openpencil/packages/docs/development/fig-reader.md
Danila Poyarkov 68c2af5600
feat(fig): occurrence-scoped instance interpretation as the single .fig reader
* refactor(fig): introduce occurrence-scoped instance interpreter

* refactor(fig): add direct occurrence materialization and render diagnostics

* fix(scene-graph): preserve nested edits and invalidate text layout caches

* refactor(fig): assemble indexed documents with occurrence provenance

* refactor(fig): validate document assembly against live scene oracles

* fix(text): preserve saved glyphs and supported run paints

* test(fig): share typed GUID fixture helper

* fix(fig): resolve component root keys in instance overrides

* fix(kiwi): reject malformed byte arrays before encoding

* fix(components): target properties by source identity through undo

* fix(fig): preserve editable occurrence export contracts

* refactor(fig): construct live component dependency closures

* fix(fig): invalidate inherited text geometry after occurrence overrides

* perf(fig): reuse component expansions and narrow payload copies

* perf(fig): avoid discarded metadata and instance definition copies

* perf(fig): transfer parsed records into archive reader ownership

* feat(fig): add incremental page sessions with load rollback

* test(fig): verify page deltas and stale revision rejection

* feat(fig): wire reader worker sessions and compact recovery checkpoints

* docs(fig): organize reader architecture and visual examples

* chore(fig): checkpoint WIP reader and writer overhaul

Preserve in-progress FIG reader, instance interpretation, editable export, and validation work on its feature branch. This is a backup checkpoint, not a release-ready or fully validated change.

* refactor(fig): resolve instance structure before expansion

Route swaps and property assignments down to the instance they configure
so each occurrence expands once with its effective component and complete
assignment list. Owners then apply property claims onto the built subtree,
which keeps values in the declaring owner's coordinate space and orders
inner owners before outer ones without re-expansion, recipes, or patch
restoration.

Track the components an occurrence expanded before an outer decision
replaced them, including intermediate swap assignments, so a claim that
resolved against a superseded component is retired while a genuinely
missing target still reports. Precedence is one rule: an explicit claim
keeps a field unless a strictly outer owner assigned it.

Drop the detached-lineage remap heuristic; unresolved assignments report
through the existing diagnostic instead of guessing a replacement target.
The Accordion source-closure fixture reports two stale overrides, not
three: the third came from a subtree the old interpreter expanded and
discarded.

* refactor(fig): derive override field handling from one registry

Describe each claimable raw field once, with its SceneGraph fields, kind,
and whether it is a length, and derive claim recording, layout-distance
scaling, and export serialization from it instead of maintaining parallel
tables.

Restore every field the uniform scaler touches from the instance record
after scaling. The record already describes the placed result, but corner
radii, dash patterns, and effects were previously scaled without being
restored, so a scaled instance with its own corner radius rendered it
doubled.

* fix(fig): retire nested swaps under a replaced component

A structural layer routed through an instance whose component an outer
owner replaced may still address the original component's children. Such
a layer is stale in the same way a property claim is: it resolved before
the outer decision and has no target now. Carry the replaced components
across that boundary and skip the layer instead of failing the file.

material3's List swaps a list item to another variant while the item's
own saved swap of a trailing checkbox still names the original variant's
child.

* fix(core): report stale Figma override records instead of refusing the file

Figma keeps override, assignment, and binding records that address nodes
it later deleted, and material3.fig could not open because the reader
ran the document session strictly. Share one set of session options
across the reader and recovery sessions that collects those records as
diagnostics and skips them; a swap whose replacement is missing remains
a structural failure.

The component-metadata expectation follows the visible Buttons page copy
of the component set, which the dependency closure now resolves instead
of an internal-only copy.

* fix(fig): keep instances of deleted components when opening a document

Figma retains instances whose main component was deleted, and material3's
Internal Only Canvas has 56 of them, so an edited document could not be
exported: export loads every page and the reader refused the page over
missing reachable sources.

The dependency closure now separates deleted components from broken
hierarchy, which remains fatal. With the new onMissingComponent option the
interpreter keeps such an instance as a childless occurrence that retains
its saved reference, applies only its root claims, and reports the owner;
strict interpretation still fails. The core reader opts in, shares one
diagnostics sink with recovery and export sessions, and exposes it through
readerDiagnostics(). Property defaults naming a deleted component are kept
the same way, so an edited export no longer rejects them.

* fix(fig): resolve variant property values through the component set

A variant's saved specs name variant definitions that its component set
owns, so occurrence conversion left them keyed by definition id. Resolve
them to names once the set is in the graph, as the previous importer did.

The component-metadata expectation follows the visible Buttons set's
axes; the Style axis belonged to an internal-only copy.

* refactor(fig): satisfy type-aware lint in the interpreter and export

* fix(fig): keep an instance fill override's variable alias across export

A fill or stroke override on an instance descendant lost its colour
variable on export: the paint claim was written without the alias, and a
boundVariables override for a paint colour produced no claim at all
because paint colours are not node-level consumption fields. The reopened
paint therefore bound to the component's default variable.

Write override paints through the same alias-aware builder as node
paints, serialize a paint colour binding override as the paint claim
itself, and on import record the binding claim alongside a claimed paint
that carries an alias so a later component sync cannot restore the
component's binding.

On an edited material3.fig round trip this removes all 10,329 fill
differences; 2,217 of 78,425 nodes still change, almost all text metadata
Figma keeps on outlined vectors.

* docs(fig): describe the single reader, its diagnostics policy, and paint claims

The status documents still said the replacement reader covered only some
worker paths and that old-reader removal was pending. Every import path
now uses it and the previous importer is deleted, so state that and move
the open items to fidelity and performance.

Record the contracts added recently: strict-by-default interpretation
with per-session diagnostic handlers that the application reader opts
into, instances of deleted components kept as childless instances, the
shared override field registry, paint colour aliases serialized inside
paint claims, and variant values resolved through the component set.
Correct the clipboard ownership rule in AGENTS.md: the envelope belongs
to fig, pasted records go through the same reader as documents.

* docs: note exported instance overrides in the changelog

* refactor(fig): share record indexing and symbol data access

Five modules built their own GUID-to-record index with the same idiom;
they now use the source index, or indexRecords when child order is not
needed. The Kiwi codec types only symbolID, so every reader cast
symbolData to reach overrides and the uniform scale; symbolDataOf,
symbolOverridesOf, and uniformScaleOf replace those casts. idOf and
parentIdOf name the record identity conversions used by ancestry walks.

* refactor(fig): share tree search and traversal across records and occurrences

The rule that a path segment may pass through ordinary containers but
never implicitly into an instance existed three times, once per tree.
findWithinBoundary owns it now, parameterized by a tree shape; the
occurrence resolver and the static record resolver are two callers.
An occurrences() iterator replaces hand-rolled recursion in the
component planner, closure, layout scaler, and correspondence linker,
forEachOverrideRecord replaces the record-plus-overrides walks in the
dependency scans, and one child-pairing generator serves both
source-children matchers.

* refactor(fig): serialize override claims from the field registry

Split export-node.ts: export-context.ts owns the serialization context,
GUID allocation, and paint builders; override-claims.ts owns instance
override serialization. The override serializer was a chain of field
checks that had to agree with the registry materialization records
claims from; it is now one switch over the registry's field kinds, the
export side of that table, with swaps and variable bindings as the two
cases the registry does not describe.

Decoded record streams for an edited gold-preview export and a
synthetic bound-fill export are identical before and after.

* fix(core): record instance overrides for FigmaAPI rename and resize

The name setter and resize() wrote to the graph directly, so a rename or
resize of an instance child through the Figma API was never recorded as
an override: component sync reverted it and export did not write it.
Route both through the shared recording update like every other setter.

* fix(fig): address overrides inside nested instances by the definition child

An override on a child of a nested instance was addressed through the
enclosing component's own copy of that child. That node lives inside an
instance and is never written as a record, so Figma could not resolve the
path and dropped the override. Follow the correspondence until it leaves
every instance, which yields the nested component's child, the record
Figma itself names in the same situation (verified against Figma's
clipboard encoding of the identical edit and by reopening the export).

* test(fig): record the Figma reopen of reader exports

* test(fig): compare reopened exports with the oracle tool

The interpreted-document comparison already reads Figma's interpretation
of an archive against the reader's; pointing it at an exported archive and
its imported Figma file makes it the reopen check. Captures need the
imported file to be the active document, so add an activate-tab operation
that brings a desktop tab to the front through the shell page. Record the
comparison results for the three reopened exports and document the
procedure.

* fix(scene-graph): keep a nested instance's correspondence across a swap

Children populated by cloning link to the enclosing component's record
through componentId. Swapping a nested instance replaced that field with
the new component, so the swap was exported against the replacement
component's GUID instead of the nested instance record and Figma could not
apply it. Record the correspondence as the owner's sourceComponentId
override and the swap as its componentId override, as materialized
documents already carry them.

* fix(core): treat applied shared styles as instance overrides

Style references were not instance sync fields, so a text style applied
inside an instance was neither recorded as an override nor exported, and a
component's style change did not reach its instances, although the reader
records styleIdForText claims from Figma. Add the style reference fields
to the sync set and expose them on the Figma API proxy under Figma's
names so assignments through the API record overrides.

* test: record the second Figma reopen round for the reader export

Figma confirmed stroke and corner-radius variable bindings, an applied
text style, nested-frame layout distances and sizing modes, visibility,
and a nested swap. A size claim on an auto-layout child inside an
instance is not applied, matching Figma's own resize refusal there.

* chore: format the merged structural export test

* refactor: group export and instance sync modules into domain folders

The node-change export context, node serializer, runtime, and override
claims move under node-change/export/, and the scene graph's instance
child sync and sync field lists move under instances/, keeping the
public instances module to its API.

* fix(fig): address exported instance overrides by override key

Figma resolves an override path segment through the target record's
override key, never its GUID: in gold-preview.fig all 10,341 override
and 12,838 derived-geometry segments resolve that way and none resolve
to a node GUID. A component imported from Figma keeps its keys, but one
authored here has none, so the writer addressed its descendants by GUID.
Figma tolerated that for most fields and silently dropped the geometry,
so a descendant resized inside an instance reopened at the component's
size.

Definition records — a component and everything inside it — now carry an
override key, minted from the shared identity counter when the node has
none, and paths name that key. One map spans the document because the
serializer runs once per top-level child.

The library content hash ignores the key, which identifies a record
rather than the component's content, and the clipboard export passes its
variable mode map as modeIdToGuid instead of propertyIdToGuid.

* docs: record how Figma resolves an override path

* Revert "fix(fig): address exported instance overrides by override key"

This reverts commit 38eebb2e5, except its clipboard argument fix.

The change came from gold-preview.fig, where every override path segment
resolves through a record's override key. material3.fig shows the
opposite: 51,332 of its segments are node GUIDs against 24 keys, and only
16 of 87,237 records carry a key at all. gold-preview is a file of
library instances, where the key is the cross-file identity; addressing
by GUID is what Figma writes for locally authored components, which is
what the writer already did. It was also not the reason Figma ignored a
descendant's size claim, which is still open.

The clipboard export keeps passing its variable mode map as modeIdToGuid
rather than propertyIdToGuid, which was an unrelated defect in the same
call.

* docs: correct the override addressing note and record the size gap

* docs: settle the descendant size gap as a Figma constraint

* chore: format the JSON fixtures this branch adds

format:check runs the formatter and fails on any change, so the fixtures
have to be committed as oxfmt writes them.

* test(tools): smoke the instance override subpath's current exports

populateAndApplyOverrides belonged to the importer this branch removes.

* perf(fig): index the archive once per document, not once per page

Selecting a page rebuilt both whole-document source indexes, so opening
material3.fig with its 33 pages indexed 87,237 records 33 times and
86,888 records another 33 times: 102 index builds where 36 are needed.
Only the page's own subset varies, so the full index and the component
interpreter move into state shared across selections, and the initial
read path passes its index to inheritance, style lookup, the dependency
closure and component planning rather than each building its own.

The paint and component-property passes iterate keys directly instead of
materializing an entry array for every node, most of which bind nothing.

Loading material3.fig goes from about 9.5s to about 7.5s on the same
machine, measured back to back with the machine otherwise idle.

* docs: note the faster multi-page .fig load

* perf(fig): apply document passes to the nodes a page materialized

Linking component property values, resolving variant values and applying
layout and paint bindings each walked the whole graph and skipped what
was already there, so every page load re-visited every node the earlier
pages had produced. On nuxtui.fig, 121 pages over a graph that reaches
354,000 nodes, those four passes were 22.7% of the profile after only
six pages and grew from there.

Each pass now takes the nodes just materialized. Component property
types are remembered across page loads instead, because an assignment on
a new node can name a definition an earlier page introduced; seeding that
cache is the only pass that still reads the whole graph, once per
document rather than once per page.

Pages 3 to 20 of nuxtui.fig fall from 90.0s to 51.6s. The first page is
unchanged: it materializes 256,354 nodes and is dominated by that.

* docs: note the per-page load improvement

* test(fig): keep the fig package suite off Core

Twenty package tests reached for Core's writer and editor through
@open-pencil/core, a package that depends on fig. Nothing declared that
edge, so the suite passed only because the workspace root hoists Core.
Their subject is the writer, so they move to tests/engine/io/fig, where
half the domain already spans both packages.

The package no longer escapes its own root: tsconfig drops the #tests/*
mapping, expectDefined is three lines beside the other helpers, and the
gold archive is read through the LFS-guarded fixture helper instead of a
hand-built ../../../../tests/fixtures URL.

#fig/ and #fig-tests/ join the steiger alias tables and the AGENTS.md
list, so the foreign-alias rule can see them. Fig's tests mirror its
source tree rather than sitting flat like kiwi's, so they address it by
alias instead of drilling, and the guid helper is imported one way.

* refactor(fig): drop code the reader replacement left behind

resolveDsdGeometry lost every production importer when the old derived
symbol data modules went, so it and the three tests that only exercised
it go too, and the folder collapses to one file. validateVariableAliases
was called only by its own test and wiring it in would mean a new public
diagnostic handler; it is removed rather than left dangling.
recordInstanceOverrideValue had no caller in either base or head, and
its comment began mid-sentence. SymbolOverrideFields had no consumers,
and savedTextEligibility is used only inside its module.

The clipboard's NON_VISUAL_TYPES was a hand-copied union of the two sets
behind isFigClipboardVisualType, which had no consumer of its own; the
classifier now serves both and leaves the root export.

FIG_PACKAGE_STATUS reads document-reader, and assertFigPackageReady is
gone: the package reads archives into a SceneGraph rather than telling
callers to use Core.

sceneNodeToKiwi takes its ten optional maps as an options object. That
removes the signature Core's wrapper had to restate, which was the last
clone blocking packages/fig/src from the duplication gate, and the
undefined holes at the clipboard's two call sites.

* refactor(core): share identity allocation between the two .fig writers

The clipboard allocated variable, mode and shared-style GUIDs its own
way while the document exporter did the same work in assignVariableGuids
and appendInternalResources. The two already disagreed: the exporter
reuses an id that is already GUID-shaped and dedupes against node source
GUIDs, the clipboard always minted a fresh sessionID 1. Both now call
one pair of helpers in variable-export.ts, so a change to how a document
names its resources reaches the clipboard too.

* refactor(fig): name the values that were spelled out in several places

exportSizing existed to name the HUG ternary but the inline layout
branch still wrote it out. The winding-rule conversions become
toKiwiWindingRule and fromKiwiWindingRule rather than the same ternary
three times and its inverse once. sameId duplicated sameGuid. The style
reference field list existed twice, and one site built a GUID string by
hand instead of calling guidToString. The opacity percent-to-unit factor
and the alias-or-expression test each have a name now.

fig.kiwi declares parameterConsumptionMap as a VariableDataMap and
PropRefValue as a variable value, but the codec typed neither, so four
call sites cast. Typing them in kiwi removes the casts, and the merge
that spread two maps now builds the only field the message has. Schema
coverage counts one more modeled field and one fewer raw-preserved.

* refactor(fig): require the index instead of rebuilding it behind a default

createScopedReader is private and always receives the shared state, and
the closure, component planning and property inheritance always get an
index from it; the optional parameters existed only so two tests could
omit them, and each hid a second full pass over every record. They are
required now, and the tests build an index the way production does.

materializeReader returned a fresh object that dropped definitionTypes,
so the first loadPage after createFigDocumentSession reseeded the cache
it was meant to reuse; it returns the state it was given.

The shared style reference shape is a named type built with the rest of
the export context rather than written inline twice and filled lazily
inside a getter, and the population client derives its two responses
from FigSessionResponse instead of restating one and casting to it.

* refactor(fig): give materializeInstance named options

Three of its seven parameters were defaulted maps that call sites passed
unnamed, so a call read as a list of empty collections. They become an
options object, matching how InterpretInstanceOptions is passed in the
same folder.

That change also caught a latent hazard: an empty array satisfies an
all-optional interface structurally, so a call site left on the old
positional form type-checked while silently dropping its source-child
map. Converting the remaining call sites fixed a component sync test
that had started failing for exactly that reason.

The DOCUMENT/VARIABLE guard is one assertion function rather than two
copies, and it narrows the node type for the creation that follows.

* refactor: group the prefixed siblings this PR left behind

instance-overrides kept layout-scale, text-scale, interpret-bindings and
variable-bindings as prefixed siblings while the same PR introduced
scene-graph/src/{scaling,variables}/. They become scale/{layout,text}
and bindings/{properties,variables}. The empty derived-symbol-data
folder is gone now that it holds one file.

STRING_BINDING_FIELDS and BOOLEAN_BINDING_FIELDS stayed in variables.ts
after NUMERIC_FIELDS moved to variables/fields.ts; all three live
together.

* docs(fig): describe the reader as it is, not as a replacement

The README, document-sessions, validation notes and several comments
still framed the work as pending: an old reader to delete, a migration
to finish, variables and lazy loading not yet integrated. All of that
landed. Error messages and a worker adapter that called themselves
"replacement reader" and "format-neutral" say what they are.

Comments that described the wrong function are reattached: the root
layer note belonged to resolveRoot rather than bindingHistory, the
expand note was duplicated onto bindRecord, the owner-scope note sat on
pairSourceChildren instead of linkInstanceSourceChildren, sync.ts put
its module summary on setSceneProp, and transfer/history.ts ended with
an orphan.

The visual oracle's interpret-instance and compare interpreted-document
are citty subcommands like the rest, its SCREAMING-CASE note folds into
packages/fig/docs/validation.md without the benchmark observation, and
its two tests mirror the source tree using the package alias.

* docs(fig): keep Figma observation records out of the fixture tree

Ten JSON records, twelve notes and a screenshot under tests/fixtures had
no code consumer: they are what Figma reported for a given document,
cited by packages/fig/docs. They move to packages/fig/docs/observations
beside the prose that reads them. The three JSON files tests do load,
and the eight screenshots the raster comparisons load, stay where the
tests expect them.

Fixture READMEs follow their fixtures: the gold layout and shared scale
notes to tests/engine/io/fig/instance, the export contract note to
tests/engine/io/fig/export. Numbers fused to the words before them are
separated throughout the notes.

Path failures assert the diagnostic reason through one helper rather
than matching 'found 0' or a full sentence, which is the pattern
materialize.test.ts already used.

* refactor(core): name the reader state module for what it owns

session/recovery.ts holds the per-graph reader state and, with it, page
population, diagnostics and export population as well as recovery. The
functions cannot move out without exporting that state map, so the file
takes an accurate name instead, and the state type follows.

io/formats/fig/index.ts keeps its aliased re-export: the relative path
is three levels up, which no-deep-parent-relative-imports rejects.

* chore: adopt the js-base64 rule master added

* test: move the new tests to the homes master's gate requires

#790 added check:test-homes: a new test under tests/engine is rejected,
and the baseline of existing ones shrinks. This branch had added 46.

Their owner is whichever package the test's subject lives in, not the
directory the old shard map implies. Forty test Core's writer, editor or
reader session and move to packages/core/tests, which gains the test
tsconfig and scripts the other packages already have; six test Fig alone
and move to packages/fig/tests. verifier-contracts covers the roundtrip
helpers that eight grandfathered engine tests share, so it stays beside
them and joins the baseline.

Package tests no longer reach outside their package for support: each
has local assert, guid, fixture and nested-binding helpers, and shared
archives under tests/fixtures are read through a helper path rather than
imported as modules across the root. interpretComponent,
materializeComponentClosure and the source-children helpers are public,
because tests outside Fig legitimately need them.

The steiger owner for #core/ and #fig/ is the package rather than its
src, since a package's own tests mirror the source tree and would
otherwise drill through ../../src.

* test: mirror each package's source tree in its test tree

The relocated tests kept their tests/engine directory names, which do
not match the packages they landed in: figma/api against src/figma-api,
render/canvas against src/canvas, io/fig against src/io/formats/fig, and
a fig tests/io and tests/text with no counterpart in that package. Each
now mirrors its source domain.

Two had no home in the package they were put in. The derived-text layout
invalidation test only exercises Scene Graph, so it moves there, and the
transfer plan test spans Scene Graph and Fig with neither owning it, so
it becomes the first tests/integration spec, which is what that
directory is for.

tests/AGENTS.md named a baseline path the tools reorganization moved,
and packages/fig/AGENTS.md now records its own test alias.

* fix(fig): open a file whose swap names a layer its component lost

Preline UI's `_header/navbar` keeps a swap addressing 4473:100430, a
node the archive no longer contains, while the replacement it names is
still there. Figma opens that file and so did the previous importer;
this reader refused it.

The rule was written for a swap whose replacement is missing, which
nothing can resolve, but the code threw for any unresolved swap. A path
that matches no record is a record Figma kept after deleting the layer
it named, which is the case the property and assignment diagnostics
already cover. A path that matches more than one record is a wrong
address rather than a stale one and still fails.

* fix(fig): address an override through the variant that holds its layer

An instance path names a layer by the identity it had in the variant the
override was written against. Switching variants keeps the override in
Figma, so a segment that names no layer of the variant an occurrence
expands now addresses the layer at the same position there, when the two
agree on type and name.

Resolution reports the path it took, so a claim recorded after a
translated segment stays addressable when the instance materializes.
Each component set's addressable layers are indexed once on first use
rather than rescanning every sibling variant per segment.

* fix(fig): read text bound to a string variable

Figma stores a bound layer's resolved characters, but an instance
override carries the binding alone, and a literal override of a bound
layer is retired rather than applied. Reading neither left the badge on
Preline's navbar showing its component's own text where Figma shows the
variable's value, and the input placeholder showing a literal override
Figma ignores.

Text joins font family as a bindable string field, the reader records a
TEXT_DATA alias like any other binding, and a post-pass resolves it once
hierarchy and modes exist, next to the paint bindings it mirrors.
Resolving after property claims is what makes a binding win over a
literal, the way Figma retires the override.

Validated by reopening an exported file in Figma: the collection, the
string variable, and the binding on both the component and its instance
survive the round trip.

* fix(fig): take a bound paint's transparency from its variable

A solid fill draws at its paint opacity, not its colour's alpha, so a
colour variable carrying transparency has to supply that opacity.
Resolving the binding into the colour alone left a translucent token
applied twice on Preline's navbar links, and left a Divider at the
opacity of an override the binding supersedes.

The variable now owns the whole colour: its alpha becomes the paint's
opacity and the colour keeps none of its own.

* test(tools): compare paint in the interpreted-document oracle

The oracle checked type, name, visibility, text, main component and box,
so every fill and stroke a reader produced went unchecked. A wrong fill
transparency on Preline's navbar passed it.

Paints are captured on both sides as the alpha drawing actually uses,
which is the paint's opacity for a solid, and reported as visible-paint
or hidden-paint like geometry. A Scene Graph stroke is always solid, so
it is encoded as one rather than through a type it does not carry.

* perf(fig): synchronise a component once per page load, not once per instance

Materializing an instance into an open document re-synchronised every
instance of its component, and synchronising walks each one's subtree.
A page that places a component many times therefore paid that walk once
per placement. Opening Preline's CMS page ran 954 synchronisations over
39225 instances for the 954 it placed.

Components are collected while the page is built and synchronised once
each afterwards: 31 calls over 1283 instances, and the page loads in
3.9s rather than 11.6s. The resulting graph is unchanged, by digest over
every node's geometry, text, paint, bindings and override keys for that
page and for a second page loaded on top of it.

* Revert "fix(fig): address an override through the variant that holds its layer"

This reverts commit fcdc7660f.

Figma does not carry an override onto the corresponding layer of another
variant, so translating a segment that way applies overrides it drops.
On Preline's Alerts frame the translation raises semantic differences
against live Figma from 2 to 54: 127 buttons read their own label where
Figma reads the component's. It fixed nothing visible — the five text
differences it was written for turned out to be string variable
bindings, fixed separately — so it only ever added wrong overrides.

* docs(fig): restore the guide rules the master merges dropped

Splitting the root guide into nested ones lost three rules this branch
had added, and left the fig guide claiming clipboard records are
converted to a SceneGraph in `@open-pencil/fig/clipboard`, which is now
`materializeFigFragment` driven from Core.

Records what the reader cannot do as well: a string binding resolves
once at read time, so text bound to a variable goes stale when the
variable or the node's mode changes, unlike a numeric or colour one.

Groups the four `*-bindings` siblings under `document/bindings/`, the
convention the branch already applied to `instance-overrides/bindings/`.

* perf(fig): copy archive records directly instead of structurally

Every expanded record is deep-copied so an occurrence shares no mutable
data with the archive, a contract two tests state. `structuredClone`
was a third of the time spent opening a page, and records are plain
Kiwi data, so copying them field by field is several times quicker —
43944 records of Preline UI clone identically either way, 218ms against
26ms. Byte buffers and anything else that is not an object literal keep
the structured algorithm.

Preline's CMS page now loads in 2.8s rather than 5.6s, and with the
per-component synchronisation fix in 0d1854a3a, 11.6s before either.

* test(tools): compare a reader's whole output, not one frame

`compare interpreted-document` checks one frame against live Figma. A
rule can leave that frame untouched and still change pages it does not
cover: addressing an override through a sibling variant reported no
difference on the frame under test while rewriting 127 button labels
elsewhere, and was reverted only after a whole-document comparison
found them.

`compare digest` captures every page a reader produces and diffs it
against an earlier capture, reusing the same node capture and
difference categories, so a before-and-after needs no Figma. Replaying
the reverted change against a baseline reports 110 semantic
differences. Unresolved-override counts are reported beside the nodes,
since a reader change usually moves those too.
2026-10-01 11:20:27 +04:00

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Markdown

# .fig Reader Architecture
The reader interprets Figma source records into independently editable scene occurrences.
One reader serves the application, CLI, MCP, and worker paths; the earlier importer and its
repair pipeline are gone.
::: warning Implementation status
The reader is the only import path: synchronous parsing, the document worker, page population,
recovery, export, and clipboard paste all use it, and the previous importer is removed.
Corpus-wide fidelity (export still reassigns node identities and drops some raw text metadata)
and performance acceptance remain unfinished. The diagram describes responsibilities, not a
claim of complete Figma parity.
:::
```mermaid
flowchart TD
Archive[FIG archive and resources] --> Sources[Indexed source records]
Sources --> Closure[Selected pages and component dependencies]
Closure --> Evaluation[Occurrence evaluation and provenance]
Evaluation --> Graph[Editable SceneGraph]
Graph --> Sessions[Page sessions and recovery]
Graph --> Editor[Editor actions and undo]
Editor --> Export[FIG export]
Export --> Oracle[Figma reopen and visual validation]
```
## Key distinctions
- A **source record** identifies an archive node; an **occurrence** identifies one use of it.
- An **owner** establishes the component scope for an override **claim**.
- An effective value is not enough to determine whether it is inherited or overridden.
- Saved appearance, editable layout, and exported-file fidelity are separate contracts.
```text
Inherited default Explicit equal value
Initial text "Badge" "Badge"
Component changes "Updated" "Updated"
Instance result "Updated" "Badge"
```
## Package documentation
The canonical implementation documentation lives alongside the package in
[`packages/fig/docs`](https://github.com/open-pencil/open-pencil/tree/master/packages/fig/docs).
This page is the development-site entry point, not a second copy of those contracts.
Read in order:
1. [Architecture and ownership](https://github.com/open-pencil/open-pencil/blob/master/packages/fig/docs/architecture.md)
2. [Source model and identities](https://github.com/open-pencil/open-pencil/blob/master/packages/fig/docs/source-model.md)
3. [Instance evaluation and precedence](https://github.com/open-pencil/open-pencil/blob/master/packages/fig/docs/instance-evaluation.md)
4. [SceneGraph materialization](https://github.com/open-pencil/open-pencil/blob/master/packages/fig/docs/materialization.md)
5. [Document sessions, rollback, and recovery](https://github.com/open-pencil/open-pencil/blob/master/packages/fig/docs/document-sessions.md)
6. [Export contracts](https://github.com/open-pencil/open-pencil/blob/master/packages/fig/docs/export.md)
7. [Validation and oracle methodology](https://github.com/open-pencil/open-pencil/blob/master/packages/fig/docs/validation.md)
See also [system architecture](./architecture), [testing](./testing), and the
[development roadmap](./roadmap). Fixture provenance belongs next to fixtures; individual
benchmark runs and temporary oracle results do not belong in architecture documentation.