refactor: remove random subchunk ordering#4011
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* feat: subchunk write order * chore: export `SubchunkWriteOrder` * chore: docs * chore: relnote * rename * refactor: no enums * Update docs/user-guide/performance.md Co-authored-by: Davis Bennett <davis.v.bennett@gmail.com> * feat: deterministic but random order * fix: make vectorized fetching less reliant on matching order * chore: add hypothesis * refactor: dead code * refactor: more cleanup * don't shard unless there is something to shard * fix: dont mix chunk grid and sharding --------- Co-authored-by: Davis Bennett <davis.v.bennett@gmail.com> (cherry picked from commit 093a153)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…hrough pickle Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…_write_order The hypothesis arrays() strategy passed both shards= and a ShardingCodec serializer, which nested the codecs and left subchunk_write_order governing only a 1-element inner grid. Drive sharding through the serializer alone. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…sted Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
… FIXME Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…ering Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Resolves conflicts in the sharding codec, strategy, tests, docs, and changelog by keeping this branch's rng-free implementation (unordered = no-promise) over the incoming original feature commit (093a153), which reintroduced the rng. Non-sharding incoming changes (string dtype pruning, metadata fixes) merged cleanly and are kept.
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #4011 +/- ##
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- Coverage 93.55% 93.53% -0.02%
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Files 88 88
Lines 11896 11894 -2
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- Hits 11129 11125 -4
- Misses 767 769 +2
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ilan-gold
approved these changes
Jun 3, 2026
These changes were patching a latent bug in `arrays()` where ShardingCodec-as-serializer was being double-stacked with `shards=...`, producing nested sharding. Splitting to a follow-up PR so this one stays focused on removing the `rng`/random-subchunk-order surface. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
d-v-b
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Jun 5, 2026
After merging zarr-developers#4011 (which made 'unordered' deterministic and warns callers not to rely on its layout), drop the two places my earlier fixes special-cased it by name: - Byte-range write fast path: remove the 'subchunk_write_order != unordered' gate. The rank map is derived from _subchunk_order_iter(self.subchunk_write_ order), which is the single source of truth for physical layout — correct for every order without a name check. _subchunk_order_iter is the only place that knows a given order's layout. - Parity test: assert byte-equality across pipelines for ALL orders, not just 'deterministic' ones. The check verifies the two pipelines AGREE (they share _subchunk_order_iter), which holds whatever an order resolves to; it makes no assumption about what 'unordered' means. 540 parity+sharding and 862 codec/indexing tests pass under both pipelines; mypy clean. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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This PR reverts the addition of random subchunk ordering in the sharding codec which was introduced in #3826. After this PR, choosing "unordered" will write chunks lexicographically but only as an implementation detail.