# Line Counter Verification Report (Q125)

## Artifact
`wizard-work/spark/line_counter.py` — 1,542 bytes, 48 lines,
md5 `30f1ee5c8c32642336f45a13d724eff5` (working tree @ HEAD, this host).

## Purpose
The lane's surviving text-statistics tool: counts lines (`count` mode) and
counts comma-separated fields on the first row (`csv` mode) of a single file.
It takes `<filepath> <mode>` and prints one number; exit 0 on success, 2 on
an unreadable or missing file, 1 on a usage error. It grades nothing but its
own output and prints nothing but the number (or an error on stderr).

## Counting definitions (stated in the tool's README section)
- `count <file>`: one count per line yielded by iterating the file as text —
  every `\n`-terminated line, plus one final count for an unterminated
  trailing fragment. On files without a trailing newline this is one more
  than `wc -l`, which counts newline characters only.
- `csv <file>`: fields in the first row via `str.split(',')`. Quoted commas
  are not unescaped: `"a,b",c` reads 3 fields, not 2. Quoted-field CSV
  parsing requires the `csv` module and is not what this tool does.

## What this verification certifies
`bash wizard-work/spark/verify_line_counter.sh` grades five readings against
fixtures beside the tool: count = 10 on test_log.txt, csv = 5 on
test_data.csv, count = 4 on test_blank.txt (blank lines are lines), missing
file -> exit 2, missing mode -> exit 1. `python3 wizard-work/spark/test_line_counter.py`
runs the same readings as subprocess cells plus the error-handling cell.

## What this verification does NOT certify
- The retired host-path artifact at
  `/root/.hermes/wizard-outputs/spark/line_counter.py` (the pre-Q125 tool
  pinned by the old verify script) — that tool and its `Total lines: 5587`
  figure belong to a different directory and are not this tool.
- Any of the ten other counters in the lane
  (`count_python.py`, `count_python_lines.py`, `py_loc.py`, `lwc_counter.py`,
  `linecount_pycount.py`, `text_stats.py`, `word_stats.py`, `file_stats.py`,
  `code_stats.py`, `loc_counter.py`) — they remain in the tree untouched;
  retiring them is a separate change and is not claimed here.
- Recursive directory walking or code/comment/blank breakdowns: this tool
  counts one file at a time.

## Test command (runnable from the repo root)
```bash
cd /root/troupe-standup
python3 wizard-work/spark/test_line_counter.py
bash wizard-work/spark/verify_line_counter.sh
```