feat: monostate1 support

.github/workflows/ci.yml

@@ -10,12 +10,12 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.74.0
+          - 1.79.0
           - stable
           - beta
           - nightly
         include:
-          - rust: 1.74.0
+          - rust: 1.79.0
             allow_failure: false
           - rust: stable
             allow_failure: false
@@ -27,7 +27,7 @@ jobs:
     steps:
       - uses: actions/checkout@v5
       - name: Downgrade packages for MSRV
-        if: matrix.rust == '1.74.0'
+        if: matrix.rust == '1.79.0'
         run: |
           cargo add --dev garde --git https://github.com/jprochazk/garde.git --rev be00ddddf8de14530ee890ccfdbaf0b13fb32852
           cargo add --dev validator@0.19
@@ -40,15 +40,17 @@ jobs:
         continue-on-error: ${{ matrix.allow_failure }}
         working-directory: ./schemars
       - name: Run tests
+        if: matrix.rust != '1.79.0'
         run: cargo test --verbose --all-features --no-fail-fast
         continue-on-error: ${{ matrix.allow_failure }}
         working-directory: ./schemars
       - name: Run derive tests
+        if: matrix.rust != '1.79.0'
         run: cargo test --verbose --all-features --no-fail-fast
         continue-on-error: ${{ matrix.allow_failure }}
         working-directory: ./schemars_derive
       - name: Check with latest dependency versions
-        if: matrix.rust != '1.74.0'
+        if: matrix.rust != '1.79.0'
         run: |
           cargo update
           cargo check --all-features --verbose --example main

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Added
+
+- Add monostate1 feature (https://github.com/GREsau/schemars/pull/508)
+
 ## [1.2.2] - 2026-07-27
 
 - Update to syn 3 in schemars_derive

README.md

@@ -4,7 +4,7 @@
 [![Crates.io](https://img.shields.io/crates/v/schemars)](https://crates.io/crates/schemars)
 [![API Docs](https://img.shields.io/docsrs/schemars/latest?label=API%20docs)](https://docs.rs/schemars/latest)
 [![Usage Docs](https://img.shields.io/badge/Usage%20docs-graham.cool%2Fschemars-blue)](https://graham.cool/schemars)
-[![MSRV 1.74+](https://img.shields.io/badge/msrv-1.74-blue)](https://blog.rust-lang.org/2023/11/16/Rust-1.74.0/)
+[![MSRV 1.79+](https://img.shields.io/badge/msrv-1.79-blue)](https://blog.rust-lang.org/2024/06/13/Rust-1.79.0/)
 
 Generate JSON Schema documents from Rust code
 

schemars/Cargo.toml

@@ -10,11 +10,11 @@ license = "MIT"
 readme = "README.md"
 keywords = ["rust", "json-schema", "serde"]
 categories = ["encoding", "no-std"]
-rust-version = "1.74"
+rust-version = "1.79"
 
 [dependencies]
 schemars_derive = { version = "=1.2.2", optional = true, path = "../schemars_derive" }
-serde = { version = "1.0.194", default-features = false, features = ["alloc"] }
+serde = { version = "1.0.222", default-features = false, features = ["alloc"] }
 serde_json = { version = "1.0.127", default-features = false, features = ["alloc"] }
 dyn-clone = "1.0.17"
 ref-cast = "1.0.22"
@@ -27,6 +27,7 @@ chrono04 = { version = "0.4.39", default-features = false, optional = true, pack
 either1 = { version = "1.3", default-features = false, optional = true, package = "either" }
 indexmap2 = { version = "2.2.3", default-features = false, optional = true, package = "indexmap" }
 jiff02 = { version = "0.2", default-features = false, optional = true, package = "jiff" }
+monostate1 = { version = "1.0", default-features = false, optional = true, package = "monostate" }
 rust_decimal1 = { version = "1.13", default-features = false, optional = true, package = "rust_decimal" }
 semver1 = { version = "1.0.9", default-features = false, optional = true, package = "semver" }
 smallvec1 = { version = "1.0", default-features = false, optional = true, package = "smallvec" }

schemars/src/json_schema_impls/mod.rs

@@ -78,6 +78,9 @@ mod indexmap2;
 #[cfg(feature = "jiff02")]
 mod jiff02;
 
+#[cfg(feature = "monostate1")]
+mod monostate1;
+
 #[cfg(feature = "semver1")]
 mod semver1;
 

schemars/src/json_schema_impls/monostate1.rs

@@ -0,0 +1,57 @@
+use crate::*;
+use std::{borrow::Cow, format};
+
+macro_rules! impls {
+    ($($ident:ident<const V: $ty:ident>),* $(,)?) => {$(
+        impl<const V: $ty> JsonSchema for monostate1::$ident<V> {
+            fn schema_name() -> Cow<'static, str> {
+                Cow::Owned(format!("{}<{}>", stringify!($ident), V))
+            }
+            fn json_schema(_: &mut SchemaGenerator) -> Schema {
+                json_schema!({
+                    "const": V,
+                })
+            }
+            fn inline_schema() -> bool {
+                true
+            }
+            fn schema_id() -> Cow<'static, str> {
+                Cow::Owned(format!("monostate::{}", Self::schema_name()))
+            }
+        }
+    )*};
+}
+
+impls! {
+    MustBeBool<const V: bool>,
+    MustBeChar<const V: char>,
+
+    MustBeI8<const V: i8>,
+    MustBeI16<const V: i16>,
+    MustBeI32<const V: i32>,
+    MustBeI64<const V: i64>,
+    MustBeI128<const V: i128>,
+
+    MustBeU8<const V: u8>,
+    MustBeU16<const V: u16>,
+    MustBeU32<const V: u32>,
+    MustBeU64<const V: u64>,
+    MustBeU128<const V: u128>,
+}
+
+impl<V: monostate1::ConstStr> JsonSchema for monostate1::MustBeStr<V> {
+    fn schema_name() -> Cow<'static, str> {
+        Cow::Owned(format!("{}<{}>", stringify!($ident), V::VALUE))
+    }
+    fn json_schema(_: &mut SchemaGenerator) -> Schema {
+        json_schema!({
+            "const": V::VALUE,
+        })
+    }
+    fn inline_schema() -> bool {
+        true
+    }
+    fn schema_id() -> Cow<'static, str> {
+        Cow::Owned(format!("monostate::{}", Self::schema_name()))
+    }
+}

schemars_derive/Cargo.toml

@@ -10,7 +10,7 @@ license = "MIT"
 readme = "README.md"
 keywords = ["rust", "json-schema", "serde"]
 categories = ["encoding", "no-std"]
-rust-version = "1.74"
+rust-version = "1.79"
 
 [lib]
 proc-macro = true