1. Multi-class shares: prefer the single dei:EntityCommonStockSharesOutstanding
cover-page fact; else fall back to us-gaap:CommonStockSharesOutstanding at
period end (Alphabet has no dei fact). Never sum class facts (companyfacts is
non-dimensional) and never use weighted-average/diluted; conflicting values ->
null, counted as an "ambiguous shares outstanding" note in validation. Plan's
"sum class-specific" wording corrected. Verified live: Alphabet shares now
populate (12.1B), Apple still uses its dei cover date.
2. Fiscal context is the majority (fy, fp) among facts ending at reportDate, with
ties rejected — no longer the arbitrary first fact.
3. Hardening: catalog selectors require taxonomy == "us-gaap"; indexing drops
malformed facts (missing accession/end, non-finite value) so a custom concept
or bad date can't be selected.
Tests: +8 (dei precedence, us-gaap fallback, conflict->null, no weighted-average,
tie-context skip, foreign-taxonomy/malformed ignored, ambiguous-shares note).
14 passed, 1 skipped.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
dennisthiessenandClaude Opus 4.8
4754dbc17b