[thomasklemm]

Statement#step allocates a row array before handling SQLITE_DONE, then discards it. Handle completion after the suppressed-callback exception check but before sqlite3_column_count / rb_ary_new2. Row conversion, freezing, and the error/reset paths are unchanged.

This saves one array per completed statement, not per row. A warmed 10,000-iteration GC.stat(:total_allocated_objects) probe on Ruby 4.0.7 measured 2 → 1 objects for an empty SELECT, 4 → 3 for a one-row SELECT, and 2 → 1 for an empty UPDATE. Stepping an already-done statement remains at zero allocations. This is an allocation-only improvement; no speed, latency, or CPU no-regression claim is made.

Validation on the PR head (Ruby 4.0.7):

• bundle exec rake: RuboCop clean; 379 tests / 772 assertions, no failures or skips (vendored SQLite 3.54.1).
• SQLITE3_TEST_GC_LEVEL=verify bundle exec rake test: 379 / 772, no failures or skips.
• bundle exec rake compile test:valgrind: 379 / 749, no failures or memory errors; 7 test-defined skips.
• System SQLite 3.40.1: build and normal/GC-verify suites pass, 379 / 761 with 11 feature/platform skips. Compiler diagnostics match baseline.

Before/after behavior probes also agree for retained frozen rows, Unicode/blob/null values, reset/repeated DONE, constraint and callback exceptions, compaction, BUSY/LOCKED retries, and statement lifetime after closing the database.

[flavorjones]

Thank you for this contribution! If it goes green, I'll merge it.