[slop]fix(rivetkit): surface raw error messages instead of generic

[abcxff]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.

Type of change

• Bug fix (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)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[railway-app]

🚅 Deployed to the rivet-pr-4985 environment in rivet-frontend

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[abcxff]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• donotmerge: rivetkit test #4991
• [slop]fix(rivetkit): surface raw error messages instead of generic #4985 👈 (View in Graphite)
• [slop]fix(rivetkit): remove async drizzle db proxy #4984 : 1 other dependent PR (#4986 )
• fix(rivetkit-napi): demote bridge error decode log from warn to debug #4983
• fix(rivetkit): use keepAwake for websocket callback tracking to prevent c.vars crash after grace deadline #4978 : 1 other dependent PR (#4990 )
• main

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[claude]

Code Review

Overview

This PR makes two changes: (1) removes the RIVET_EXPOSE_ERRORS env-var gate so that all internal errors now always surface their raw message to callers, and (2) adds a structured sqlite.query_failed error type for user SQL errors (syntax, constraints, etc.).

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Security Regression — build_internal always exposes raw messages

File: engine/packages/error/src/error.rs

The previous expose_internal_errors() gate controlled whether build_internal populated the message field. Without it, every unstructured anyhow::Error that falls through RivetError::extract as INTERNAL_ERROR will now include the raw error string in the message field sent to actor clients.

This directly contradicts CLAUDE.md:

The dev-mode toggle that exposes raw messages lives in core (reads env at build_internal), not in the TS bridge.

The toggle was meant to stay in build_internal — not be removed entirely. In production, an actor client will now receive raw internal error messages (e.g. file paths, DB connection details, internal state) for any unhandled actor error that isn't already a structured RivetError.

Suggested fix: Restore the env-var gate, or replace it with a build-time feature flag if the goal is a cleaner dev/prod split:

message: expose_internal_errors().then(|| format!("{}", error)),

Note: The API builder (engine/packages/api-builder) does its own chain traversal and sanitizes internal errors separately, so REST API responses are unaffected. The exposure is specifically through the rivetkit actor error response path where RivetError::extract is called and its result serialized for the caller.

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sqlite.query_failed error type (good addition)

Files: rivetkit-rust/packages/rivetkit-core/src/error.rs, rivetkit-rust/engine/artifacts/errors/sqlite.query_failed.json, rivetkit-rust/packages/rivetkit-core/src/actor/sqlite.rs

The structured QueryFailed variant and its 400 status code mapping are correct. User SQL errors (constraint violations, syntax errors) are caller-triggered and should surface a meaningful message — this is the right classification.

The map_local_worker_error fall-through is reasonable: the function already handles all lifecycle errors (Overloaded, Closed, Dying, Fatal) explicitly, so the remainder are indeed SQLite engine errors from user-provided SQL. If internal VFS-level errors can also reach this path without being classified as lifecycle errors, they'd get a 400 query_failed instead of a 500 — but that's a separate concern from this PR.

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Minor Issues

• Missing EOF newline: rivetkit-rust/engine/artifacts/errors/sqlite.query_failed.json is missing a trailing newline.
• PR description is empty: The checklist is unchecked and there is no summary, issue link, or test description. Even for a draft, a one-liner on intent helps reviewers.

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Summary

Change	Assessment
Remove RIVET_EXPOSE_ERRORS gate	Needs the gate restored — violates CLAUDE.md and leaks internal error details in production
Add sqlite.query_failed error type	Correct and well-scoped
Map unknown local worker errors to QueryFailed	Reasonable given the call context
Missing EOF newline in JSON artifact	Minor