LEDMatrix/docs/SPORTS_UNIFICATION.md

Sports Code Unification — Architecture

How the nine sports scoreboard plugins converge onto shared core code without becoming nine clients of a god class.

The problem

Nine plugins (afl, baseball, basketball, football, hockey, lacrosse, nrl, soccer, ufc) each ship a ~3,000-line sports.py descended from this repo's former src/base_classes/sports.py (since removed). They have drifted into three lineages, and only 28 of the 66 methods appearing across them are present in all nine. One logical fix (the UTC start-time bug) cost 75 files.

Merging everything into one base class would fix the duplication and create a worse problem: a single 2,500-line class that all nine plugins inherit, where any change has a nine-plugin blast radius and per-sport behavior survives only as if self.sport == "hockey" branches.

Three properties, three mechanisms

These are independent concerns. Conflating them is what produces god classes.

Upgradability — a plugin keeps working across core versions

Rule	Mechanism
Plugin loads on a core that predates a module	Guarded import with a bundled fallback (try: from src.X import Y / except ModuleNotFoundError: from y import Y)
Plugin loads on a core that predates a method	Capability probing — hasattr(SportsCore, "_detect_stale_games") — never a version comparison. The loader's compat check is advisory-only (it logs and continues), so probing is the real protection.
Core changes never break a plugin's rendering	The view-model contract: the game dict each plugin's _extract_game_details_common builds is read by the shared src/common renderers, so its keys may be added, never renamed or removed.
A plugin can drop its bundled copy safely	The sunset rule: its manifest must floor ledmatrix_min_version at the first core release shipping the module (recorded in CHANGELOG.md) — necessary but not sufficient. The store enforces that floor on every registry-managed install and on both supported update paths (sideloading via install_from_url is not gated), but a floor cannot reach a user who never updates, so the copy also waits for the B6 gate below.

The core API is additive-only. A method the plugins call is never removed or given a new required parameter; new behavior arrives as new methods with defaults, or as capabilities they opt into.

Reusability — write once, nine plugins benefit

Only code that is identical across every plugin that carries it moves into core. Stages 0–3 moved the copies that already were; what is left has drifted, and earns promotion by being reconciled first — made identical in all nine plugins, one method family per release, with every visible difference decided rather than averaged away. See Roadmap.

Modularity — a change to one feature cannot reach a plugin that doesn't use it

This is the property the naive merge destroys, and it is enforced structurally:

1. Capabilities are separate modules composed by inheritance, not config branches inside the base class. Hockey has no celebrations, so HockeyLive does not inherit CelebrationMixin — the celebration code is not merely disabled for hockey, it is not in hockey's MRO at all. No shared state, no dead branches, no risk. Contrast with if self.celebrations_enabled: inside SportsLive, where a bug in celebration code can still crash a plugin that never wanted the feature.

2. Variant behavior is a strategy object chosen by name, not a branch. Live rotation exists in three dialects across the lineages; core ships all three behind rotation_strategy: "swrr" | "weighted" | "simple" and a plugin may register its own. Core never learns sport names.

3. Sport-specific behavior is a documented override point. The base class declares the seam; the plugin fills it. Basketball's tournament-round parsing and baseball's BDF sizing stay in their plugins forever — they are not candidates for promotion, and core must never grow a branch for them.

4. Files bound the blast radius. Capabilities live in their own modules so a diff shows at a glance which plugins a change can reach.

Layering

src/base_classes/ has been removed: no scoreboard plugin built on it. B1 and B2 below promoted code into it (SportsCore, the mode classes, CelebrationMixin, the rotation strategies); the override points and capabilities sections record that design, but none of it ships in core any more. Shared sports code lives in src/common:

Module	Since	Holds
sports_scroll.py	3.2.0	SportsScrollDisplay / SportsScrollDisplayManager — scroll orchestration (content building stays in the plugins)
sports_card.py	3.3.0	Free functions for card settings, colours, favourite-team rules, dates and font sizes
sports_game_renderer.py	3.3.0	SportsGameRendererMixin — scroll/Vegas card geometry
sports_shared.py	3.3.0	SportsCoreSharedMixin, SportsLiveSharedMixin, SportsRecentSharedMixin — the sport-independent sports.py methods
sports_helpers.py	3.5.0	clamp/logo/rotation free functions and SportsHelpersMixin, plus the _favorite_key seam
espn_dates.py	3.5.0	ESPN date-range and limit workarounds
favorite_team_check.py	3.6.0	FavoriteTeamCheck — logs why a favourite team code shows nothing
sports_timezone.py	3.6.0	Which timezone start times are drawn in (resolve_timezone_name)
sports_celebration.py	3.7.0	SportsCelebrationMixin — draws the score/win takeover; colour helpers
sports_fetch.py	3.7.0	SportsFetchMixin — season fetch, live lookback and live-odds decisions
sports_card_wrappers.py	3.7.0	SportsCardWrappersMixin — the game renderer's sports_card delegations

Each is described in src/common/README.md.

Converging on src/common

The scoreboards never built on src/base_classes (now removed); their own sports.py copies had moved past it. So shared code now lands in hardware-free src/common modules taken from the plugin copies, each a new module rather than growth on an existing one: a plugin that deletes a method copy and relies on an older module having gained it fails at runtime with an AttributeError, while a missing module fails at load, where the version checks can see it. sports_helpers.py holds _favorite_key, the override point listed below. Each promoted module has a parity test that compares its bodies against the plugin copies when LEDMATRIX_PLUGINS points at a checkout (test_sports_helpers.py, test_sports_stage3_parity.py), and test/test_common_is_hardware_free.py keeps src/common free of rgbmatrix, src.display_manager and src.plugin_system. How a plugin adopts a module and drops its copy is documented in the plugins repo's docs/plugin-development/08-shared-sports-code.md.

Override points (the plugin-facing seam)

The base class calls these; plugins implement or override them. This table is the contract — additions require a default implementation, removals require a deprecation cycle.

Hook	Purpose	Default
_fetch_data()	Sport's schedule source	abstract
_extract_game_details(event)	Sport-specific view-model fields on top of the common ones	delegates to _extract_game_details_common
_draw_scorebug_layout(game, force_clear)	Sport's card rendering	base layout
_custom_scorebug_layout(game, draw)	Per-sport overlay on the base layout	no-op
score_phrase(points, team_abbr)	Celebration wording ("GOOOOAAALLL!" vs "TOUCHDOWN!"). points is the score delta, which sports with variable-value scores use to name the play	"<abbr> SCORES!" — only consulted when CelebrationMixin is present
win_phrase(team_abbr)	Win-celebration wording	"<abbr> WINS!" — mixin only
_favorite_key(game, side)	Which view-model field identifies a team for favorites matching	game["<side>_abbr"]
_config_schema_path()	Plugin's config_schema.json — returning it routes _get_layout_offset through the src.element_style resolver (and gives it the defaults to compare against)	None, i.e. the classic inline customization.layout read
_font_root()	Directory to resolve assets/fonts against	core install root

Two class attributes serve the same purpose for values that are per-sport constants rather than behavior:

Attribute	Meaning	Default
FINAL_PERIOD	Period at/after which a zero clock can mean "over"	4 (hockey overrides to 3)
CLOCK_COUNTS_DOWN	Whether 0:00 means "expired"	True (soccer/afl/nrl override to False — their clocks count up, so 0:00 is kickoff)
COALESCE_SCORING_SEQUENCE	Fold score increments arriving during an active celebration into that one celebration	False (football overrides to True — a touchdown lands as +6, then +1 for the extra point)

Why these are seams and not branches

_favorite_key exists because NRL abbreviations are not unique — "NEW" is both Newcastle Knights and New Zealand Warriors, "CAN" both Canberra and Canterbury — so NRL matches favorites on team ID. Flattening every plugin to abbreviations would silently select the wrong club for NRL users. The base declares the seam, NRL fills it, and core never learns the string "nrl".

CLOCK_COUNTS_DOWN exists for the same reason in the opposite direction: a soccer clock reading 0:00 means the match has not kicked off, so running the clock-expiry branch there would evict live games.

COALESCE_SCORING_SEQUENCE is the third of the same kind. In football one scoring play arrives as two score updates, so the follow-up must be folded into the first celebration; in soccer two increments a few seconds apart are two real goals, and folding them would swallow one. Neither default is "right" — which is precisely why it is a declared per-sport constant rather than a hidden assumption baked into the shared body.

Capabilities

capabilities/
  celebrations.py   CelebrationMixin        opt-in: afl, nrl, soccer, football
  rotation.py       RotationStrategy + registry

CelebrationMixin merges the two dialects the lineages grew (_check_for_goal/celebrate_opponent_goals vs _check_for_score/celebrate_opponent_scores). Their bodies were identical apart from three things, each now a seam: wording (score_phrase), follow-up suppression (COALESCE_SCORING_SEQUENCE), and team identity (_favorite_key, so NRL matches on id). Both config spellings are read, so a plugin adopting the mixin keeps working with the keys already in its published schema.

Mix it in before the mode class — class SoccerLive(CelebrationMixin, SportsLive) — so the celebration display() runs first and falls through to the scorebug via super().

What shipped is narrower. src/common/sports_celebration.py (SportsCelebrationMixin) holds only the drawing, which is identical in the five scoreboards that celebrate (afl, football, hockey, nrl, soccer — hockey grew celebrations after this was written). Arming a celebration stays in each plugin: the trigger bodies differ (nrl matches favourites by team id, football folds a touchdown's extra point into one celebration and picks scenery by points), and so does display(). The seams above were not needed to move the drawing, so none was added.

Rotation strategies. The three "dialects" turned out to be one algorithm (Smooth Weighted Round-Robin) in two shapes: an incremental picker holding state across calls (afl/nrl/soccer) and a precomputed per-cycle list (football/baseball/basketball, and hockey with a different loop shape). They agree within a cycle and differ only at the boundary — the incremental form has no restart seam — so core ships both rather than declaring a winner:

self.rotation = get_rotation_strategy("swrr", weight_for=self._live_weight)

weight_for is supplied by the host, so the favorites policy stays with the plugin and rotation.py never learns what a favorite is. An unknown strategy name degrades to simple rather than raising: the name comes from user config, and a typo should cost the boost, not the scoreboard. When a plugin needs an ordering that core does not ship, it calls register_rotation_strategy to add its own — rather than core growing a branch for it.

test_sports_capabilities.py (removed with src/base_classes) checked each strategy against a verbatim transcription of the plugin code it replaces, over every live-game shape up to four games. That differential is what B5 deletes the bundled copies on the strength of.

Scroll display — where the promotion line falls

src/common/sports_scroll.py is deliberately not a superset of the ten scroll_display.py copies. A method-level comparison of the eight that share a shape (f1 and ufc are genuine forks) found a sharp split:

Layer	Evidence	Outcome
Orchestration — get_all_vegas_content_items, clear_all, get_scroll_info, get_dynamic_duration, is_complete, display_frame	identical to 96–100% similar across all eight	promoted
Settings — _get_scroll_settings	one algorithm; the copies differ only in which league keys they walk	promoted, with the ladder as data (SCROLL_LEAGUE_KEYS)
Content — prepare_scroll_content, _load_separator_icons	8 distinct bodies across 8 plugins (145 lines, 53% similar at worst); icons 6%	override point, permanently

Same name, different job: prepare_scroll_content draws this sport's game card. Merging the eight bodies would be the exact mistake the promotion rule exists to prevent, so the base class raises NotImplementedError rather than rendering something plausible — a base that rendered something would let a plugin ship a silently blank scroll.

The one behavior the upstreamed version adds is native global_config['target_fps'] support. The bundled copies hardcode ~100 FPS via scroll_delay = 0.01 and never consult the global smooth-scrolling target; Part A threaded it through each copy by hand, and this makes that threading legacy compatibility rather than the mechanism.

Superseded. Once presentation became frame-locked (#545) the helper steps a fixed whole-pixel amount per presented frame and the panel presents at its own refresh, so honouring target_fps only turned it into a speed multiplier (60 doubled a scoreboard's speed, 200 halved it). sports_scroll no longer reads it: the crisp-speed ladder uses the panel refresh (display_manager.refresh_hz), and speed comes from scroll_settings.scroll_speed alone. See docs/SCROLL_PERFORMANCE.md.

Roadmap

Done: stages 0–3

The second project, after the B phases below: move what the nine sports.py copies (and their support files) carried byte-identically into src/common, one new module per stage, and delete the copies once the plugins floor on the release that ships it.

Stage	Core	Plugins (ledmatrix-plugins)	What moved
0	none needed; found #662 (odds no_odds marker) and #663 (a reloaded plugin's dir goes first on sys.path)	#562	Deleted the bundled copies nothing could reach (base_odds_manager, logo_downloader, three unused data sources, ~4.2k lines); three UFC fixes
1	3.5.0: sports_helpers (#583), espn_dates, json_body	#563 (1a, the eight team scoreboards), #564 (1b, ufc); floor 3.5.0	The identical helpers and ESPN date-range handling; ufc also adopted the sports_shared mixins
2	3.6.0: favorite_team_check, sports_timezone; fixes in 3.6.1 (#667) and 3.6.2 (#670)	#565 (guarded adoption), #567 (f1), #570 (sunset, floor 3.6.1), #571 (soccer, 3.6.2)	The favourite-team check (seven copies) and the timezone resolver (ten); each plugin keeps a thin timezone binding
3	3.7.0 (#672): sports_celebration, sports_fetch, sports_card_wrappers	#572 (goldens first), #574 (floor 3.7.0, copies deleted)	Celebration drawing (five plugins), four fetch methods (nine), seventeen card delegations (eight renderers)

Stage 3 was re-checked independently when this roadmap was written: #574's parent and #574 itself, rendered through the core harness against core 3.7.0, gave pixel-identical output for all 399 frames (192 harness screens across the nine plugins at the eight default sizes, 72 scroll/Vegas cards, 135 celebration frames), with a parent-vs-parent rerun as the determinism control.

Why the method changes

Byte-identical promotion has nearly run dry. Measured on ledmatrix-plugins 4327c2e (2026-09-29, after stage 3) with scripts/sports_drift_report.py:

File	Method families	In all nine	Method lines	Identical copies beyond the first	Drifted families
sports.py	94	30	30,976	1,479 lines	19
manager.py	114	36	27,137	3,198 lines	38
game_renderer.py (8 plugins)	89	—	6,830	546 lines	11

"Drifted" means in at least seven plugins with at least three different bodies. Everything still identical adds up to about 5,200 duplicated lines; the rest of the ~65,000 method lines is drifted, one outlier away from identical, or unique to one plugin. Drifted code cannot move unchanged, so consolidation stalls unless the copies are made identical first. manager.py, the largest copy of all and the layer the display controller and Vegas talk to, was in no plan before this one.

The method: reconcile, then promote

Owner decision (2026-09-29): each release, pick one drifted method family, make all nine copies identical, then promote it to core. A family here is a set of methods that share state and ship together (the rankings methods, the game-over check); the report measures each method in it. The procedure:

1. Measure. python scripts/sports_drift_report.py --family sports.py::<name> --diff lists which plugins share each body and diffs every variant against the most common one. Put the grouping in the PR.
2. Classify every difference, and say which class in the PR:
   • A fix one copy has and the others lack (a lock, a guard, a correct season year). Port it. It is a behaviour change, so it gets a CHANGELOG line in each plugin.
   • A per-sport fact (hockey ends in period 3; a soccer clock counts up). Make it a declared class constant or override point with a default, as FINAL_PERIOD, CLOCK_COUNTS_DOWN, COALESCE_SCORING_SEQUENCE and _favorite_key are, and add it to the tables above. Never a sport-name branch: core must not learn sport names.
   • A product difference: anything a user can see (which games show, a colour, a date, a badge, how long a screen stays). The owner picks the behaviour before the code changes; the decision goes in the PR and in a test that pins it (as test/test_sports_twins.py pins the twins).
   • Noise: comments, log wording, dead branches. Pick one.
3. Pin the output first. Before touching the family, its output must be covered: the harness goldens (test/golden), the scroll cards (golden-cards) and celebrations (golden-celebration) for drawing families; for logic families, a table-driven test over the nine plugins' fixture games. Missing coverage lands in its own PR first, as #572 did for stage 3.
4. Reconcile in the plugins (a monorepo PR). The report must show one variant per class for the family. Render every touched plugin before and after through the harness and diff pixels, not hashes. Every differing frame must match a recorded product decision; any other difference is a bug. Bump each plugin's version, add a versions[] entry and a CHANGELOG entry, and run update_registry.py.
5. Promote in core: a new src/common module per family (a new module, not growth on an old one, for the reason under Converging on src/common), a parity test against the plugin copies, and a CHANGELOG module entry naming the release that ships it.
6. Adopt once that release is out: each plugin floors on it, inherits the mixin, deletes its copy, gains a sunset guard (like the monorepo's scripts/test_stage3_mixin_copies.py), and is pixel-diffed again; the expected difference is zero.
7. Re-measure and update the numbers here.

A family is only reconciled when all nine agree. Leaving one plugin behind recreates the drift the report exists to measure.

Soaks: pixel diffs prove the drawing, not the timing. A family that changes when data arrives or which games are live (5, 7, 9, 13 and 14 below) needs a live-game soak on a rig, and out-of-season sports wait for their season. Before a soak, check the rig's *_display_mode: a board in switch mode tells you nothing about the scroll path.

Order

One family per release, in this order. Variant counts are from the report above (per method: distinct bodies across the plugins that carry it, counted per class role). Stage 4 needs no reconciliation and can ride along with any release.

#	Family	Methods (variants)	Why here
4	Identical sweep	manager.py: _dispatch_switch_refresh, _favorite_team_is_live, get_vegas_priority_weight, _game_involves, _favorite_scan_targets, _favorite_scan_games, _get_total_games_for_manager (all nine, 1); the live-scroll helpers _preserving_scroll_position, _refresh_live_scroll_managers, _live_scroll_managers, _note_live_scroll_built, _live_scroll_needs_rebuild, _live_scroll_fields (eight, 1). sports.py: _card_option, _filtered_or_all, _effective_live_duration, _recent_date_text (eight, 1). 58 identical families in all	Nothing to decide; brings manager.py into core as a SportsPluginHostMixin. _resolve_font_path (identical in nine sports.py and eight renderers) is replaced by core's font_layout.resolve_asset_path rather than promoted
5	Game-over check	SportsLive._is_game_really_over (5)	Pure logic, no pixels; its seams (FINAL_PERIOD, CLOCK_COUNTS_DOWN) were designed in B1. The pilot for the procedure
6	Favourite matching	_is_favorite_game (7 across three classes), _select_games_for_display (2: nrl), _select_recent_games_for_display (3)	Everything that asks "is this a favourite" goes through the 3.5.0 _favorite_key seam
7	Other-games rotation	_by_importance, _other_games_window, _advance_other_games_if_due (2 each: football), _rotate_other_games_on_display (2: ufc)	One outlier each; football carries two fixes the other eight lack
8	Rankings	_fetch_team_rankings (3), _choose_poll (3), _load_division_team_ids, _passes_other_filters, _best_rank, _is_ranked_game (2 each: football)	Needs 7; the rank badge and the "ranked only" filter read it
9	Live fetch and odds	_fetch_todays_games (5), _fetch_odds (3), _attach_odds_to_rotated_games (3)	The prerequisite for one shared ESPN poller across plugins
10	View model	_extract_game_details_common (9 of 9)	Every renderer reads it; its keys are additive-only, so reconcile to the superset and leave sport extras in _extract_game_details
11	Switch scorebug	_load_fonts (4), _load_custom_font_from_element_config (6), _get_layout_offset (5), _fit_score_font (2: football), _load_and_resize_logo (9), _draw_dynamic_odds (9), then _draw_scorebug_layout (20: Upcoming 9, Recent 8, Live 2, ufc's Core 1)	Needs 10 and the twin decisions below. Several releases: fonts and offsets, logos, odds, then one mode's layout per release
12	Scroll/Vegas card	game_renderer.py: render_game_card (6), _load_and_resize_logo (8), _load_custom_font, preload_logos, __init__ (7 each), _draw_records_or_rankings (6), _load_fonts, _draw_dynamic_odds, _draw_live_game_status, _draw_recent_game_status, _get_team_display_text (5 each), _draw_text_with_outline (2: football)	Same decisions as 11; sequence after the scroll-performance work on pre-rendered strips lands
13	Mode lifecycle	sports.py: update (23), __init__ (16), display (13), _advance_live_game_if_due (6)	Where per-sport behaviour lives; last in sports.py. Each difference becomes a seam or a strategy chosen by name (live rotation already has three)
14	manager.py host	Nine different bodies in nine plugins: __init__, display, update, has_live_content, get_live_modes, get_vegas_content, on_config_change, _initialize_managers, _get_available_modes, _get_current_manager, _adapt_config_for_manager. Dynamic duration: _evaluate_dynamic_cycle_completion (9), _record_dynamic_progress (8), get_cycle_duration (8), get_dynamic_duration_cap (6), supports_dynamic_duration, is_cycle_complete (5 each), reset_cycle_state (4). Scroll: _display_scroll_mode (8), _ensure_scroll_content_for_vegas (8), _collect_games_for_scroll (7), _should_use_scroll_mode, _has_any_scroll_mode (6 each)	See below

manager.py. Reconciling it body by body would take a release per method. The plan is a host class in core, SportsScoreboardPlugin(BasePlugin), that takes the plugin's leagues as data (key, label, ESPN path, Live, Recent and Upcoming classes: basketball's manager.py already describes its leagues as such a table) and a typed mode key instead of the mode-name string parsing (endswith('_live'), split('_')) every copy repeats. Order within it: stage 4's identical helpers first; then dynamic duration, then live priority (has_live_content, get_live_modes, has_live_priority), then Vegas content, then mode resolution, then the lifecycle methods. Pilot the whole host on nrl or afl, the smallest copies (about 1,850 lines each), with a frame soak and a live-game soak before a second plugin moves. get_vegas_content is also being changed by the scroll-performance work: coordinate before touching it.

Held: data_sources.py (nine copies; soccer's matches core's) and dynamic_team_resolver.py (eight true forks, a different constructor from core's). Effort on data fetching is better spent on the shared poller that family 9 prepares.

Product decisions each family needs

Owner calls to make before (or while) reconciling. Items marked verify are suspected behaviour that needs a payload or a rig to confirm first.

• 5, game-over check. Which rule each sport gets: the clock never ends a game in afl, nrl and soccer (CLOCK_COUNTS_DOWN = False); hockey ends at 0:00 from period 3, basketball, football and lacrosse from period 4. baseball and ufc share a copy that reads a missing clock as "0:00": dormant in baseball (its games carry no period), and not triggered by ufc's round breaks either. ESPN sends a break as STATUS_END_OF_ROUND with displayClock -, not 0:00 (verified against recorded payloads; ledmatrix-plugins#580 pins it). Whatever rule ufc gets must not read - as 0:00. Decide ufc's rule: no clock rule (ESPN's STATUS_FINAL is the only end signal it needs; this also closes a ~1 s window at the horn when the ticking clock reads 0:00), or its own final period.

• 6, favourite matching. NRL keeps matching favourites by team id (abbreviations collide: NEW, CAN), through _favorite_key rather than its own copies of the selection methods. Six plugins log the recent-games selection at INFO; baseball, football and ufc do not.

• 7, other-games rotation. football advances the rotation window under _games_lock (update() and display() both advance it; interleaved, a window of games is skipped) and fixes a favourites-only pool that recomposed the list on every frame. Port both. ufc does not attach odds to fights rotated in: decide whether rotated fights show odds.

• 8, rankings. (a) afl, basketball, nrl and soccer turn a standings payload into ranks (a pro league's standings position becomes the rank badge); baseball, hockey, lacrosse, ufc and football do not. Which is right is visible on every pro-league card with "show ranking" on. (b) football also keys ranks by team id, so two schools sharing an abbreviation across divisions cannot be confused: adopt for all. (c) football asks for the division roster of the season year (July onward is this year's season), which is right for football and wrong for college basketball, hockey and lacrosse, whose ESPN season is the year it ends: a per-sport seam, not football's constant. (d) baseball's _choose_poll calls dynamic_team_resolver.choose_top_division_poll, the others inline it: one home, in core.

• 9, live fetch and odds. (a) afl, basketball, nrl and soccer cache the live scoreboard for 30 s under <sport_key>_scoreboard_current; the others do not (the harness fixtures seed that key, so the change shows up there). (b) basketball fetches college games with no dates parameter, citing a 404 (verify now that espn_dates handles ranges). (c) odds are fetched three ways: blocking (hockey, lacrosse), a thread waited on for 1.5–2 s (six plugins), or fire-and-forget for upcoming games (basketball). This sets how long update() takes and when an odds line appears. (d) nrl guards on a missing odds manager; port it.

• 10, view model. Per key, whether every sport emits it. Additive only: no key is renamed or removed.

• 11 and 12, the scorebug and the card. The pinned divergences in test/test_sports_twins.py, where switch mode and scroll mode draw the same game differently:

  • weekday timezone: the card reads only config["timezone"] and falls back to UTC, so a board with only the global zone labels an evening kickoff with the next day. Decided 2026-09-24: use the plugin's timezone (fix); not yet implemented;
  • an out-of-range start time: the scorebug drops the weekday, the card raises;
  • favourite result on a nested payload, which score wins when flat and nested disagree, and where the favourites come from (the manager's list vs the game's stamped list plus config);
  • the element vocabulary (team_text vs team_name; rank and odds in one map, not the other), and its consequences: a team_name colour reaching one team face and not the other, and the odds face shared with the score face in scroll mode only;
  • per-mode colour overrides, which apply in switch mode only;
  • by design, kept unless the owner says otherwise: the date format (switch_date_format "numeric" vs the card's "abbrev") and the upcoming centre (switch_upcoming_center "date_time" vs "vs"), both with an "inherit" opt-in; and the two schema-font caches (per class vs per path).

  Also: football's _fit_score_font swaps to the narrow score face at any panel height when the score overflows, where the other seven keep the design face at or below the design height (a 64x32 board shows the difference); and whether switch mode and the card become one renderer drawn at two sizes.

• 13, mode lifecycle. The live-rotation dialect per sport (incremental SWRR in afl, nrl and soccer; a precomputed schedule elsewhere); which sports arm celebrations and on what (stays in each plugin, as in stage 3).

• 14, manager.py. Dynamic-duration semantics (what completes a cycle, the floor and cap per mode), what counts as live content for live priority (favourites only or any live game), and the order of Vegas content.

Measuring progress

scripts/sports_drift_report.py prints the numbers above for any ledmatrix-plugins checkout (--plugins <path> or LEDMATRIX_PLUGINS). CI runs it on every push and PR against the monorepo's main (the "Sports drift report" job in .github/workflows/test.yml): report only, never failing, with the tables in the job summary and the full JSON as an artifact. The monorepo's scripts/check_sports_drift.py is the gate: it fails when a function that agrees across the plugins starts to differ. A stage is done when its family shows one variant per class here and its copies are gone.

python scripts/sports_drift_report.py --plugins ../ledmatrix-plugins
python scripts/sports_drift_report.py --family sports.py::_is_game_really_over --diff

Phases B0–B6 (history)

The first project: it moved the scroll orchestration into core and proved the upgrade path (floors, the store's compatibility gate, the sunset). All seven phases are done. They are kept because the reasoning in B4–B6 is what every later stage relies on; the plan from here is Roadmap.

B0–B3 shipped in core 3.2.0. The rollout after them split into three phases with very different risk profiles, because one of them cannot break a user on an old core and the other can.

Phase	Scope	Status	Gate
B0	Characterization tests, CI unit job, element_style, font cwd fix, CHANGELOG discipline	✅	—
B1	Promote the nine universal methods; convert sports.py → package	✅	Characterization suite green; no behavior change intended
B2	CelebrationMixin + rotation strategies as opt-in capabilities	✅	Non-adopters have zero new code in their MRO; strategies checked against verbatim plugin transcriptions
B3	Upstream the scroll orchestration layer as src/common/sports_scroll.py, reading global_config['target_fps'] natively	✅	Content building stays per-sport
B4	Ship 3.2.0 and make version reporting trustworthy	✅	Released 2026-08-03; tag, release and src.__version__ agree; compatibility gate merged (#428, #431, #433)
B5	Adoption — guarded core imports, all eight. Bundled copies stay.	✅	All eight adopted; harness byte-identical; see the B5 retrospective below — four shipped broken and were repaired in plugins #251
B6	Sunset — delete the bundled copies	✅	Ran 2026-09-01, all eight. Floors at 3.2.0; the store refuses on all three routes in (#431/#433, #508, #510). See "B6 — what actually happened"

B4 — what "ship 3.2.0" actually requires

Cutting the tag is the small part. The version number has to become something a floor can be trusted against, and today it is not:

• The tag and src.__version__ have never agreed. v3.1.0 was tagged 2026-05-31; __version__ only became "3.1.0" on 2026-07-12 (7f7f0d64). The v3.1.0 release therefore reports __version__ = "1.0.0".

• Which silences the compatibility warning entirely for that population. PluginLoader._warn_if_incompatible skips the check when the parsed core version is below (2, 0, 0) — an anti-spam guard that, given the above, matches exactly the users most likely to be behind.

• Nothing enforces a floor anyway. The check is advisory (it logs and continues), and neither StoreManager.install_plugin nor StoreManager.update_plugin compares the core version at all — update_plugin compares the plugin's manifest version against the registry's latest_version and nothing else.

  Fixed, in two parts. install_plugin gained the gate in #431/#433, which covers every registry-managed install and, through _reinstall_with_rollback, the update path that re-downloads. update_plugin's git branch pulls in place and re-downloads nothing, so it stayed ungated until _gate_pulled_commit closed it — checked after the pull (the registry then carried no floor field, so the incoming floor was unknowable before it) and undone with git reset --hard to the pre-pull commit. The registry now publishes ledmatrix_min_version, and install and update refuse on it before downloading or pulling; both post-download gates remain as the fallback for older registries, other branches and compatible_versions. That route is rare in practice, since monorepo plugins install as archives; it was closed because the sunset rule in the plugins repo's 08-shared-sports-code.md states as condition 3 that the core enforces the floor "at install/update time", and B6 rests on that being true rather than merely written down. install_from_url — sideloading a plugin from a URL — is still ungated.

So B4 is: tag and release 3.2.0; make the tag, the release, and __version__ agree, and keep them agreeing; reconsider the < 2.0.0 skip; migrate manifests from ledmatrix_min to ledmatrix_min_version; and add the install/update compatibility gate that B6 depends on.

Two fields express compatibility, and the gate only reads one

compatible_versions is the canonical contract: schema/manifest_schema.json requires it, all 42 published manifests carry it, and it holds semver ranges — [">=2.0.0"] in 41 of them, [">=1.0.0"] in 7-segment-clock. ledmatrix_min_version is the optional per-release floor inside versions[].

The gate as merged reads only the floor. Today that is harmless: no manifest uses an upper bound, and the two fields agree everywhere except 7-segment-clock (>=1.0.0 against a 2.0.0 floor). But the fields can disagree, and the range syntax the schema already permits includes upper bounds — a plugin declaring ["2.0.0 - 2.9.9"] means "not compatible with 3.x" and the gate would install it on 3.2.0 regardless.

Before B6, the gate must evaluate compatible_versions as well, and the manifest migration must reconcile the two fields rather than only renaming the floor. Deciding which wins when they disagree is part of that work; the safe default is the more restrictive.

(The schema also deprecates a top-level ledmatrix_version in favour of compatible_versions. No manifest still carries it, so there is nothing to migrate there.)

B5 — the fallback is safe by construction; the modern path is not

The heading matters, because the unqualified version of this claim is false and this document proves it two sections down: four of the eight adopted plugins shipped with scroll mode broken on a 3.2.0 core. What is safe by construction is narrower than "adoption".

A plugin adopting core imports keeps its bundled copy and reaches it through the guarded import (see the Upgradability table above). On a core that doesn't ship the module the plugin falls back and behaves exactly as it does today. That fallback compatibility — and only that — is safe by construction. On a core that does ship the module, correctness is not automatic — object-level and scroll-mode validation (building both classes and comparing, per the retrospective below) is required to prove full behavior. There is no version of this step that breaks a user on an old core, which is why it does not wait for B6's gate.

The hockey scroll-display pilot is already validated: adopted against a core carrying 3.2.0, scroll_display.py went from 691 to 289 lines and all 16 harness renders (8 sizes × 2 screens) came out byte-for-byte identical to the pre-adoption run. That byte-comparison is the acceptance gate for every adoption. The recipe and its two gotchas are in the plugins repo's docs/plugin-development/08-shared-sports-code.md.

B6 — why the sunset needs more than a version floor

Deleting a bundled copy removes the fallback, so the guarded import becomes a hard dependency. On a core without the module the plugin raises ModuleNotFoundError at load; PluginManager.load_plugin catches it, records PluginState.ERROR, logs one line, and continues. Nothing crashes — the user simply loses that scoreboard, with no visible explanation.

Verified against a v3.1.0 worktree: src/common/sports_scroll.py, src/element_style.py and the src/base_classes/sports/ package are all absent there, and the import fails with exc.name == 'src.common.sports_scroll'. Guard sets must name that exact dotted path — {"src"} alone does not match it.

Combined with the B4 findings, a plugin that deletes its copy today reaches an un-updated user through a normal store update, fails to load, and warns nobody. B6 therefore waits for B4's compatibility gate to have shipped and to have been in users' hands long enough that the population running a core without it is small. The bundled copies cost disk space; deleting them early costs scoreboards, silently. That trade is not close.

Before the first sunset, add a compatibility regression test. Built: core test/test_sports_sunset_matrix.py (#505). It has to cover four cases, not one — B5's safety claim and B6's failure mode are different propositions and only the second is obvious:

	bundled copy present	bundled copy removed
pinned old core	loads — this is B5's whole guarantee, that the guarded import falls back	PluginState.ERROR, and the recorded error names the exact missing module
current core	loads, using core code	loads, using core code

The top-left cell is the one worth writing first: nothing in the suite currently proves that an adopted plugin still works on a core that predates the module, which is the entire basis for saying B5 is safe to run ahead of the gate.

Assert the old-core/removed-copy case as PluginState.ERROR plus the missing module path, not as an uncaught exception. PluginManager.load_plugin catches ModuleNotFoundError, so nothing propagates — a test expecting a raise would pass for the wrong reason on a core where the module is merely broken rather than absent. "Fails loudly" is aspirational, not what the code does today: it fails into ERROR state with one log line, which is precisely why B6 needs the gate rather than trusting the failure to be noticed.

The same suite should exercise the install/update gate, since it is the other half of the guarantee.

B6 — what actually happened

Ran 2026-09-01, across all eight scoreboards. Held from 2026-08-05 to 2026-09-01 on the argument below, which is kept because the reasoning applies to the next module, not because it is still in force.

The hold, and why it lifted. The stated gate was evidence of 3.2.0 uptake — "a few months of it being the default download, or store-side install data". That evidence never arrived and could not: the core updates by git pull --rebase, so release-asset counts cannot measure uptake, and no store-side telemetry exists. What changed instead is that the risk the gate protected against was closed directly. The store now refuses a plugin whose floor exceeds the running core on all three routes in:

route	gated by
install_plugin — every path that re-downloads, _reinstall_with_rollback included	#431, #433
update_plugin's git branch — pulls in place, re-downloads nothing	#508
install_from_url — sideloading	#510

With all three closed a pre-3.2.0 user cannot receive a sunset plugin at all; they keep the version they already run. The population the hold existed to protect is protected by refusal rather than by a bundled copy — which is what the copy was standing in for.

What shipped. Eight plugins, ~5,800 lines of frozen fallback deleted. Each: copy removed, guarded import collapsed to a plain one, floor raised to 3.2.0, test_core_fallback.py rewritten as test_core_scroll.py asserting the sunset rather than the fallback. scripts/check_scroll_adoption.py gained sunset_violations and a SUNSET_PLUGINS set naming all eight, so a resurrected copy or a returned guard fails CI.

Delivered as plugins #346 (hockey, later folded into #351), #349 (football), #350 (baseball), #351 (the remaining six).

Two things found by doing it, both worth carrying forward:

• Only one fallback held orchestration logic the core lacked. baseball's _configure_scroll_helper reinterpreted scroll_speed as pixels-per-frame when speed × delay fell outside the 0.1–5.0 window — measured, 10–20× faster than configured for a speed between 1.0 and 5.0. Standardised onto the core's behaviour (honour the documented px/sec, clamp) rather than preserved. Every other difference across the eight was a docstring, an unreachable scroll_helper is None guard, or an equivalent diagnostic.
• Two tests had been leaning on the guard without anyone knowing. soccer/test_live_screens.py stubbed src in a way that shadowed the core, so its guarded import fell back and the test had been exercising the frozen copy rather than the shipping class since B5. Before sunsetting anything else that carries a guarded core import, grep for tests that stub src.

The floor-raising traps still apply to any future sunset: four plugins declare their floor top-level, where editing versions[0] is a silent no-op, and the floor has three live spellings (min_ledmatrix_version, requires.min_ledmatrix_version, versions[].ledmatrix_min_version, plus deprecated ledmatrix_min). See src/plugin_system/compatibility.py:declared_min_version for the resolution order any floor-raising tool must reproduce — and note the name is inverted between the top level and versions[].

The modules held back then (data_sources.py, game_renderer.py, base_odds_manager.py) have since gone different ways: the eight team scoreboards import core's base_odds_manager (ufc keeps an MMA fork), the game renderers inherit core's SportsCardWrappersMixin (3.7.0) but keep their drawing, and data_sources.py is still copied. Their status is under Roadmap. B5's lesson applies to all of them: build the object and diff rendered output rather than trust a static check.

B5 retrospective — what the adoption actually cost

Recorded because it is the evidence behind the two decisions above, and because "the adoption went fine" is not what happened.

Four of the eight shipped with scroll mode broken on a 3.2.0 core, and were repaired in plugins-repo #251. The restructure lifted the content methods verbatim but left the state they read off self behind: separator-icon constants (hockey, basketball, lacrosse) and the game-renderer cache (afl). hockey/basketball/lacrosse could not construct the scroll display at all; afl raised inside prepare_scroll_content, which the core base catches, so its only symptom was scroll mode silently drawing nothing.

Three things are worth carrying forward:

• The bundled fallback did not protect anyone from this. The break was on the modern path, which the fallback never touches. Carrying the second copy bought nothing against the actual defect while creating the divergence that produced it. That is an argument for B6, not against it.
• Every gate was green. The safety harness renders the scoreboard screens, not scroll mode; test_core_fallback.py checked that methods existed and that their globals resolved, and self.NHL_SEPARATOR_ICON is an attribute read, invisible to an AST scan for Name loads. The fix was to stop reasoning about source and build the object: construct both classes on both paths, compare the separator icons they end up with, and assert the adopted class ends up with every instance attribute the bundled one sets.
• Test what the change touches, not what is convenient to render. Scroll mode had no coverage because the harness could not reach it. A comparison harness that renders the same games through both paths and diffs the pixels needs no per-sport knowledge of the right answer, only that adopting core code did not change it.

The ledger. Before adoption, eight duplicated copies totalled 5,685 lines. After adoption plus the frozen legacy copies it was 10,610; removing the dead inline duplication (plugins #252) brought it to roughly 8,620. B6 would take it to about 3,300 including the shared core module — some 2,400 fewer than before this project started. Until B6 runs, the adoption is net negative on disk, and its one delivered user-visible gain was that adopted plugins honoured the global target_fps instead of hardcoding ~100 FPS (since withdrawn: see the note under the B3 design above).

Decision: stop adopting further modules until B6 closes (lifted)

Held from B5 until B6 ran on 2026-09-01: each adoption added a second copy to keep in step against a payoff that depended on the sunset. Once the store refused a too-new plugin on every route, adopting and sunsetting in one stage became safe, and stages 0–3 under Roadmap did exactly that.

How to keep this project healthy

Lessons this migration paid for, worth applying beyond it:

• A version number is a promise; keep it in one place. Three different answers to "what version am I on" (tag, release, __version__) is what made the floor untrustworthy. Assert their agreement mechanically.
• Advisory checks protect nobody. If a rule matters, enforce it where the action happens — the install path, not a log line the user will never read. If it doesn't matter enough to enforce, don't write the rule.
• Prefer failures that are loud and early. A plugin that dies at load with one journal line is indistinguishable, to a user, from a plugin that was never installed. Surface plugin health in the UI.
• Keep the two repos' rules in sync deliberately. The sunset rule lives in both this file and the plugins repo's docs/plugin-development/08-shared-sports-code.md. When one changes, change the other in the same PR — drift between them is how a contributor ends up following a rule that was superseded.
• Measure before and after, on real hardware. Byte-identical harness renders and a device soak caught what unit tests could not. Reserve "it should be fine" for things you have actually looked at.

Rules for contributors

• Promote on evidence, not intuition. A method moves to core when every copy that has it is identical. Drifted copies are reconciled first, one family per release, with each visible difference an owner decision (see Roadmap); until then they stay in the plugins.
• Never add a sport name to core. If core needs to know which sport it is, the design is wrong — add an override point instead.
• A capability that is not opted into must not execute. If you find yourself writing if self.<capability>_enabled inside a base class, it belongs in a mixin.
• Touch the view-model keys only additively. The shared src/common renderers read them.
• Every promotion lands with the characterization suite green, and every pilot adoption lands with that plugin's harness and golden suites green.