CLI: Add --mount support for create and run - #41337

src/windows/common/MountSpecParsing.cpp:583

• FormatTmpfsOptions also omits an explicitly provided tmpfs-size=0 by skipping size when the parsed value is 0. If the user passes tmpfs-size=0, that intent should be preserved and forwarded (and kept consistent with existing --tmpfs behavior, which can pass size=0).

    if (mount.TmpfsSizeBytes.has_value() && mount.TmpfsSizeBytes.value() != 0)
    {
        options.emplace_back(std::format("size={}", FormatDockerTmpfsSize(mount.TmpfsSizeBytes.value())));
    }

src/windows/common/MountSpecParsing.cpp:579

• FormatTmpfsOptions drops an explicitly provided tmpfs-mode=0000 because it omits the mode option when the parsed value is 0. That changes user-requested semantics (and differs from --tmpfs, which forwards options verbatim), since mode=0 is a meaningful tmpfs setting.

This issue also appears on line 580 of the same file.

    if (mount.TmpfsMode.has_value() && mount.TmpfsMode.value() != 0)
    {
        options.emplace_back(std::format("mode={:o}", mount.TmpfsMode.value()));
    }

src/windows/common/MountSpecParsing.cpp:14

• New files should use the repository’s single-line copyright header format (// Copyright (C) Microsoft Corporation. All rights reserved.). This file currently uses the older block header style.

/*++

Copyright (c) Microsoft. All rights reserved.

src/windows/common/MountSpecParsing.h:14

• New files should use the repository’s single-line copyright header format (// Copyright (C) Microsoft Corporation. All rights reserved.). This header currently uses the older block header style.

/*++

Copyright (c) Microsoft. All rights reserved.

test/windows/wslc/WSLCCLIMountParserUnitTests.cpp:14

• New files should use the repository’s single-line copyright header format (// Copyright (C) Microsoft Corporation. All rights reserved.). This test file currently uses the older block header style.

/*++

Copyright (c) Microsoft. All rights reserved.

src/windows/common/MountSpecParsing.cpp:159

• Minor typo in the digit set passed to find_last_of: it includes an extra '0' ("01234567890. "), which is confusing to readers even though it likely doesn’t change behavior.

        const auto separator = input.find_last_of("01234567890. ");

src/windows/wslc/arguments/ArgumentValidation.cpp:234

• The mount parser’s ValidationException::Reason() is composed of hard-coded English strings (from MountSpecParsing.cpp) and is surfaced directly to users via WSLCCLI_InvalidMountError. This means a significant portion of the user-facing error text is not localizable, which conflicts with the PR’s stated goal of localized errors for unsupported/invalid mount specs.

            catch (const mount::ValidationException& ex)
            {
                throw ArgumentException(Localization::WSLCCLI_InvalidMountError(value, ex.Reason()));
            }

test/windows/wslc/WSLCCLIMountParserUnitTests.cpp:222

• This mount spec (type=volume,...,bind-recursive=enabled) is listed as a valid case here, but the same exact input is also listed as an invalid (bind-* family mismatch) case later in c_invalidMountCases (lines ~350-351). With the current parser, bind-recursive is a bind-only option, so this entry will make the valid-case loop fail.

        {L"type=volume,source=data-volume,target=/data,bind-recursive=enabled",
         mount::Type::Volume,
         L"data-volume",
         "/data",
         false,
         {},
         {},
         ""},

test/windows/wslc/e2e/WSLCE2EContainerCreateTests.cpp:802

• This test is in WSLCE2EContainerCreateTests.cpp and is named Container_Create_*, but it invokes container run. Because run has additional behavior (and can exercise different code paths than create), this doesn’t reliably validate container create rejecting missing bind sources.

        auto result = RunWslc(std::format(
            L"container run --name {} --mount \"type=bind,source={},target=/data\" {} true",
            WslcContainerName,
            source.wstring(),
            AlpineImage.NameAndTag()));
        result.Verify({.Stdout = L"", .Stderr = FormatWslcError(Localization::MessageWslcBindSourcePathNotFound(source.wstring())), .ExitCode = 1});

test/windows/wslc/e2e/WSLCE2EContainerCreateTests.cpp:820

• This Container_Create_* test also runs container run instead of container create, so it’s not specifically exercising the create path’s behavior around creating missing bind-source directories. Either switch to container create (and clean up the created container), or rename/move the test so it’s clear it’s validating run.

        auto result = RunWslc(std::format(
            L"container run --name {} --volume \"{}:/data\" {} true", WslcContainerName, source.wstring(), AlpineImage.NameAndTag()));
        result.Verify({.Stdout = L"", .Stderr = L"", .ExitCode = 0});
        VERIFY_IS_TRUE(std::filesystem::is_directory(source));
        EnsureContainerDoesNotExist(WslcContainerName);

src/windows/common/MountSpecParsing.cpp:585

• PR description says anonymous volumes are rejected, but ValidateMountSpec currently allows type=volume with an empty source (i.e., anonymous volume) as long as the name is either empty or a valid named volume. Either update the PR description to match the implemented behavior, or enforce source for type=volume if anonymous volumes truly aren’t supported.

    case Type::Volume:
        if (!mount.Source.empty() && !IsValidNamedVolumeName(mount.Source))
        {
            ThrowValidation(Localization::WSLCCLI_MountVolumeSourceInvalidError());
        }

test/windows/wslc/e2e/WSLCE2EContainerCreateTests.cpp:817

• This test is in the ContainerCreate suite but the command uses container run, so it’s not actually validating container create behavior when a host --volume source is missing.

        auto result = RunWslc(std::format(
            L"container run --name {} --volume \"{}:/data\" {} true", WslcContainerName, source.wstring(), AlpineImage.NameAndTag()));

test/windows/wslc/e2e/WSLCE2EContainerCreateTests.cpp:801

• These two E2E tests are in the ContainerCreate suite and are named ..._Container_Create_..., but the command under test uses container run. That means the test is exercising the run code path (which may have additional behaviors) instead of create, so it won’t reliably catch regressions specific to container create.

This issue also appears on line 816 of the same file.

        auto result = RunWslc(std::format(
            L"container run --name {} --mount \"type=bind,source={},target=/data\" {} true",
            WslcContainerName,
            source.wstring(),
            AlpineImage.NameAndTag()));

src/windows/wslc/services/ContainerService.cpp:32

• namespace mount = wsl::windows::common::mount; is declared but never used in this translation unit (there are no mount:: references). This can trigger unused-alias warnings depending on compiler settings and adds noise.

namespace mount = wsl::windows::common::mount;

test/windows/wslc/e2e/WSLCE2EHelpers.h:29

• FormatWslcError uses std::format and std::wstring_view but this header doesn’t include <format> / <string_view>. Relying on transitive includes makes the header brittle and can break if include order changes.

inline std::wstring FormatWslcError(const std::wstring& message, std::wstring_view errorCode = L"E_INVALIDARG")
{
    return std::format(L"{}\r\nError code: {}\r\n", message, errorCode);
}

src/windows/wslcsession/WSLCContainer.cpp:643

• If a mount destination pointer is unexpectedly null (e.g., Volumes[i].ContainerPath, NamedVolumes[i].ContainerPath, or Tmpfs[i].Destination), this currently throws E_INVALIDARG without any context. Using the _MSG form here makes failures much easier to diagnose.

    const auto addDestination = [&](const char* destination) {
        THROW_HR_IF_NULL(E_INVALIDARG, destination);

src/windows/wslcsession/WSLCContainer.cpp:1859

• There’s a nearby TODO saying “Return mounts once --mount is implemented”, but HostConfig.Mounts is already being used here to enrich inspect output. Updating/removing that TODO would avoid misleading future readers.

        wslc_schema::InspectMount mountInfo{};
        mountInfo.Type = volume.Type;
        mountInfo.Name = volume.Name;
        const auto structuredMount = std::ranges::find_if(dockerInspect.HostConfig.Mounts, [&](const auto& mount) {
            return mount.Type == "volume" && mount.Target == volume.Destination;

src/windows/wslc/services/ContainerModel.cpp:290

• ValidateUniqueMountDestinations rethrows mount::MountException for non-duplicate errors. If this function is ever called with a mount spec that bypassed arg validation (or new validation is added later), that would propagate a non-WIL exception through the CLI path and produce inconsistent error handling.

Consider translating all mount::MountException instances to a user-facing HRESULT here (similar to other validation helpers).

void ValidateUniqueMountDestinations(const ContainerOptions& options)
{
    try
    {
        mount::ValidateMountCollection(options.Mounts);
    }
    catch (const mount::MountException& ex)
    {
        if (ex.Error() == mount::ValidationError::DuplicateDestination)
        {
            THROW_HR_WITH_USER_ERROR(E_INVALIDARG, Localization::WSLCCLI_DuplicateMountDestinationError(MultiByteToWide(ex.Destination())));
        }

        throw;
    }

src/windows/common/MountSpecParsing.cpp:566

• The PR description says anonymous volumes are rejected, but ValidateMountSpec currently allows Type::Volume mounts with an empty Source (which enables anonymous volumes, and is also exercised by the added e2e coverage).

Please align behavior with the stated intent by either rejecting empty volume sources here, or updating the PR description/notes to reflect that anonymous volumes are supported.

    case Type::Volume:
        if (!mount.Source.empty() && !IsValidNamedVolumeName(mount.Source))
        {
            ThrowValidation(Localization::WSLCCLI_MountVolumeSourceInvalidError());
        }
        break;

src/windows/wslc/services/ContainerService.cpp:34

• Unused namespace alias mount was introduced but is never referenced in this file. This can trigger unused-declaration warnings (and adds noise).

namespace wsl::windows::wslc::services {
namespace mount = wsl::windows::common::mount;

test/windows/wslc/WSLCCLIMountParserUnitTests.cpp:66

• PR description says anonymous volumes are rejected, but the parser/tests explicitly accept type=volume,target=... (empty source) which results in an anonymous volume. Please either update the PR description to match the implemented behavior, or change validation to reject empty volume sources if that was the intent.

    constexpr ValidMountCase c_validMountCases[] = {
        {L"type=volume,target=/data", mount::Type::Volume, L"", "/data", false, {}, {}, ""},
        {L"source=data-volume,target=/data", mount::Type::Volume, L"data-volume", "/data", false, {}, {}, ""},

src/windows/wslcsession/WSLCContainer.cpp:695

• ConvertAndValidateMounts() checks NamedVolumes[].Name for null but can pass a null NamedVolumes[].ContainerPath into addDestination(), which produces an unhelpful generic failure. Add an explicit null check with index context before addDestination().

    THROW_HR_IF(E_INVALIDARG, containerOptions.NamedVolumesCount > 0 && containerOptions.NamedVolumes == nullptr);
    for (ULONG i = 0; i < containerOptions.NamedVolumesCount; ++i)
    {
        THROW_HR_IF_NULL_MSG(E_INVALIDARG, containerOptions.NamedVolumes[i].Name, "NamedVolume at index %lu has null Name", i);
        addDestination(containerOptions.NamedVolumes[i].ContainerPath);
    }

src/windows/wslcsession/WSLCContainer.cpp:701

• ConvertAndValidateMounts() can pass a null Tmpfs[*].Destination into addDestination(), which fails without any index context. Add an explicit null check with a message before calling addDestination().

    THROW_HR_IF(E_INVALIDARG, containerOptions.TmpfsCount > 0 && containerOptions.Tmpfs == nullptr);
    for (ULONG i = 0; i < containerOptions.TmpfsCount; ++i)
    {
        addDestination(containerOptions.Tmpfs[i].Destination);
    }

src/windows/wslcsession/WSLCContainer.cpp:688

• ConvertAndValidateMounts() validates Volumes[].HostPath but can pass a null Volumes[].ContainerPath into addDestination(), which then fails with a generic E_INVALIDARG and no index context. Add an explicit null check with an index-specific message before calling addDestination().

This issue also appears in the following locations of the same file:

• line 690
• line 697

    for (ULONG i = 0; i < containerOptions.VolumesCount; ++i)
    {
        THROW_HR_IF_NULL_MSG(E_INVALIDARG, containerOptions.Volumes[i].HostPath, "Volumes[%lu].HostPath is null", i);
        addDestination(containerOptions.Volumes[i].ContainerPath);
    }

src/windows/wslcsession/WSLCContainer.cpp:747

• PrepareBindMount() calls std::filesystem::is_regular_file(hostPath) without the error_code overload. On access/permission issues this can throw std::filesystem::filesystem_error, bypassing the HRESULT/user-error flow and potentially failing the operation with an unhandled exception. Use the error_code overload and convert failures into a localized user error.

        std::error_code ec;
        hostPath = std::filesystem::canonical(hostPath, ec);
        if (!ec)
        {
            if (std::filesystem::is_regular_file(hostPath))

src/windows/wslcsession/WSLCContainer.cpp:695

• ConvertAndValidateMounts() does not emit an indexed diagnostic if NamedVolumes[i].ContainerPath is null (it falls back to addDestination()'s generic null check). Adding an explicit THROW_HR_IF_NULL_MSG here would make failures actionable.

    for (ULONG i = 0; i < containerOptions.NamedVolumesCount; ++i)
    {
        THROW_HR_IF_NULL_MSG(E_INVALIDARG, containerOptions.NamedVolumes[i].Name, "NamedVolume at index %lu has null Name", i);
        addDestination(containerOptions.NamedVolumes[i].ContainerPath);
    }

src/windows/wslcsession/WSLCContainer.cpp:688

• ConvertAndValidateMounts() relies on addDestination()'s generic null check for Volumes[i].ContainerPath. This loses the index/context in the failure, and it’s inconsistent with the explicit HostPath null check above.

This issue also appears on line 691 of the same file.

    for (ULONG i = 0; i < containerOptions.VolumesCount; ++i)
    {
        THROW_HR_IF_NULL_MSG(E_INVALIDARG, containerOptions.Volumes[i].HostPath, "Volumes[%lu].HostPath is null", i);
        addDestination(containerOptions.Volumes[i].ContainerPath);
    }

src/windows/wslcsession/WSLCContainer.cpp:701

• ConvertAndValidateMounts() should report which tmpfs entry is invalid when Tmpfs[i].Destination is null (currently it throws E_INVALIDARG without context via addDestination()).

    for (ULONG i = 0; i < containerOptions.TmpfsCount; ++i)
    {
        addDestination(containerOptions.Tmpfs[i].Destination);
    }