Remove encoding/gob dependency entirely

[friedenberg]

Summary

encoding/gob is used throughout the codebase for serializing store configs,
object metadata, indexes, and collection types. It forces fields that should be
private to be exported (e.g. objects.metadata), requires a global registry of
types via gob.Register in init() functions, and couples unrelated packages
through shared serialization concerns. The codebase has been migrating toward
hyphence (typed blob) serialization and binary codecs, but gob remains as
legacy scaffolding.

TODO comments

• internal/oscar/store_config/main.go:25 — "remove gob entirely and cleanly
  separate store functionality (mutation, changes, loading and unloading) from
  config functionality (reading properties)"
• internal/oscar/store_config/persist.go:4 — "remove once V13 support dropped"
• internal/golf/env_repo/genesis.go:162 — "remove gob"
• internal/bravo/ids/registry.go:13 — "remove this once gob is removed
  entirely"
• lib/charlie/quiter/keyer_stringer.go:13 — "remove when removing gob"

Affected files

Direct gob usage (encode/decode calls)

File	Usage
internal/oscar/store_config/persist.go	gob encode/decode for store config persistence (V13 compat)
internal/oscar/store_config/main.go	gob.Register in init() for collection types
internal/golf/env_repo/genesis.go	gob encode during genesis
internal/hotel/store_abbr/main.go	gob encode/decode for abbreviation store
internal/hotel/log_remote_inventory_lists/v0.go	gob encode/decode for remote inventory
internal/sierra/store_browser/cache.go	gob encode/decode for browser cache
internal/foxtrot/zettel_id_index/v1/main.go	gob encode/decode for zettel ID index
internal/foxtrot/zettel_id_index/v0/main.go	gob encode/decode for zettel ID index (v0)
internal/charlie/hyphence/coder_gob.go	dedicated gob coder for hyphence (bridge code)
internal/mike/store_fs/main.go	gob.Register(sku.Transacted{})

gob.Register init() scaffolding (no encode/decode, just registration)

File	What it registers
internal/bravo/ids/registry.go	generic ID types + collection sets
internal/golf/sku/collections.go	TransactedSetEmpty, MakeTransactedMutableSet
internal/golf/sku/keyers.go	transactedKeyerObjectId
internal/golf/sku/main.go	Transacted{}
lib/charlie/quiter/keyer_stringer.go	StringerKeyer variants
lib/delta/collections_value/gob.go	generic Set/MutableSet
lib/delta/collections_value/construction.go	5x gob.Register for constructed sets
lib/delta/collections_ptr/gob.go	generic Set/MutableSet (ptr variant)
lib/delta/tridex/main.go	&Tridex{}
lib/echo/thyme/time.go	Time{}

Structural debt forced by gob

File	Issue
internal/delta/objects/main.go:20-21	"all the fields need to be public for gob's stupid illusions, but should be private once moving away from the gob entirely"
internal/delta/objects/index.go:41	ImplicitTags is "public for gob, but should be private"

Test-only gob usage

File	Notes
internal/bravo/ids/zettel_id_test.go	gob round-trip test for ZettelId
internal/bravo/ids/gob_test.go	dedicated gob serialization test
lib/delta/collections/bitset_test.go	gob encode/decode test for bitset
lib/delta/trie/main.go	gob encode/decode in trie (may be test-adjacent)

Approach considerations

• Store config persistence (oscar/store_config/persist.go) gates on V13
  support — dropping gob there requires deciding the minimum supported store
  version
• objects.metadata fields can be made private once gob is gone, which is a
  significant encapsulation win
• The hyphence/coder_gob.go bridge can be deleted once no persisted data uses
  gob format
• gob.Register calls in init() across ~15 files can be removed wholesale
  once no code path calls gob.NewEncoder/gob.NewDecoder
• collections_value/gob.go and collections_ptr/gob.go are dedicated gob
  files that can be deleted entirely

[friedenberg]

Dependency analysis: most gob removal is NOT blocked on V13

Only 1 of 10 encode/decode sites depends on the V13 store config decision (oscar/store_config/persist.go). The rest are independent caches or dead code.

Unblocked work (can proceed now)

Dead code (immediate deletion):

• golf/env_repo/genesis.go — gob encoder is unreachable (all callers pass "", string branch always fires)
• charlie/hyphence/coder_gob.go — CoderGob type has zero callers anywhere in the codebase

Regenerable caches (switch format, cache rebuilds on first run):

• hotel/store_abbr/main.go — abbreviation index (tridex of object/blob IDs)
• foxtrot/zettel_id_index/v0/main.go — zettel ID pool (map-based, older impl)
• foxtrot/zettel_id_index/v1/main.go — zettel ID pool (bitset-based, current)
• sierra/store_browser/cache.go — browser extension cache (behind chrest build tag)
• hotel/log_remote_inventory_lists/v0.go — remote sync log (has TODO: "not really used")

Supporting data structures (remove once callers above are migrated):

• lib/delta/trie/main.go — GobEncode/GobDecode methods (serve abbr + remote log)
• lib/delta/tridex/main.go — gob registration + struct encoding (serve abbr + remote log)

Blocked on V13 decision

• oscar/store_config/persist.go — gob read path for V13 store configs (write path already uses stream index unconditionally)

Cleanup after encode/decode removal

Once no gob.NewEncoder/gob.NewDecoder calls remain, all ~15 files with gob.Register in init() can be deleted wholesale, along with the structural debt (making objects.metadata fields private).

[friedenberg]

Status update (2026-03-28)

Completed

• hyphence/coder_gob.go — deleted (zero callers)
• env_repo/genesis.go — dead gob branch removed
• foxtrot/zettel_id_index/v0 and v1 — switched to encoding/binary / encoding.BinaryMarshaler
• hotel/log_remote_inventory_lists — deleted entirely (dead code, design noted in FDR-0004)
• hotel/store_abbr — switched to binary tridex serialization
• lib/delta/trie — GobEncode/GobDecode removed
• lib/delta/tridex — gob.Register and commented-out gob methods removed
• Added MarshalBinary/UnmarshalBinary to Tridex (sorted string list format)

Gob files reduced from 27 → 19.

Remaining (19 files)

Encode/decode sites (2):

• oscar/store_config/persist.go — V13 read path, blocked on V13 migration decision
• sierra/store_browser/cache.go — behind chrest build tag, low priority

Scaffolding (17 files, delete once above 2 are gone):

• gob.Register calls: oscar/store_config/main.go, mike/store_fs/main.go, golf/sku/{main,collections,keyers,transacted}.go, bravo/ids/{registry,tag_collections}.go, lib/charlie/quiter/keyer_stringer.go, lib/echo/thyme/time.go, lib/delta/collections_value/{gob,construction}.go, lib/delta/collections_ptr/gob.go
• Structural debt: delta/objects/main.go (fields public for gob)
• Tests: bravo/ids/{gob_test,zettel_id_test}.go, lib/delta/collections/bitset_test.go

Critical lesson: atomic removal required

The gob.Register(&Tridex{}) in tridex, GobEncode/GobDecode on trie, and store_abbr's gob usage are tightly coupled and must be removed atomically:

• gob.Register is needed because store_abbr.indexCodable.SeenIds is map[Genre]TridexMutable — gob can't encode *Tridex behind an interface without registration
• Trie's GobEncode/GobDecode are needed because gob uses them to recursively encode tridex's Root node structure
• Removing any one without the others causes silent data loss or panics

This same coupling likely applies to store_config — check what types it gob-encodes through interfaces before removing any remaining gob.Register calls.

Fixture contamination warning

Switching serialization format for caches (like the Abbr index) contaminates test fixtures. The binary-format Abbr file persists in zz-tests_bats/previous_versions/v14/ and causes gob: decoding into local type *tridex.Tridex, received remote type Tridex errors if the code is reverted to gob. Always regenerate fixtures (just test-bats-update-fixtures) after format changes. See #70 for proposal to always regenerate.