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fix(task)!: default ofTask configureAwait to true - #39

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xperiandri wants to merge 1 commit into
fix/iter-async-guardfrom
fix/of-task-configure-await
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xperiandri wants to merge 1 commit into
fix/iter-async-guardfrom
fix/of-task-configure-await

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@xperiandri

@xperiandri xperiandri commented Oct 5, 2026 •

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Proposed Changes

Part of splitting #22 into small pull requests that can be reviewed one at a time. It is stacked on #38 (fix/iter-async-guard), so it shows only its own change; merge #38 first.

Both ofTask overloads declared [<Optional>] configureAwait without a default value, so an omitted argument passed false, while R3's FromAsync, ofAsync, ProcessingOptions.Default and ChunkConfiguration.AsyncWindow all default to true. A UI handler subscribed through ofTask therefore ran off its synchronization context. The parameter now defaults to true, and both overloads are documented.

Types of changes

What types of changes does your code introduce to FSharp.Control.R3?
Put an x in the boxes that apply

  • Bugfix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

  • Build and tests pass locally – 0 warnings, Fantomas is clean, and the tests that exist at this commit pass
  • I have added tests that prove my fix is effective or that my feature works (if appropriate) – in test: cover the library with integration tests #22, the top of this stack
  • I have added necessary documentation (if appropriate)

Further comments

Breaking change: callers that omit configureAwait now resume on the captured synchronization context; pass false to keep the old behaviour.

Tests (in #22): TaskObservableTests.fs – ofTask resumes on the captured synchronization context when configureAwait is omitted, ... when configureAwait is true and ofTask does not resume on the captured synchronization context when configureAwait is false.

Stack – every pull request is based on the one before it, so each shows only its own change. Merge them in this order:

  1. refactor!: prefix AwaitOperationConfiguration cases with Await #23 refactor!: prefix AwaitOperationConfiguration cases with Await
  2. fix: validate the concurrency limit of mapAsync options eagerly #24 fix: validate the concurrency limit of mapAsync options eagerly
  3. fix(rxquery): emit yield/zero synchronously to keep element order #25 fix(rxquery): emit yield/zero synchronously to keep element order
  4. fix(rxquery)!: stop seeding sumBy with Unchecked.defaultof #26 fix(rxquery)!: stop seeding sumBy with Unchecked.defaultof
  5. feat(rxquery): add rxqueryWith to cancel the terminal query operators #27 feat(rxquery): add rxqueryWith to cancel the terminal query operators
  6. docs(rxquery): document the query builder and every query operator #28 docs(rxquery): document the query builder and every query operator
  7. feat(observable)!: make ofSeq reachable as Observable.ofSeq #29 feat(observable)!: make ofSeq reachable as Observable.ofSeq
  8. feat(observable)!: make Observable.choose take a voption chooser, add ObservableOption #30 feat(observable)!: make Observable.choose take a voption chooser, add ObservableOption
  9. feat(observable): add chunkByBoundaries for boundaries of any element type #31 feat(observable): add chunkByBoundaries for boundaries of any element type
  10. fix(observable): validate every chunk length eagerly #32 fix(observable): validate every chunk length eagerly
  11. docs: document the processing and chunk configuration types #33 docs: document the processing and chunk configuration types
  12. docs(observable): correct misleading XML docs and document every function #34 docs(observable): correct misleading XML docs and document every function
  13. fix(async)!: remove the ignored cancellationToken from toLookup #35 fix(async)!: remove the ignored cancellationToken from toLookup
  14. fix(async)!: surface the original exception and cancellation from Async wrappers #36 fix(async)!: surface the original exception and cancellation from Async wrappers
  15. fix: wait for iterAsync through ForEachAsync instead of CountAsync #37 fix: wait for iterAsync through ForEachAsync instead of CountAsync
  16. fix: stop iterAsync reliably and never lose a failure of its action #38 fix: stop iterAsync reliably and never lose a failure of its action
  17. fix(task)!: default ofTask configureAwait to true #39 fix(task)!: default ofTask configureAwait to true ← this pull request
  18. feat(task)!: move toArray and toList into the Task.Observable module #40 feat(task)!: move toArray and toList into the Task.Observable module
  19. docs: correct the Async and Task module docs and document every member #41 docs: correct the Async and Task module docs and document every member
  20. docs: document the R3 1.3.1 limitations of bind, catch and mapAsync #42 docs: document the R3 1.3.1 limitations of bind, catch and mapAsync
  21. test: categorize the tests per tested component #43 test: categorize the tests per tested component
  22. test: cover the library with integration tests #22 test: cover the library with integration tests

🤖 Generated with Claude Code

Both `ofTask` overloads declared `[<Optional>] configureAwait` without a
default value, so an omitted argument passed `false`, while R3's
`FromAsync`, `ofAsync`, `ProcessingOptions.Default` and
`ChunkConfiguration.AsyncWindow` all default to `true`. A UI handler
subscribed through `ofTask` therefore ran off its synchronization
context. The parameter now defaults to `true`, and both overloads are
documented.

BREAKING CHANGE: callers that omit `configureAwait` now resume on the
captured synchronization context; pass `false` to keep the old
behaviour.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Copilot AI balanced review requested due to automatic review settings October 5, 2026 00:18

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Copilot review overview

🟢 Approval recommended

Both overloads consistently implement the intended default, preserve explicit overrides, and have matching documentation.

Review effort: Balanced
Findings: None

What changed in this PR

Aligns ofTask with R3 and ofAsync by enabling synchronization-context capture by default.

Changes:

  • Sets configureAwait to true for both overloads; explicit false preserves previous behavior.
  • Documents factory behavior and records the breaking change.
File Description
src/​FSharp.Control.R3/​TaskObservable.fs Updates both defaults and their XML documentation.
CHANGELOG.md Records the breaking default change.

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