Add support for JSONC Wrangler configuration files.

Cargo.toml

@@ -49,6 +49,7 @@ rand = { version = "0.9.0", features = ["small_rng"] }
 reqwest = "0.12.15"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+serde_json5 = "0.2.1"
 serde_with = { version = "3.12", features = ["chrono"] }
 thiserror.workspace = true
 tokio = { workspace = true, features = ["full"] }

src/fs/mod.rs

@@ -12,7 +12,7 @@ use std::{
 pub(crate) use file::File;
 pub(crate) use manifest::application_manifest;
 pub(crate) use session::{Session, SessionFile, UserCreds};
-pub(crate) use wrangler::{JsonWranglerFile, TomlWranglerFile};
+pub(crate) use wrangler::{JsonWranglerFile, JsoncWranglerFile, TomlWranglerFile};
 
 use manifest::{JsonManifest, Manifest, TomlManifest};
 use wrangler::Wrangler;
@@ -77,15 +77,17 @@ impl FileSystem {
         Ok(manifest_box)
     }
 
-    /// Load the wrangler configuration file, looking for both TOML and JSON formats
+    /// Load the wrangler configuration file, looking for TOML, JSON, and JSONC formats
     pub fn wrangler_config(&self) -> Result<Wrangler, WranglerMissing> {
-        // Attempt to load a TOML wrangler file. Fallback to JSON.
+        // Attempt to load a TOML wrangler file. Fallback to JSON, then JSONC.
         let toml_wrangler = self.load_file(TomlWranglerFile);
         let json_wrangler = self.load_file(JsonWranglerFile);
-        let wrangler_config = match (toml_wrangler, json_wrangler) {
-            (Ok(wrangler), _) => wrangler,
-            (Err(_), Ok(wrangler)) => wrangler,
-            (Err(_), Err(_)) => return Err(WranglerMissing),
+        let jsonc_wrangler = self.load_file(JsoncWranglerFile);
+        let wrangler_config = match (toml_wrangler, json_wrangler, jsonc_wrangler) {
+            (Ok(wrangler), _, _) => wrangler,
+            (Err(_), Ok(wrangler), _) => wrangler,
+            (Err(_), Err(_), Ok(wrangler)) => wrangler,
+            (Err(_), Err(_), Err(_)) => return Err(WranglerMissing),
         };
         Ok(wrangler_config)
     }
@@ -119,6 +121,7 @@ impl FileSystem {
         match F::EXTENSION {
             "toml" => self.read_toml_file(file),
             "json" => self.read_json_file(file),
+            "jsonc" => self.read_jsonc_file(file),
             _ => Err(miette!(
                 "Extension unknown! Internal error. Please file this error as a bug."
             )),
@@ -150,6 +153,18 @@ impl FileSystem {
         Ok(document)
     }
 
+    /// Open the file and deserialize it with serde (JSONC with comments support).
+    fn read_jsonc_file<F: File>(&self, file: F) -> Result<F::Data> {
+        // • Get the path to the file.
+        let path = file.path(self)?;
+        // • Open it as a byte stream, then deserialize those bytes.
+        let mut buffer = String::new();
+        let mut file = std::fs::File::open(path).into_diagnostic()?;
+        file.read_to_string(&mut buffer).into_diagnostic()?;
+        let document = serde_json5::from_str(&buffer).into_diagnostic()?;
+        Ok(document)
+    }
+
     /// Store the file, using its canonical path.
     pub(crate) fn save_file<F: File>(&self, file: &F, blob: &F::Data) -> Result<()> {
         // • Get the path to the file.
@@ -159,6 +174,7 @@ impl FileSystem {
         let marshalled = match F::EXTENSION {
             "toml" => toml::to_string_pretty(blob).into_diagnostic()?,
             "json" => serde_json::to_string_pretty(blob).into_diagnostic()?,
+            "jsonc" => serde_json5::to_string(blob).into_diagnostic()?,
             _ => {
                 return Err(miette!(
                     "Extension unknown! Internal error. Please file this error as a bug."

src/fs/wrangler.rs

@@ -94,7 +94,7 @@ pub struct Wrangler {
 }
 
 const WRANGLER_PREFIX: &str = "wrangler";
-const WRANGLER_EXTENSIONS: [&str; 2] = ["toml", "json"];
+const WRANGLER_EXTENSIONS: [&str; 3] = ["toml", "json", "jsonc"];
 
 /// A TOML formatted wrangler file
 pub struct TomlWranglerFile;
@@ -116,6 +116,16 @@ impl StaticFile for JsonWranglerFile {
     const EXTENSION: &'static str = WRANGLER_EXTENSIONS[1];
 }
 
+/// A JSONC formatted wrangler file
+pub struct JsoncWranglerFile;
+
+impl StaticFile for JsoncWranglerFile {
+    type Data = Wrangler;
+    const DIR: DirectoryType = DirectoryType::ApplicationRoot;
+    const NAME: &'static str = WRANGLER_PREFIX;
+    const EXTENSION: &'static str = WRANGLER_EXTENSIONS[2];
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -188,4 +198,67 @@ mod tests {
         let _deserialized: Wrangler =
             toml::from_str(&toml_str).expect("Failed to deserialize from TOML");
     }
+
+    #[test]
+    fn test_wrangler_serde_jsonc() {
+        const RAW_JSONC: &str = r#"/**
+ * For more details on how to configure Wrangler, refer to:
+ * https://developers.cloudflare.com/workers/wrangler/configuration/
+ */
+{
+    "$schema": "node_modules/wrangler/config-schema.json",
+    "name": "multitool-quickstart",
+    "account_id": "986dc7f2976d17c6205288a7a946ef6a",
+    "main": "src/index.js",
+    "compatibility_date": "2025-11-06",
+    "observability": {
+        "enabled": true
+    }
+    /**
+     * Smart Placement
+     * Docs: https://developers.cloudflare.com/workers/configuration/smart-placement/#smart-placement
+     */
+    // "placement": { "mode": "smart" }
+    /**
+     * Bindings
+     * Bindings allow your Worker to interact with resources on the Cloudflare Developer Platform, including
+     * databases, object storage, AI inference, real-time communication and more.
+     * https://developers.cloudflare.com/workers/runtime-apis/bindings/
+     */
+    /**
+     * Environment Variables
+     * https://developers.cloudflare.com/workers/wrangler/configuration/#environment-variables
+     */
+    // "vars": { "MY_VARIABLE": "production_value" }
+    /**
+     * Note: Use secrets to store sensitive data.
+     * https://developers.cloudflare.com/workers/configuration/secrets/
+     */
+    /**
+     * Static Assets
+     * https://developers.cloudflare.com/workers/static-assets/binding/
+     */
+    // "assets": { "directory": "./public/", "binding": "ASSETS" }
+    /**
+     * Service Bindings (communicate between multiple Workers)
+     * https://developers.cloudflare.com/workers/wrangler/configuration/#service-bindings
+     */
+    // "services": [{ "binding": "MY_SERVICE", "service": "my-service" }]
+}"#;
+
+        let observed: Wrangler = serde_json5::from_str(RAW_JSONC).expect("Failed to parse JSONC");
+
+        assert_eq!(observed.name, "multitool-quickstart");
+        assert_eq!(
+            observed.account_id,
+            Some("986dc7f2976d17c6205288a7a946ef6a".to_string())
+        );
+        assert_eq!(observed.main, "src/index.js");
+        assert_eq!(observed.compatibility_date, Some("2025-11-06".to_string()));
+        assert!(observed.observability.is_some());
+        if let Some(observability) = observed.observability {
+            assert!(observability.enabled);
+            assert_eq!(observability.head_sampling_rate, None);
+        }
+    }
 }