feat: add JSONC support (#10083)

### Description

JSONC allows the use of comments in JSON files. Until now, our
configuration parser allowed comments in JSON by accident, which made
for awkwardness talked about in #3793.

With this PR, we're now able to support `turbo.jsonc` in both the root
configuration and in Package Configurations. The file will be properly
used for hashing and users can use `.jsonc` that will work with their
editors and other tooling.

### Testing Instructions

Tests have been added in this PR and I've hand-tested with
`create-turbo`, both `turbo` and some packages. Would appreciate some
more hand-testing, just in case, along with your code review.

---------

Co-authored-by: Chris Olszewski <[email protected]>

Author: anthonyshew

crates/turborepo-filewatch/src/package_watcher.rs

@@ -449,13 +449,15 @@ impl Subscriber {
             tracing::debug!("handling change to workspace {path_workspace}");
             let package_json = path_workspace.join_component("package.json");
             let turbo_json = path_workspace.join_component("turbo.json");
+            let turbo_jsonc = path_workspace.join_component("turbo.jsonc");
 
-            let (package_exists, turbo_exists) = join!(
+            let (package_exists, turbo_json_exists, turbo_jsonc_exists) = join!(
                 // It's possible that an IO error could occur other than the file not existing, but
                 // we will treat it like the file doesn't exist. It's possible we'll need to
                 // revisit this, depending on what kind of errors occur.
                 tokio::fs::try_exists(&package_json).map(|result| result.unwrap_or(false)),
-                tokio::fs::try_exists(&turbo_json)
+                tokio::fs::try_exists(&turbo_json),
+                tokio::fs::try_exists(&turbo_jsonc)
             );
 
             changed |= if package_exists {
@@ -464,7 +466,14 @@ impl Subscriber {
                         path_workspace.to_owned(),
                         WorkspaceData {
                             package_json,
-                            turbo_json: turbo_exists.unwrap_or_default().then_some(turbo_json),
+                            turbo_json: turbo_json_exists
+                                .unwrap_or_default()
+                                .then_some(turbo_json)
+                                .or_else(|| {
+                                    turbo_jsonc_exists
+                                        .unwrap_or_default()
+                                        .then_some(turbo_jsonc)
+                                }),
                         },
                     )
                     .is_none()

crates/turborepo-lib/src/commands/login/manual.rs

@@ -44,11 +44,8 @@ pub async fn login_manual(base: &mut CommandBase, force: bool) -> Result<(), Err
     // update global config with token
     write_token(base, token)?;
     // ensure api url & team id/slug are present in turbo.json
-    write_remote(
-        &base.root_turbo_json_path(),
-        api_client.base_url(),
-        team_identifier,
-    )?;
+    let turbo_json_path = base.root_turbo_json_path()?;
+    write_remote(&turbo_json_path, api_client.base_url(), team_identifier)?;
     Ok(())
 }
 

crates/turborepo-lib/src/commands/mod.rs

@@ -10,6 +10,7 @@ use crate::{
     cli,
     config::{ConfigurationOptions, Error as ConfigError, TurborepoConfigBuilder},
     opts::Opts,
+    turbo_json::{CONFIG_FILE, CONFIG_FILE_JSONC},
     Args,
 };
 
@@ -139,8 +140,27 @@ impl CommandBase {
     fn root_package_json_path(&self) -> AbsoluteSystemPathBuf {
         self.repo_root.join_component("package.json")
     }
-    fn root_turbo_json_path(&self) -> AbsoluteSystemPathBuf {
-        self.repo_root.join_component("turbo.json")
+    fn root_turbo_json_path(&self) -> Result<AbsoluteSystemPathBuf, ConfigError> {
+        let turbo_json_path = self.repo_root.join_component(CONFIG_FILE);
+        let turbo_jsonc_path = self.repo_root.join_component(CONFIG_FILE_JSONC);
+
+        let turbo_json_exists = turbo_json_path.exists();
+        let turbo_jsonc_exists = turbo_jsonc_path.exists();
+
+        if turbo_json_exists && turbo_jsonc_exists {
+            return Err(ConfigError::MultipleTurboConfigs {
+                directory: self.repo_root.to_string(),
+            });
+        }
+
+        if turbo_json_exists {
+            Ok(turbo_json_path)
+        } else if turbo_jsonc_exists {
+            Ok(turbo_jsonc_path)
+        } else {
+            Ok(turbo_json_path) // Default to turbo.json path even if it doesn't
+                                // exist
+        }
     }
 
     pub fn api_auth(&self) -> Result<Option<APIAuth>, ConfigError> {

crates/turborepo-lib/src/config/mod.rs

@@ -26,7 +26,7 @@ use turborepo_repository::package_graph::PackageName;
 pub use crate::turbo_json::{RawTurboJson, UIMode};
 use crate::{
     cli::{EnvMode, LogOrder},
-    turbo_json::CONFIG_FILE,
+    turbo_json::{CONFIG_FILE, CONFIG_FILE_JSONC},
 };
 
 #[derive(Debug, Error, Diagnostic)]
@@ -74,10 +74,15 @@ pub enum Error {
     #[error(transparent)]
     PackageJson(#[from] turborepo_repository::package_json::Error),
     #[error(
-        "Could not find turbo.json.\nFollow directions at https://turbo.build/repo/docs to create \
+        "Could not find turbo.json or turbo.jsonc.\nFollow directions at https://turbo.build/repo/docs to create \
          one."
     )]
     NoTurboJSON,
+    #[error(
+        "Found both turbo.json and turbo.jsonc in the same directory: {directory}\nRemove either \
+         turbo.json or turbo.jsonc so there is only one."
+    )]
+    MultipleTurboConfigs { directory: String },
     #[error(transparent)]
     SerdeJson(#[from] serde_json::Error),
     #[error(transparent)]
@@ -396,10 +401,29 @@ impl ConfigurationOptions {
         self.run_summary.unwrap_or_default()
     }
 
-    pub fn root_turbo_json_path(&self, repo_root: &AbsoluteSystemPath) -> AbsoluteSystemPathBuf {
-        self.root_turbo_json_path
-            .clone()
-            .unwrap_or_else(|| repo_root.join_component(CONFIG_FILE))
+    pub fn root_turbo_json_path(
+        &self,
+        repo_root: &AbsoluteSystemPath,
+    ) -> Result<AbsoluteSystemPathBuf, Error> {
+        if let Some(path) = &self.root_turbo_json_path {
+            return Ok(path.clone());
+        }
+
+        // Check if both files exist
+        let turbo_json_path = repo_root.join_component(CONFIG_FILE);
+        let turbo_jsonc_path = repo_root.join_component(CONFIG_FILE_JSONC);
+        let turbo_json_exists = turbo_json_path.try_exists()?;
+        let turbo_jsonc_exists = turbo_jsonc_path.try_exists()?;
+
+        match (turbo_json_exists, turbo_jsonc_exists) {
+            (true, true) => Err(Error::MultipleTurboConfigs {
+                directory: repo_root.to_string(),
+            }),
+            (true, false) => Ok(turbo_json_path),
+            (false, true) => Ok(turbo_jsonc_path),
+            // Default to turbo.json if neither exists
+            (false, false) => Ok(turbo_json_path),
+        }
     }
 
     pub fn allow_no_turbo_json(&self) -> bool {
@@ -450,16 +474,6 @@ impl TurborepoConfigBuilder {
         self
     }
 
-    // Getting all of the paths.
-    #[allow(dead_code)]
-    fn root_package_json_path(&self) -> AbsoluteSystemPathBuf {
-        self.repo_root.join_component("package.json")
-    }
-    #[allow(dead_code)]
-    fn root_turbo_json_path(&self) -> AbsoluteSystemPathBuf {
-        self.repo_root.join_component("turbo.json")
-    }
-
     fn get_environment(&self) -> HashMap<OsString, OsString> {
         self.environment
             .clone()
@@ -517,9 +531,12 @@ mod test {
     use tempfile::TempDir;
     use turbopath::{AbsoluteSystemPath, AbsoluteSystemPathBuf};
 
-    use crate::config::{
-        ConfigurationOptions, TurborepoConfigBuilder, DEFAULT_API_URL, DEFAULT_LOGIN_URL,
-        DEFAULT_TIMEOUT,
+    use crate::{
+        config::{
+            ConfigurationOptions, TurborepoConfigBuilder, DEFAULT_API_URL, DEFAULT_LOGIN_URL,
+            DEFAULT_TIMEOUT,
+        },
+        turbo_json::{CONFIG_FILE, CONFIG_FILE_JSONC},
     };
 
     #[test]
@@ -542,7 +559,7 @@ mod test {
         })
         .unwrap();
         assert_eq!(
-            defaults.root_turbo_json_path(repo_root),
+            defaults.root_turbo_json_path(repo_root).unwrap(),
             repo_root.join_component("turbo.json")
         )
     }
@@ -635,4 +652,66 @@ mod test {
         assert!(!config.preflight());
         assert_eq!(config.timeout(), 123);
     }
+
+    #[test]
+    fn test_multiple_turbo_configs() {
+        let tmp_dir = TempDir::new().unwrap();
+        let repo_root = AbsoluteSystemPath::from_std_path(tmp_dir.path()).unwrap();
+
+        // Create both turbo.json and turbo.jsonc
+        let turbo_json_path = repo_root.join_component(CONFIG_FILE);
+        let turbo_jsonc_path = repo_root.join_component(CONFIG_FILE_JSONC);
+
+        turbo_json_path.create_with_contents("{}").unwrap();
+        turbo_jsonc_path.create_with_contents("{}").unwrap();
+
+        // Test ConfigurationOptions.root_turbo_json_path
+        let config = ConfigurationOptions::default();
+        let result = config.root_turbo_json_path(repo_root);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_only_turbo_json() {
+        let tmp_dir = TempDir::new().unwrap();
+        let repo_root = AbsoluteSystemPath::from_std_path(tmp_dir.path()).unwrap();
+
+        // Create only turbo.json
+        let turbo_json_path = repo_root.join_component(CONFIG_FILE);
+        turbo_json_path.create_with_contents("{}").unwrap();
+
+        // Test ConfigurationOptions.root_turbo_json_path
+        let config = ConfigurationOptions::default();
+        let result = config.root_turbo_json_path(repo_root);
+
+        assert_eq!(result.unwrap(), turbo_json_path);
+    }
+
+    #[test]
+    fn test_only_turbo_jsonc() {
+        let tmp_dir = TempDir::new().unwrap();
+        let repo_root = AbsoluteSystemPath::from_std_path(tmp_dir.path()).unwrap();
+
+        // Create only turbo.jsonc
+        let turbo_jsonc_path = repo_root.join_component(CONFIG_FILE_JSONC);
+        turbo_jsonc_path.create_with_contents("{}").unwrap();
+
+        // Test ConfigurationOptions.root_turbo_json_path
+        let config = ConfigurationOptions::default();
+        let result = config.root_turbo_json_path(repo_root);
+
+        assert_eq!(result.unwrap(), turbo_jsonc_path);
+    }
+
+    #[test]
+    fn test_no_turbo_config() {
+        let tmp_dir = TempDir::new().unwrap();
+        let repo_root = AbsoluteSystemPath::from_std_path(tmp_dir.path()).unwrap();
+
+        // Test ConfigurationOptions.root_turbo_json_path
+        let config = ConfigurationOptions::default();
+        let result = config.root_turbo_json_path(repo_root);
+
+        assert_eq!(result.unwrap(), repo_root.join_component(CONFIG_FILE));
+    }
 }

crates/turborepo-lib/src/config/turbo_json.rs

@@ -52,7 +52,7 @@ impl<'a> ResolvedConfigurationOptions for TurboJsonReader<'a> {
         &self,
         existing_config: &ConfigurationOptions,
     ) -> Result<ConfigurationOptions, Error> {
-        let turbo_json_path = existing_config.root_turbo_json_path(self.repo_root);
+        let turbo_json_path = existing_config.root_turbo_json_path(self.repo_root)?;
         let turbo_json = RawTurboJson::read(self.repo_root, &turbo_json_path).or_else(|e| {
             if let Error::Io(e) = &e {
                 if matches!(e.kind(), std::io::ErrorKind::NotFound) {
@@ -72,6 +72,7 @@ mod test {
     use tempfile::tempdir;
 
     use super::*;
+    use crate::turbo_json::CONFIG_FILE;
 
     #[test]
     fn test_reads_from_default() {
@@ -82,7 +83,7 @@ mod test {
             ..Default::default()
         };
         repo_root
-            .join_component("turbo.json")
+            .join_component(CONFIG_FILE)
             .create_with_contents(
                 serde_json::to_string_pretty(&serde_json::json!({
                     "daemon": false

crates/turborepo-lib/src/opts.rs

@@ -14,7 +14,7 @@ use crate::{
     },
     config::ConfigurationOptions,
     run::task_id::TaskId,
-    turbo_json::UIMode,
+    turbo_json::{UIMode, CONFIG_FILE},
     Args,
 };
 
@@ -287,7 +287,10 @@ pub enum ResolvedLogPrefix {
 
 impl<'a> From<OptsInputs<'a>> for RepoOpts {
     fn from(inputs: OptsInputs<'a>) -> Self {
-        let root_turbo_json_path = inputs.config.root_turbo_json_path(inputs.repo_root);
+        let root_turbo_json_path = inputs
+            .config
+            .root_turbo_json_path(inputs.repo_root)
+            .unwrap_or_else(|_| inputs.repo_root.join_component(CONFIG_FILE));
         let allow_no_package_manager = inputs.config.allow_no_package_manager();
         let allow_no_turbo_json = inputs.config.allow_no_turbo_json();
 
@@ -553,7 +556,7 @@ mod test {
         commands::CommandBase,
         config::ConfigurationOptions,
         opts::{Opts, RunCacheOpts, ScopeOpts},
-        turbo_json::UIMode,
+        turbo_json::{UIMode, CONFIG_FILE},
         Args,
     };
 
@@ -694,7 +697,9 @@ mod test {
                 .map(|(base, head)| (Some(base), Some(head))),
         };
         let config = ConfigurationOptions::default();
-        let root_turbo_json_path = config.root_turbo_json_path(&AbsoluteSystemPathBuf::default());
+        let root_turbo_json_path = config
+            .root_turbo_json_path(&AbsoluteSystemPathBuf::default())
+            .unwrap_or_else(|_| AbsoluteSystemPathBuf::default().join_component(CONFIG_FILE));
 
         let opts = Opts {
             repo_opts: RepoOpts {
@@ -801,11 +806,11 @@ mod test {
         let tmpdir = TempDir::new()?;
         let repo_root = AbsoluteSystemPathBuf::try_from(tmpdir.path())?;
 
-        repo_root
-            .join_component("turbo.json")
-            .create_with_contents(serde_json::to_string_pretty(&serde_json::json!({
+        repo_root.join_component(CONFIG_FILE).create_with_contents(
+            serde_json::to_string_pretty(&serde_json::json!({
                 "remoteCache": { "enabled": true }
-            }))?)?;
+            }))?,
+        )?;
 
         let mut args = Args::default();
         args.command = Some(Command::Run {

crates/turborepo-lib/src/run/builder.rs

@@ -383,19 +383,21 @@ impl RunBuilder {
         let task_access = TaskAccess::new(self.repo_root.clone(), async_cache.clone(), &scm);
         task_access.restore_config().await;
 
+        let root_turbo_json_path = self.opts.repo_opts.root_turbo_json_path.clone();
+
         let turbo_json_loader = if task_access.is_enabled() {
             TurboJsonLoader::task_access(
                 self.repo_root.clone(),
-                self.opts.repo_opts.root_turbo_json_path.clone(),
+                root_turbo_json_path.clone(),
                 root_package_json.clone(),
             )
         } else if is_single_package {
             TurboJsonLoader::single_package(
                 self.repo_root.clone(),
-                self.opts.repo_opts.root_turbo_json_path.clone(),
+                root_turbo_json_path.clone(),
                 root_package_json.clone(),
             )
-        } else if !self.opts.repo_opts.root_turbo_json_path.exists() &&
+        } else if !root_turbo_json_path.exists() &&
         // Infer a turbo.json if allowing no turbo.json is explicitly allowed or if MFE configs are discovered
         (self.opts.repo_opts.allow_no_turbo_json || micro_frontend_configs.is_some())
         {
@@ -407,14 +409,14 @@ impl RunBuilder {
         } else if let Some(micro_frontends) = &micro_frontend_configs {
             TurboJsonLoader::workspace_with_microfrontends(
                 self.repo_root.clone(),
-                self.opts.repo_opts.root_turbo_json_path.clone(),
+                root_turbo_json_path.clone(),
                 pkg_dep_graph.packages(),
                 micro_frontends.clone(),
             )
         } else {
             TurboJsonLoader::workspace(
                 self.repo_root.clone(),
-                self.opts.repo_opts.root_turbo_json_path.clone(),
+                root_turbo_json_path.clone(),
                 pkg_dep_graph.packages(),
             )
         };

crates/turborepo-lib/src/run/watch.rs

@@ -120,7 +120,9 @@ impl WatchClient {
         let signal = get_signal()?;
         let handler = SignalHandler::new(signal);
 
-        if base.opts.repo_opts.root_turbo_json_path != base.repo_root.join_component(CONFIG_FILE) {
+        // Check if the turbo.json path is the standard one
+        let standard_path = base.repo_root.join_component(CONFIG_FILE);
+        if base.opts.repo_opts.root_turbo_json_path != standard_path {
             return Err(Error::NonStandardTurboJsonPath(
                 base.opts.repo_opts.root_turbo_json_path.to_string(),
             ));