Before correction
{
"id": "C01",
"status": "FAIL",
"error_type": "AssertionError",
"error": "('iterator outlived its connection', 'Pool size: 1 Connections in pool: 1 Current Overflow: 0 Current Checked out connections: 0')"
}WORKED EVIDENCE / SOFTWARE REPAIR
A repair that
review changed.
The returned rows looked correct. An additional check found that the iterator had outlived its connection context.
Setting: an authored reporting application using pandas 1.5.3, SQLAlchemy 1.4.46 and 2.0.0, and SQLite.
The historical library incompatibility was real. The application, requirements and tests were authored for the study. These are retained results, not a live execution on this website.
| Stage | Observation and response |
|---|---|
| Trigger | The provider upgrade left 1 of 12 selected primary checks passing. |
| Repair | The revised application passed 12 of 12 selected primary checks on each tested stack. |
| Further review | A separate lifetime check found zero checked-out connections while iteration was in progress. The requirement was one. |
| Correction | Keep the generator inside the connection context through consumption, exhaustion, close or error. |
| Verification | The lifetime check changed from FAIL to PASS. All four additional challenges passed. |
RETAINED TEST RECORDS
The observation
behind the claim.
After correction
{
"id": "C01",
"status": "PASS",
"observation": "Connection retained during iteration and released on exhaustion"
}The core assertion, with formatting normalized from the retained traceback:
assert e.pool.checkedout() == 1THE MECHANISM
Ownership follows consumption.
This schematic illustrates the repair described in the study. It is not the original executed source or a complete production patch. The helper represents the selected chunked query path.
Defective pattern
with engine.connect() as connection:
return read_chunks(connection, statement, params)Revised pattern
with engine.connect() as connection:
yield from read_chunks(connection, statement, params)Returning lets the function leave its connection context immediately. Yielding inside the context keeps that ownership aligned with consumption.
The baseline stays visible.
| Engineering condition | Selected primary checks passed |
|---|---|
| Original application / old stack | 11 / 12 |
| Provider upgrade alone | 1 / 12 |
| First application repair | 11 / 12 |
| Ordinary pandas upgrade | 11 / 12 |
| Revised repair / upgraded provider | 12 / 12 |
| Revised repair / old stack | 12 / 12 |
The original rollback defect predates the upgrade. These twelve primary checks are a separate set from the four additional challenges.
What each part contributed
The assistant interpreted the library change and wrote the repair. Document-guided HSDLG methods structured review and correction. Selected local HSDLG controls supplied bounded execution, retained records and replay/accounting behavior. The study did not isolate their causal contributions.
One known transition, exposed tests and same-assistant production and review. The result does not establish an independent efficacy estimate, a general repair success rate or unattended maintenance.