[Kinflou]

Step 3 of per-format sizes (docs plan: real data-format sizes). Replaces the codec-independent wire-size estimate with a per-format byte range, driven by the specification's size rules (comline-catalog bumped to specification@9a7142c, ComlineProject/specification#4).

What it does

schema::ir::size works on the frozen IR and returns Range { min, max: Option<u64>, upper_bound } for a TypeRef, a format's Sizes and a Lookup for the names in it. None means it can't be sized: a union, a non-unit enum or an enum with no variants, a format without sizes, an unresolved name, a type that has to contain itself.

• Headers (varint_leb128, msgpack_str, msgpack_array, delimited) are applied to the byte or item count at each end: the least uses the header for 0 or the minimum, the most the header for the maximum (char[max N] is header(4N) + 4N in UTF-8, 2 + 6N in JSON).
• @max_depth expands a recursive struct to its depth (an option at level D+1 is absent, an array empty); each level is sized once, so a tree of 8 children 20 deep is instant. Without a limit the maximum is None. Each struct in a cycle counts its own nesting.
• Where the formats stop: a count or length above 2^32 - 1 is cut to what a header can say, and a fixed one above it can't be written (no size). A maximum above u64::MAX is None; a minimum above it isn't sized. Documented in the module header, tested in where_the_formats_stop.
• witnesses() builds a least and a most value in the spec's typed notation ({"u8": 0}, ...) from the same code as the range, for the runtime's differential test (step 4). Bounded by a budget; a value too large to write down is left out.
• FrozenLookup resolves names across schemas (own declarations, uses with aliases and globs, qualified paths, then any schema's), the way compat finds declarations.

Replaced

schema::idl::size: WireSize, size_of_type, size_of_struct and size_of_enum are gone. The editor's entry is now range_of_type, range_of_field, range_of_struct and range_of_enum, which freeze the grammar through TypeRef::from_grammar_sized and call the same sizer. SizeLookup and SizeTarget are unchanged. A constant a size names that the caller can't resolve is "no size", not 0.

The language server uses all of it in handlers/hover.rs; its next core bump has to change that (see below).

Doc model

Additive (DOC_MODEL_VERSION stays 1; schemas/doc-model.json re-blessed): SizeRange { format, min, max?, upper_bound? } as sizes on struct, enum and type alias units, sizes on each function argument and returns_sizes on the function, for each official format the package's protocols use (the package default when it has none). Absent where it can't be told, for a dependency's units, and in model_frozen (a built version keeps no protocol to say which formats).

Tests

• Every case of the spec's size vectors (176 across the three formats): the computed range equals the case's [min, max] and upper_bound; the min/max witnesses conform to the case's type; for each primitive, core's witnesses are values the case itself measures as the least and most.
• Hand-written: bounded types finite, unbounded None, msgpack tier boundaries (strings, arrays, struct field counts), JSON escaping worst case, recursion with and without @max_depth (mutual, deep, too deep), union / non-unit enum / no variants / unknown format None, limits, aliases across schemas, witnesses.
• Doc model: ranges per format for a package on packed@1 and on json@1.

How the vectors reach the tests

The git dependency's checkout isn't reachable from a test without asking cargo, and comline-catalog doesn't expose a path, so the three sizes-*.json files (about 1 MB) are vendored in core/tests/spec/vectors with a REV. core/tests/spec/vendor.sh --check (a new CI job) compares them with the spec at that rev, and a test fails when REV and the comline-catalog rev in Cargo.toml differ, so a bump can't leave stale vectors.

Language server

handlers/hover.rs imports WireSize, size_of_type, size_of_struct and size_of_enum. On its next bump it replaces them with size::range_of_type / range_of_field / range_of_struct / range_of_enum (taking size::rules("packed@1"), or the package's format, and a constant resolver, &|_| None to keep today's behaviour) and renders Option<Range> instead of WireSize::{Fixed, Variable, Unknown}. field_size's optional special case goes: range_of_field handles it. HoverSizeLookup stays as is.

Local work

The checkout's uncommitted edits to schema/idl/size.rs and the size2.rs stub are superseded by this; rebase will conflict on size.rs.