Introduce three shared helpers in session-parser.ts that both the full
parser and the lightweight metadata extractor can use:
- forEachJsonlLine(content, onLine): Iterates JSONL lines with consistent
malformed-line handling. Skips invalid JSON lines identically to how
parseSessionContent handles them. Returns parse error count for diagnostics.
- countMessagesForLine(parsed): Returns the number of messages a single
JSONL line expands into, using the same classification rules as the
full parser. User arrays expand tool_result and text blocks; assistant
arrays expand thinking, text, and tool_use.
- classifyLine(parsed): Classifies a parsed line into one of 8 types
(user, assistant, system, progress, summary, file_snapshot, queue, other).
The internal extractMessages() function now uses these shared helpers,
ensuring no behavior change while enabling the upcoming metadata extraction
service to reuse the same logic. This guarantees list counts can never drift
from detail-view counts, regardless of future parser changes.
Test coverage includes:
- Malformed line handling parity with full parser
- Parse error counting for truncated/corrupted files
- countMessagesForLine output matches extractMessages().length
- Edge cases: empty files, progress events, array content expansion
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
c20652924d