[BUG](pyspark) Honor string min_length in base-row generation#578
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Seth Fitzsimmons (sethfitz) wants to merge 1 commit into
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[BUG](pyspark) Honor string min_length in base-row generation#578Seth Fitzsimmons (sethfitz) wants to merge 1 commit into
Seth Fitzsimmons (sethfitz) wants to merge 1 commit into
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_value_from_check_string_min_length ignored the descriptor's min_length and always returned a single character, so a string field with min_length > 1 would get a base/valid row value that already violates the constraint -- making the generated conformance ::valid row invalid and the ::invalid scenario's baseline wrong. Read the min_length bound from the descriptor and emit a filler of that length. Latent today (no live schema field declares string min_length > 1); surfaced while working the generalize-field-path branch (bd-swy2). Fixes bd-mwy8. Signed-off-by: Seth Fitzsimmons <seth@mojodna.net>
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Seth Fitzsimmons (sethfitz)
marked this pull request as draft
July 21, 2026 03:34
Seth Fitzsimmons (sethfitz)
marked this pull request as ready for review
July 21, 2026 04:16
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Summary
_value_from_check_string_min_length(base-row test-data synthesis) ignored the descriptor'smin_lengthand always returned a single character. For any string field withmin_length > 1, the synthesized base/valid row value ('a', length 1) already violates the constraint -- so the generated conformance::validrow would be invalid and the::invalidscenario's baseline wrong.The fix reads the
min_lengthbound from the descriptor and emits a filler of that length ('a' * min_length).Scope
Latent on
maintoday: no live schema field declares a stringmin_length > 1, so the conformance suite stays green and generated output is unchanged. The defect surfaced while working the generalize-field-path branch, where a mixed-shape test had to usemin_length=1rather than3to keep its valid row valid. Genuinely orthogonal to that branch -- it does not mask a defect in #570.The analogous array min-length synthesizer (
_min_length_from_shape_constraints) already readsmin_lengthcorrectly and generates that many elements; string max-length and array max-length are not lower bounds and need no base-row value. The string min-length synthesizer was the sole offender.Part of #517.