Allow to pick up certain template group or certain template to be run in case of ambiguity

At the moment 2 cases for ambiguity may happen during template instantiation:

• different template groups may have same short name
• different templates in one group may have same precedence and it is not possible to determine the one to be run

Those cases may be solved by uninstalling one of the packages in template groups are coming from different packages, however if they are coming from single one the situation cannot be resolved.

Suggesting the following options to resolve these conflicts:

• --group allows to specify group identity to run
• --identity allows to specify template identity to run

The error cases should be modified as following: (ambiguous group) Unable to resolve the template, these templates matched your input:

Name	Short name	Group
Template 1	short	Group.Identity1
Template 2	short	Group.Identity2

To run specific template, specify its group using --group option. dotnet new short --group Group.Identity1.

(ambiguous template) Unable to resolve the template, these templates matched your input:

Name	Short name	Identity
Template 1	short	Templ.Identity1
Template 2	short	Templ.Identity2

This may happen due to authoring error or ambiguous parameter set. To run specific template, specify the identity using --identity option. dotnet new short --identity Templ.Identity1

[sayedihashimi]

For the Authoring case, I think this should be a warning and not an error.

[sayedihashimi]

I ran my tool to identify templates that re-use the identity value across templates.

I only found 4 IDs that are actually being used in different templates.

template-pack-id						identity
Microsoft.DotNet.Web.ItemTemplates		Microsoft.Web.Grpc.Protobuf
Microsoft.DotNet.Web.ItemTemplates.6.0	Microsoft.Web.Grpc.Protobuf
VijayAnand.BlazorTemplates				VijayAnand.WindowsForms.Blazor
VijayAnand.BlazorTemplates				VijayAnand.Wpf.Blazor

My report did include the following as well, but that is due to this bug https://github.com/dotnet/templating/issues/4140. Those are listed below.

template-pack-id						identity
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Item.SpecFlowFeature
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Item.SpecFlowConfiguration
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Item.SpecFlowPlusProfile
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Project
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Item.SpecFlowFeature
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Item.SpecFlowConfiguration
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Item.SpecFlowPlusProfile
SpecFlow.Templates.DotNet				SpecFlowTemplates.DotNET.Project
Threenine.ApiProject					Threenine.ApiProject
Threenine.ApiProject					Threenine.ApiProject
VijayAnand.Wpf.Blazor					VijayAnand.Wpf.Blazor
VijayAnand.WindowsForms.Blazor			VijayAnand.WindowsForms.Blazor
Laconic.AppTemplate					Laconic.AppTemplate
Laconic.AppTemplate					Laconic.AppTemplate
VijayAnand.BlazorTemplates				VijayAnand.WindowsForms.Blazor
VijayAnand.BlazorTemplates				VijayAnand.Wpf.Blazor
E5R.Architecture.Template				E5R.Architecture.Template.FullSolution
E5R.Architecture.Template				E5R.Architecture.Template.FullSolution
sayedha.templates						Sayedha.Templates.CliTool
sayedha.templates						Sayedha.Templates.IdeHostJson
sayedha.templates						Sayedha.Templates.TemplateJson
sayedha.templates						Sayedha.Templates.TemplatePackJson
sayedha.templates						Sayedha.Templates.CliTool
sayedha.templates						Sayedha.Templates.IdeHostJson
sayedha.templates						Sayedha.Templates.TemplateJson
sayedha.templates						Sayedha.Templates.TemplatePackJson