Defer

[patrick91]

Another attempt :D

Summary by Sourcery

Implement experimental incremental execution in the GraphQL schema to support deferred and streamed responses. Refactor the async run method to handle incremental execution results. Add end-to-end tests for Apollo and Relay clients, and introduce a new CI workflow for running these tests.

New Features:

• Introduce experimental incremental execution support in the GraphQL schema, allowing for deferred and streamed responses.

Enhancements:

• Refactor the async run method to handle GraphQLIncrementalExecutionResults, enabling streaming responses for incremental execution.

CI:

• Add a new GitHub Actions workflow for running end-to-end tests using Playwright.

Documentation:

• Add a README file for the e2e directory, providing setup and configuration instructions for React, TypeScript, and Vite.

Tests:

• Add end-to-end tests for GraphQL queries using Apollo and Relay clients, including tests for deferred and streamed responses.

[sourcery-ai[bot]]

Reviewer's Guide

Integrates experimental incremental GraphQL execution by switching to graphql-core’s experimental_execute_incrementally when enabled; adds multipart streaming support in the async HTTP view; extends schema definitions and printer to include @defer and @stream directives; introduces Streamable annotations; and adds comprehensive incremental tests and E2E suites with a dedicated CI workflow.

Sequence diagram for incremental execution and streaming HTTP response

sequenceDiagram
    participant Client
    participant AsyncBaseView
    participant Schema
    participant experimental_execute_incrementally
    participant GraphQLIncrementalExecutionResults

    Client->>AsyncBaseView: HTTP GraphQL request
    AsyncBaseView->>Schema: execute(...)
    Schema->>experimental_execute_incrementally: execute if incremental enabled
    experimental_execute_incrementally-->>Schema: GraphQLIncrementalExecutionResults
    Schema-->>AsyncBaseView: GraphQLIncrementalExecutionResults
    AsyncBaseView->>AsyncBaseView: stream() (yields multipart chunks)
    AsyncBaseView-->>Client: multipart/mixed streaming response

ER diagram for BlogPost, Comment, and Author (E2E test schema)

erDiagram
    BLOGPOST ||--o{ COMMENT : has
    COMMENT }o--|| AUTHOR : written_by
    BLOGPOST {
        ID id
        STRING title
        STRING content
    }
    COMMENT {
        ID id
        STRING content
    }
    AUTHOR {
        ID id
        STRING name
    }

Class diagram for Streamable and related types

classDiagram
    class StrawberryStreamable
    class Streamable {
        <<Annotated[AsyncGenerator[T, None], StrawberryStreamable()]>>
    }
    class AsyncGenerator
    class T
    Streamable --|> AsyncGenerator : Annotated
    Streamable --* StrawberryStreamable : Annotated
    Streamable ..> T : generic

Class diagram for incremental execution integration in Schema

classDiagram
    class Schema {
        +execute(...)
        +execute_sync(...)
        +_handle_execution_result(...)
        +_parse_and_validate_async(...)
        -_schema
        -config
    }
    class StrawberryConfig {
        +enable_experimental_incremental_execution: bool
    }
    class GraphQLIncrementalExecutionResults
    class experimental_execute_incrementally
    Schema --> StrawberryConfig : config
    Schema ..> GraphQLIncrementalExecutionResults : uses
    Schema ..> experimental_execute_incrementally : uses

File-Level Changes

Change	Details	Files
Implement HTTP streaming of incremental GraphQL results	Detect GraphQLIncrementalExecutionResults in async_base_view.run and generate multipart/mixed streams Refactor encode_multipart_data to pre-encode JSON, include Content-Length and charset headers Update process_result in http/init.py to accept and early-return incremental results	strawberry/http/async_base_view.py strawberry/http/__init__.py
Integrate experimental incremental execution into schema execution	Add enable_experimental_incremental_execution config flag and choose experimental_execute_incrementally when active Handle GraphQLIncrementalExecutionResults early in _handle_execution_result Update execute and execute_sync to switch execution function based on config Adapt build_resolve_info signature for graphql-core 3.3 compatibility	strawberry/schema/schema.py
Introduce Streamable annotation support	Define StrawberryStreamable and Streamable alias in strawberry/streamable.py Enhance annotation resolver to recognize Streamable types Extend ResultType union to include GraphQLIncrementalExecutionResults Expose GraphQLIncrementalExecutionResults and directives via _graphql_core	strawberry/streamable.py strawberry/annotation.py strawberry/schema/_graphql_core.py
Extend schema printer to include defer and stream directives	Guard access to strawberry-definition extension Append @defer and @stream directive definitions when incremental execution is enabled	strawberry/printer/printer.py
Add end-to-end and incremental test suites with CI workflow	Create Playwright-based E2E tests for Apollo and Relay clients in e2e directory Add incremental defer and stream HTTP tests under tests/http/incremental Introduce GitHub Actions workflow 🎭 E2E Tests for running Playwright suite on PRs Include setup docs and configs (README, tsconfigs, CI, noxfile bump)	.github/workflows/e2e-tests.yml e2e/ tests/http/incremental/

Possibly linked issues

• #2567: The PR implements first-class support for @stream/@defer, matching the issue's main requirements and initial steps.
• #3082: The PR implements support for @stream and @defer, directly addressing the issue's request for these features.

---

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[botberry]

Apollo Federation Subgraph Compatibility Results

Federation 1 Support	Federation 2 Support
_service 🟢 @key (single) 🟢 @key (multi) 🟢 @key (composite) 🟢 repeatable @key 🟢 @requires 🟢 @provides 🟢 federated tracing 🔲	@link 🟢 @shareable 🟢 @tag 🟢 @override 🟢 @inaccessible 🟢 @composeDirective 🟢 @interfaceObject 🟢

Learn more:

• Apollo Federation Subgraph Specification
• Compatibility Tests

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 57.49235% with 139 lines in your changes missing coverage. Please review.

Project coverage is 94.40%. Comparing base (6f5c600) to head (bf42f98).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3819      +/-   ##
==========================================
- Coverage   94.76%   94.40%   -0.36%     
==========================================
  Files         520      527       +7     
  Lines       33971    34230     +259     
  Branches     1760     1785      +25     
==========================================
+ Hits        32193    32316     +123     
- Misses       1497     1625     +128     
- Partials      281      289       +8     

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• :package: JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #3819 will not alter performance

_{Comparing feature/defer (bf42f98) with main (6f5c600)}

Summary

✅ 26 untouched benchmarks

[botberry]

Pre-release

:wave:

Pre-release 0.276.0.dev.1752831589 [830ca949678760ed2e883a7768bc7fa97351cee9] has been released on PyPi! :rocket: You can try it by doing:

poetry add strawberry-graphql==0.276.0.dev.1752831589

[patrick91]

/pre-release

[codeflash-ai[bot]]

⚡️ Codeflash found optimizations for this PR

📄 100% (1.00x) speedup for process_result in strawberry/http/__init__.py

⏱️ Runtime : 1.78 millisecond → 892 microseconds (best of 28 runs)

I created a new dependent PR with the suggested changes. Please review:

• #3827

If you approve, it will be merged into this PR (branch feature/defer).

[patrick91]

/pre-release

[matclayton]

Did a quick test on this and fairly sure I've got the following crash. Its possible I've misconfigured something, but this is best understanding on how to enable it

[codeflash-ai[bot]]

This PR is now faster! 🚀 @patrick91 accepted my optimizations from:

• #3827

[codeflash-ai[bot]]

This PR is now faster! 🚀 codeflash-ai[bot] accepted my code suggestion above.

[patrick91]

@matclayton sorry, I totally missed that message! do you know if you can write a small reproduction? or was that fixed with GraphQL-core 3.3.0a7?

[matclayton]

Sorry I didn't follow up here, this is fixed in GraphQL core 3.3.0va7, btw we're running GraphQL-core 3.3.0v7 in prod now, and not seen a single issue so far. Need to still confirm the other bits of this PR, I'm hoping the team can take it off me the next week or so.

[patrick91]

/pre-release

[patrick91]

this doesn't render/print the directives (to double check)

[patrick91]

worth checking if those directive should be printed, since we don't print directives like @include and @skip

[patrick91]

/pre-release

[patrick91]

/pre-release

[matclayton]

We've managed to get this up and running in django 5.1, Channels and with granian in our codebase by the way. Works fantastically. We haven't managed to update the Relay Network to make use of it yet (we have quite a complex setup there) but its looking nice! @millar is who's been looking at it on our end.

[Speedy1991]

Just tried the pre release and i found a small bug: If you use MaskErrors it checks for result.errors. In a defer response this is nested in result.initial_result.errors

[millar]

We've fully integrated this into our stack now without any issues!

[patrick91]

@millar @Speedy1991 thank you both! I'll see if I can update the extension!

Also, I think that would work only on the first response? I'll double check

[Speedy1991]

@patrick91 maybe it would be better to fix https://github.com/strawberry-graphql/strawberry/issues/3844 first? This would avoid errors in other extensions too?

[millar]

Any chance of another pre release of this with all the latest changes in please?

[patrick91]

/pre-release

[codeflash-ai[bot]]

⚡️ Codeflash found optimizations for this PR

📄 12% (0.12x) speedup for process_result in strawberry/http/__init__.py

⏱️ Runtime : 100 microseconds → 89.8 microseconds (best of 153 runs)

I created a new dependent PR with the suggested changes. Please review:

• #3938

If you approve, it will be merged into this PR (branch feature/defer).

[botberry]

Thanks for adding the RELEASE.md file!

Here's a preview of the changelog:

---

This release adds experimental support for GraphQL's @defer and @stream directives, enabling incremental delivery of response data.

Note: this only works when using Strawberry with graphql-core>=3.3.0a9.

Features

• @defer directive: Allows fields to be resolved asynchronously and delivered incrementally
• @stream directive: Enables streaming of list fields using the new strawberry.Streamable type
• strawberry.Streamable[T]: A new generic type for defining streamable fields that work with @stream

Configuration

To enable these experimental features, configure your schema with:

from strawberry.schema.config import StrawberryConfig

schema = strawberry.Schema(
    query=Query, config=StrawberryConfig(enable_experimental_incremental_execution=True)
)

Here's the tweet text:

🆕 Release (next) is out! Thanks to @patrick91 for the PR 👏

This release adds experimental support for GraphQL's @defer and @stream directives, enabling incremental delivery of response data! 🚀

Get it here 👉 https://strawberry.rocks/release/(next)

[patrick91]

/pre-release

[codeflash-ai[bot]]

⚡️ Codeflash found optimizations for this PR

📄 24% (0.24x) speedup for type in strawberry/experimental/pydantic/object_type.py

⏱️ Runtime : 182 microseconds → 146 microseconds (best of 9 runs)

I created a new dependent PR with the suggested changes. Please review:

• #3948

If you approve, it will be merged into this PR (branch feature/defer).