Fix Python callback handle wrapping

[Sébastien Ros (sebastienros)]

Description

Python callbacks exported as Action<IResourceBuilder<T>> received a raw Handle because .NET marshalled the callback argument with the generic builder ATS type ID while the generated Python wrapper registry used the concrete resource type ID. Calls such as with_host_port therefore failed at runtime.

Generated callback registrations now carry their concrete handle parameter type IDs. The Python runtime preserves exact runtime-type resolution and uses this metadata only as a fallback when the incoming type ID has no registered wrapper. This keeps other callback argument handling unchanged and does not alter TypeScript generation.

User-facing usage

Typed integration callbacks can invoke exported wrapper methods:

def configure_redis_commander(container: RedisCommanderResource) -> None:
    container.with_host_port(port=8082)

cache.with_redis_commander(configure_container=configure_redis_commander)

Regression coverage executes an exported Action<IResourceBuilder<TestRedisResource>> callback and verifies that the typed wrapper invokes another exported method. The Redis Python polyglot fixture also exercises RedisCommanderResource.with_host_port.

Validation:

• Python code generation tests: 25 passed
• TypeScript code generation tests: 128 passed
• Redis Python AppHost restored and generated SDK callback execution invoked withRedisCommanderHostPort with port 8082

Fixes: #19869

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 -- 19870

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 19870"

[github-actions]

Tests selector

2 / 99 PR test projects · 3 PR jobs · 0 advisory-only targets, from 7 changed files.

Selected PR test projects (2 / 99)

Aspire.Hosting.CodeGeneration.Python.Tests, Aspire.Hosting.RemoteHost.Tests

Selected PR jobs (3)

extension-e2e, polyglot, typescript-api-compat

Advisory workflow impact (0)

none

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How these were chosen — grouped by what changed

🔧 src/Aspire.Hosting.CodeGeneration.Python/AtsPythonCodeGenerator.cs (changed source)
→ 1 directly: Aspire.Hosting.CodeGeneration.Python.Tests
→ 1 via the project graph: Aspire.Hosting.RemoteHost.Tests

🔧 src/Aspire.Hosting.CodeGeneration.Python/PythonModuleBuilder.cs (changed source)
→ 1 directly: Aspire.Hosting.CodeGeneration.Python.Tests

🧪 tests/Aspire.Hosting.CodeGeneration.Python.Tests/AtsPythonCodeGeneratorTests.cs (changed test)
→ 1 directly: Aspire.Hosting.CodeGeneration.Python.Tests

🧪 tests/Aspire.Hosting.CodeGeneration.Python.Tests/PythonTestExtensions.cs (changed test)
→ 1 directly: Aspire.Hosting.CodeGeneration.Python.Tests

🧪 tests/Aspire.Hosting.CodeGeneration.Python.Tests/Snapshots/AtsGeneratedAspire.verified.py (changed test)
→ 1 directly: Aspire.Hosting.CodeGeneration.Python.Tests

🧪 tests/Aspire.Hosting.CodeGeneration.Python.Tests/Snapshots/TwoPassScanningGeneratedAspire.verified.py (changed test)
→ 1 directly: Aspire.Hosting.CodeGeneration.Python.Tests

Job reasons

Job	Triggered by
extension-e2e	• src/Aspire.Hosting.CodeGeneration.Python/AtsPythonCodeGenerator.cs, src/Aspire.Hosting.CodeGeneration.Python/PythonModuleBuilder.cs • affected project Aspire.Hosting.CodeGeneration.Python
polyglot	• tests/PolyglotAppHosts/Aspire.Hosting.Redis/Python/apphost.py • affected project Aspire.Hosting.CodeGeneration.Python
typescript-api-compat	affected project Aspire.Hosting.CodeGeneration.Python

---

Selection computed for commit 051993c.

[Copilot]

🟢 Approval recommended

The reviewed changes have regression coverage and no unresolved issues.

Pull request overview

Fixes Python callback handle wrapping so generic resource-builder callbacks resolve to typed generated wrappers.

Changes:

• Adds callback parameter type IDs as fallback wrapper metadata.
• Preserves exact runtime-type resolution.
• Adds regression coverage and updates generated snapshots.

File summaries

File	Description
tests/PolyglotAppHosts/Aspire.Hosting.Redis/Python/apphost.py	Exercises the typed Redis Commander callback.
tests/Aspire.Hosting.CodeGeneration.Python.Tests/Snapshots/TwoPassScanningGeneratedAspire.verified.py	Updates two-pass generation expectations.
tests/Aspire.Hosting.CodeGeneration.Python.Tests/Snapshots/AtsGeneratedAspire.verified.py	Updates generated Python expectations.
tests/Aspire.Hosting.CodeGeneration.Python.Tests/PythonTestExtensions.cs	Adds the test callback export.
tests/Aspire.Hosting.CodeGeneration.Python.Tests/AtsPythonCodeGeneratorTests.cs	Executes the callback regression scenario.
src/Aspire.Hosting.CodeGeneration.Python/PythonModuleBuilder.cs	Applies fallback wrapper resolution.
src/Aspire.Hosting.CodeGeneration.Python/AtsPythonCodeGenerator.cs	Emits callback handle type metadata.

Review details

• Files reviewed: 6/7 changed files
• Comments generated: 0
• Review effort level: Balanced

---

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[Sébastien Ros (sebastienros)]

LGTM. The generated callback metadata fixes generic IResourceBuilder handle wrapping without changing exact-type resolution or TypeScript behavior, and the regression executes an exported method through the typed Python wrapper.

[aspire-repo-bot]

Pull request created: #1614

Generated by PR Documentation Check · auto · 118.1 AIC · ⌖ 17.6 AIC · ⊞ 19.6K

[aspire-repo-bot]

📝 Documentation has been drafted in microsoft/aspire.dev#1614 targeting release/13.6.

Added documentation for the Python callback handle wrapping fix:

• whats-new/aspire-13-6.mdx: new bullet under Integration updates describing the fix and the configure_container/WithRedisCommander example.
• extensibility/multi-language-integration-authoring.mdx: new note in the callback-context section explaining that Action<IResourceBuilder<T>> callbacks are marshalled by concrete resource type so guest-language wrappers (e.g. Python) resolve correctly.

Note

This draft PR needs human review before merging.

[github-actions]

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