RDDT0002: Rolldown Log Reader Bad Line

Message

Rolldown log reader skipped bad line {line}:

Cause

Rolldown writes its build logs as newline-delimited JSON (NDJSON). When the devtools plugin reads these files, it parses each line individually. If a line cannot be parsed as a valid Rolldown debug event, this warning is emitted and the line is skipped.

Common reasons a line might fail to parse:

• The log file was truncated during a crash or interrupted build.
• The file was corrupted by concurrent writes or disk issues.
• A non-JSON line (such as a trailing newline or debug output) was written into the log file.

The warning includes the line number, the parse error message, and a preview of the offending line (truncated to 256 characters) to help diagnose the issue.

Fix

This warning is non-fatal -- the bad line is skipped and processing continues with the remaining lines. If you see this warning frequently or for many lines:

1. Delete the node_modules/.rolldown/ directory.
2. Run a clean build to regenerate the log files.
3. If the problem persists, check that no other process is writing to the .rolldown directory concurrently.

Source

• packages/rolldown/src/node/rolldown/events-reader.ts — readEventLines() logs RDDT0002 with the line number, error message, and a 256-character preview when parsing a log line fails.