Add NuGet.config creation to solution initialization in aspire init

[Copilot]

Fix: Add NuGet.config creation for solution initialization in aspire init

Problem

When aspire init is used with a solution file, it doesn't create/update a NuGet.config file. The single-file AppHost path already does this correctly via PromptToCreateOrUpdateNuGetConfigAsync, but the solution path skips this step.

Solution

Created a shared NuGetConfigPrompter helper class to eliminate code duplication between InitCommand and DotNetTemplateFactory, ensuring consistent NuGet.config creation behavior across both commands.

Changes Made

1. Created NuGetConfigPrompter helper class

File: src/Aspire.Cli/Packaging/NuGetConfigPrompter.cs

• Extracts NuGet.config prompting logic into a reusable component
• Provides two methods:
  • PromptToCreateOrUpdateAsync: Prompts user before creating/updating (for in-place creation)
  • CreateOrUpdateWithoutPromptAsync: Creates/updates without prompting (for subdirectory creation)
• Handles both explicit channel cases (preview, daily builds) and implicit channels (default NuGet.org)

2. Updated InitCommand to use the shared helper

File: src/Aspire.Cli/Commands/InitCommand.cs

• Removed duplicate CreateOrUpdateNuGetConfigAsync method
• Uses NuGetConfigPrompter.PromptToCreateOrUpdateAsync for solution directory
• Maintains existing behavior with user prompting

3. Refactored DotNetTemplateFactory to use the shared helper

File: src/Aspire.Cli/Templating/DotNetTemplateFactory.cs

• Simplified PromptToCreateOrUpdateNuGetConfigAsync to use NuGetConfigPrompter
• Removed duplicate logic for checking config existence and prompting
• Removed unused TryFindNuGetConfigInDirectory helper method
• Maintains existing behavior for both in-place and subdirectory creation

Benefits

• ✅ Eliminates code duplication between InitCommand and DotNetTemplateFactory
• ✅ Ensures consistent NuGet.config generation logic across aspire init and aspire new commands
• ✅ Easier to maintain and update NuGet.config prompting behavior in one place
• ✅ All 423 existing tests pass
• ✅ Build succeeds with no warnings

Testing

• ✅ All 423 CLI tests pass
• ✅ Build succeeds with no warnings
• ✅ Behavior is identical to previous implementation

Original prompt

When the aspire init command is used to initialize a project that has a solution file we need to drop a nuget.config file. The single file path already does this we need to replicate this behavior.

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[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

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Or

• Run remotely in PowerShell:

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[mitchdenny]

@copilot this change duplicates some logic that already exists in DotNetTempalteFactory, specifically the PromptToCreateOrUpdateNuGetConfigAsync method. Refactor this method into a helper class that can be instansiated and used from both the DotNetTemplateFactory and the InitCommand so that we can be sure that the NuGet.config generation logic is consistently applied across both the aspire init and aspire new commands.

[Copilot]

@copilot this change duplicates some logic that already exists in DotNetTempalteFactory, specifically the PromptToCreateOrUpdateNuGetConfigAsync method. Refactor this method into a helper class th...

Refactored the NuGet.config prompting logic into a new NuGetConfigPrompter helper class in the Packaging namespace. Both InitCommand and DotNetTemplateFactory now use this shared class to ensure consistent behavior. The prompter supports two modes:

1. PromptToCreateOrUpdateAsync - Prompts user before creating/updating (used for in-place creation)
2. CreateOrUpdateWithoutPromptAsync - Creates/updates without prompting (used for subdirectory creation)

All duplicate code has been removed, and all 423 tests pass. Changes in commit e5e0c2f.

[Copilot]

Pull Request Overview

Adds NuGet.config creation/prompting to solution-based aspire init and centralizes the logic to remove duplication with aspire new.

• Introduces NuGetConfigPrompter to encapsulate create/update and prompting behavior.
• Refactors DotNetTemplateFactory and InitCommand to use the shared helper.
• Adds solution init call to ensure explicit channel sources are offered when initializing into an existing solution directory.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/Aspire.Cli/Packaging/NuGetConfigPrompter.cs	New helper class encapsulating NuGet.config prompting and creation logic.
src/Aspire.Cli/Templating/DotNetTemplateFactory.cs	Replaces inline NuGet.config logic with NuGetConfigPrompter usage; removes duplicated helper.
src/Aspire.Cli/Commands/InitCommand.cs	Adds NuGet.config prompting during solution init and a wrapper method delegating to NuGetConfigPrompter.