fix_moon_phase: also pin ubirthday and getyear() to the seed - #130
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kenforthewin wants to merge 1 commit into
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fix_moon_phase: also pin ubirthday and getyear() to the seed#130kenforthewin wants to merge 1 commit into
kenforthewin wants to merge 1 commit into
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NetHack hashes ubirthday for between-game flavor variation without consuming game RNG: shopkeeper names (shknam.c), shop surcharge parity (shk.c), antholemon() species (mkroom.c), scroll labels (read.c). fix_moon_phase pins the struct-tm path but ubirthday was still raw time(NULL), so wall-clock leaked into fully seeded games (observed as session-dependent shopkeeper names and message-pagination step drift; prices and anthole species are gameplay-relevant channels). Derive ubirthday from settings.time_seed via the same ISAAC64 pattern as nle_fill_fixed_tm, and route getyear() through the fixed-tm wrapper. No change when fix_moon_phase is off.
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Thanks for the PR! Is there any way that you could add a test to the suite for this functionality? |
StephenOman
requested changes
Aug 15, 2026
| isaac64_init(&time_rng, seed_bytes, sizeof(seed_bytes)); | ||
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| /* Arbitrary fixed epoch range: 2000-01-01 plus up to ~40 years. */ | ||
| return (time_t) (946684800UL |
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Can you replace these UL literals with macros that describe what they mean please?
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Fixes #129.
fix_moon_phasepins thestruct tmpath butubirthdaywas still rawtime(NULL), so wall-clock leaked into fully seeded games through the flavor-variation hashes (shopkeeper names inshknam.c, shop surcharge parity inshk.c,antholemon()species inmkroom.c, scroll labels inread.c).getyear()also bypassed the fixed-tm wrapper.This derives
ubirthdayfromsettings.time_seedvia the same ISAAC64 pattern asnle_fill_fixed_tm(), and routesgetyear()throughnle_getlt_maybe_fixed(). No behavior change whenfix_moon_phaseis off.Verified: same seed run in sessions 96 seconds apart yields identical action SHA-256 and identical shopkeeper name; previously the same seed produced different shopkeeper names (and step counts, via message pagination) across sessions. No seeded outcome changed in our regression fixtures (details in #129).