On a student Spark the API answered with 746 stocks while `quantcore
risk` found no data, and after a restart the test bench answered 503
"no market data yet". Cause: `install.sh --rebuild-data` renamed the data
folder; a container that still has a folder mounted keeps using it under
its new name, and the data jobs ran inside the API -- so the rebuilt data
went into ~/quantcore/data.<date> while the commands read the new, empty
~/quantcore/data. Pasting the README's command block made it visible: it
contained `qc stop / qc start`, which stopped the service.
- install.sh --rebuild-data stops the service, checks that it stopped,
and moves the folder's contents, never the folder itself
- data jobs (setup, update) always run in a fresh container on the data
folder; a running API is restarted afterwards (stopped during setup);
`qc data-import` restarts it too; stop waits and forces if needed
- `qc status` warns when the API serves a different data set than the
folder, and lists earlier data sets with the command to restore one;
`qc start` does the same when the folder is empty
- the CLI prints three lines instead of a traceback when there is no data
- README and guide: command blocks only read, so they can be pasted whole;
start, stop, update, upgrade and --rebuild-data are in tables
- lookups that may find nothing are guarded under pipefail (one ended
`qc status` silently)
Tested on a stripped-down machine: the README block pasted whole keeps the
service running; `quantcore update` restarts the API and status agrees;
the broken state is detected and restored with `qc data-import`;
`install.sh --rebuild-data` with the service running rebuilt 745 stocks,
and API, CLI and folder agree afterwards. 142 tests pass.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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