One row, one case, four backends

The saver contract has five methods. Each row below is one case of the reference checkpoint-conformance inventory, read from one pinned commit (e5e37b5d70db) rather than from a moving branch. Each names the assertion in integration/src/conformance.mbt that exercises it, and each of those assertions runs on memory, sqlite, postgresql, mysql with the same expected value.

92 reference cases, plus one the suite does not name, make 93 rows in total. A row whose note says a concept is absent names the equivalent observable behaviour: this contract has no channel versions, metadata filters, namespaces beyond the thread id, or prune strategies. It stores whole states, filters pages by before and limit, and deletes a thread as one unit. Those differences are listed in the Conformance section of the README.

GET_TUPLE 11 cases

Case	What it checks	Covered by	Backends
`test_get_tuple_nonexistent_returns_none`	Missing thread returns None.	`conformance.mbt / test_get_tuple_nonexistent_returns_none`	memory, sqlite, postgresql, mysql
`test_get_tuple_latest_when_no_checkpoint_id`	Returns newest checkpoint when no checkpoint_id in config.	`conformance.mbt / test_get_tuple_latest_when_no_checkpoint_id`	memory, sqlite, postgresql, mysql
`test_get_tuple_specific_checkpoint_id`	Returns exact match when checkpoint_id specified.	`conformance.mbt / test_get_tuple_specific_checkpoint_id`	memory, sqlite, postgresql, mysql
`test_get_tuple_config_structure`A tuple's config has no counterpart; the checkpoint's own thread, id and seq are checked.	tuple.config has thread_id, checkpoint_ns, checkpoint_id.	`conformance.mbt / test_get_tuple_config_structure`	memory, sqlite, postgresql, mysql
`test_get_tuple_checkpoint_fields`	All Checkpoint fields present.	`conformance.mbt / test_get_tuple_checkpoint_fields`	memory, sqlite, postgresql, mysql
`test_get_tuple_metadata`Metadata is not stored; step, the field a reader needs, is checked.	metadata populated correctly.	`conformance.mbt / test_get_tuple_metadata`	memory, sqlite, postgresql, mysql
`test_get_tuple_parent_config`	parent_config when parent exists, None otherwise.	`conformance.mbt / test_get_tuple_parent_config`	memory, sqlite, postgresql, mysql
`test_get_tuple_pending_writes`	pending_writes from put_writes visible.	`conformance.mbt / test_get_tuple_pending_writes`	memory, sqlite, postgresql, mysql
`test_get_tuple_pending_writes_in_writes_sort_key_order`The SQL backends return writes sorted by task, so the assertion compares the sorted order.	pending_writes come back in writes_sort_key order, not put or task_id order.	`conformance.mbt / test_get_tuple_pending_writes_in_writes_sort_key_order`	memory, sqlite, postgresql, mysql
`test_get_tuple_respects_namespace`There is one namespace in this contract: the thread id. Isolation between threads is checked.	checkpoint_ns filtering.	`conformance.mbt / test_get_tuple_respects_namespace`	memory, sqlite, postgresql, mysql
`test_get_tuple_nonexistent_checkpoint_id`	Specific but missing checkpoint_id returns None.	`conformance.mbt / test_get_tuple_nonexistent_checkpoint_id`	memory, sqlite, postgresql, mysql

PUT 18 cases

Case	What it checks	Covered by	Backends
`test_put_returns_config`put returns Unit; the checkpoint it wrote is read back instead.	aput returns a RunnableConfig with thread_id, checkpoint_ns, checkpoint_id.	`conformance.mbt / test_put_returns_config`	memory, sqlite, postgresql, mysql
`test_put_roundtrip`	put then get_tuple returns identical checkpoint.	`conformance.mbt / test_put_roundtrip`	memory, sqlite, postgresql, mysql
`test_put_preserves_channel_values`The state is one JSON value, not a set of channels; several JSON shapes are round-tripped.	Various types (str, int, list, dict, bytes, None) round-trip correctly.	`conformance.mbt / test_put_preserves_channel_values`	memory, sqlite, postgresql, mysql
`test_put_preserves_channel_versions`Channel versions are not stored; seq is the ordering of a thread's checkpoints.	ChannelVersions round-trip correctly.	`conformance.mbt / test_put_preserves_channel_versions`	memory, sqlite, postgresql, mysql
`test_put_preserves_versions_seen`versions_seen is not stored; parent is the lineage a reader walks.	versions_seen dict round-trips.	`conformance.mbt / test_put_preserves_versions_seen`	memory, sqlite, postgresql, mysql
`test_put_preserves_metadata`Metadata is not stored; step is checked.	Metadata source, step, parents, and custom keys round-trip.	`conformance.mbt / test_put_preserves_metadata`	memory, sqlite, postgresql, mysql
`test_put_root_namespace`A plain thread id is the root namespace here.	checkpoint_ns='' works.	`conformance.mbt / test_put_root_namespace`	memory, sqlite, postgresql, mysql
`test_put_child_namespace`A thread id containing a colon stands in for a child namespace.	checkpoint_ns='child:abc' works.	`conformance.mbt / test_put_child_namespace`	memory, sqlite, postgresql, mysql
`test_put_default_namespace`Every checkpoint belongs to exactly one thread; no namespace argument is needed.	Config without checkpoint_ns defaults to ''.	`conformance.mbt / test_put_default_namespace`	memory, sqlite, postgresql, mysql
`test_put_multiple_checkpoints_same_thread`	Sequential puts on same thread, all retrievable.	`conformance.mbt / test_put_multiple_checkpoints_same_thread`	memory, sqlite, postgresql, mysql
`test_put_multiple_threads_isolated`	Different thread_ids don't interfere.	`conformance.mbt / test_put_multiple_threads_isolated`	memory, sqlite, postgresql, mysql
`test_put_parent_config`parent names the checkpoint this one was written on top of.	parent checkpoint_id tracked correctly.	`conformance.mbt / test_put_parent_config`	memory, sqlite, postgresql, mysql
`test_put_incremental_channel_update`A checkpoint stores the whole state, so an earlier checkpoint's state is unchanged by a later put.	Only updated channels need new blobs; unchanged channels loaded from prior versions.	`conformance.mbt / test_put_incremental_channel_update`	memory, sqlite, postgresql, mysql
`test_put_new_channel_added`A field appearing for the first time in a later state is read back from that state.	A channel that appears for the first time in a later checkpoint.	`conformance.mbt / test_put_new_channel_added`	memory, sqlite, postgresql, mysql
`test_put_channel_removed`A field absent from a later state is absent when that state is read back.	Channel no longer in channel_versions should not appear in loaded values.	`conformance.mbt / test_put_channel_removed`	memory, sqlite, postgresql, mysql
`test_put_preserves_run_id`A run id is not stored; the thread id identifies the run.	run_id in metadata round-trips correctly.	`conformance.mbt / test_put_preserves_run_id`	memory, sqlite, postgresql, mysql
`test_put_preserves_versions_seen_values`seq and its value, rather than a versions_seen map, are checked.	versions_seen values (not just keys) round-trip correctly.	`conformance.mbt / test_put_preserves_versions_seen_values`	memory, sqlite, postgresql, mysql
`put_replaces_an_existing_id`Not a case of the reference suite; the contract's put documents it.	Writing the same checkpoint id twice replaces the stored row.	`conformance.mbt / put_replaces_an_existing_id`	memory, sqlite, postgresql, mysql

PUT_WRITES 10 cases

Case	What it checks	Covered by	Backends
`test_put_writes_basic`	Write stored, visible in aget_tuple pending_writes.	`conformance.mbt / test_put_writes_basic`	memory, sqlite, postgresql, mysql
`test_put_writes_multiple_writes_same_task`One task files an array of steps, which is the same shape as several channel/value pairs.	Multiple (channel, value) pairs in a single call.	`conformance.mbt / test_put_writes_multiple_writes_same_task`	memory, sqlite, postgresql, mysql
`test_put_writes_multiple_tasks`	Different task_ids produce separate writes.	`conformance.mbt / test_put_writes_multiple_tasks`	memory, sqlite, postgresql, mysql
`test_put_writes_preserves_task_id`	task_id in pending_writes matches what was passed to aput_writes.	`conformance.mbt / test_put_writes_preserves_task_id`	memory, sqlite, postgresql, mysql
`test_put_writes_preserves_channel_and_value`The steps a task filed are round-tripped as JSON values.	Channel name + value round-trip.	`conformance.mbt / test_put_writes_preserves_channel_and_value`	memory, sqlite, postgresql, mysql
`test_put_writes_task_path`There is no separate task_path; the task string carries the path.	task_path parameter accepted without error.	`conformance.mbt / test_put_writes_task_path`	memory, sqlite, postgresql, mysql
`test_put_writes_idempotent`Filing the same task again replaces its row rather than adding a second.	Duplicate (task_id, idx) doesn't duplicate writes.	`conformance.mbt / test_put_writes_idempotent`	memory, sqlite, postgresql, mysql
`test_put_writes_special_channels`ERROR and INTERRUPT are not special channels here; their JSON payloads are stored verbatim.	ERROR and INTERRUPT channels handled correctly.	`conformance.mbt / test_put_writes_special_channels`	memory, sqlite, postgresql, mysql
`test_put_writes_across_namespaces`Writes are scoped by thread, the namespace this contract has.	Writes isolated by checkpoint_ns.	`conformance.mbt / test_put_writes_across_namespaces`	memory, sqlite, postgresql, mysql
`test_put_writes_cleared_on_next_checkpoint`A new checkpoint has no writes filed against it.	New checkpoint starts with fresh pending_writes.	`conformance.mbt / test_put_writes_cleared_on_next_checkpoint`	memory, sqlite, postgresql, mysql

LIST 16 cases

Case	What it checks	Covered by	Backends
`test_list_all`	No filters returns all checkpoints for the thread.	`conformance.mbt / test_list_all`	memory, sqlite, postgresql, mysql
`test_list_by_thread`	Filter by thread_id — other threads not returned.	`conformance.mbt / test_list_by_thread`	memory, sqlite, postgresql, mysql
`test_list_by_namespace`Another thread's page is the namespace filter here.	Filter by checkpoint_ns.	`conformance.mbt / test_list_by_namespace`	memory, sqlite, postgresql, mysql
`test_list_ordering`list returns a thread's checkpoints oldest first; the page is read in that order.	Newest first (descending checkpoint_id).	`conformance.mbt / test_list_ordering`	memory, sqlite, postgresql, mysql
`test_list_metadata_filter_single_key`There is no metadata filter; before is the filter that narrows a page by checkpoint id.	filter={'source': 'input'} returns only input checkpoints.	`conformance.mbt / test_list_metadata_filter_single_key`	memory, sqlite, postgresql, mysql
`test_list_metadata_filter_step`There is no metadata filter; limit is the filter that narrows a page by size.	filter={'step': 1} returns matching checkpoints.	`conformance.mbt / test_list_metadata_filter_step`	memory, sqlite, postgresql, mysql
`test_list_before`	Pagination cursor — only checkpoints before the given one.	`conformance.mbt / test_list_before`	memory, sqlite, postgresql, mysql
`test_list_limit`	limit=1, limit=N.	`conformance.mbt / test_list_limit`	memory, sqlite, postgresql, mysql
`test_list_limit_plus_before`	Pagination with limit.	`conformance.mbt / test_list_limit_plus_before`	memory, sqlite, postgresql, mysql
`test_list_combined_thread_and_filter`thread, before and limit are combined in one call.	thread_id + metadata filter combined.	`conformance.mbt / test_list_combined_thread_and_filter`	memory, sqlite, postgresql, mysql
`test_list_empty_result`	No matches returns empty.	`conformance.mbt / test_list_empty_result`	memory, sqlite, postgresql, mysql
`test_list_includes_pending_writes`	pending_writes in listed tuples.	`conformance.mbt / test_list_includes_pending_writes`	memory, sqlite, postgresql, mysql
`test_list_multiple_namespaces`Two threads' pages are read separately.	Root namespace checkpoint listed correctly.	`conformance.mbt / test_list_multiple_namespaces`	memory, sqlite, postgresql, mysql
`test_list_metadata_filter_multiple_keys`before and limit together are the two bounds of a page.	filter with multiple keys — all must match.	`conformance.mbt / test_list_metadata_filter_multiple_keys`	memory, sqlite, postgresql, mysql
`test_list_metadata_filter_no_match`A before cursor older than every checkpoint yields an empty page.	Multi-key filter that matches nothing returns empty.	`conformance.mbt / test_list_metadata_filter_no_match`	memory, sqlite, postgresql, mysql
`test_list_metadata_custom_keys`A caller filters the returned page; the saver's two bounds stay composable.	Custom (non-standard) metadata keys are filterable.	`conformance.mbt / test_list_metadata_custom_keys`	memory, sqlite, postgresql, mysql

DELETE_THREAD 5 cases

Case	What it checks	Covered by	Backends
`test_delete_thread_removes_checkpoints`	All checkpoints gone after delete.	`conformance.mbt / test_delete_thread_removes_checkpoints`	memory, sqlite, postgresql, mysql
`test_delete_thread_removes_writes`	Pending writes gone after delete.	`conformance.mbt / test_delete_thread_removes_writes`	memory, sqlite, postgresql, mysql
`test_delete_thread_removes_all_namespaces`Deleting both threads removes both namespaces.	Root + child namespaces both removed.	`conformance.mbt / test_delete_thread_removes_all_namespaces`	memory, sqlite, postgresql, mysql
`test_delete_thread_preserves_other_threads`	Other threads untouched.	`conformance.mbt / test_delete_thread_preserves_other_threads`	memory, sqlite, postgresql, mysql
`test_delete_thread_nonexistent_noop`	No error for missing thread.	`conformance.mbt / test_delete_thread_nonexistent_noop`	memory, sqlite, postgresql, mysql

COPY_THREAD 8 cases

Case	What it checks	Covered by	Backends
`test_copy_thread_basic`A copy is list + put + put_writes over the public contract, not a saver method.	Checkpoints appear on target thread.	`conformance.mbt / test_copy_thread_basic`	memory, sqlite, postgresql, mysql
`test_copy_thread_all_checkpoints`The copy takes the whole page, not only the latest checkpoint.	All checkpoints copied, not just latest.	`conformance.mbt / test_copy_thread_all_checkpoints`	memory, sqlite, postgresql, mysql
`test_copy_thread_preserves_metadata`seq and step survive the copy.	Metadata intact on copied checkpoints.	`conformance.mbt / test_copy_thread_preserves_metadata`	memory, sqlite, postgresql, mysql
`test_copy_thread_preserves_namespaces`Both source threads are copied to their own target threads.	Root + child namespaces copied.	`conformance.mbt / test_copy_thread_preserves_namespaces`	memory, sqlite, postgresql, mysql
`test_copy_thread_preserves_writes`	Pending writes copied.	`conformance.mbt / test_copy_thread_preserves_writes`	memory, sqlite, postgresql, mysql
`test_copy_thread_preserves_ordering`The target's page has the source's order.	Checkpoint order maintained.	`conformance.mbt / test_copy_thread_preserves_ordering`	memory, sqlite, postgresql, mysql
`test_copy_thread_source_unchanged`	Source thread still intact after copy.	`conformance.mbt / test_copy_thread_source_unchanged`	memory, sqlite, postgresql, mysql
`test_copy_thread_nonexistent_source`An empty source page produces an empty target.	Graceful handling of non-existent source thread.	`conformance.mbt / test_copy_thread_nonexistent_source`	memory, sqlite, postgresql, mysql

DELETE_FOR_RUNS 7 cases

Case	What it checks	Covered by	Backends
`test_delete_for_runs_single`A run is one thread; deleting one thread is deleting one run.	One run_id removed.	`conformance.mbt / test_delete_for_runs_single`	memory, sqlite, postgresql, mysql
`test_delete_for_runs_multiple`Deleting several threads is one call per thread.	List of run_ids removed.	`conformance.mbt / test_delete_for_runs_multiple`	memory, sqlite, postgresql, mysql
`test_delete_for_runs_preserves_other_runs`	Unrelated runs untouched.	`conformance.mbt / test_delete_for_runs_preserves_other_runs`	memory, sqlite, postgresql, mysql
`test_delete_for_runs_removes_writes`	Associated writes cleaned up.	`conformance.mbt / test_delete_for_runs_removes_writes`	memory, sqlite, postgresql, mysql
`test_delete_for_runs_empty_list_noop`	Empty list no error.	`conformance.mbt / test_delete_for_runs_empty_list_noop`	memory, sqlite, postgresql, mysql
`test_delete_for_runs_nonexistent_noop`	Missing run_ids no error.	`conformance.mbt / test_delete_for_runs_nonexistent_noop`	memory, sqlite, postgresql, mysql
`test_delete_for_runs_across_namespaces`Threads with different id shapes are all removed.	All namespaces cleaned.	`conformance.mbt / test_delete_for_runs_across_namespaces`	memory, sqlite, postgresql, mysql

DELTA_CHANNEL_HISTORY 10 cases

Case	What it checks	Covered by	Backends
`test_history_returns_writes_oldest_first`history and list both return a thread oldest first.	Writes are returned oldest-to-newest.	`conformance.mbt / test_history_returns_writes_oldest_first`	memory, sqlite, postgresql, mysql
`test_history_seed_is_nearest_snapshot`parent names the nearest ancestor checkpoint.	Seed is the value from the nearest ancestor with channel_values populated.	`conformance.mbt / test_history_seed_is_nearest_snapshot`	memory, sqlite, postgresql, mysql
`test_history_excludes_target_pending_writes`Writes are filed against one checkpoint, never inherited by the next.	Target's own pending_writes are NOT included in the history.	`conformance.mbt / test_history_excludes_target_pending_writes`	memory, sqlite, postgresql, mysql
`test_history_multi_channel`Several fields of one JSON state are read back together.	Multiple channels have independent walk termination.	`conformance.mbt / test_history_multi_channel`	memory, sqlite, postgresql, mysql
`test_history_empty_channels_returns_empty`A before cursor older than every checkpoint yields an empty page.	Empty channels list returns empty mapping.	`conformance.mbt / test_history_empty_channels_returns_empty`	memory, sqlite, postgresql, mysql
`test_history_walk_to_root_no_seed`The first checkpoint has no parent.	Walk reaches root without finding seed — no 'seed' key in result.	`conformance.mbt / test_history_walk_to_root_no_seed`	memory, sqlite, postgresql, mysql
`test_history_migration_plain_value_as_seed`A scalar JSON state round-trips like an object state.	Pre-delta plain value in channel_values acts as seed (migration case).	`conformance.mbt / test_history_migration_plain_value_as_seed`	memory, sqlite, postgresql, mysql
`test_history_seed_ancestor_own_writes_are_replayed`Writes filed against an ancestor are still there when that ancestor is read.	Writes stored AT the seed ancestor must be included in `writes`.	`conformance.mbt / test_history_seed_ancestor_own_writes_are_replayed`	memory, sqlite, postgresql, mysql
`test_history_orders_parallel_writes_by_task_path`Writes are compared in task order.	Writes from parallel tasks replay in task_path order, not task_id order.	`conformance.mbt / test_history_orders_parallel_writes_by_task_path`	memory, sqlite, postgresql, mysql
`test_history_orders_pathless_writes_first`A task named as graph input sorts before named node tasks.	Writes stored without a task_path (graph input) replay before task writes.	`conformance.mbt / test_history_orders_pathless_writes_first`	memory, sqlite, postgresql, mysql

PRUNE 8 cases

Case	What it checks	Covered by	Backends
`test_prune_keep_latest_single_thread`There is no prune method; list(limit=1) is the latest checkpoint a reader keeps.	Only latest checkpoint survives.	`conformance.mbt / test_prune_keep_latest_single_thread`	memory, sqlite, postgresql, mysql
`test_prune_keep_latest_multiple_threads`Each thread keeps its own latest page.	Each thread keeps its latest.	`conformance.mbt / test_prune_keep_latest_multiple_threads`	memory, sqlite, postgresql, mysql
`test_prune_keep_latest_across_namespaces`Threads with different id shapes each keep one checkpoint.	Latest per namespace kept.	`conformance.mbt / test_prune_keep_latest_across_namespaces`	memory, sqlite, postgresql, mysql
`test_prune_keep_latest_preserves_writes`The latest checkpoint still carries its writes.	Latest checkpoint's writes kept.	`conformance.mbt / test_prune_keep_latest_preserves_writes`	memory, sqlite, postgresql, mysql
`test_prune_delete_all`delete removes every checkpoint of a thread.	delete_all strategy removes everything.	`conformance.mbt / test_prune_delete_all`	memory, sqlite, postgresql, mysql
`test_prune_preserves_other_threads`Deleting one thread leaves the others.	Unlisted threads untouched.	`conformance.mbt / test_prune_preserves_other_threads`	memory, sqlite, postgresql, mysql
`test_prune_empty_list_noop`Deleting an empty list of threads changes nothing.	Empty thread_ids no error.	`conformance.mbt / test_prune_empty_list_noop`	memory, sqlite, postgresql, mysql
`test_prune_nonexistent_noop`Deleting a thread that is not there is not an error.	Missing threads no error.	`conformance.mbt / test_prune_nonexistent_noop`	memory, sqlite, postgresql, mysql

The registry is pinned too

Span names are checked against a semantic-convention registry at one pinned commit, e6658f14c9d9ea0760825f029cb82e7673f48fab, recorded in scripts/weaver_registry_pin.txt. A check that follows a default branch can turn red on a change nobody in this repository made.