eslint-factory: prefer-core-logging rewrites console.error/console.warn (stderr) to core.error/core.warning (stdout), corrupting [Content truncated due to length]

[github-actions]

Summary

prefer-core-logging suggests replacing every console.* call with a core.* method. But the two families write to different streams: console.error / console.warn go to the process stderr, while @actions/core logging methods (core.info / core.error / core.warning / core.debug) emit GitHub Actions workflow commands to stdout. For processes that own stdout as a data/protocol channel — the stdio MCP servers and transports in actions/setup/js — moving diagnostics onto stdout corrupts the JSON-RPC stream. The stream change (stderr -> stdout) is not behavior-preserving.

Grounded evidence (all linted; config ignores only *.test.cjs)

• safe_outputs_mcp_server.cjs:101 — console.error(...) in the stdio server startup catch path (the server writes JSON-RPC to stdout).
• mcp_scripts_mcp_server.cjs:87 and :105 — console.error(...) usage/startup errors.
• mcp_http_transport.cjs:295 — console.error("MCP HTTP Transport error:", error).
• safe_outputs_mcp_server_http.cjs, mcp_scripts_mcp_server_http.cjs — same pattern.

These files deliberately log to stderr precisely to keep stdout clean for the protocol. Rewriting to core.error would write ::error::... to stdout and break framing.

Acceptance criteria

• Do not offer a core.* rewrite for console.error / console.warn (stderr -> stdout is a semantic change), or exclude MCP server/transport entrypoints from the rule (config ignores glob, or a documented filename/heuristic guard).
• At minimum, downgrade console.error / console.warn to report-only (no autofix) so the harmful transform is never auto-applied.
• Add tests: console.error / console.warn produce no autofix (or no report) in the excluded contexts; console.log / console.info -> core.info still behaves as today.
• Document the stream-semantics rationale in the rule's README section so future readers understand why stderr logging is intentionally exempt.

Generated by 🤖 ESLint Refiner · 312.3 AIC · ⌖ 12.9 AIC · ⊞ 4.6K · ◷

• expires on Jul 25, 2026, 10:22 PM UTC-08:00