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Document what OperatingSystemUtils and OperatingSystemUtils.hostPlatform is representing #184358

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#185369
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Document what OperatingSystemUtils and OperatingSystemUtils.hostPlatform is representing#184358
#185369
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P3Issues that are less important to the Flutter projectc: proposalA detailed proposal for a change to Flutterd: api docsIssues with https://api.flutter.dev/team-toolOwned by Flutter Tool teamtoolAffects the "flutter" command-line tool. See also t: labels.triaged-toolTriaged by Flutter Tool team

Description

@Gustl22
Gustl22
opened on Mar 30, 2026

Use case

I recently stumbled across the class OperatingSystemUtils in flutter_tools.

I noticed that the implementation of hostPlatform differs from platform to platform.
E.g. Windows uses Abi.current to determine its architecture variants, whereas all others use their custom implementation.

Wouldn't it make sense for all to use Abi.current.
See:

flutter/packages/flutter_tools/lib/src/base/os.dart

Line 135 in a647115

HostPlatform get hostPlatform;

One reason I can think about it is not done on purpose, because the platform (TARGET) Dart runs on can differ from actual machine platform (HOST), e.g. when cross-platform building. But then Windows should use its own implementation without using Abi.current.

I am no expert there, I just want to be sure. Maybe Abi.current also reflects the real host (?), but I think it doesn't.

Therefore it would be good to have documented, what OperatingSystemUtils and OperatingSystemUtils.hostPlatform is representing and for what it can be used.

Proposal

I would like to propose to document the usage of this class properly and in a second step, if feasable, replace the implementation with Darts built-in Abi.current implementation on all platforms.

See commit: dd69590

Activity

  1. Gustl22
    added a commit that references this issue on Mar 30, 2026

    refactor: Replace get hostPlatform with Dart's `Abi.current` (flutter…

    dd69590

  2. VaradGupta23 commented on Mar 31, 2026

    @VaradGupta23
    VaradGupta23
    on Mar 31, 2026

    Good observation — this can definitely be confusing without clear documentation,

    I think the key point here is the distinction between host platform (the machine running the tool) and target platform (the platform being built for). In some scenarios—especially cross-compilation—these can differ, which might explain why hostPlatform doesn’t consistently rely on Abi.current across all implementations.

    My understanding is that Abi.current reflects the runtime environment of the Dart VM, which may not always map cleanly to the actual host machine characteristics that flutter_tools needs to reason about (e.g., when invoking platform-specific tooling).

    So documenting:

    • what exactly OperatingSystemUtils.hostPlatform represents
    • how it differs from Dart’s Abi.current
    • and when each should be used

    would be really valuable for contributors.

    Regarding unifying the implementation using Abi.current, it might be worth validating whether it fully covers cases like cross-platform builds or toolchain-specific behavior before standardizing on it.

    Overall, +1 for improving documentation first — that would make the intent much clearer before considering any refactor.

  3. mbcorona
    added
    toolAffects the "flutter" command-line tool. See also t: labels.
    d: api docsIssues with https://api.flutter.dev/
    c: proposalA detailed proposal for a change to Flutter
    team-toolOwned by Flutter Tool team
    on Mar 31, 2026

  4. mbcorona commented on Mar 31, 2026

    @mbcorona
    mbcorona
    on Mar 31, 2026
    Member

    Hi @Gustl22 , thanks for reporting.

    I am routing this to the tool team so they can review your findings and determine the best path forward for the documentation and potential refactor.

  5. bkonyi commented on Apr 1, 2026

    @bkonyi
    bkonyi
    on Apr 1, 2026
    Contributor

    I think rewriting those getters to use Abi.current() is a reasonable cleanup (although looking at your linked commit, we definitely wouldn't need to check for Fuchsia or Android for the flutter CLI tool). I'd be happy to review a PR if you're willing to upload one!

  6. bkonyi
    added
    P3Issues that are less important to the Flutter project
    triaged-toolTriaged by Flutter Tool team
    on Apr 1, 2026
  7. bkonyi
    added 5 commits that reference this issue on Apr 22, 2026

    [flutter_tools] Fix tests failing after hostPlatform refactor

    fc8831c

    [flutter_tools] Fix xcodeproj tests failing after hostPlatform refactor

    98e55ca

    [flutter_tools] Fix xcresult tests failing after hostPlatform refactor

    3e503ac

    [flutter_tools] Fix cocoapods tests failing after hostPlatform refactor

    a8e0a8e

    [flutter_tools] Fix cache tests failing on Linux bots

    9a360c6

  8. 37 remaining items

  9. bkonyi
    added 10 commits that reference this issue on May 27, 2026

    [flutter_tools] Fix build_test.dart failures caused by sysctl mock mi…

    8124008

    [flutter_tools] Use fake OS utils by default in XcodeProjectInterpret…

    af360aa

    [flutter_tools] Revert test changes in xcodeproj.dart

    23b3a59

    [flutter_tools] Fix analyzer errors in xcodeproj_test.dart caused by …

    d1a9e6d

    [flutter_tools] Mock sysctl in xcodeproj_test.dart to avoid sequence …

    f2d8bc6

    [flutter_tools] Mock sysctl manually in specific tests in xcodeproj_t…

    5efba67

    [flutter_tools] Hardcode xcrun in xcresult_test.dart to avoid sysctl …

    b50bda7

    [flutter_tools] Mock sysctl in cocoapods and xcode_validator tests to…

    c1def34

    [flutter_tools] Fix sequence failures in xcresult, cocoapods, and xco…

    29f6469

    [flutter_tools] Clean up sysctl mock constants in tests

    4e4ed73
  10. auto-submit
    closed this as completedin #185369on Jun 2, 2026
  11. victorsanni
    added a commit that references this issue on Jun 3, 2026

    [flutter_tools] Refactor hostPlatform to use Abi.current() (flutter#1…

    565231d
  12. via-guy
    added a commit that references this issue on Jun 26, 2026

    [flutter_tools] Refactor hostPlatform to use Abi.current() (flutter#1…

    fc6024d

  13. github-actions commented on Jul 14, 2026

    @github-actions
    github-actionsbot
    on Jul 14, 2026 – with GitHub Actions

    This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

  14. github-actions
    locked as resolved and limited conversation to collaborators on Jul 14, 2026
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