that the error message is not great, but we plan to improve it in scope of bigger task #2623.

[markcandelora]

I've confirmed this works. I went back to the documentation and also confirmed that looks correct (I could have sworn I got the syntax I used from the docs, but obviously not).

Also, I'm a huge fan of good error messages, so good to know that's being worked on as well!

Thank you for the assistance!