M8: an explicit variables file is refused past 256 MiB or when it isn't a regular file (part of #1114)

variable.import and the variables parameter of file.open and file.import read an explicit path
with the uncapped reader, while the sibling variables.json next to a REST file already went
through read_capped with MAX_VARIABLES_FILE. variables_param now uses that capped read for paths
on native builds; the browser keeps its no-file-system error. Inline objects and JSON text, and
access roots, are unchanged. The check reads the size before the file, so it does not bound a
file that grows or is replaced in between. Primary file reads and image.place stay uncapped.
variable.import's help and docs/mcp.md name the limit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Co-Authored-By: GPT-6.1 Sol <noreply@openai.com>
Co-Authored-By: GPT-6 Astra <noreply@openai.com>

docs/components-parity.md

@@ -1,6 +1,6 @@
 # Components, variants, styles and variables parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (component properties keep the order they were made in when one is renamed, and Make slot asks for the slot's name first (#1536, #1537); components can't contain their own instances, directly or through others (#1084); the instance-swap menus have a search field (#1338); an instance-swap property's default menu scrolls (#1338); variables on a text style's fields from the style editor; instance-swap properties in the component playground; duplicating or Alt-dragging a main component makes an instance of it (#892); a bound colour variable's alpha applies once (#802); variables import reads `variables` outside `meta` and warns when it imports none (#790); variant properties reorder by drag; library files saved right after a read are read again; Hide when publishing note corrected; size and resizing overrides of layers inside instances (#731); variables export in the browser as a download; core editor leftovers: component playground, variables inside styles; layers and assets panels behaviour suite and fixes; extended collections tail; styles and variables behaviour suite and fixes; components behaviour suite and fixes; team libraries on the server, library usage and swapping a library; extended collections, variables import/export, gradient stops and variant properties bound to variables) · **Target:** Figma Design (desktop app 126.10.7)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (an explicit variables file path (`variable.import`, the `variables` of `file.open` and `file.import`) is refused past 256 MiB or when it isn't a regular file, as the sibling `variables.json` already was (part of #1114); component properties keep the order they were made in when one is renamed, and Make slot asks for the slot's name first (#1536, #1537); components can't contain their own instances, directly or through others (#1084); the instance-swap menus have a search field (#1338); an instance-swap property's default menu scrolls (#1338); variables on a text style's fields from the style editor; instance-swap properties in the component playground; duplicating or Alt-dragging a main component makes an instance of it (#892); a bound colour variable's alpha applies once (#802); variables import reads `variables` outside `meta` and warns when it imports none (#790); variant properties reorder by drag; library files saved right after a read are read again; Hide when publishing note corrected; size and resizing overrides of layers inside instances (#731); variables export in the browser as a download; core editor leftovers: component playground, variables inside styles; layers and assets panels behaviour suite and fixes; extended collections tail; styles and variables behaviour suite and fixes; components behaviour suite and fixes; team libraries on the server, library usage and swapping a library; extended collections, variables import/export, gradient stops and variant properties bound to variables) · **Target:** Figma Design (desktop app 126.10.7)
 
 Design systems are why teams adopt Figma. **Components: breadth ~96%, ready ~72%. Styles and
 variables: breadth ~95%, ready ~76% (estimated).** QA'd with a synthetic design system of ~300
@@ -71,13 +71,14 @@ updates with overrides kept: `library_tests.rs`, `components_scale_tests.rs`.
 | Explicit modes per frame, library collections' modes | done | |
 | Gradient stops and variant properties bound to variables | done | a stop's binding follows it when earlier stops are removed |
 | Extended collections | done | library collections, including a library's own extended collections (chains through libraries); overrides per mode with reset; follow library updates, variables new to the library collection being an update of their own; modes inherited. Checked with synthetic libraries only ([gaps](gaps.md) #14) |
-| Variables import/export (JSON) | done | the REST local variables shape (round-trips; merges by collection, mode and variable name; `variableCollections` and `variables` read under `meta` or at the top level, a warning when no variables are found or fewer than the collections list); CSS custom properties and Dart constants (Flutter) export; in the browser the export arrives as a download (import there still needs a file picker) |
+| Variables import/export (JSON) | done | the REST local variables shape (round-trips; merges by collection, mode and variable name; `variableCollections` and `variables` read under `meta` or at the top level, a warning when no variables are found or fewer than the collections list); CSS custom properties and Dart constants (Flutter) export; a variables file named by path must be a regular file of at most 256 MiB; in the browser the export arrives as a download (import there still needs a file picker) |
 | Expressions in prototype set-variable actions | done | see [prototyping-parity](prototyping-parity.md) |
 
 ## Revision history
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-30 | minor | M8, #1114: variables import from an explicit file path (`variable.import`, the `variables` of `file.open` and `file.import`) takes regular files of at most 256 MiB, the limit the sibling `variables.json` already had; anything else is refused before the document changes. Grade unchanged. Tests: `import_export_tests::an_explicit_variables_path_is_capped_like_the_sibling_file`, `variables_io_tests::variables_import_caps_the_file_it_reads` |
 | 2026-10-30 | minor | M3, #1536 and #1537: component properties are listed in the order they were made in, and renaming one keeps its place (they were sorted by name, so a rename moved the property); that holds for every kind, on every variant of a set and on instances, in `component.properties`, the Design panel and `.fig` export. Files from before keep their properties by name until one is added or renamed. Make slot (the Slot menu of a frame inside a component) asks for the slot's name first: a field under the Slot row with the frame's name selected, Enter or Make slot to make it, Escape to cancel; a name taken keeps the field open. Renaming stays in the component's Properties list. Tests: `engine/src/prop_order_tests.rs`, `ui-egui/src/make_slot_naming_tests.rs`. Left: dragging the shared properties to reorder them, and renaming a slot with only its frame selected. Numbers unchanged |
 | 2026-10-29 | minor | M3, #1338: the instance-swap property's menu (on an instance, its main component's default and the component playground) and the instance's swap menu open with a search field at the top that has the keyboard; typing filters the components by name (any case, headings without matches drop out), an empty result reads "No matching components", Up and Down step through the matches and Enter picks one (the first without a step), Escape clears the search and then closes the menu. Only the list scrolls; the menu grows back when the search is cleared. Tests: `component_swap_search_tests`. Numbers unchanged |
 | 2026-10-26 | minor | An instance-swap property's default menu scrolls (#1338): on the main component's Properties row the menu listed every component in the file at full height, so in a file with many (an icon library) the bottom ones ran off the screen and couldn't be picked. It now scrolls past 320 pt like the instance's swap menu, is at least 200 pt wide, ticks the current default and is named for assistive technology (`component_swap_default_tests`). Left: searching these menus. Numbers unchanged. |

docs/mcp.md

@@ -1140,7 +1140,8 @@ default mode's named after the collection and the others after the collection an
 `static const` `Color`, `double`, `String` or `bool` per variable; names become camelCase Dart
 identifiers kept apart, aliases are resolved to their value in that mode), and
 returns `{text}` (or writes `path` and returns `{path}`). `variable.import {variables}` (an object,
-JSON text or a path; `variableCollections` and `variables` under `meta` or at the top level) reads
+JSON text or a path to a regular file of at most 256 MiB;
+`variableCollections` and `variables` under `meta` or at the top level) reads
 one back: a collection joins this file's collection of the same name
 (values matched by mode name, new modes and variables added, a same-named variable of another type
 skipped with a warning; library copies and extended collections are never targets), others are