Make ProjectTemplates replacement incremental

[Clint Rutkas (crutkas)]

Description

ProjectTemplates replacement currently runs after every Build, even when neither the template inputs nor replacement values changed. This makes the response-file preparation stable and the replacement target incremental while preserving generated and packaged output.

Summary

• Split stable response-file preparation from template replacement.
• Make replacement incremental across template, project, localization, script, and every replacement-value change.
• Invalidate through Clean, Rebuild, and missing generated output while preserving response-file, Pack, Windows catalog ordering, and error semantics.
• Add focused cross-platform regression coverage.

Performance

• HOBL matched warm whole-solution evidence on x64: Windows mean 77.761883s -> 73.405682s, 5.6% faster; baseline/candidate ratio 1.059344, 95% CI 1.025741..1.093331.
• WSL mean 51.938818s -> 51.887158s; ratio 1.000996, 95% CI 0.904533..1.084117, so no confirmed regression.
• Cold results were single-pair and neutral, so no cold performance claim is made.
• This is x64 evidence. ARM64 performance remains a separate hardware gate.

Validation

• Windows focused regression and production Clean, Build, unchanged Build, Rebuild, and Pack smoke tests.
• WSL-native focused test passed 1/1, plus production Clean, Build, unchanged Build, Pack, changed replacement value/input, long response file, and failure propagation coverage.
• Generated and packaged content matched exactly: 314 Windows entries including the catalog and 313 Linux entries, with no remaining replacement tokens.
• Formatting and diff checks passed, the branch is clean, and final independent review found no significant issues.

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No

[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.

curl -fsSL https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 19413

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 19413"

[Copilot]

Pull request overview

Makes ProjectTemplates replacement incremental while preserving generated and packaged outputs.

Changes:

• Separates response-file preparation from replacement.
• Adds stamp-based invalidation for changed inputs, missing outputs, Clean, and Rebuild.
• Adds regression coverage for generation and packaging behavior.

Show a summary per file

File	Description
src/Aspire.ProjectTemplates/Aspire.ProjectTemplates.csproj	Implements incremental template replacement and invalidation.
tests/Infrastructure.Tests/ProjectTemplates/ProjectTemplatesIncrementalBuildTests.cs	Tests replacement, rebuilding, cleaning, failure, and packaging scenarios.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced