feat: Remove daemon from turbo run, deprecate daemon flags and config

The daemon provided no measurable performance benefit for turbo run
and added IPC overhead. Benchmarks across multiple repos showed
--no-daemon consistently matching or beating daemon mode.

The daemon is still used by turbo watch and the Turborepo LSP.
The --daemon, --no-daemon flags and the daemon turbo.json option
are deprecated and will be removed in version 3.0.

Author: anthonyshew

CONTRIBUTING.md

@@ -127,7 +127,7 @@ devturbo run build --skip-infer
 A non-exhaustive list of things to check on:
 
 - Features related to your changes
-- Test with and without daemon
+- Test with and without daemon (daemon is deprecated for `turbo run` but still used by `turbo watch`)
 - Installation scenarios
   - Global only. `turbo` is installed as global binary without a local `turbo` in repository.
   - Local only. `turbo` is installed as local binary without global `turbo` in PATH. `turbo` is invoked via a root package

Cargo.lock

@@ -168,20 +168,9 @@ Specify the filesystem cache directory.
 
 ### `daemon`
 
-Default: `true`
-
-Turborepo runs a background process to pre-calculate some expensive operations. This standalone process (daemon) is a performance optimization, and not required for proper functioning of `turbo`.
+**Deprecated**: The daemon is no longer used for `turbo run` and this option will be removed in version 3.0. The `--daemon` and `--no-daemon` flags are also deprecated.
 
-```jsonc title="./turbo.json"
-{
-  "daemon": true,
-}
-```
-
-<Callout type="info">
-  When running in a CI environment the daemon is always disabled regardless of
-  this setting.
-</Callout>
+The daemon is still used by `turbo watch` and the Turborepo LSP.
 
 ### `envMode`
 

apps/docs/content/docs/reference/configuration.mdx

@@ -121,6 +121,6 @@ The three strategies listed above are in order of precedence. Where a flag value
 | ---------------------- | -------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------- | ------------------------------------------------ |
 | Binary path            | -                                                                          | [`TURBO_BINARY_PATH`](/docs/reference/system-environment-variables#turbo_binary_path)                       | -                                                |
 | Download local `turbo` | -                                                                          | [`TURBO_DOWNLOAD_LOCAL_ENABLED`](/docs/reference/system-environment-variables#turbo_download_local_enabled) | -                                                |
-| Daemon                 | [`--daemon` / `--no-daemon`](/docs/reference/run#--daemon-and---no-daemon) | -                                                                                                           | [`daemon`](/docs/reference/configuration#daemon) |
+| Daemon (deprecated)    | [`--daemon` / `--no-daemon`](/docs/reference/run#--daemon-and---no-daemon) | -                                                                                                           | [`daemon`](/docs/reference/configuration#daemon) |
 
 </div>

apps/docs/content/docs/reference/options-overview.mdx

@@ -415,11 +415,9 @@ turbo run dev --no-cache
 
 ### `--daemon` and `--no-daemon`
 
-`turbo` can run a background process to pre-calculate values used for determining work that needs to be done. This standalone process (daemon) is an optimization, and not required for proper functioning of `turbo`.
+**Deprecated**: The daemon is no longer used for `turbo run`. These flags are ignored and will be removed in version 3.0.
 
-The default daemon usage is set for your repository using [the `daemon` field in `turbo.json`](/docs/reference/configuration#daemon). Passing `--daemon` requires `turbo` to use the standalone process, while `--no-daemon` instructs `turbo` to avoid using or creating the standalone process.
-
-The same behavior can also be set via the `TURBO_DAEMON=true` system variable.
+The daemon is still used by `turbo watch` and the Turborepo LSP.
 
 ### `--output-logs <option>`
 

apps/docs/content/docs/reference/run.mdx

@@ -15,7 +15,7 @@ turbo scan
 You'll be taken through a short series of steps to enable the fastest settings for your Turborepo. These optimizations include:
 
 - **Git FS Monitor**: `turbo` leans on Git to do file change discovery. Since we have to wait for `git` to tell us about changes, we can use [Git's built-in filesystem monitor](https://git-scm.com/docs/git-fsmonitor--daemon) to get those notifications sooner.
-- **Turborepo Daemon**: Turborepo's daemon optimistically understands your repository in the background. By doing shared, common work that `turbo` will need to do when running tasks beforehand, `turbo` will run your tasks faster.
+- **Turborepo Daemon** (deprecated for `turbo run`): Turborepo's daemon is no longer used for `turbo run`. It is still used by `turbo watch` and the Turborepo LSP.
 - **Remote Caching**: While Turborepo can cache your work locally, it can also share a cache across all of your machines. Enabling [Remote Caching](/docs/core-concepts/remote-caching) makes your caching **multiplayer**, ensuring that you, your teammates, and your CI machines, never do the same work twice.
 - **Check `turbo` version**: We're always working towards making `turbo` better. To ensure you are using the latest version of Turborepo, we'll check your version and remind you to install `latest` if you aren't using it yet.
 - **Check for Turborepo LSP**:

apps/docs/content/docs/reference/scan.mdx

@@ -342,16 +342,15 @@ impl ConfigurationOptions {
     }
 
     pub fn daemon(&self) -> Option<bool> {
-        // hardcode to off in CI
-        if turborepo_ci::is_ci() {
-            if Some(true) == self.daemon {
-                debug!("Ignoring daemon setting and disabling the daemon because we're in CI");
-            }
-
-            return Some(false);
+        // The daemon is no longer used for `turbo run`. Always return None
+        // (no daemon preference) regardless of configuration.
+        if self.daemon.is_some() {
+            tracing::warn!(
+                "the `daemon` configuration option is deprecated and will be removed in version \
+                 3.0. The daemon is no longer used for `turbo run`."
+            );
         }
-
-        self.daemon
+        None
     }
 
     pub fn env_mode(&self) -> EnvMode {

crates/turborepo-config/src/lib.rs

@@ -135,8 +135,10 @@ mod test {
 
         let reader = TurboJsonReader::new(repo_root);
         let config = reader.get_configuration_options(&existing_config).unwrap();
-        // Make sure we read the default turbo.json
-        assert_eq!(config.daemon(), Some(false));
+        // The raw field is populated from turbo.json
+        assert_eq!(config.daemon, Some(false));
+        // But the getter always returns None since daemon is deprecated for turbo run
+        assert_eq!(config.daemon(), None);
     }
 
     #[test]
@@ -165,8 +167,10 @@ mod test {
 
         let reader = TurboJsonReader::new(repo_root);
         let config = reader.get_configuration_options(&existing_config).unwrap();
-        // Make sure we read the correct turbo.json
-        assert_eq!(config.daemon(), Some(false));
+        // The raw field is populated from the custom turbo.json path
+        assert_eq!(config.daemon, Some(false));
+        // But the getter always returns None since daemon is deprecated for turbo run
+        assert_eq!(config.daemon(), None);
     }
 
     #[test]

crates/turborepo-config/src/turbo_json.rs

@@ -7,13 +7,10 @@ license = "MIT"
 [features]
 # Allows configuring a specific tls backend for reqwest.
 # See top level Cargo.toml for more details.
-default = ["rustls-tls", "daemon-package-discovery"]
+default = ["rustls-tls"]
 native-tls = ["turborepo-api-client/native-tls", "turbo-updater/native-tls"]
 rustls-tls = ["turborepo-api-client/rustls-tls", "turbo-updater/rustls-tls"]
 
-daemon-package-discovery = []
-daemon-file-hashing = []
-
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [dev-dependencies]
 anyhow = { workspace = true, features = ["backtrace"] }

crates/turborepo-lib/Cargo.toml

@@ -356,6 +356,18 @@ impl Args {
                      version. Use --cache=local:rw,remote:r"
                 );
             }
+            if run_args.daemon {
+                warn!(
+                    "--daemon is deprecated and will be removed in version 3.0. The daemon is no \
+                     longer used for `turbo run`."
+                );
+            }
+            if run_args.no_daemon {
+                warn!(
+                    "--no-daemon is deprecated and will be removed in version 3.0. The daemon is \
+                     no longer used for `turbo run`."
+                );
+            }
         }
 
         clap_args
@@ -991,13 +1003,13 @@ pub struct RunArgs {
     // clap does not have negation flags such as --daemon and --no-daemon
     // so we need to use a group to enforce that only one of them is set.
     // -----------------------
-    /// Force turbo to use the local daemon. If unset
-    /// turbo will use the default detection logic.
+    /// [DEPRECATED] The daemon is no longer used for `turbo run`.
+    /// This flag will be removed in version 3.0.
     #[clap(long, group = "daemon-group")]
     pub daemon: bool,
 
-    /// Force turbo to not use the local daemon. If unset
-    /// turbo will use the default detection logic.
+    /// [DEPRECATED] The daemon is no longer used for `turbo run`.
+    /// This flag will be removed in version 3.0.
     #[clap(long, group = "daemon-group")]
     pub no_daemon: bool,