fix(manager): keep fatal VM errors internal

[kp2pml30]

Auto-opened executor mirror of genlayerlabs/genvm-manager#27.

Carries the executor-side work for that manager PR. Auto-closed as merged when the manager PR lands (its pr/v0.3/fix/fatal-errors branch is moved onto v0.3-dev).

Summary by CodeRabbit

• Bug Fixes

  • Improved handling of fatal VM errors in top-level executions.
  • Ensured contract-visible results are encoded consistently across leader and validator execution paths.
  • Prevented fatal outcomes from being published as contract results.
  • Improved reporting of malformed nondeterministic outputs and corresponding VM error codes.

• Tests

  • Added coverage for top-level and nested fatal-result handling, outcome encoding, and invalid leader results.

[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 615156ea-e43a-49b6-b17c-3fe15b69ffd8

📥 Commits

Reviewing files that changed from the base of the PR and between a54b15b and 55b1336.

⛔ Files ignored due to path filters (1)

• executor/fuzz/shared/leader-result.rs is excluded by !**/fuzz/**

📒 Files selected for processing (7)

• executor/src/host/mod.rs
• executor/src/lib.rs
• executor/src/rt/supervisor/mod.rs
• executor/src/rt/vm/mod.rs
• executor/src/wasi/genlayer_sdk/mod.rs
• executor/src/wasi/genlayer_sdk/run.rs
• executor/src/wasi/genlayer_sdk/tests.rs

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

The executor introduces contract-visible outcome types, separates publication and validation handling, and preserves fatal VM errors through nested execution. Top-level reporting coalesces fatal results into VmError, while nested execution retains FatalVmError.

Changes

Fatal outcome reporting

Layer / File(s)	Summary
Contract outcome representation executor/src/rt/vm/mod.rs, executor/src/rt/supervisor/mod.rs	ContractOutcome and ContractResultBytes now handle contract-visible encoding. Fatal VM errors cannot convert to contract bytes. Top-level fatal results can be coalesced into VmError.
Leader publication and validation flow executor/src/wasi/genlayer_sdk/..., executor/src/lib.rs, executor/src/rt/supervisor/mod.rs	Leader and validator paths parse, convert, encode, store, and validate ContractOutcome values. Publication strips VM-error details. Validation preserves the fatal RunOk result.
Top-level fatal-result normalization executor/src/lib.rs, executor/src/host/mod.rs, executor/src/rt/vm/mod.rs	run_with distinguishes top-level and nested execution. Final results are normalized only at the top-level reporting boundary. Tests verify the resulting codes and decoded error kinds.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: ⚪ Minimal · up to 55b13

The change keeps fatal VM errors internal; it is merge-ready after normal checks and review, with no actionable merge-blocking risk remaining.

Sequence Diagram(s)

sequenceDiagram
  participant Executor
  participant Leader
  participant Supervisor
  participant Validator
  participant Host
  Executor->>Leader: compute nondeterministic result
  Leader->>Executor: convert result to ContractOutcome
  Executor->>Supervisor: store encoded ContractResultBytes
  Supervisor->>Validator: provide leader result bytes
  Validator->>Executor: return validated outcome and RunOk
  Executor->>Host: coalesce fatal result only for top-level execution

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Possibly related PRs

• genlayerlabs/genvm-executor#22: Both changes update fatal-error reporting and propagation across executor and SDK paths.
• genlayerlabs/genvm-executor#24: Both changes update fatal VM error handling and nested execution behavior.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: keeping fatal VM errors internal within the executor.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch pr/v0.3/fix/fatal-errors

Warning

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