Emit errors and warnings as structured ScriptResponse JSON by theelliotm · Pull Request #1482 · microsoft/mxc

Elliot (theelliotm) · 2026-10-13T18:45:33Z

📖 Description

Executors now report failures and warnings as structured JSON instead of prose, so a caller can branch on a code rather than match backend-specific text.

Errors: each failure is one {"error":{"code","message"}} line on stderr. The exit code follows the code.
Warnings: ScriptResponse gains warnings (Option<Box<Vec<String>>>, which keeps the struct within the 128-byte result_large_err limit; a size test guards this). Executors write each warning as a {"warning":{"message"}} line on stderr.
Executor setup paths: wxc and lxc errors, including --setup-*, emit typed envelopes.

Code	Who can fix it	Exit
`policy_validation`	the request	`1`
`backend_unavailable`	the host	`-1`
`backend_error`	the runtime, during an accepted run	`-1`
`malformed_request`, `unsupported_containment`, other phase codes	the request	`1`

SDK compatibility: sites where a new code would break SDK v1 callers keep their v1 code. Each has a // SDK v2: comment naming its intended code. They are listed in docs/development/plans/sdk-v2-error-codes.md and tracked in #1595. The new codes apply everywhere else, for example Hyperlight, WSLC, Windows Sandbox and IsolationSession inherited stdio.

Out of scope:

warnings in the Rust, .NET and Node SDK result types.
Prose that backends still print alongside the envelope.
A result channel separate from the workload's stderr (Separate MXC diagnostics from the workload's stderr #1596). Envelopes on stderr are diagnostics; the exit code and a held ScriptResponse are the authoritative result.

🔗 References

Resolves #612

Follow-ups: Adopt the standardized SDK error codes at sites that keep SDK v1 codes #1595 (SDK v2 error codes), Separate MXC diagnostics from the workload's stderr #1596 (separate MXC diagnostics from workload stderr)
Builds on Exit codes are consistent cross-backend w/ structured ScriptResponse JSON #1336
Contract: docs/development/architecture/versioning.md (## Error Contract); backend notes under docs/backends/

🔍 Validation

Local, Windows 11 ARM64, after merging main:

Command	Result
`cargo fmt --all -- --check`	passed
`cargo clippy -p mxc-sdk -p wxc -p lxc --all-targets --features "mxc-sdk/wslc mxc-sdk/isolation_session" -- -D warnings`	passed
`cargo clippy -p mxc-sdk --all-targets --target x86_64-unknown-linux-gnu -- -D warnings`	passed
`cargo clippy -p mxc-sdk --all-targets --target aarch64-apple-darwin -- -D warnings`	passed
`cargo test -p mxc-sdk --lib --features "wslc isolation_session"`	2985 passed, 70 failed (local sandbox: registry, telemetry consent, sockets, PSEC; same set as `main`)
`cargo test -p wxc`	156 passed, 2 failed (local hard-link restriction; same as `main`)

Earlier scheduled validation run: 38377047465. It fixed the [P8d]/[P8e] hostLoopback failures. Its debian13-bubblewrap failure is pre-existing on main.

Not run locally: host suites under tests/scripts/ (Bubblewrap, LXC, Seatbelt, WSLC, IsolationSession). They need a new scheduled run on this revision.

✅ Checklist

Signed the Contributor License Agreement
Linked to an issue
Updated documentation (if applicable)
Updated Copilot instructions (if build, architecture, or conventions changed)
If this PR changes Cargo.lock, the dependency-feed-check check passes (see pull request builds)

📋 Issue Type

Bug fix
Feature
Task

Microsoft Reviewers: Open in CodeFlow

Entry-point failures printed a bare line and exited 1, which a caller could not tell apart from a typed policy rejection, and warnings were written as unstructured stderr text. Classify every wxc-exec failure by whose problem it is, emit it as a typed JSON envelope, and carry warnings on ScriptResponse. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Backends reported failures inconsistently: some flattened everything to a generic backend error, the Bubblewrap and LXC runners set no failure phase at all, and WSLC rejections exited -1 while ProcessContainer rejections exited 1. A caller could not tell a refused request from an unavailable host, and the PowerShell suites had to match on prose banners to find out. Classify each failure by whose problem it is and derive both the wire code and the exit code from that: the request is at fault Rejected policy_validation exit 1 the host is at fault BackendUnavailable backend_unavailable exit -1 the runtime faulted mid-run other phases backend_error exit -1 Every backend now sets a phase, and `ScriptResponse::failure_exit_code` is the single place the exit code comes from. Two consequences are worth calling out. A capability the host's Windows build cannot represent -- `enumeratePaths`, `hostLoopback='allow'` -- now reaches the wire as `policy_validation`, because dropping the field runs; it used to be reported as an unavailable backend, which told the caller to give up on the host. Conversely, a backend this build did not compile in now reports `backend_unavailable` from the one-shot path too, matching what the state-aware path already returned, because only a rebuilt executor can serve it. Add an optional `warnings` array to `ScriptResponse` so the executors stop interleaving advisory diagnostics with the error channel. It is boxed to keep the struct under clippy's `result_large_err` threshold, and omitted from the wire when a run produced none. Fixes #612 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The P14b and P14c behavioural assertions gate on the `nativeCaptureAvailable` probe, which answers whether the Learning Mode API is present. That is not the same question as whether it is implemented: on a host whose exports resolve but return E_NOTIMPL, the probe says the provider is usable, both runs then fail before an output path exists, and P14c reports three failures on empty strings. The runtime already classifies that outcome correctly -- `is_api_unavailable()` maps it to `BackendUnavailable`, which reaches stderr as a typed `backend_unavailable` envelope. Gate on what the run reported rather than on the probe alone, via a shared `Test-BackendUnavailable`. Keying on the typed code covers every reason a host cannot provide capture, not just the ones a probe knows to ask about. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Dispatch runs after the policy is accepted, so a failure there is the host failing to build the tier the policy asked for, not a verdict on the request. Classifying fallback and capture-provider failures as policy_validation made wxc-exec log them as unsupported_field_for_backend and exit 1, which the process-container suites read as a validation rejection of a config they require to be accepted. Only a SID that could not be derived or ACEs that could not be applied keep their own codes. Update the harnesses that encoded the previous exit codes: WSLC and isolation session rejections now exit 1, and the two process-container dispatch refusals now exit -1. Match the Bubblewrap cwd advisory piecewise, since the advisory is carried in a JSON warning envelope that escapes the quotes around the path. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…tier Two different failures share DispatchError. A field the selected tier cannot represent names that field and is documented as a rejection, so collapsing it into backend_unavailable made hostLoopback=allow and enumeratePaths exit -1, which the suites read as 'accepted and silently dropped' -- the one outcome P8d and P8e exist to rule out. A tier that could not be built at all, or a missing denial-capture provider, stays backend_unavailable: no tier existed to judge the policy against. Restore the enumeratePaths harness to exit 1 to match. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…ackend-error-contract

Audit finalization raised its cleanup diagnostics as bare stderr prose, so a caller had to scrape them while every other warning arrived as a JSON envelope. They now travel on the response and are emitted with the rest. The finalization failure arm hard-coded exit -1 regardless of how the backend had already classified the run, which could pair a rejection envelope with an exit status that contradicts it. Deriving the status from the failure phase keeps the two in agreement, and the appended message reaches stderr through the error envelope rather than a separate prose line. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

azure-pipelines · 2026-10-13T18:45:44Z

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Copilot

🟡 Changes recommended

Failure classification remains inconsistent across validation and streaming paths, and the Seatbelt availability check can reject valid default executions.

5 open findings

What changed in this PR

Standardizes backend failures by responsible party and emits machine-readable error/warning envelopes.

Changes:

Maps policy, host availability, and runtime failures to consistent codes and exits.
Adds structured warning handling to ScriptResponse.
Updates backend implementations, tests, and documentation.

File	Description
`tests/scripts/run_wslc_all_tests.ps1`	Updates rejection exit expectations.
`tests/scripts/run_processcontainer_filesystem_enumerate_test.ps1`	Clarifies enumeration rejection behavior.
`tests/scripts/run_processcontainer_dacl_disabled_test.ps1`	Expects unavailable-tier semantics.
`tests/scripts/run_processcontainer_capture_denials_test.ps1`	Skips assertions on unavailable hosts.
`tests/scripts/run_isolation_session_tests.ps1`	Updates policy rejection exits.
`tests/scripts/run_bwrap_cwd_advisory_test.sh`	Validates structured warning output.
`tests/scripts/lib/WinProcessContainer.Common.ps1`	Adds typed availability detection.
`src/tools/wxc/src/main.rs`	Emits typed errors and warnings.
`src/tools/mxc_darwin/src/main.rs`	Adds structured executor diagnostics.
`src/tools/lxc/src/main.rs`	Adds structured executor diagnostics.
`src/mxc-sdk/src/core/mxc_engine/run.rs`	Classifies resolution failures.
`src/mxc-sdk/src/core/mxc_engine/error.rs`	Converts SDK errors back to wire errors.
`src/mxc-sdk/src/core/mxc_engine/dispatch.rs`	Preserves dispatcher classifications.
`src/mxc-sdk/src/core/mxc_common/script_runner.rs`	Adds shared envelope emitters.
`src/mxc-sdk/src/core/mxc_common/mxc_error.rs`	Centralizes error exits and serialization.
`src/mxc-sdk/src/core/mxc_common/models.rs`	Adds warnings and failure helpers.
`src/mxc-sdk/src/core/mxc_common/error.rs`	Classifies common errors.
`src/mxc-sdk/src/core/mxc_common/config_parser.rs`	Converts parse failures to typed errors.
`src/mxc-sdk/src/backends/wslc/common/wsl_container_runner.rs`	Updates rejection assertions.
`src/mxc-sdk/src/backends/wslc/common/error.rs`	Derives exits from failure phase.
`src/mxc-sdk/src/backends/windows_sandbox/lifecycle/state_aware.rs`	Classifies unavailable sandbox hosts.
`src/mxc-sdk/src/backends/windows_sandbox/lifecycle/error.rs`	Separates host and policy failures.
`src/mxc-sdk/src/backends/seatbelt/common/seatbelt_runner.rs`	Classifies Seatbelt failures.
`src/mxc-sdk/src/backends/process_container/common/dispatcher.rs`	Classifies dispatch failures.
`src/mxc-sdk/src/backends/process_container/common/base_container_runner.rs`	Distinguishes unsupported host baselines.
`src/mxc-sdk/src/backends/process_container/common/appcontainer_runner.rs`	Classifies BFS and launch failures.
`src/mxc-sdk/src/backends/nanvix/runner/mod.rs`	Splits policy, availability, and runtime errors.
`src/mxc-sdk/src/backends/lxc/common/lxc_runner.rs`	Adds detailed LXC failure phases.
`src/mxc-sdk/src/backends/lxc/common/availability.rs`	Adds uncached execution-time probing.
`src/mxc-sdk/src/backends/isolation_session/common/sandbox.rs`	Preserves typed launch classifications.
`src/mxc-sdk/src/backends/isolation_session/common/one_shot.rs`	Classifies lifecycle and process exits.
`src/mxc-sdk/src/backends/isolation_session/common/error.rs`	Maps backend errors to response phases.
`src/mxc-sdk/src/backends/hyperlight/common/mod.rs`	Splits Hyperlight failure categories.
`src/mxc-sdk/src/backends/bubblewrap/common/bwrap_runner.rs`	Classifies Bubblewrap failures.
`docs/development/architecture/versioning.md`	Documents error and warning contracts.
`docs/development/architecture/container-lifecycle.md`	Documents exit-code behavior.
`docs/development/architecture/backends/isolation-session/state-aware-rust.md`	Updates IsolationSession semantics.
`docs/backends/seatbelt/seatbelt-backend.md`	Documents Seatbelt failures.
`docs/backends/lxc/lxc-backend.md`	Adds LXC troubleshooting guidance.
`docs/backends/hyperlight/hyperlight-backend.md`	Adds Hyperlight failure guidance.
`docs/backends/bwrap/bubblewrap-backend.md`	Adds Bubblewrap failure guidance.

🧠 Review effort: Balanced

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Three surfaces reached the same condition by a different route and reported it differently. Shared request validation returned a runtime error, so an empty script was a rejection through `validate` but a `backend_error` through `spawn`, which is the path callers actually take. Both shared checks judge the request, so they are rejections. `enumeratePaths` on a backend that cannot represent it now also matches how the process-container dispatcher classifies the same field. The streaming and PTY arms for a backend this build omits returned `unsupported_containment`, while run-to-completion resolution called the same build and host `backend_unavailable`. The code no longer depends on which operation the caller chose. Arms for a backend belonging to another operating system are untouched. Seatbelt probed for Apple's sandbox CLI on every launch, but only the `Open` method shells out to it; `Exec`, the default, applies the profile through `sandbox_init`. A host without the CLI no longer loses the launch method that does not need it. Documents the stderr warning envelope alongside the response array, since the two shapes differ and only the array was described, and records why a missing experimental opt-in is a host-side code. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

🔵 Needs a closer look

Several post-telemetry early exits still discard retained warnings instead of emitting structured warning envelopes.

2 open findings

3 resolved since last review

Previously missed (1)

In code that hasn't changed since last review

Drain retained telemetry warnings before early exits

src/tools/wxc/src/main.rs:1424

This early exit occurs after telemetry::init may have retained a warning (for example, ETW registration failure), but it bypasses the only one-shot warning drain at line 1660. The error envelope is emitted while that warning is silently lost from stderr, despite warnings being documented as emitted on failures too. Drain structured warnings before exiting; the same is needed at the other post-telemetry early exits.

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

line 1436
line 1465
line 1591

🧠 Review effort: Balanced

…ackend-error-contract

Copilot

🟡 Changes recommended

Warning delivery, resolver and timeout classification, and lifecycle exit statuses still have unresolved contract inconsistencies.

5 open findings

2 resolved since last review

🧠 Review effort: Balanced

Gudge (MGudgin)

Verified adversarial review of #1482

I reviewed the 43-file diff from base 8188df6 to head 9b7a541 and confirmed that its normalized contents match gh pr diff 1482. The inline comments below are anchored only on added lines; unchanged supporting files were byte-compared with the base. The strongest gap is that Unix executable tests do not assert the new JSON-code/exit contract. This is a COMMENT review, not a request for changes based on claim-only findings. No local build, platform-dependent integration suite, or end-to-end test was run as part of filing this review.

Findings on existing open threads

#3, live Bubblewrap DNS failures mislabeled as policy refusal: continued in discussion_r4277475899.
#6, state-aware error/status mismatch with the PR's blanket claim: continued in discussion_r4277476083 as claim_mismatch, not an introduced runtime regression.
#13, warning JSON test can miss a malformed line: continued in discussion_r4277475994.
#20, ProcessContainer DACL warnings plus other unstructured wxc-exec advisories despite “Resolves #612”: continued in discussion_r4277476034 as claim_mismatch.

Claim-only and unchanged supporting locations

#15 (claim_mismatch, Medium): new docs/development/architecture/versioning.md:718-719 promises wrong-OS unsupported_containment, but the byte-identical state-aware WSLC/IsolationSession gates still return backend_unavailable. The inline comment targets the new claim, not the old gates.
#16-19 (newly_exposed_by_change, Medium): the changed IsolationSession policy mapping, one-shot parser, Hyperlight policy phase, and Windows WSLC feature-off arm leave docs/development/architecture/backends/isolation-session/oneshot.md, the one-shot paragraph of docs/development/architecture/container-lifecycle.md, the earlier Hyperlight exit row, and docs/backends/wslc/wsl-container-getting-started.md stale. Each comment is anchored to the changed behavior rather than forcing an anchor into an unchanged paragraph.
#22 (claim_mismatch, Low): the PR's all-failures envelope wording includes dry-run failures, but the unchanged handle_dry_run_exit path in wxc, lxc, and mxc_darwin exits before emit_backend_error_envelope; dry-run callers still get a human summary rather than an error JSON line. Either emit the envelope on a failing dry run or limit the claim explicitly. This pre-existing early-exit path is not asserted as a new regression.

Verified pre-existing behavior, not attributed as a new regression

mxc_engine/state_aware.rs is byte-identical between base and head; it already returned backend_unavailable for certain missing-feature paths. The state-aware terminal branches already hard-coded exit 1. Finding #6 addresses only the PR's new universal promise.
The host DNS lookup in bubblewrap/common/proxy_network.rs is byte-identical. Finding #3 concerns the new rejected conversion of its errors at bwrap_runner.rs:472, not the resolver itself.
The older Seatbelt Exec-versus-Open rejection and the streaming feature-off classification have resolved review threads. New comments #11, #15, #19, and #24 address separate residual test, state-aware, and documentation gaps; they are not requests to reopen the fixed behavior.

Gudge (MGudgin) · 2026-10-15T14:39:46Z

    pub fn error_code(&self) -> MxcErrorCode {
        match self {
            FailurePhase::Rejected => MxcErrorCode::PolicyValidation,
+            FailurePhase::BackendUnavailable => MxcErrorCode::BackendUnavailable,


Medium (security) - workload stderr can impersonate MXC's JSON error.

Attribution: newly_exposed_by_change - the new backend_unavailable code is presented as a machine-readable host-failure signal on the same stderr channel the sandboxed program can write.

wxc-exec relays workload stderr before calling emit_backend_error_envelope; that emitter writes nothing for an ordinary nonzero workload exit because error_message is empty (script_runner.rs:104-120). A workload can print a plausible {"error":{"code":"backend_unavailable",...}} and exit nonzero. A CLI consumer parsing these lines cannot establish whether this diagnostic came from MXC or from contained code. This is conditional on a consumer trusting stderr; I did not find an in-repo SDK making fallback decisions from it.

Fix: Put executor-originated results on a host-owned channel the workload cannot write to. Until then, document these shared-stream lines as untrusted and do not recommend switching containment based solely on them.

This is pre-existing. I think another PR could add a host-owned channel.

Medium, conditional CLI-consumer risk (still open). Attribution: newly_exposed_by_change for the newly meaningful backend_unavailable stderr signal. The new documentation correctly warns that workload stderr may contain forged envelope-shaped lines; that mitigates the claim but does not give a CLI consumer a way to authenticate MXC's JSON diagnostics. For a normal nonzero workload exit with empty error_message, emit_backend_error_envelope writes no authoritative result. I have not found an in-repo SDK making an unsafe backend selection from stderr, so this is not a demonstrated sandbox escape or a blocker on its own. If machine-readable CLI error codes are intended for decisions, provide a host-owned result channel; otherwise please track the channel work separately and keep the untrusted-stream limitation explicit.

Gudge (MGudgin) · 2026-10-15T14:39:46Z

+/// A refused request and an unusable host have their own constructors on
+/// [`ScriptResponse`]; this covers the faults that stay `backend_error` and
+/// only say *where* the run came apart.
+fn response_with_phase(phase: FailurePhase, message: &str) -> ScriptResponse {


Medium (maintainability) - centralize phase-aware ScriptResponse construction.

Attribution: introduced_by_change - this PR adds the same response/phase assembly here and in lxc_runner.rs:47, appcontainer_runner.rs:95, seatbelt_runner.rs:1104, and isolation_session/common/sandbox.rs:91.

The implementations already differ in whether they copy the diagnostic into standard_err, which affects bare-prose duplication alongside the new JSON envelope. Maintaining one error contract through five near-identical constructors invites drift.

Fix: Put the phase-aware response construction in a small shared ScriptResponse constructor and use it at the backend call sites; preserve intentionally different stderr behavior explicitly.

Gudge (MGudgin)

Changes requested

This follow-up changes my verdict from the COMMENT review 5534936733 on the same PR head (9b7a541). The 17 inline comments in that review and four subsequent replies already contain the detailed evidence; I am not opening duplicate threads.

Please address these change-attributable issues before merge:

High - Unix executor contract coverage (discussion_r4284388975, introduced_by_change): no Unix executor suite asserts both the structured error code and its exact process exit status for the new failure contract. Add a real refusal and unavailable-backend subprocess case, plus an envelope-serialization assertion.
Medium - Bubblewrap host DNS misclassified as request refusal (discussion_r4277475899, introduced_by_change): SandboxProxy::resolve can fail on host DNS timeout/thread failure, but the new rejected mapping emits policy_validation/exit 1. Keep static invalid-input errors as policy refusals and classify host lookup failures separately.
Medium - response warnings are missing for in-process callers (discussion_r4284389019, introduced_by_change): the new ScriptResponse.warnings field is not populated by mxc_engine::run even when the logger records advisories. Populate it at the shared run boundary or narrow the published response-level contract.

The state-aware exit mismatch in discussion_r4277476083 predates this PR and is a claim_mismatch, not a merge condition by itself. Other Medium/Low comments remain actionable but are not the basis for this verdict. The PR base and head are unchanged since the earlier review; no local build or host-dependent test suite was run for this follow-up.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 1c677fc2-77c3-43b0-a06f-da11d11447c8

Seatbelt profile preparation moved to profile_preparation.rs on main; its path and working-directory errors now classify request faults as policy_validation and host faults as backend_error. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 1c677fc2-77c3-43b0-a06f-da11d11447c8

Copilot

🟡 Changes recommended

Supported V1 SDK error behavior changes without compatibility handling, and Bubblewrap still misclassifies denied-path host I/O failures.

6 open issues

1 resolved since last review

Map host lookup failures to setup errors, not policy validation

_{Review effort: Balanced}

Share the path-vs-host I/O classification between bwrap and Seatbelt, and gate the Windows-only hyperlight Ambiguous variant. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 1c677fc2-77c3-43b0-a06f-da11d11447c8

Copilot

🔵 Needs a closer look

Cross-platform error and timeout changes need human sign-off on host validation, including the failures in the linked scheduled run.

4 open issues

2 resolved since last review

_{Review effort: Balanced}

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: d3b6643f-9e96-44f0-9860-8c7a1796421a

Restore SDK v1 codes at sites where the new classification would change published SDK behavior, with a `// SDK v2:` comment naming the intended code. Document the deferred work in docs/development/plans/sdk-v2-error-codes.md (tracked in #1595). Also address review feedback: Hyperlight permission-denied is a policy refusal, wxc/lxc --setup-* errors emit typed envelopes, and a Bubblewrap spawn failure is covered by a test. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: d3b6643f-9e96-44f0-9860-8c7a1796421a

# Conflicts: # src/mxc-sdk/src/core/mxc_engine/run.rs # src/tools/wxc/src/main.rs

Copilot

🟡 Changes recommended

The scheduled IsolationSession timeout scenario still accepts the pre-fix outcome without verifying the structured timeout error.

5 open issues

2 resolved since last review

_{Review effort: Balanced}

Copilot

🟡 Changes recommended

The IsolationSession host timeout regression still accepts the old ambiguous result without verifying the structured timeout diagnostic.

5 open issues

1 resolved since last review

Preserve V1 UnsupportedContainment mapping for Windows wslc absence

_{Review effort: Balanced}

The timeout scenario now requires exit -1 and a backend_error envelope reporting the timeout. The not-compiled-backend test uses Hyperlight, since MicroVM reports backend_unavailable on Windows. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: d3b6643f-9e96-44f0-9860-8c7a1796421a

Copilot

🔵 Needs a closer look

Cross-platform diagnostic and timeout changes still need current-revision host-suite validation and final maintainer review.

1 open issue

Require timeout exit and backend_error envelope in isolation test

4 resolved since last review

_{Review effort: Balanced}

Gudge (MGudgin)

Approving the current revision, c7bfbe5. I rechecked the previously requested Rust V1 error-code mappings, Hyperlight permission classification, structured setup errors, the Bubblewrap spawn-failure test, and the IsolationSession timeout assertion. All 29 PR checks pass. Focused local Windows tests passed for the ProcessContainer V1 mapping, the default-feature missing-backend mapping, and the Hyperlight permission classifier (3 tests); I did not run Linux/macOS paths locally.

This approval does not claim a clean scheduled host run: run 40594896918 on this head failed seven jobs (five WSLC image-pull failures, one WSLC stdin-output-loss test, and one MicroVM guest-startup failure). A later mainline run failed in the same WSLC/MicroVM categories, but those failures are not proven unrelated to this PR. The separate host-owned diagnostic channel is tracked in #1596; the remaining Bubblewrap launch/PTY coverage discussion is recorded on the PR.

Elliot (theelliotm) and others added 7 commits October 12, 2026 16:40

Merge remote-tracking branch 'origin/main' into user/emichlin/cross-b…

0a3b502

…ackend-error-contract

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Elliot (theelliotm) changed the title ~~Classify every backend failure by who can act on it~~ Emit errors and warnings as structured ScriptResponse JSON Oct 13, 2026

Elliot (theelliotm) self-assigned this Oct 13, 2026

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Elliot (theelliotm) marked this pull request as ready for review October 13, 2026 19:17

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Elliot (theelliotm) requested review from Gudge (MGudgin) and Branden Bonaby (bbonaby) October 13, 2026 19:18

Merge remote-tracking branch 'origin/main' into user/emichlin/cross-b…

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…ackend-error-contract

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Elliot (theelliotm) and others added 3 commits October 23, 2026 15:31

Condense error-classification text in versioning.md into a table

7264314

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 1c677fc2-77c3-43b0-a06f-da11d11447c8

Scope fmt::Write import to the wslc arm so non-wslc builds compile

4fb15f6

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 1c677fc2-77c3-43b0-a06f-da11d11447c8

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Comment thread src/mxc-sdk/src/core/mxc_engine/dispatch.rs Resolved

Comment thread src/mxc-sdk/src/backends/bubblewrap/common/bwrap_runner.rs Resolved

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Merge origin/main into user/emichlin/cross-backend-error-contract

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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: d3b6643f-9e96-44f0-9860-8c7a1796421a

This was referenced Oct 27, 2026

Adopt the standardized SDK error codes at sites that keep SDK v1 codes #1595

Open

Separate MXC diagnostics from the workload's stderr #1596

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Elliot (theelliotm) added this to the November 2026 (2nd week) milestone Oct 27, 2026

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Merge origin/main into user/emichlin/cross-backend-error-contract

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# Conflicts: # src/mxc-sdk/src/core/mxc_engine/run.rs # src/tools/wxc/src/main.rs

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Comment thread src/mxc-sdk/src/backends/isolation_session/common/one_shot.rs Resolved

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Comment thread src/mxc-sdk/src/backends/isolation_session/common/manager.rs Resolved

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Gudge (MGudgin) approved these changes Oct 29, 2026

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Elliot (theelliotm) merged commit ed8639d into main Oct 29, 2026
65 of 72 checks passed

Elliot (theelliotm) deleted the user/emichlin/cross-backend-error-contract branch October 29, 2026 01:35

microsoft-github-policy-service Bot removed the Needs-Attention Requires attention or a decision from the MXC maintainers. label Oct 29, 2026

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Elliot (theelliotm) commented Oct 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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📖 Description

🔗 References

🔍 Validation

✅ Checklist

📋 Issue Type

Microsoft Reviewers: Open in CodeFlow

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azure-pipelines Bot commented Oct 13, 2026

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🟡 Changes recommended

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🔵 Needs a closer look

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🟡 Changes recommended

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Verified adversarial review of #1482

Findings on existing open threads

Claim-only and unchanged supporting locations

Verified pre-existing behavior, not attributed as a new regression

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Changes requested

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🟡 Changes recommended

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Elliot (theelliotm) commented Oct 13, 2026 •

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