S130 — A game can move onto new content, and replays exactly across it

[The-Running-Dev]

What

A running game can now move onto another published version of its campaign. Engine.adoptContent(state, to) runs 16 §5.4's steps 0–8. On success it appends a LoggedContent entry, restamps campaignVersion and moves the envelope to formatVersion: 2. On refusal it returns a reason and leaves the state as it was. actionLog is now LoggedEntry[], and an epoch entry consumes a seq. deserialize reads both envelope shapes and refuses a stamp the log contradicts (C26). The §14 harness replays content entries through adoptContent. A game that never adopts still serializes as formatVersion: 1, byte for byte.

Criteria

• S130.1 — met: engine.test.ts › S130.1: an action after an adoption takes seq 2, and its stream equals the one an uncrossed log of the same length derives. A third test covers startingCampaignVersion.

• S130.2 — met: engine.test.ts › S130.2. One test per pinned reason: session_ended; unknown_campaign for the target and for the source; content_kind_changed; content_not_adoptable; migration_failed (fails and throws); content_incompatible (refuses and throws); invalid_state. Each asserts no state key and a deep-unchanged input. A further test shows the kind judges the target campaign's migrated state.

• S130.3 — met: engine.test.ts › S130.3: the entry is appended and the envelope restamped; one core.content.adopted and one core.content.pinned, each with versions and reason; the same version returns the same object and emits nothing; a second adoption chains from the first.

• S130.4 — met: engine.test.ts › S130.4. 8 negative cases, each invalid_state:

  • v1 with an epoch entry;
  • a last to that is not campaignVersion;
  • formatVersion 3;
  • v2 with no epoch entry;
  • an epoch entry with an actionId;
  • an unknown system;
  • a non-string to;
  • an out-of-place seq.

  2 positive cases: a valid v2 state round-trips byte-identically, and a migration entry whose from no archive holds is accepted without being resolved.

• S130.5 — met: harness.test.ts › S130.5. A fixture crossing 1 → 2 on a test kind that declares adoptContent produces identical traceFixture output, one serialize() per entry, across two runs. Three fixtures fail: one whose content entry now refuses, one whose entry moves from an epoch the replay is not on, and one carrying a migration entry.

• S130.6 — met: engine.test.ts › S130.4 › S130.6 (an unepoched state stays at formatVersion: 1). No golden file or replay-corpus fixture changed, and the full suite passes unchanged.

• S130.7 — met: engine.test.ts imports LoggedEntry, LoggedContent, LoggedMigration, AdoptionResult and AdoptDecision from the package root. S130.7 asserts the three new base reason codes and their messages.

Differs from design

• branchSession refuses a crossed log, as an interim measure. It refuses any source whose log carries an epoch entry with invalid_state and writes nothing (store.test.ts: refuses a log that crossed an epoch). Branching across epochs is S134's job; without this guard, a branch would silently replay a crossed log onto the default epoch. Recorded in 90-decisions.md.
• Three interpretations are recorded in 90-decisions.md:
  • step 0 emits no event;
  • a v2 state with no epoch entry is refused;
  • the harness checks a content entry's from before adopting.
• A missing kind at adoption pins with content_not_adoptable.
• The internal harness gains traceFixture. runFixture serializes once, because a per-entry trace pushed the long-horizon fixture past its 5 s timeout. The harness is not a package-root export.

Verified

• npm run typecheck, npm run lint, npm test: 115 files, 2257 tests passing.
• ./build/ConvertTo-HumanDocumentation.ps1 and ./build/Test-Documentation.ps1 pass. git diff --check is clean.
• Reverting each guard makes its tests fail:
  • removing the C26 stamp check: 4 S130.4 tests fail;
  • removing the branchSession guard: its test fails;
  • removing the harness from check: the mismatch test fails.
• Not run locally: ./docs.ps1 -BuildOnly (no installed docs.ps1); the Verify Documentation Build check covers it.