Gating pruning in CI

The failure mode delta-explain was built to catch: a change quietly breaks pruning — a table gets rewritten without partitioning, a query loses its partition filter — nothing errors, and every downstream scan silently reads the whole table. A gate turns that into a failed build.

The flags

• --min-pruning <PCT> — exit 1 if total pruning is below the threshold.
• --assert-stats — exit 1 if any file is missing statistics.

delta-explain s3://lake/events -w "region = 'eu' AND ts > '2026-06-01'" \
  --min-pruning 80

On failure the report still prints (with result: "fail") and stderr carries ASSERTION FAILED: .... The exit-code contract is precise and stable — see the table in What delta-explain guarantees.

In a pipeline (JSON)

delta-explain ./table -w "..." --min-pruning 80 --format json \
  | jq -e '.result == "pass"'

stdout is always a complete report or empty, so a downstream jq never parses a partial document.

GitHub Action

A composite action wraps the CLI with matching inputs. Pin the release tag:

- uses: cdelmonte-zg/delta-explain@v0.6.0
  with:
    table: s3://lake/events
    where: "region = 'eu'"
    min-pruning: "80"

Attach a report artifact

Generate a verbose JSON report and render it with the report viewer into a self-contained report.html, uploaded as a run artifact — so a reviewer of a failed gate sees which phase did not prune and which files survived, instead of an exit code.