internal: Upgrade schemars.

CHANGELOG.md

@@ -31,6 +31,17 @@ while the schema types have been updated to be more flexible and composable.
 
 ##### Schema
 
+- Updated `schemars` to v1, which replaces its typed schema model with plain JSON. This reshapes
+  `JsonSchemaOptions`:
+  - `visitors: Vec<Box<dyn GenVisitor>>` is now `transforms: Vec<Box<dyn GenTransform>>`.
+  - `option_nullable` and `option_add_null_type` were removed. Schemars no longer has them, and this
+    renderer never read them.
+  - `definitions_path` keeps its meaning as the `$ref` prefix, and is no longer inherited from
+    schemars, whose field of that name is now a JSON pointer.
+  - `JsonSchemaRenderer` implements `SchemaRenderer<schemars::Schema>` rather than
+    `SchemaRenderer<schemars::schema::Schema>`.
+- Changed a `$ref` with no sibling keys to render on its own, instead of inside a single-element
+  `allOf`. The two are equivalent, and a `$ref` that does have siblings is still wrapped.
 - Changed `SchemaType::Reference` from a newtype into a struct variant. Serde is unable to
   internally tag a newtype whose value isn't a map, so any schema containing a reference (which is
   how cycles are represented) previously failed to serialize.

book/src/schema/generator/json-schema.md

@@ -69,9 +69,13 @@ JsonSchemaRenderer::new(JsonSchemaOptions {
 });
 ```
 
-> This type also contains all fields from the upstream
-> [`SchemaSettings`](https://docs.rs/schemars/latest/schemars/gen/struct.SchemaSettings.html) type
-> from the `schemars` crate. Refer to their documentation for more information.
+> This type also carries some fields from the upstream
+> [`SchemaSettings`](https://docs.rs/schemars/latest/schemars/generate/struct.SchemaSettings.html)
+> type in the `schemars` crate — `meta_schema`, `transforms`, and `inline_subschemas`. Refer to
+> their documentation for more information.
+
+> `definitions_path` is the prefix each `$ref` is built from, such as `#/definitions/`. Schemars
+> models its own field of that name as a JSON pointer instead, so the two are not interchangeable.
 
 ### Markdown descriptions
 

crates/schematic/Cargo.toml

@@ -49,7 +49,7 @@ serde_json = { workspace = true, optional = true, features = [
 
 # json schema
 markdown = { version = "1.0.0", optional = true }
-schemars = { version = "0.8.22", optional = true, default-features = false }
+schemars = { version = "1.2.2", optional = true, default-features = false }
 
 # pkl
 rpkl = { workspace = true, optional = true }
@@ -144,7 +144,7 @@ schematic = { path = ".", features = [
 serial_test = "4.0.1"
 # Only to prove loading works from inside an async runtime
 tokio = { version = "1.53.1", features = ["macros", "rt"] }
-similar = "3.1.2"
+similar = "3.2.0"
 starbase_sandbox = { workspace = true }
 strip-ansi-escapes = "0.2.1"
 derive_more = { version = "2.1.1", features = ["try_into", "as_ref"] }