# fix(measurement): restore JSON records into the existing singleton

Target: `Akkudoktor-EOS/EOS:main`.
Local branch: `fix/measurement-json-reload`.
Local head: `ce132ea` (based on main `4a37244`).
Status: published with explicit user approval as [PR #1322](https://github.com/Akkudoktor-EOS/EOS/pull/1322).
Two commits, two files; published head and diff verified. Not merged.
The second commit adds an explicit non-null timestamp assertion after CI mypy
flagged the test. All 49 local tests still pass. Pre-commit (including mypy),
CodeQL and Docker build passed on ce132ea. Full pinned Linux/Python 3.13 CI pytest
also passed: 1,884 passed, 16 skipped, including --finalize and config side-effect
checks (run 35118801197). PR remains open and mergeable; no merge performed.

## Proposed PR body

When measurement persistence falls back to JSON, loading a saved file reports success
but does not restore its records: validating a second `Measurement` returns the
existing singleton. Parse and validate the individual records before inserting them
into that singleton. Invalid files now return `False` instead of reporting success.

Regression coverage checks round trips, timestamp preservation, repeated loading,
merging with existing timestamps, malformed files without partial validation writes,
and database-provider precedence. Four regression cases fail on unchanged main.
With the fix, all 49 measurement tests pass.

Validation: `python -m pytest tests/test_measurement_file_restore.py tests/test_measurement.py -q`;
Ruff check and format check of the changed source; `git diff --check`.
Run locally on Windows/Python 3.11.9, followed by successful pinned Linux/Python 3.13
CI and its complete test suite as recorded above.

No settings or API schema changes. This fix is independent of #1256, #1305 and the
GENETIC port.

## Exact review scope

- `src/akkudoktoreos/measurement/measurement.py`
- `tests/test_measurement_file_restore.py`

Only these two files differ from the pinned main. Do not publish the integration
branch as part of this PR. Publication approval was received on 2026-09-16. Only this named branch was pushed.
Inspect CI and review before any merge; merging was not part of this publication request.