Add JSONC Support for Project, Meta, and Model JSON files (#1144)

Replaces `serde_json` parsing with `jsonc-parser` throughout the
codebase, enabling support for **comments** and **trailing commas** in
all JSON files including `.project.json`, `.model.json`, and
`.meta.json` files.
MSRV bumps from `1.83.0` to `1.88.0` in order to
use the jsonc_parser dependency.

.github/workflows/ci.yml

@@ -60,7 +60,7 @@ jobs:
         submodules: true
 
     - name: Install Rust
-      uses: dtolnay/rust-toolchain@1.83.0
+      uses: dtolnay/rust-toolchain@1.88.0
 
     - name: Restore Rust Cache
       uses: actions/cache/restore@v4

CHANGELOG.md

@@ -5,10 +5,12 @@
 * Added `sourcemap.json` into the defualt `.gitignore` files ([#1145])
 * Fixed a bug where the last sync timestamp was not updating correctly in the plugin ([#1132])
 * Improved the reliability of sync replacements by adding better error handling and recovery ([#1135])
+* Added support for JSON comments and trailing commas in project, meta, and model json files ([#1144])
 
 [#1145]: https://github.com/rojo-rbx/rojo/pull/1145
 [#1132]: https://github.com/rojo-rbx/rojo/pull/1132
 [#1135]: https://github.com/rojo-rbx/rojo/pull/1135
+[#1144]: https://github.com/rojo-rbx/rojo/pull/1144
 
 ## 7.6.0 - October 10th, 2025
 * Added flag to `rojo init` to skip initializing a git repository ([#1122])

Cargo.lock

@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "addr2line"
@@ -243,7 +243,7 @@ checksum = "ae6371b8bdc8b7d3959e9cf7b22d4435ef3e79e138688421ec654acf8c81b008"
 dependencies = [
  "heck",
  "proc-macro-error",
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
  "syn 1.0.109",
 ]
@@ -665,9 +665,9 @@ version = "0.3.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
 ]
 
 [[package]]
@@ -1033,6 +1033,15 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "jsonc-parser"
+version = "0.27.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ec4ac49f13c7b00f435f8a5bb55d725705e2cf620df35a5859321595102eb7e"
+dependencies = [
+ "serde_json",
+]
+
 [[package]]
 name = "kernel32-sys"
 version = "0.2.2"
@@ -1393,9 +1402,9 @@ checksum = "fdc17e2a6c7d0a492f0158d7a4bd66cc17280308bbaff78d5bef566dca35ab80"
 dependencies = [
  "pest",
  "pest_meta",
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
 ]
 
 [[package]]
@@ -1478,7 +1487,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
 dependencies = [
  "proc-macro-error-attr",
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
  "syn 1.0.109",
  "version_check",
@@ -1490,7 +1499,7 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
  "version_check",
 ]
@@ -1518,9 +1527,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.78"
+version = "1.0.103"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2422ad645d89c99f8f3e6b88a9fdeca7fabeac836b1002371c4367c8f984aae"
+checksum = "5ee95bc4ef87b8d5ba32e8b7714ccc834865276eab0aed5c9958d00ec45f49e8"
 dependencies = [
  "unicode-ident",
 ]
@@ -1542,7 +1551,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8021cf59c8ec9c432cfc2526ac6b8aa508ecaf29cd415f271b8406c1b851c3fd"
 dependencies = [
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
 ]
 
 [[package]]
@@ -1560,7 +1569,7 @@ version = "1.0.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "291ec9ab5efd934aaf503a6466c5d5251535d108ee747472c3977cc5acc868ef"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
 ]
 
 [[package]]
@@ -1903,6 +1912,7 @@ dependencies = [
  "hyper",
  "insta",
  "jod-thread",
+ "jsonc-parser",
  "log",
  "maplit",
  "memofs",
@@ -2054,10 +2064,11 @@ checksum = "92d43fe69e652f3df9bdc2b85b2854a0825b86e4fb76bc44d945137d053639ca"
 
 [[package]]
 name = "serde"
-version = "1.0.197"
+version = "1.0.228"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fb1c873e1b9b056a4dc4c0c198b24c3ffa059243875552b2bd0933b1aee4ce2"
+checksum = "9a8e94ea7f378bd32cbbd37198a4a91436180c5bb472411e48b5ec2e2124ae9e"
 dependencies = [
+ "serde_core",
  "serde_derive",
 ]
 
@@ -2072,25 +2083,36 @@ dependencies = [
 ]
 
 [[package]]
-name = "serde_derive"
+name = "serde_core"
-version = "1.0.197"
+version = "1.0.228"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7eb0b34b42edc17f6b7cac84a52a1c5f0e1bb2227e997ca9011ea3dd34e8610b"
+checksum = "41d385c7d4ca58e59fc732af25c3983b67ac852c1a25000afe1175de458b67ad"
 dependencies = [
- "proc-macro2 1.0.78",
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
+dependencies = [
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
 ]
 
 [[package]]
 name = "serde_json"
-version = "1.0.114"
+version = "1.0.145"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c5f09b1bd632ef549eaa9f60a1f8de742bdbc698e6cee2095fc84dde5f549ae0"
+checksum = "402a6f66d8c709116cf22f558eab210f5a50187f702eb4d7e5ef38d9a7f1c79c"
 dependencies = [
  "itoa",
+ "memchr",
  "ryu",
  "serde",
+ "serde_core",
 ]
 
 [[package]]
@@ -2195,18 +2217,18 @@ version = "1.0.109"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
  "unicode-ident",
 ]
 
 [[package]]
 name = "syn"
-version = "2.0.52"
+version = "2.0.108"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b699d15b36d1f02c3e7c69f8ffef53de37aefae075d8488d4ba1a7788d574a07"
+checksum = "da58917d35242480a05c2897064da0a80589a2a0476c9a3f2fdc83b53502e917"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
  "unicode-ident",
 ]
@@ -2289,9 +2311,9 @@ version = "1.0.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a953cb265bef375dae3de6663da4d3804eee9682ea80d8e2542529b73c531c81"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
 ]
 
 [[package]]
@@ -2401,9 +2423,9 @@ version = "0.1.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
 ]
 
 [[package]]
@@ -2638,9 +2660,9 @@ dependencies = [
  "bumpalo",
  "log",
  "once_cell",
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
  "wasm-bindgen-shared",
 ]
 
@@ -2672,9 +2694,9 @@ version = "0.2.92"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e94f17b526d0a461a191c78ea52bbce64071ed5c04c9ffe424dcb38f74171bb7"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
@@ -2970,9 +2992,9 @@ version = "0.7.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
 dependencies = [
- "proc-macro2 1.0.78",
+ "proc-macro2 1.0.103",
  "quote 1.0.35",
- "syn 2.0.52",
+ "syn 2.0.108",
 ]
 
 [[package]]

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "rojo"
 version = "7.6.0"
-rust-version = "1.83"
+rust-version = "1.88"
 authors = [
     "Lucien Greathouse <me@lpghatguy.com>",
     "Micah Reid <git@dekkonot.com>",
@@ -85,7 +85,8 @@ reqwest = { version = "0.11.24", default-features = false, features = [
 ritz = "0.1.0"
 roblox_install = "1.0.0"
 serde = { version = "1.0.197", features = ["derive", "rc"] }
-serde_json = "1.0.114"
+serde_json = "1.0.145"
+jsonc-parser = { version = "0.27.0", features = ["serde"] }
 toml = "0.5.11"
 termcolor = "1.4.1"
 thiserror = "1.0.57"

README.md

@@ -40,7 +40,7 @@ Check out our [contribution guide](CONTRIBUTING.md) for detailed instructions fo
 
 Pull requests are welcome!
 
-Rojo supports Rust 1.83 and newer. The minimum supported version of Rust is based on the latest versions of the dependencies that Rojo has.
+Rojo supports Rust 1.88 and newer. The minimum supported version of Rust is based on the latest versions of the dependencies that Rojo has.
 
 ## License
 Rojo is available under the terms of the Mozilla Public License, Version 2.0. See [LICENSE.txt](LICENSE.txt) for details.

src/glob.rs

@@ -43,8 +43,8 @@ impl Serialize for Glob {
 
 impl<'de> Deserialize<'de> for Glob {
     fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
-        let glob = <&str as Deserialize>::deserialize(deserializer)?;
+        let glob = String::deserialize(deserializer)?;
 
-        Glob::new(glob).map_err(D::Error::custom)
+        Glob::new(&glob).map_err(D::Error::custom)
     }
 }

src/json.rs

@@ -0,0 +1,313 @@
+//! Utilities for parsing JSON with comments (JSONC) and deserializing to Rust types.
+//!
+//! This module provides convenient wrappers around `jsonc_parser` and `serde_json`
+//! to reduce boilerplate and improve ergonomics when working with JSONC files.
+
+use anyhow::Context as _;
+use serde::de::DeserializeOwned;
+
+/// Parse JSONC text into a `serde_json::Value`.
+///
+/// This handles the common pattern of calling `jsonc_parser::parse_to_serde_value`
+/// and unwrapping the `Option` with a clear error message.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - The text is not valid JSONC
+/// - The text contains no JSON value
+pub fn parse_value(text: &str) -> anyhow::Result<serde_json::Value> {
+    jsonc_parser::parse_to_serde_value(text, &Default::default())
+        .context("Failed to parse JSONC")?
+        .ok_or_else(|| anyhow::anyhow!("File contains no JSON value"))
+}
+
+/// Parse JSONC text into a `serde_json::Value` with a custom context message.
+///
+/// This is useful when you want to provide a specific error message that includes
+/// additional information like the file path.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - The text is not valid JSONC
+/// - The text contains no JSON value
+pub fn parse_value_with_context(
+    text: &str,
+    context: impl Fn() -> String,
+) -> anyhow::Result<serde_json::Value> {
+    jsonc_parser::parse_to_serde_value(text, &Default::default())
+        .with_context(|| format!("{}: JSONC parse error", context()))?
+        .ok_or_else(|| anyhow::anyhow!("{}: File contains no JSON value", context()))
+}
+
+/// Parse JSONC text and deserialize it into a specific type.
+///
+/// This combines parsing JSONC and deserializing into a single operation,
+/// eliminating the need to manually chain `parse_to_serde_value` and `from_value`.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - The text is not valid JSONC
+/// - The text contains no JSON value
+/// - The value cannot be deserialized into type `T`
+pub fn from_str<T: DeserializeOwned>(text: &str) -> anyhow::Result<T> {
+    let value = parse_value(text)?;
+    serde_json::from_value(value).context("Failed to deserialize JSON")
+}
+
+/// Parse JSONC text and deserialize it into a specific type with a custom context message.
+///
+/// This is useful when you want to provide a specific error message that includes
+/// additional information like the file path.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - The text is not valid JSONC
+/// - The text contains no JSON value
+/// - The value cannot be deserialized into type `T`
+pub fn from_str_with_context<T: DeserializeOwned>(
+    text: &str,
+    context: impl Fn() -> String,
+) -> anyhow::Result<T> {
+    let value = parse_value_with_context(text, &context)?;
+    serde_json::from_value(value).with_context(|| format!("{}: Invalid JSON structure", context()))
+}
+
+/// Parse JSONC bytes into a `serde_json::Value` with a custom context message.
+///
+/// This handles UTF-8 conversion and JSONC parsing in one step.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - The bytes are not valid UTF-8
+/// - The text is not valid JSONC
+/// - The text contains no JSON value
+pub fn parse_value_from_slice_with_context(
+    slice: &[u8],
+    context: impl Fn() -> String,
+) -> anyhow::Result<serde_json::Value> {
+    let text = std::str::from_utf8(slice)
+        .with_context(|| format!("{}: File is not valid UTF-8", context()))?;
+    parse_value_with_context(text, context)
+}
+
+/// Parse JSONC bytes and deserialize it into a specific type.
+///
+/// This handles UTF-8 conversion, JSONC parsing, and deserialization in one step.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - The bytes are not valid UTF-8
+/// - The text is not valid JSONC
+/// - The text contains no JSON value
+/// - The value cannot be deserialized into type `T`
+pub fn from_slice<T: DeserializeOwned>(slice: &[u8]) -> anyhow::Result<T> {
+    let text = std::str::from_utf8(slice).context("File is not valid UTF-8")?;
+    from_str(text)
+}
+
+/// Parse JSONC bytes and deserialize it into a specific type with a custom context message.
+///
+/// This handles UTF-8 conversion, JSONC parsing, and deserialization in one step.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - The bytes are not valid UTF-8
+/// - The text is not valid JSONC
+/// - The text contains no JSON value
+/// - The value cannot be deserialized into type `T`
+pub fn from_slice_with_context<T: DeserializeOwned>(
+    slice: &[u8],
+    context: impl Fn() -> String,
+) -> anyhow::Result<T> {
+    let text = std::str::from_utf8(slice)
+        .with_context(|| format!("{}: File is not valid UTF-8", context()))?;
+    from_str_with_context(text, context)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde::Deserialize;
+
+    #[test]
+    fn test_parse_value() {
+        let value = parse_value(r#"{"foo": "bar"}"#).unwrap();
+        assert_eq!(value["foo"], "bar");
+    }
+
+    #[test]
+    fn test_parse_value_with_comments() {
+        let value = parse_value(
+            r#"{
+            // This is a comment
+            "foo": "bar" // Inline comment
+        }"#,
+        )
+        .unwrap();
+        assert_eq!(value["foo"], "bar");
+    }
+
+    #[test]
+    fn test_parse_value_with_trailing_comma() {
+        let value = parse_value(
+            r#"{
+            "foo": "bar",
+            "baz": 123,
+        }"#,
+        )
+        .unwrap();
+        assert_eq!(value["foo"], "bar");
+        assert_eq!(value["baz"], 123);
+    }
+
+    #[test]
+    fn test_parse_value_empty() {
+        let err = parse_value("").unwrap_err();
+        assert!(err.to_string().contains("no JSON value"));
+    }
+
+    #[test]
+    fn test_parse_value_invalid() {
+        let err = parse_value("{invalid}").unwrap_err();
+        assert!(err.to_string().contains("parse"));
+    }
+
+    #[test]
+    fn test_parse_value_with_context() {
+        let err = parse_value_with_context("{invalid}", || "test.json".to_string()).unwrap_err();
+        assert!(err.to_string().contains("test.json"));
+        assert!(err.to_string().contains("parse"));
+    }
+
+    #[derive(Debug, Deserialize, PartialEq)]
+    struct TestStruct {
+        foo: String,
+        bar: i32,
+    }
+
+    #[test]
+    fn test_from_str() {
+        let result: TestStruct = from_str(r#"{"foo": "hello", "bar": 42}"#).unwrap();
+        assert_eq!(
+            result,
+            TestStruct {
+                foo: "hello".to_string(),
+                bar: 42
+            }
+        );
+    }
+
+    #[test]
+    fn test_from_str_with_comments() {
+        let result: TestStruct = from_str(
+            r#"{
+            // Comment
+            "foo": "hello",
+            "bar": 42, // Trailing comma is fine
+        }"#,
+        )
+        .unwrap();
+        assert_eq!(
+            result,
+            TestStruct {
+                foo: "hello".to_string(),
+                bar: 42
+            }
+        );
+    }
+
+    #[test]
+    fn test_from_str_invalid_type() {
+        let err = from_str::<TestStruct>(r#"{"foo": "hello"}"#).unwrap_err();
+        assert!(err.to_string().contains("deserialize"));
+    }
+
+    #[test]
+    fn test_from_str_with_context() {
+        let err = from_str_with_context::<TestStruct>(r#"{"foo": "hello"}"#, || {
+            "config.json".to_string()
+        })
+        .unwrap_err();
+        assert!(err.to_string().contains("config.json"));
+        assert!(err.to_string().contains("Invalid JSON structure"));
+    }
+
+    #[test]
+    fn test_parse_value_from_slice_with_context() {
+        let err = parse_value_from_slice_with_context(b"{invalid}", || "test.json".to_string())
+            .unwrap_err();
+        assert!(err.to_string().contains("test.json"));
+        assert!(err.to_string().contains("parse"));
+    }
+
+    #[test]
+    fn test_parse_value_from_slice_with_context_invalid_utf8() {
+        let err = parse_value_from_slice_with_context(&[0xFF, 0xFF], || "test.json".to_string())
+            .unwrap_err();
+        assert!(err.to_string().contains("test.json"));
+        assert!(err.to_string().contains("UTF-8"));
+    }
+
+    #[test]
+    fn test_from_slice() {
+        let result: TestStruct = from_slice(br#"{"foo": "hello", "bar": 42}"#).unwrap();
+        assert_eq!(
+            result,
+            TestStruct {
+                foo: "hello".to_string(),
+                bar: 42
+            }
+        );
+    }
+
+    #[test]
+    fn test_from_slice_with_comments() {
+        let result: TestStruct = from_slice(
+            br#"{
+            // Comment
+            "foo": "hello",
+            "bar": 42, // Trailing comma is fine
+        }"#,
+        )
+        .unwrap();
+        assert_eq!(
+            result,
+            TestStruct {
+                foo: "hello".to_string(),
+                bar: 42
+            }
+        );
+    }
+
+    #[test]
+    fn test_from_slice_invalid_utf8() {
+        let err = from_slice::<TestStruct>(&[0xFF, 0xFF]).unwrap_err();
+        assert!(err.to_string().contains("UTF-8"));
+    }
+
+    #[test]
+    fn test_from_slice_with_context() {
+        let err = from_slice_with_context::<TestStruct>(br#"{"foo": "hello"}"#, || {
+            "config.json".to_string()
+        })
+        .unwrap_err();
+        assert!(err.to_string().contains("config.json"));
+        assert!(err.to_string().contains("Invalid JSON structure"));
+    }
+
+    #[test]
+    fn test_from_slice_with_context_invalid_utf8() {
+        let err =
+            from_slice_with_context::<TestStruct>(&[0xFF, 0xFF], || "config.json".to_string())
+                .unwrap_err();
+        assert!(err.to_string().contains("config.json"));
+        assert!(err.to_string().contains("UTF-8"));
+    }
+}

src/lib.rs

@@ -10,6 +10,7 @@ mod tree_view;
 mod auth_cookie;
 mod change_processor;
 mod glob;
+mod json;
 mod lua_ast;
 mod message_queue;
 mod multimap;

src/project.rs

@@ -11,7 +11,7 @@ use rbx_dom_weak::{Ustr, UstrMap};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
-use crate::{glob::Glob, resolution::UnresolvedValue, snapshot::SyncRule};
+use crate::{glob::Glob, json, resolution::UnresolvedValue, snapshot::SyncRule};
 
 static PROJECT_FILENAME: &str = "default.project.json";
 
@@ -214,8 +214,11 @@ impl Project {
         project_file_location: PathBuf,
         fallback_name: Option<&str>,
     ) -> Result<Self, Error> {
-        let mut project: Self = serde_json::from_slice(contents).map_err(|source| Error::Json {
+        let mut project: Self = json::from_slice(contents).map_err(|e| Error::Json {
-            source,
+            source: serde_json::Error::io(std::io::Error::new(
+                std::io::ErrorKind::InvalidData,
+                e.to_string(),
+            )),
             path: project_file_location.clone(),
         })?;
         project.file_location = project_file_location;
@@ -399,13 +402,13 @@ mod test {
 
     #[test]
     fn path_node_required() {
-        let path_node: PathNode = serde_json::from_str(r#""src""#).unwrap();
+        let path_node: PathNode = json::from_str(r#""src""#).unwrap();
         assert_eq!(path_node, PathNode::Required(PathBuf::from("src")));
     }
 
     #[test]
     fn path_node_optional() {
-        let path_node: PathNode = serde_json::from_str(r#"{ "optional": "src" }"#).unwrap();
+        let path_node: PathNode = json::from_str(r#"{ "optional": "src" }"#).unwrap();
         assert_eq!(
             path_node,
             PathNode::Optional(OptionalPathNode::new(PathBuf::from("src")))
@@ -414,7 +417,7 @@ mod test {
 
     #[test]
     fn project_node_required() {
-        let project_node: ProjectNode = serde_json::from_str(
+        let project_node: ProjectNode = json::from_str(
             r#"{
                 "$path": "src"
             }"#,
@@ -429,7 +432,7 @@ mod test {
 
     #[test]
     fn project_node_optional() {
-        let project_node: ProjectNode = serde_json::from_str(
+        let project_node: ProjectNode = json::from_str(
             r#"{
                 "$path": { "optional": "src" }
             }"#,
@@ -446,7 +449,7 @@ mod test {
 
     #[test]
     fn project_node_none() {
-        let project_node: ProjectNode = serde_json::from_str(
+        let project_node: ProjectNode = json::from_str(
             r#"{
                 "$className": "Folder"
             }"#,
@@ -458,7 +461,7 @@ mod test {
 
     #[test]
     fn project_node_optional_serialize_absolute() {
-        let project_node: ProjectNode = serde_json::from_str(
+        let project_node: ProjectNode = json::from_str(
             r#"{
                 "$path": { "optional": "..\\src" }
             }"#,
@@ -471,7 +474,7 @@ mod test {
 
     #[test]
     fn project_node_optional_serialize_absolute_no_change() {
-        let project_node: ProjectNode = serde_json::from_str(
+        let project_node: ProjectNode = json::from_str(
             r#"{
                 "$path": { "optional": "../src" }
             }"#,
@@ -484,7 +487,7 @@ mod test {
 
     #[test]
     fn project_node_optional_serialize_optional() {
-        let project_node: ProjectNode = serde_json::from_str(
+        let project_node: ProjectNode = json::from_str(
             r#"{
                 "$path": "..\\src"
             }"#,
@@ -494,4 +497,57 @@ mod test {
         let serialized = serde_json::to_string(&project_node).unwrap();
         assert_eq!(serialized, r#"{"$path":"../src"}"#);
     }
+
+    #[test]
+    fn project_with_jsonc_features() {
+        // Test that JSONC features (comments and trailing commas) are properly handled
+        let project_json = r#"{
+            // This is a single-line comment
+            "name": "TestProject",
+            /* This is a
+               multi-line comment */
+            "tree": {
+                "$path": "src", // Comment after value
+            },
+            "servePort": 34567,
+            "emitLegacyScripts": false,
+            // Test glob parsing with comments
+            "globIgnorePaths": [
+                "**/*.spec.lua", // Ignore test files
+                "**/*.test.lua",
+            ],
+            "syncRules": [
+                {
+                    "pattern": "*.data.json",
+                    "use": "json", // Trailing comma in object
+                },
+                {
+                    "pattern": "*.module.lua",
+                    "use": "moduleScript",
+                }, // Trailing comma in array
+            ], // Another trailing comma
+        }"#;
+
+        let project = Project::load_from_slice(
+            project_json.as_bytes(),
+            PathBuf::from("/test/default.project.json"),
+            None,
+        )
+        .expect("Failed to parse project with JSONC features");
+
+        // Verify the parsed values
+        assert_eq!(project.name, Some("TestProject".to_string()));
+        assert_eq!(project.serve_port, Some(34567));
+        assert_eq!(project.emit_legacy_scripts, Some(false));
+
+        // Verify glob_ignore_paths were parsed correctly
+        assert_eq!(project.glob_ignore_paths.len(), 2);
+        assert!(project.glob_ignore_paths[0].is_match("test/foo.spec.lua"));
+        assert!(project.glob_ignore_paths[1].is_match("test/bar.test.lua"));
+
+        // Verify sync_rules were parsed correctly
+        assert_eq!(project.sync_rules.len(), 2);
+        assert!(project.sync_rules[0].include.is_match("data.data.json"));
+        assert!(project.sync_rules[1].include.is_match("init.module.lua"));
+    }
 }

src/resolution.rs

@@ -248,14 +248,15 @@ fn nonexhaustive_list(values: &[&str]) -> String {
 #[cfg(test)]
 mod test {
     use super::*;
+    use crate::json;
 
     fn resolve(class: &str, prop: &str, json_value: &str) -> Variant {
-        let unresolved: UnresolvedValue = serde_json::from_str(json_value).unwrap();
+        let unresolved: UnresolvedValue = json::from_str(json_value).unwrap();
         unresolved.resolve(class, prop).unwrap()
     }
 
     fn resolve_unambiguous(json_value: &str) -> Variant {
-        let unresolved: UnresolvedValue = serde_json::from_str(json_value).unwrap();
+        let unresolved: UnresolvedValue = json::from_str(json_value).unwrap();
         unresolved.resolve_unambiguous().unwrap()
     }
 

src/snapshot_middleware/json.rs

@@ -1,10 +1,10 @@
 use std::path::Path;
 
-use anyhow::Context;
 use memofs::{IoResultExt, Vfs};
 use rbx_dom_weak::ustr;
 
 use crate::{
+    json,
     lua_ast::{Expression, Statement},
     snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
 };
@@ -19,8 +19,9 @@ pub fn snapshot_json(
 ) -> anyhow::Result<Option<InstanceSnapshot>> {
     let contents = vfs.read(path)?;
 
-    let value: serde_json::Value = serde_json::from_slice(&contents)
+    let value = json::parse_value_from_slice_with_context(&contents, || {
-        .with_context(|| format!("File contains malformed JSON: {}", path.display()))?;
+        format!("File contains malformed JSON: {}", path.display())
+    })?;
 
     let as_lua = json_to_lua(value).to_string();
 

src/snapshot_middleware/json_model.rs

@@ -9,6 +9,7 @@ use rbx_dom_weak::{
 use serde::Deserialize;
 
 use crate::{
+    json,
     resolution::UnresolvedValue,
     snapshot::{InstanceContext, InstanceSnapshot},
     RojoRef,
@@ -28,8 +29,9 @@ pub fn snapshot_json_model(
         return Ok(None);
     }
 
-    let mut instance: JsonModel = serde_json::from_str(contents_str)
+    let mut instance: JsonModel = json::from_str_with_context(contents_str, || {
-        .with_context(|| format!("File is not a valid JSON model: {}", path.display()))?;
+        format!("File is not a valid JSON model: {}", path.display())
+    })?;
 
     if let Some(top_level_name) = &instance.name {
         let new_name = format!("{}.model.json", top_level_name);

src/snapshot_middleware/meta_file.rs

@@ -4,7 +4,7 @@ use anyhow::{format_err, Context};
 use rbx_dom_weak::{types::Attributes, Ustr, UstrMap};
 use serde::{Deserialize, Serialize};
 
-use crate::{resolution::UnresolvedValue, snapshot::InstanceSnapshot, RojoRef};
+use crate::{json, resolution::UnresolvedValue, snapshot::InstanceSnapshot, RojoRef};
 
 /// Represents metadata in a sibling file with the same basename.
 ///
@@ -34,7 +34,7 @@ pub struct AdjacentMetadata {
 
 impl AdjacentMetadata {
     pub fn from_slice(slice: &[u8], path: PathBuf) -> anyhow::Result<Self> {
-        let mut meta: Self = serde_json::from_slice(slice).with_context(|| {
+        let mut meta: Self = json::from_slice_with_context(slice, || {
             format!(
                 "File contained malformed .meta.json data: {}",
                 path.display()
@@ -131,7 +131,7 @@ pub struct DirectoryMetadata {
 
 impl DirectoryMetadata {
     pub fn from_slice(slice: &[u8], path: PathBuf) -> anyhow::Result<Self> {
-        let mut meta: Self = serde_json::from_slice(slice).with_context(|| {
+        let mut meta: Self = json::from_slice_with_context(slice, || {
             format!(
                 "File contained malformed init.meta.json data: {}",
                 path.display()

src/web/api.rs

@@ -17,6 +17,7 @@ use rbx_dom_weak::{
 };
 
 use crate::{
+    json,
     serve_session::ServeSession,
     snapshot::{InstanceWithMeta, PatchSet, PatchUpdate},
     web::{
@@ -139,7 +140,7 @@ impl ApiService {
 
         let body = body::to_bytes(request.into_body()).await.unwrap();
 
-        let request: WriteRequest = match serde_json::from_slice(&body) {
+        let request: WriteRequest = match json::from_slice(&body) {
             Ok(request) => request,
             Err(err) => {
                 return json(

tests/rojo_test/serve_util.rs

@@ -157,14 +157,20 @@ impl TestServeSession {
         let url = format!("http://localhost:{}/api/rojo", self.port);
         let body = reqwest::blocking::get(url)?.text()?;
 
-        Ok(serde_json::from_str(&body).expect("Server returned malformed response"))
+        let value = jsonc_parser::parse_to_serde_value(&body, &Default::default())
+            .expect("Failed to parse JSON")
+            .expect("No JSON value");
+        Ok(serde_json::from_value(value).expect("Server returned malformed response"))
     }
 
     pub fn get_api_read(&self, id: Ref) -> Result<ReadResponse<'_>, reqwest::Error> {
         let url = format!("http://localhost:{}/api/read/{}", self.port, id);
         let body = reqwest::blocking::get(url)?.text()?;
 
-        Ok(serde_json::from_str(&body).expect("Server returned malformed response"))
+        let value = jsonc_parser::parse_to_serde_value(&body, &Default::default())
+            .expect("Failed to parse JSON")
+            .expect("No JSON value");
+        Ok(serde_json::from_value(value).expect("Server returned malformed response"))
     }
 
     pub fn get_api_subscribe(